author: Mr. Chief Justice TANEY Mr. Justice 'DANIEL.

text:
    Neil, Moore & Company, Plaintiffs in Error, v. The State of Ohio, Defendant.
    Under the acts of Congres^_and of the State of Ohio, relating to the surrender and - acceptance of the •Cumberland road, a toll charged upon passengers travel-lingin-the'mairstages, without being charged also upon passengers travelling . id other stages, is against the contract,-and void.
    It jests altogether in the discretion of the postmaster-general, to determine at . what hours the mail shall leave particular places and arrive at others, and . to determine whether it shall -leave' the same place only onee a day or more frequently.. .
    It is not, therefore, the mere frequency of the departure of carriages, carrying the snail; that constitutes an abuse of the.privilege of the United States, hut tb.p Unnecéssaryidivision of the.mail hags amongst a number of carriages in order to evade the payment of .tolls.
    This casé was brought up under the 25th section of the Judiciary Act, by writ, of error, from the Supreme Court of Ohio!

      It involved the construction of the- acts of Congress and the state of Ohio, relative to the cession of the'Cumberland road,- which are narrate'd in a preceding part of this volume, in the case of Searight v. Stokes et ah, p. 151.
    It is proper, however, to state the law of Ohio with more particularity than it was necessary to do in the report of that case. The. proviso contained in the 4th section of the act of 1831, was there recited, but the 5th section was not. They are as follows:
    Sect. 4 lays tolls, and adds: “ Provided, That nothing in this act shall'be construed so as to authorize any tolls to be received'or collected from any person passing to or from public worship/or to or from any muster, or to- or from his common business on his farm or woodland, or to or from a funeral, or to or from a mill, or to or from his common place of trading or marketing, within the county in which he resides, including their wagons, carnages. and horses, or oxen drawing the same: Provided also, That no toll shall be received or collected for the passage of any stage or coach conveying the United States mail, or horses-bearing the same, or any wagon or carriage laden with the property or the United States, or any cavalry or other troops, arms or military stores belonging to the same, 'or to any of the states comprising this union, or any person or persons on duty in the military service of the United States, or of. the militia of any of the states.
    “ Sect. 5. That it shall be lawful for the General Assembly, *at any future session thereof, without the. consent of Congress, to change, alter, or1 amend this act: Provided, That the same shall not be so changed, altered, or amended, as to reduce of increase the rates of toll hereby established, below or above a sum necessary to defray the expenses incident to, the preservation and repair of the said road, to the erection of gates and toll houses thereon, and for the payment of the fees or. salaries of the superintendent, the collectors of tolls, and of such other agents as may be necessarily employed in the preservation and repair of the same, according to the true, intent and meaning of this act.”
    On the 6th of February, 1837, the- -state of Ohio passed an act, containing, amongst other provisions, the following, viz.;
    . “ Sect. 4. That one daily stage, coach, or other vehicle, and rio • more, with the horses drawing the "same, belonging to any contractor or contractors for carrying the United States mail on said road, with the passengers therein, shall be permitted to pass in each direction free, from the payment of tolls; and each additional stage, coach, or other vehicle belonging to such contractor or contractors, although the same may cOntairi a mail, or portion thereof, shall be charged with the same tolls as other vehicles of the like kind. But if the postmaster-general shall order the mail to be divided, and car-, ried in two or more stages, coaches, or vehicles, -in any one direction daily, then in such case the coaches or vehicles in which mails sh'all actually be carried, shall pass free of toll; but on each passenger transported in any>such additional stage, coach, or vehicle, there shall be charged and collected at each’ gate, three cents, in manner hereinafter provided.
    “Sect..5. ..That each and every driver of any stage, coach, or other vehicle, belonging to any such mail contractor' or contractors, other than such as pire entitled to carry passengers free of toll, shall, at éach and every gate, report the number of seats occupied in such stage/ coach, or other vehicle, to the keeper of such gate, whose duty it shall be to open an account against the proprietor or proprietors of such stage, coach-, or other vehicle, and charge, in a book' to be kept for that purpose, three cents for each passenger, as'provided in the .preceding section of this act; and said proprietor or proprietors shall pay over’to such gate keeper, at the end of .every three months after the taking effect of.this act, the aggregate amount of tolls which shall have become due for "passengers, and charged as above provided.
    “ Sect. -6. That should the driver of any stage, coach, or' other vehicle, belonging to such mail contractor or contractors, other than such as are entitled to carry passengers free of toll, neglect or refuse to report to any gate keeper tho number of seats occupied in said stage, coach, or vehicle, it shall be the duty of such gate keeper to charge the proprietor or proprietors of such stage, coach, or. other-vehicle, at the rate aforesaid, for each and every- seat which might be occupied in the same, to be recovered in an action of debt, m. the name of the State of Ohio, in'any Court having competent jurisdiction.
    “Sect,. 8. That the,Board of Public Works, or their authorized agent, may be'allowed to collect tolls from any proprietor or, proprietors of any line of stages, post-coaches, or other vehicles for the conveyance of passengers, quarterly; and if any proprietor or pr'oprietors-of any .such line of stages,' post-coaches, or other vehicles as aforesaid,' shall neglect, or refuse to pay quarterly, that from and after ihich neglect or refusal, the said proprietor or proprietors as aforesaid shall be required tó pav at each and every gate as they pass: Provided, That the Bo'ard.of Public Works, or’their authorized agent, shall have made out and.presented to any such proprietor or proprietors, or any one of them, the amount of the toll due from him or them for each and every gate.?1
    The act of-the .legislature, of March 19,1838, provides as follows:
    “ Sect. 24. That the said Board of Public Works shall have power to. revise the rates of toll to be paid by persons passing on or using the National road in' Ohio, and so to modify the same, from time.to time,- as to raise and collect, in the most equal manner, the sum necessary to defray the expenses incident to the preservation and repair of said road, to the erection of gatés añd toll-houses thereon, and for the payment .of the fees or salaries of the superintendent, the collectors of-tolls, and of such other agents as may be necessarily employed in the repair- and preservation Ofthe samé, Recording to the true intend and meaning of the act, passed February 4th. 1831, entitled cAn act for the preservation and repair of the United States road;’”
    The order of the Board of Public Works, above referred to, is as follows:
    ' “By virtue of the. powers vested'in the Board of-Public Works, by the 24th section of the act ‘in addition to an a'ct'for die preservation and repair of the United States road,’ passed Márchl9th-,-1838, it is-hereby
    ' “ Ordered, That instead of the rate -pf toll charged on each passenger by the 4th section of - the act ‘ fixing the rates of tolls on the National road,’ passed February 6th, 1837, there shall be charged ten cents, at each gáte, on each of such passengérs.”
    In October, 1842, a suit was brought in the Court of Common Pleas, in-Franklin county, against Neil, Moore & Co.$ for tolls on passengers conveyed' in stages by the defendants, on the National road., and the following agreed Statement of facts was filed:
    “In this case, the following facts are agreed by the parties: The partnership of the defendants, as alleged-, is admitted. ' ■ The plaintiff claims to -recover for tolls on passengérs. carried upon the National road, in Ohio, in coaches ^belonging to the defendants, other than and besides one daily stage-coach, carrying the mail of the United' States-; whiph said coach, with the horses, passengers, and every thing else pertaining- to it, was permitted to pass toll free. The order of the Board of Public Works, hereto annexed, was made in due form, at the date thereof, and is to be admitted in evidence. The passengers upon whom toll is sought to be recovered, were carried by the defendants, as above mentioned, between the first days of April and October, a, d. 1842. -The defendants were contractors for carrying'the mail of the United States úpon.said road, and said passengers were all carried in coaches in which a part of said mail was carried at the same time; the mail being thus carried in more than one. coach, pursuant to orders from the postmaster-general f one coach, containing a part of the mail, and;' the- passengers, • and baggage,, and every thing oh it, being, at tWsame' time, permitted to pass toll free, as above stated. The mail was carried in one line of.coaches, down to the time stated in the annexed statement of the postmasten-general, which,- together with the accompanying orders of the department, are taken in evidence in .this case. Both before and.since the construction of the National road, it was the .uniform practice, in Ohio, to carry passengérs on the coaches carrying the mail;' and since the construction of the National road, no claim was made-for toll on such passengers, or coaches, or on any thing pertaining to them, except as shown by the case of The State of Ohio v. Neil and Moore, 7 Ohio Rep. T32. Until the mail was carried in two separate line's of coaches, as -specified in the said-statement of .the postmaster-general, and -in the manner and for the purpose therein mentioned, the defendants were required fo Garry the mail in two separate lines of coaches, and did so carry, it accordingly. It is admitted that the acts of the legislature of Ohio, and the orders of the Board of Public Works, in existence when the tolls in question accrued, did not reduce or increase the rates of toll, hereby established, below or above a sum necessary to defray the expenses incident to the preservation and repair of the said road, to the erection of gates and toll-houses, thereon, and for the payment of the fees or salaries of the superintendent, the collectors of tolls, and of such other agents as may.be necessarily employed in thepreservation and repair of'the same;, but it is not intended by this admission to preclude the defendants from objecting to the validity or legality of said charge of toll upon passengers, upon any ground they may think proper to take, in the argument. It is understood and agreed that, this case shall not' in anywise prejudice the rights of the plaintiff, nor of the defendants, in any other suit, upon any demand not included in the facts hereby agreed. For the mutual convenience of the parties, this, case is narrowed • down so as to present only thé- question arising upon the facts above stated. Any material fact left out in this'agreement, may b.e supplied,' by proof, on the trial, by either party, after giving' the other party reasonable notice' of such intention. It is agreed by the parties that the whole number of passengers charged with toll at all'the gates, between the first days of April and July, a. d. 1842, was ten thousand seven hundred and fifty-six, and that the whole number chargeable between the first day of July and October, a. d. 1842, was twelve thousand six hundred and seventeen; and that if the plaintiff be entitled to recover, judgment shall be entered for the sum of $1075 with interest from the first <d ay. of July, 1842, and $1261 67^-, with-interest from the first day of October, a. d. 1842, and costs, or for such other sums as may be due, computing the tolls1 on said passengers at any other rate than that fixed by . the Board of Public Works, if .the court deem it competent to adopt any other rate, with'interest on the’ gross sums due on die-first days of July and October above mentioned, from those times respectively, and costs.”’
    The Court of Common Pleas were'of opinion that judgment should be entered for the plaintiff,-and the damages were assessed at $2438 25’. ' '
    The defendants carried the case to the Supreme Court of Ohio, where, in. December, 1843», the- judgment of the. court below was affirmed, and the following certificate'was -annexed, to-the record..
    .“And it is hereby certified, that on the-trial of this cause the defendants set up and claimed the right and authority to transport, in their two daily lines of mail-coaches, which carried the United States mail, under á contract with the postmaster-general, arid by the authority of the United States, passengers travelling therein, free of toll, along .the United States.road, in the state of Ohio, and. through the toll-gates erected by .the said state thereon; that tbs said defendants set up and claimed this -power and authority under and by virtue of the act of Congress approved the 2d day of March, a. d. 1831, entitled “An act declaring the assent of Congress to the act of the General Assembly of the state of Ohio,” recited therein; and that in-said case there were drawn in question the construction, effect, and validity, of said act of Congress, ánd the,right and authority claimed by the said defendants under the United States, by -virtue thereof, and that the decision was against the validity of said act to confer the right and authority so claimed.”
    The defendants sued out a writ of error, to bring this decision of the Supreme Gourt of-Ohio before this court.

      Ewing, (in writing,) for plaintiffs in error.

      Swayne, for defendant in error.
    , \Evdng referred to the law of Ohio, passed in 1838, and the order of the Board of Public Works, (both of which have been already cited,) and then proceeded thus:
    Under this law 'and this order, there was. charged against the plaintiffs in error, on passengers transported in one of their lines of coaches, in which they carried the United States mail, by order of the postmastér-general, a large amount of tolls, which' charge, as stated in the agreed' case, is toe foundation of this suit.
    I contend that toe second proviso in toé 4to .section of the statute of Ohio, of February 4to, 1831, which.,exempts' from the payment of toll “ any stágé or coach conveying the United States mail,” &c., when assented to by the act of Congress of March 2d,1831, became and was an essential part of a contract, over which Ohio alone had no power or control. On the other side, I understand, it will be contended that the 15th section of the statute, reserves to Ohio the right to alter or abolish that exemption at pleasure. This is toe first question which we present for the consideration of the court.
    If we leave out of view the 15th section, this statute, as assented to, is clearly a contract. . By it the United States surrenders toe road to Ohio, in considerátion of which Ohio agrees tp levy tolls, and keep the road in repair, and suffer toe mails and other property of toe United States to pass along it toll-free. Now, could it have been the intent of toe contracting parties to put it in the power of one of them to annul at pleasure a valuable provision of that contract, and is such intent unequivocally-expressed ini toe 15th section ? I think- not. It is not reasonable to- suppose it, and the statute does, not necessarily require, if, indeed, it will admit of a construction which will allow it. ' -
    The first four sections of toe, statute contain, 1st, a.contract,. 2d, The means, in detail, by which Ohio proposes to execute it on her part, couched in very special directions to toe governor to that effect The contract was not properly an act of the legislature, an3 X da not admit that it was so considered or treated of in the 15th section. But all those ’ matters which did not pertain to the contract, those provisions which touched hot its' execution, but the mode and manner of its execution,- fell at once within the sovereignty of Ohio; and the statute, so far as it relates • thereto, became and was, to all intents and purposes, an act of her legislature. Novv, there are here a contract and a statute. Ohio reserves the right to- “ change, alter, and amend.” the.statute, but surely not to. change, alter, and amend . the contract. Indeed, if there be a contract, such a provision would fee void, because it would be inconsistentvyithand destructive of it. Butthfetwo provisoes in the 4th section, and the proviso in the 15th section, do all, as.I think, look to the distinction between that which is contract, and that which is merely a legislative act.<
    The first proviso in the 4th section, which makes some domestic exemptions from toll, with which Congress had nothing to do, (such as persons going to market, to public worship, &c.,) is couched in this language, “provided, that ^nothing in this act shall be so construed as to .authorize” the'collection of tolls from such objects; but it does not say that no tolls shall be collected- from -them. This statute'does not authorize such collection, yet some future act may. But the second proviso which follow's this immediately, and'which might have been included under the first, Without any “provided also,” had it not been intended to'plüce the two subjects in totally different categories,.declares' “that ho toll shall be received or col-, lected fon the passage of any stage or coach- conveying the United States mail,” &c. — not confining it to the construction of this statute merely, as in the other case, but a universal prohibition, extending tb all future time.
    The1 proviso in the 15th section seems to contemplate .alteration and amendment in the rates-of toll, not in the objects on which it is to be levied.
    “ It shall be lawful for the General'Assembly, át any future session thereof, withouf'the consent of Congress, to change, alter, or amend this act': Provided, that' the same shall not fee so Changed, altered, or amended, as to reduce or increase the rates Of toll hereby established below, or above, &c.” So that the- objects exempted from toll by the second proviso, are,, for that reason, out of' the operation of the 15th- section. There- may, it i^ true, be' some inconsistency in the apparent ends and objects of the first "proviso in the 4th and the proviso in the 15th section — the one implying that'the objects subject to toll might, and the other that they might not; be thereafter - extended-. ' Yet both are inconsistent with the supposition that toll might be levied on' the objects exempted in the second proviso-. But it is still more important-that the chief end and purpose of the contract would be frustrated and destroyed by allowing Ohio to repeal that proviso.

      But if Ohio had a-right to change and alter that proviso, and if it wére so changed by the" act of February 24th, 1837, it is restored by the 24th section of the act of March 19th, 1838. That act-empowers the Board of Public Works to revise the' rate of tolls on the National road, and-to modify the same so as to raise and collect, .in the most equable manner, the sum necessary to defray expenses, &c., “ according to the true intent and meaning of the' act of February, 1831.” ' And the Board of Public Works, by virtue of the . power so. vested in them, charged the toll'which is the subject of this suit; so that at last the,case rests uponJ “ the true intent and meaning of the act of February'4th,' 183Í,” just as it stood-when it was adopted by Congress, and became a contract between the United States and ■ Ohio.
    2. I contend that the levy of the toll, which is the subject of this suit, was a violation of that contract.
    Nominally, and in express words, by the statute of March 19th,. 1838, the- second, mail-coach, as well' as the first,, is permitted to pass-toll free; but toll is charged against the proprietor of such coách' for the passengers which áre carried in it. Now, no toll is charged to persons who' pass the gates, unless they pass in a mail-coach. Out of the mail-coach they go free — in it, toll, is charged upon them against the proprietor, because'he o.wns the mail-coach; or, in other words, toll is charged upon .the mail-coach to the amount of ten • cents for each passenger which it carries.
    . Now; it cannot for a-moment be ..contended thát, under this contract, (if it be a contract,) and” within its spirit, either the horses-drawing the mail-coach, or the person driving it, can- be charged with toll. It would be a mere evasion to contract that the mail should pass toll free, and yet charge toll on its necessary incidents.
    I think it would be equally so, though not at first'viéw so striking, to-'charge toll on that which was its uniform incident at the time of the contract, because not absolutely indispensable to’its passage. Thus it is with the transportation of passengers.- The agreed case.shows that, at the time of the contract, and before and since,, it has been .the uniform practice to-carry passengers iri the mail-coaches.
    It must be presumed.that the contract was made with a view to that practice ; and’ in stipulating that the mail-coaches should pass free of toll,- that both parties intended they should' so pass with-their usual incidents^ — horses, coachmen, guards, passengers. If not with all, with what "part? ; It will be. answered, that only which is necessary. But the- question recurs, how far necessary, and who into determine the necessity which wiÚ bring the case within the spirit of the contract? Horses are necessary,.but how many? Persons to conduct the coach and protect-the mail, but how many of them?' May you take an agent or- guard free of foil? . The necessity for each of these is in the same degree-with the necessity of passengers— both tend to the security of .the mail; but it is possible that it may'
      go safely without either, and both or neither should be: exempt from toll. . '
    Such was clearly the understanding at, and long after, the date of the contract. The agreed case shows that Ohio permitted,J and still permits, one daily line of mail-coaches to go, with its passen-. gers, toll free. There was, therefore, a perfect understanding as' to what was carried, and should continue to be carried, in the mail coach,, and partake of its exemption. But the state now claims to limit,, this . exemption to the passengers in one daily line of mail-coaches, and to charge toll on those transported in the second daily line. ■ I think there is nothing to warrant this limitation; It is true, that at the time of making the contract the mail was carried in one daily line of coaches, but there is nothing in the contract to limit it' to that; but, on the contrary, it must have been within the contemplation of the parties that the nuiñber of lines should be increased according to.the wants of the country and the convenience of the department. This, also, seems to be admitted; for the second line of coaches is permitted to pass toll free, if. it carry ho passengers. Now, if the first line of coaches has a right,, under the contract, to carry its passengers toll-free, and if the second line has a right to pass toll free, nb toll can be charged upon it for its passengers, for they are just as much the usual and well understood incident of a second, as of a first line of mail-coaches. Toll, therefore, can be charged upon them only where the mail is put into, more than one line of coaches wrongfully, for the purpose of avoiding the payment of toll;- We show that such is not the case here. .
    3. But I contend, also, that' the coach carrying the United States • mail, upon a post road established by law, is a matter over which a state has no power or sovereignty, and which it cannot by law burden with any toll or imposition whatsoever.’ 'It'is another question, how a road, which is the property of a state, is to be made a.post road; but whén it once is so, and fairly the property of the United States,'as this road was, and is to that extent and for that purpose, the state has no power to interfere with, lay burdens upon, or prescribe the maimer, of its use. The mail is transported under a -law of Congress, by contracts made with the postmaster-general. For the convenience of the public and the security of the mails, he requires it tobe carried in coaches adapted to the transportation.of passengers, and the contracts could not be executed according to’' their spirit, and with due regard to the safety of the mails,, should the .contractor fail to provide for the transportation-of passenger^.
    ' The compensation paid for carrying the mail is fixed with a view to these duties and conditions, and any tax or toll levied on a contractor on account of passengers, by so.much lessens his compensation, or it compels the department to increase it to an equivalent amount. Nay,..'if such toll may be levied, it enables a state,-at pleasure, to-. prohibit the transportation of passengers in all mail-coaches,-and-thus take away, its greatest safeguard. Imlike manner, the state ■might tax, at íts.toll-gates, even to prohibition, a guard passing iipon ana with the coabh carrying the mail. This case, as I view it, falls within the reasoning of the court in Dobbins v. The Commissioners of Erie'county, 16 Peters, 448, 450.
    The transportation of the United States mail is a substantive power in Congress, to which the0establishment of post-roads, though specially granted by the constitution, is but an incident.; for it can be only with a .view to the transportation, of the mail that Congress could use the power to establish post-roads, and the passage of the mail'in the coach along the. post-road, with the horses which move it, and the drivers who guide, and the passengers, or guards who protect it from violation, are, to borrow the- language of the court, in McCulloch v. Maryland, which is repeated by Chief Justice Marshall,'in Weston v. The City of; Charleston, 2 Peters, 46, “those means which áre employed by Congress to carry, into execution the power conferred on that body by the people of the United States,”' and “ the attempt to use the power of taxation,” or the levying of tolls.“on the means-employed by the government of the union in pursuance of the Constitution, is-' itself an abuse, because it is the usurpation of a power which the. people of a. single state cannot give;” for “the states have no .power, by taxation or otherwise* to retard, impede, burden, or in any manner control the operation of the constitutional laws enacted by Congress to carry into execution the powers vested in-the general government.”
    The right to tax these contracts for the transportation of the mail, must operate upon the contractors before they make their bids, and thus- haVe a sensible effect upon the contracts.' . If this power be allowed to exist at all, in this case “ its extent depends upon the will of a distinct government. It, may be'carried to an extent which will arrest them entirely.” .

      Swayne’g argument was as follows:
    ■Before proceeding to the-discussion of the question arising in the case, I respectfully submit-to the.consideration- of. the court the.following preliminary points: . .
    • ■ 1. The act of the legislature Of Ohio, of February 4,1831, which ■lies at the bottom 'of this controversy, and Upon which if must.be determined, is a local state law, and,.being such,, this court,- in giving it a construction, will follow the decisions of .the highest judicial tribunal of that state. McKean v. Delaney’s Lessee, 5 Cranch, 32; Polk’s Lessee v.. Wendall, 9 Cranch, 87;' Mutual Ass. .Society v Watts, 1 Wheat. 279; Shipp et al. v, Miller’s, heirs, 2 Wheat. 316; Gardner Collins, 2 Peters, 58.; U. S, v. M'orriSon, 4 Peters, 127; Anderson ét, al.. v. Griffin, 5 Peters, 151. ’
    ■ “ We receive the construction given by the courts of the nation as the .true sense of the law, and feel ourselves no more at liberty' to depart from that construction than to depart from the words of the statute. 'On this principle, thé construction given by this court, to, the Constitution and laws of the-United States, is received by all as the true construction; and on the same principle, the construction given by the courts of the several states to the legislative acts of those- states, is received as true, unless it conflict with the Constitution, laws or treaties of the United States.”

      “ This course is founded upon the principle supposed to be universally recognised, that the judicial department of every government, where such department exists-, is the appropriate .organ for construing theTegislative acts of that governmént.” , Elmendorf v. Taylor et al., Í0 Wheat, 152.

      “ Nor is it questionable that a fixed and received construction of their respective laws in their own courts, makes in fact a part of the statute law of tfre country, however we may doubt the propriety of that construction.” - Shelby et al. v. Guy, 11 Wheat. 361.
    2. If there be doubt in the minds of the court as to the proper construction of the legislative act of 1831, that doubt will be so resolved as to sustain the . claim of the defendant in error. .
    ■ “ The presumption must always be in favour of the validity of laws,'' if the contrary is not clearly demonstrated.” Cooper v. Tel-fair, 4 Dali. 14. _ . ' . .
    _ . . . If the first of these points be sustained, it determines this case. This identical question has been twice decided By the highest court of judicature of the state, in favour -of .the defendant-in error. The first of these decisions was made in 1835, by the Supreme Court of the state, sitting in bank, (The State of Ohio v. Neil & Moore, 7 Ohio Rep. 132;) the second, By the 'Supreme-Court in this case.
    Why is this point not tenable ? It is. true. Congress assented to the act of the. legislature; but that assent .was given without limit or qualification. It does not make the act any the .less “ the act of the legislature’ of a particular state” — nor does it in any wise change the principles upon which it is to be ’construed. I am unable to perceive any reason why its construction should not -be determined by the same lights which are applied in this court to other state enactments; and I think it may be safely affirmed that every argument advanced in the authorities' cited, to sustain, the principle which they decide; applies with undiminished force in this case.
    . If in this I err; if these two solemn decisions of the highést judicial tribunal of the state have not settled the question, then I rely upon the merits of the case. ’
    Before considering them, it is proper briefly to advert to the circumstances under which the road, was ceded by the United States to the state of Ohio.
    “ In the construction of the statutory or local laws .of a'state, it is frequently necessary to recur to the history and situation of the country, in, order-to ascertain the reason-as-wéll as the meaning of many .of the provisions in them, to enable a court.to apply with propriety the different rules of construing statutes.” Preston v. Brow-der, Í Wheat.. 115.
    At the time of the passage of thé act of the legislature, of 1831, a considerable part of the road in Ohio had been finished and in use some time. • It was rapidly going, to rain. The general govern-. ment made no appropriations, and took no other step to keep it in repair.’ There was no.prospect of. any such provision being made. The same course had been pursued in regard to the road east of the Ohio river, and largé -sections of.it were nearly impassable. Under these circumstances, the state of Ohio came forward and proposed to take charge of the road within her limits, and. keep it in..repair upon the terms specified, in the- act .referred to. Congressimmedi-ately assented, and the state thereupon took charge of the road. This act provided for a loan pf money to the, road fund. Such loans have been frequently made, since for repairs; and notwithstanding that the tolls have been repeatedly extended and enlarged, both as to objects and rates, the ro^d.is at this time largely in debt, and yét needs constant and large repairs. With all the tolls now levied upon it, including the important item in controversy in this suit, the road is a heavy burden to the state, and has required, and still requires unremitted vigilance and effort to prevent it from becoming., an entire ruin.
    Treating-the question under consideration as an open one, I lay down two propositions:
    1st. That the state has as broad a. right to levy and collect tolls upon this road, as if it had been constructed by her, without.the United'States having been in- any wise connected with it; subject, however, to this perpetual and only restriction — that the whole amount collected shall .be neither more nor less than sufficient to' meet the costs and charges, direct and incidental, of keeping the road in repair.
    2d. That the levying-of toll upon passengers conveyed in mail-coaches is not in conflict with the proviso in the 4th section of the act of 1831 — “that no toll shall be collected for the passage of any stage or coach conveying the Uiiited States mail, or horses bearing the same.”
    If the first of these propositions be sound, the second is not material'in this case. I rely, however, confidently upon both.
    1. As to the first proposition..
    -. It has been shown already .that Congress consented unqualifiedly to all the provisions of the act of the legislature of February. 4,1831. • . For the sake of clearness ..and continuity of view, at the hazard, of being tedious, I will here again quote the 15th section of that act.'It. is- the, turning point of this- case.

      H- Sect. 15. That it shall be lawfhl for the General Assembly at •any future session thereof, without the assent of Congress, to change, alter or amend-, this act, provided the same shall not be so changed, altered or amended,-as to reduce or increase'the rates of toll, hereby established, below or above a sum necessary to defray the expenses' incident to the preservation and repair of said road, to the erection of gates and toll-houses thereon, and for the payment of the fees-or salaries of the superintendent, the'collectors of .tolls, and of such other-agénts as maybe necessarily employed in the preservation -and repair of the .same, according to the true intent and meaning of this act;”
    First.. The power to change, alter, or amend,” is given in .the broadest language. What is.the festriction? Simply that “the rates of toll” thereby, established, -shall not be reduced or increased “■ below or above a sum necessary” for the preservation and. repair of the road. ■- This is the. only restriction upon the power of the state. 'The object of both parties was-to preserve the road. Congress asked no guaranty beyond-this, and the state gave none. To •secure the preservation of the,road, and at the same time.to get rid óf the-burden, was the inducement to -the general government. To prevent the destruction of; the road,-and to provide the means of preserving it, from the. road itself, was the purpose of the state. p
    Such- being the < nly restriction- upon the power of the state, whenever any act is done by her, the validity of which is questioned, the true mode of arriving áí a sound conclusion,, is to inquire whether it is-within this restriction. If*, it be_ not, however'imwise or impolitic it may be, it is as valid as any other' act of the state.
    Since the passage of the act of 1831, various objects, hot enumerated in it, have beén -subjected-to toll'; but it is admitted iii-the agreed facts, that the ££ rates” pf all the -tolls are neither, above nor below the sum . prescribed .in- the act. Passengers, in orie of the lines of máil-.coaches are a pari; of ;these objects. Are they within this ■restriction ?' Suppose the -stages and horses carrying the mail had in like manner been embraced in these objects, and subjected to toll, as upon - other, turnpike- roads; how could they be said to be within a restriction, which does not* allude to them in the most distant jnanner, and which relates to a wholly different subject1?
    It may possibly be contended that the proviso in this-section is •confined to. the rates of toll upon the objects enumerated in that act. If it be so,, jt is immaterial in this case.. The tolls in that act have been repeatedly,increased, but never reduced. If this construction be adopted, then the agreed fact, that all the. toll's (including these upon new objects) are. neither “ below nor above” the sum required-to be collected, Is án immaterial matter. - Whichever construction.be adopted, it is clear that levying toll upon an.object not subjected to;toll.by the act of 1831, is not witbin this, restriction.
    The literal meaning of this proviso may possibly be -as suggested, but a few words will be sufficient to .show that such-is not the proper construction. If it were, this absurd consequence would follow; the state may raise the’ tolls upon- the pbjects specified in-the act so - high as to yield a sum sufficient to. keep the road in repair: and in addition, levy any- amount of tolls upon other objects, and apply it 'to other purposes. . ■
    . To insist upon, such a construction, would be about as rational as for the defendant in error to- contend* that, coaches carrying a part of the mail are not within the,terms and meaning of the clause exempting from toll coaches carrying the mail. ,
    . If we look-beyond the letter, of the proviso to the. context of the act, no doubt can remain as to-its true, meaning.. Either construction, however* affects'the defendant in error alike, and suits equally with the views here presented;
    .After this examination of the subject, can it be doubted, that it was the intention of both parties* when the acts of 1831 were passed, that the state should have all the power claimed for-it in this proposition, subject.only to the restriction-mentioned.
    Second, The act of February 4, 1831, contains a proviso, at the end of the -1st section, and two at the close of the 4th section, to,which, in connection, I desire to call the' attention of thecourt; •
    •' The'first provides that the number of gates on the road shall not exceed one for every twenty miles.
    The second exempts’from toll,-persons passing to or from public worship; or, to or from musters; or, to or from their common business Oh .their farms or woodlands; or, to or from-a funeral; or, to. or from a mill ; or* to or from ,their common places of trading, or market, including their carriages and horses, or., oxen drawing the same.. •
    .The third exempts from toll, any stage or • coach conveying the. mail of the United Státes, and the horses' drawing the same; any wagon or carriage laden with the property ofthe United States; ¿ny cavalry or-other troops'of the United Statesarms or military stores belonging to the United States; arms or military stores belonging to any.-'.of the-states, or to any person on duty in the military service ofthe United States, or of the militia of any of the' states. •
    All these provisoes stand upon, the same footing. They are alike obligatory as to duration and .inviolability.
    If the state-can ■“ alter,-amend, or change” any of, them, she can all. She-can abrogate all or none. • All'or-none were intended to be perpetüal and unalterable.,/ _
    _ The state has found it-necessary, besides increasing the rates of ■toll,.to-increase,the number of gates. There,are.gates now every tea miles, and, iñ some instances, “ half gates” at the end of five miles. •
    She has abrogated the exemption from toll in favour Of those going to mill,’, market, and their common places of trading.
    - -She has abrogated nearly all the other exemptions..
    . That in favour of -mail-coaches and horses is one of the few left.

      Was it a violation of the net of 1831 to erect these gates, and abrogate these exemptions? Was it within the restriction contained in the 15th section ?
    Have not all those passing the additional gates, and all those going to. mill, market, or their usual places of trading, much more ground for complaint than' the plaintiffs, in error ?
    Can they resist the payment of the riew.tolls imposed upon them ?
    If the state had a right to make these changes' in tire act of 1831, and to .abrogate these exemptions, has she, not the same right to abrogáte the remaining exemption as to mail-coaches, whenever she •may think proper to do so ? • Wherein lies the difference, and how are the cases distinguished ?
    It .will be observed that -these • exemptions contain no words of perpetuity.
    The part of the statute which .contains them is separated from the • part containing the power to alter and amend.and restricting it, by ten intervening, sections, which are wholly silent upon the subject.
    If it had been the intention of the legislature that this exemption as to mail-coaches and horses should be perpetual, would there not have been added, at the end of the 15th1 section, after the other perpetual restriction which it contains, a clause like this:
    “And provided also, That no to)l. shall ever be collected from any stage-coach carrying the mail of the United States, nor'from the horses drawing the same.”
    Nothing of this kind is to be found in any part of the act;
    I think these views fully sustain the first proposition.
    2. As to the second proposition.
    The ground upon which the plaintiffs in error mainly rely, is, I understand, that passengers conveyed in-coaches carrying'the mails are within the proviso of the fourth -section -of. the act of 1831, which exempts the coach and horses from toll; and. consequently that such passengers are exempted also.
    If. this were so, I think I have shown, that it was in the power .of the legislature at any time to' abrogate all or any part of this ' .exemption, and if it were necessary, I might safely contend that as respects such passengers, the legislature has. done -so.
    But I rely confidently, upon the proposition, that such passengers .are not within this exemption.
    In the year 1835, the Supreme Court ■ of .Ohio,.- in bank, in a case between the same parties, (adverted to elsewhere in this argument in another connection,) delivered-the following unanimous judgment upon this point:
    “ -First, then, is the act of the General Assembly imposing this toll, unconstitutional ? Or, in other words, is it a tax-on the coach itself, calculated in.its consequences to impede or obstruct the conveyance of the United States mail.? ■ We hold the negative. The coach, the horses, the drivers, and the proprietors are exempted in express terms. But it is said-that contracts for the transportation, of the mail were .made in reference to the conveyance of passengers. Such may have been-the case. The-postmaster-general is not authorized, however, to make any contract exempting passengers, eitherin coaches, or on foot, from the payment of toll. His contracts can extend only to the mail,' and the mode of its conveyance. The defendants have the right to the road secured to them by. the -acts of Congress, arid of the Assembly, free from toll, for such carriages, horses, and attendants, as may- be- necessary to enable'them fully to comply with their contracts; but-when they attempt to go,beyond-this,- and resort to means- to increase their profits,. not necessarily connected with their contracts, they, like others,'are rightfully subjected to the .inconvenience of paying the toll* which the convenience of a good road imposes..
    “.The proposition cannot, we think, be maintained, that passengers are necessary for the conveyance of the' mail, and if they are not, a tax on them is, in no light in which the subject can be viewed, a tax on the coach itself, nor calculated, in its consequences, to. impede or obstruct the transportation of the- mail.” State of Ohio v. Neil& Moore, 7 Ohio Rep.. 133.
    This opinion was adhered to and deliberately'affirmed-in the ease at bar. The reasoning of the court seems to me to be conclusive. It covets the whole ground of the objections urged by the plaintiffs in error. ■ Further discussion can add little to its force;- I should, not fear to rest this part of the case, entirely upon it. The proposition which it maintains, however assailed, requires, I think, little effort to-support it. It seems" to. me .to be such, as almost to present one ofthose cases; in which. “ the. truth-is discoverable by its own light* without- the aid of "argument.”
    This toll is levied, not upon the plaintiffs in error, but ripon the passengers conveyed .in their- coaches. . If those from whom it is exacted pay it, surely it is no burden upon those who convey them. The latter are not compelled-to pay it, unless.-they assume if. Stripped of all circumlocution, the' language of the plaintiffs in error is, in effect, this;. Allow us to receive this toll, instead of the at ate, and the mail will be carried at less cost to the Post-office Department. ' The same reasoning upon which they rely, would apply equally to every thing else they may choose to carry in their mail-coaches,.of, indeed, in any other vehicle in which they may carry a part of the mail,'with the sanction of the postmaster-general. The. answer is, that the general government has not asked, arid that..the state had riot-conceded, any such exemption. I do not see but thát the same, argument would apply with equal force to any other toll collected on the road. Give to the plaintiffs in error any other toll, and- undoubtedly they would carry the mail at' so much less cost to the government. — The circle .of this argument is wide enough to include every toll levied upon the road. If we depart from the construction of this exemption, contended for by the defendant\in error, where, shall the departure be limited ?
    Another act of the legislature of Ohio provides, that“ all boats” belonging^ to'the United States “shall be permitted to navigate either of. .the eanals of this state, free- from the payment of tolls.” .38 Ohio 'L¿vys,-87. . Does this exemption of the boat from- foil, exempt- from toll' also the lading upon, it belonging to private indi-vidiials?' If the exemption of the coach exempts the passengers, why does not the exemption of the boat also exempt the lading ?
    Before -and át the time of the passage of the act-of 1831, it was no more “ usual”'- to convey passengers in mail-coaches on the National road; than it was before and at the time of the passage of this law,"to transport lading in boats upon the canal. “If not necessary, it is usefúl” ip. the same manner. Were the boat removed, by contract, from point to-point upon the canal, the exemption of the lading-would as .much' lessen the cost of the removal of the boat, as the exemption-of the'passengers would lessen-the cost of'the transportation.of the mail. Were the boat a mail-boat, the exemption of'the ladingwould.be much more important'to the United. States than the exemption of -passengers as claimed' in this case\ XLading-is as closely associated with the idea of a boat upon the canal, as passengers are with - that of a mail-coach' on the National road. -The term boat as much includes lading, as the term mail-coach does passengers. I am ¿ware of no argument applicable to one, that does not apply equally to the.other. In my apprehension the parallel is perfect.
    To insist seriously that -the. exemption of the boat exempts the* ■ lading,- would probably be deemed-% all a gross absurdity. Does not this claim of the plaintiffs in error, by the clearest analogy, em- , brace that case'aiid lead to this result ?
    A proposition, leading to,a consequence so absurd, must, itself, necessarily be unsound.
    It will be observed that the decision of the Supreme Court iri 1835 was made before the.plaintiffs -in error entered into the contract with the postmaster-general, which was- in existence when this cause of action arose.- That contract was made; and this liability incurred, of .course-, with full knowledge of that decision.
    It will also be observed that the-objection to’ the toll .in question doés not come from the general, government,-which is said to be aggrieved, nor from-those upon whom the toll is laid, -but from the-mail contractors,-who have voluntarily assumed a vicarious responsibility for their passengers, and patriotically seek in-this suit, unbidden, to vindicate the violated rights of the United States.
    JJpon what consideration this is done, it is not material to inquire
    Since the foregoing-was written, ! have seen the argument of the plaintiffs in error. It renders a few additional remarks necessary..

      It is not denied that it was within the power of Congress to surrender the road to the state upon any terms .that might be agreed upon. The whole question is, What were the terms ? They are to be found in .the 15th section of the act of 1831. There is the “ contract.” The power to “alter, change, and amend,” is, (as beforé remarked,) unlimited by “any qualification,” except as to the amount to be collected. Mr. Ewing’s argument would change the contract, and impose á condition which is contrary both, to the terms and implication of the agreement. In order to warrant his construction of this act, it would be necessary (as suggested in the preceding argument) to “ dislocate” the proviso upon which hé relies from its place in the 4th section, and, thrusting it over the ten intervening sections, interpolate, it as a second proviso at the end of the 15th section. • Otherwise, it is clear that the construction for which he contends is both grammatically and logically incorrect. It is only by confusing these provisoes together, and losing sight of their different and relative places in- the context, that any doubt can ariseion this point.
    It is admitted that it was competent for the state to abrogate all the exemptions contained in the 4th section, except that relating to mail-coaches. The distinction attempted to be established between that and those which precede it, is unwarranted by any principle of construction.with1 which Í am acquainted. They stand upon the same footing, and are all alike alterable or unalterable.
    When the act of 1831 was passed, the legislature obviously believed that the road, with all 'the .exemptions specified in the 4th section, would yield a sum sufficient for its preservation. But as the experiment was an untried one, the state was willing to bind herself by no restriction whatever, but that the sum collected should be neither more nor less than sufficient to keep the road in repair. Her experience has shown the wisdom of this caution.
    The act of February 6th, 1837, imposes a toll at each gate, of three cents, upon the passengers in question. The act of March 19th, 1838, authorizes the Board of Public Works to “ revise” the rates of aU the tolls — “■ to be paid' by persons passing on, or using, the National road.” In- the exercise of this power the board has raised the toll in controversy from three to ten cents. It is admitted that they have not transcended the limitation dontained in the 15th section of the act of 1831. Their action, then, is “ according to the true intent and meaning of .the act of February 4th, 1831.” The . legislature used the language^ just quoted in tifie act of 1838, obviously with a view to the restriction contained in the 15th section of the act of 1831, and not, as intimated in argument of the plaintiff in error, for the purpose of submitting the question to the board, as án open one — whether the act of 1831 permitted such a toll to be exacted. That question had been determined by both the legislature and the Supreme Court. The duty devolved upon the board was, to “revise,” upon the principles 'indicated, the pre-existing tolls.
    It' is said that the state still exempts from-toll the two lineé of mail-coaches, and the-passengers conveyed-in one of them.
    •This is true; and the exemption, is practically larger and more injurious to the fund arising from tie road,-than it was when the act of 1831'took effect.. Then, the exemption was confined to one line.'of coaches and the passengers conveyed in it. How long the state will be able to continue this exemption in its present extent, will depend upon the. amount of expenditure necessary to keep the road in repair.’ She is bound by her contract with the United States to collect this amount.. The sum constantly increases as the road .becomes more worn. Her,forbearance during the few years which has elapsed since she took charge of the road, can surely afford no • argument against any right to which she is'entitled under-a fair con- ■ struction of the act of cession.
    It is said, also, that this road “is a post road established by law.”
    Admitting this to be so, in my view of the subject it' does not affect the question under - consideration. But the assumption is erroneous. Congress, has designated the points where post-offices shall be established,.and directed the mail to be conveyed to them; but the road- is not specified upon which it shall be conveyed. - This; then, is no moré “a post road established bylaw,” than any other' road oven which the mail is carried. Indeed, the power to establish post roads, it is said, has never been exercised by Congress in any instance. 3 Story’s Const. 43.
    Whenever' this power shall be exercised either as respects state roads already existing, or those, to be constructed for that purpose by the general government, a host of new find most difficult questions will at once arise between the several states and the United States. A glance'at the learned work referred to will show them. It is unnecessary to consider any of them here.
    This not' being a post.road established by law, the argument founded upon that assumption falls to the ground.
    It may, however, be contended, that this and-all other roads upon which the mail is conveyed, are established as post rbads by necessary implication from the acts of Congress establishing post-offices upon them, and directing the mail to be conveyed to such offices.
    If so, the answer is qbvious. -If the-United States buy in the pro- • perty of a debtor in satisfaction of a judgment, such, property-is still liable to taxation'by the state. A branch of-the Bank of the United States was not-liable do be. taxed, but the real estate held by the bank, which the branch occupied,- wás so liable.
    It has never been questioned that the coaches and horses belonging to the contractor, which he uses in the transportation'of. the mail, fire -liable to taxation by-the state, like all other individual property;. .andlf the contractor conveythe mail upon' a turnpike, on which toils are collected, he is liable to. the same tolls, as other persons. The p'ower to levy such taxes and collect such tolls, is, within the exceptions distinctly recognised in all the cases decided by this court.in which this subject has been considered. 4 Wheat. 316; 9 Wheat'. 867; 12 Wheat. 136; 2 Peters, 46; 16 Peters, 442.'
    The argument upon the other side is broad enough to maintain ' the proposition, that such coaches and horses are exempted both from",taxation, and toll..
    . Whenever the, general government uses the instrumentality of private means to effect its objects, such means are liable to taxation or toll, as the case may be, to the same extent as if they were, employed in- the business of private individuals. This reasoning applies as much to this road as to any other; and the case must necessarily turn upon other points.
    It is strenuously.contended, that the'exemption of,the coaches and •horsesfrom-toll, exempts also the passengers as an “incident.”
    It will be. readily perceived by the court, that if the argument, of the defendant in error fail on all the other points, yet, “unless the plaintiff in error succeed in maintaining this proposition, the judg-' ment below must be affirmed.”
    If my recollection serves me correctly, it is not many years since the transportation of passengers in the mail- lines, on the great routes, was greatly restricted, if not entirely prohibited, by the head of the . Post-office Department. Does he contract for the conveyancé of passengers ? Is that a matter about which the government concerns itself? The letter of the postmaster-general in this case sets up no such claim as is insisted upon by the plaintiff'in error, and manifests' no interest in the subject.
    It has been held by this court, .that a branch -of the Bank of the TJnited States was not liable to taxation by a state, bui-that the stock in the bank, held by a citizen of the state, was. 4'Wheat. 316.. Was-not tire argument for the exemption of the stock in that casé much stronger than the argument for the exemption of the.-passengers here ? The analogy is too obvious to need comment. If the right claimed to collect toll from passengers-be sustained, it is apprehended'that “the state might tax at its toll-gates, evento prohibition, a guard-passing upon.a coach carrying the mail.” The connection between the mail and the coach, horses-, -driver, and guard, is certainly very different from that which subsists between the mail-end the passengers. No right-has'been"asserted by the legislature to collect toll from the proper incidents of the mail upon this road. When such,a ease shall occur, it will be early enough to adjudicate upon it. The question in this case is a very different- one. It relates solely to' passengers.
    For a fuller examination of 'this point, I refer to the preceding argument.

      Ewing, in reply.
    I have said in the opening argument, that the National road in Ohio was, at the timé of the transfer to that state, and still is, a post road. This is denied by Mr. Swyane.

    Acts of Congress, passed every four years since its construction, direct that the mail shall be carried daily from town to town, (as from Wheeling to Zanesville, and thence to Columbus,) which towns are upon the National road. .The agreed case shows that the mail was so carried- upon said road ever since its construction. The usage applying the law to this road, and the subsequent laws coinciding with the usage, the reservation in the contract of the right to transport the mail along the road, and.its subsequent.continued transpor-' tation, make it, I contend, as fully a post road, as if it had been expressly declared-so by act of Congress.
   Mr. Chief Justice TANEY

delivered the opinion of the court.

This case has arisen out- of two acts of Assembly, passed by;the . ■ legislature of Ohio, one in 1837, and the other in 1838, and an order of the Board of Public Works of that state, whereby a toll has been imposed upon passengers travelling in the mail-stage on the Cumberland road.

We have already, at the present term, fully expressed the opinion of this court, in relation to the compacts between the United States and the states of Ohio, Pennsylvania, Maryland, and .Virginia, concerning this road, and the rules by which they ought to be interpreted! It is only necessary, therefore, on this occasipn, to apply the principles there-stated to'the case before uS.

The material parts of the laws in question are the 4th section of the act of 1837, and the 24th section of the act of 1838. The first imposes a toll of three oents on .every passengér in the mail-stage, at each toll-gate; and the secondauthorizes the Board of Public Works to revise and mddify the rates of toll to be paid by persons using the ' road; and in pursuance of this authority the board passed an order raising the toll- on each passenger in -the mail-stage to ten cents. But no toll is charged, either by the law or the order of the board, upon persons travelling in any other carriage.

The 4th section of the act of 1831 / whereby the state of Ohio proposed, with the assent of -Congress, to take charge of the road and keep it in repair, contains a specific enumeration of the tolls she intended to charge, upon carriages of every description, and other properly ; and after making this enumeration, the section concludes with the following proviso: “ That no toll should be received or collected for the passage of any stage .or coaph conveying the United States, mail, or Jhorses bearing the-same, or any wTagon or carriage laden with the property of the United States, or any cavalry or other troops, arms or military stores belonging, to the same or to any of the. states comprising this union, or any person or persons on'duty in the military service of the United States, 4>r .of the militia of aoy of the states.” -,

We shall hereafter speak of .the 15th .section of-this act, which has been supposed to justify,the toll in question. But, subject to the ■modifications, if any, authorized by thafc-section, the entire Contract in relation to the tolls,, offered by the state and ac cepted by '<£on-gress, is to be found in the 4th; the residue of the act containing nothing more than detailed regulations for the collection and appli- ' cation of the tolls'.

At the time this compact was made, it was well known that thé mail was always transported by contractors, and that whenever it’, was.conveyed in carriages, the vehicles belonged tO them, and wer-e their own private property, and not the property of the United States. It was equally well known that upon this road, as well as many others, the postmaster-general,- in his contracts, uniformly required that the mail should be carried in a stage or coach capable pf accommodating a certain number of passengers, the presence of . the passengers being regarded as adding to-the safety of the mail, , • and superseding the necessity of any other guard.

This mode of transporting the mail ^must have been perfectly ■ known to the state in 1831, when the. agreement was made; and in providing for the exemption of carriages conveying the United States mail, both parties must hav.e.intended to exempt the vehicles usually employed in that service; and' that carriages belonging to the contractors, although carrying passengers, were to pay no toll, while all other vehicles were to be charged at the rate specified in the law. The reason of this exemption is evident; for a toll charged upon the. carriages of the contractor would, in effect, be a charge upon the Post-office 'Department, since the contractor would be obliged to make provision for this expense when bidding for the contract, and regulate his bid so as to cover it..'

In the proposition made by Ohio, nothing was said of a toll on the passengers in a carriage of any kind, but the charge is made upon the carriage itself, according to its description, and the number of horses, without any regard to the number of persons that may be .travelling in it; and it. is évident that it was at that time supposed that the rates specified and agreed 'on would prove sufficient to keep the road'in repair, and.that the United States would always thereafter have the free use.of it, for mail-carriages,of the usual kind,, .without any burden upon them, direct or indirect.

If the expectations of the parties had been realized, and the tolls mentioned in the law had produced revenue enough to preserve the road, no one, we think, would have supposed that tolls could'be collected from passengers in the mail-stage, or that the specified .charges upon the carriages could have been reduced, and the deficiency supplied by a toll upon persons traveUing in the carriages which conveyed the mail.

Lx the case of Searight v. Stokes and others, we have alrdady. said, that with an agreement like this before us between the United States and a state, we must look 'at the relation in which the parties stood to one another, as’ well as to the subject-matter of the contract,, ■and the object which the high contracting parties intended to attain; and we must expound it upon principles of justice, so as to accomplish the purposes for which it was made, and not defeat their manifest intention, by a narrow and literal interpretation of its words. •And regarding it in this point of view, we think it very clear that no part of -the burden of supporting this road was intended to be levied upon the United .States, but was to be obtained altogether from other sources; and' that the relative position and privileges of the mail-coaches in regard to tolls, as prescribed ih the law, were to be always afterwards maintained, unless a deficiency or superar bundance of revenue should render it necessary to increase or dir minish the rates fixed in the law. For if this were not the case, the whole detailed and particular .provision in relation to the things to be charged, and the rates to be imposed, as set forth in thé law-of Ohio, and so cautiously recited in the act of Congress consenting to the. surrender of the road, would -be nugatory and without an object. On the. other hand, this mode of proceeding was the natural and proper one, where two sovereignties .were contracting with each other by means of legislative action; and it was obviously adopted by the parties in this instance in order to show the terms proffered by Ohio, and assented to by Congress, and forms the con- ■ ditions of the compact between them, so far as tkfeir respective rights were concerned.

We proceed to apply these principles to the question before us The law of the state, and the order of its. Board of Public'Works, impose a toll upon every one travelling in -the mail-stage, while the passengers in every other.vehicle are allowed to go free.. If this can be done, it is manifest that the United States will derive no benefit from the compact, and so far from enjoying the privilege for which they stipulated, and for which they paid-so heavily in the construction of the road, a large portion, -of the* burden of repairs will be thrown upon them. This is strikingly illustrated by comparing the toll charged upon coaches similar to those employed in conveying the mails, with the toll indirectly levied upon the mail-stage, by a charge upon its passengers.- According to the rates contained in the law of which we are speaking, a four-wheel carriage, drawn by four horses, pays at each gate thirty-one .and a quarter cents, and if it is not conveying the man, it pays nothing on its passengers. This sum is therefore the whole. amount of the toll to which it -is liable. Now the mails on this road have, we -understand, been always tranáportéd in coaches, of the above 'description, and' although under the order of the Board of Public Works no toll is charged directly upon the carriage, yet every passenger must pay ten cents at each gate,, so that the carriage of a mail-contractor, containing six passengers, pays nearly double as much as a like carriage owned by any one else with the same number.' And what still more strongly marks the disadvantages to which the-United States are subjected by this order of the board, these passengers may be persons in the service of the United States, passing along the road in the execution of some public duty, for the order makes no exceptions in .their favour. And although, this toll, in form, is laid upon the, passengers and not upon the vehicle, the result is the same; for in either case it is, in effect, a charge upon the proprietor of the carriage, diminishing his profits in that portion of his business; and when thus levelled exclusively at passengers in the mail-stage, it accomplishes indirectly what evidently cannot be done directly by a toll upon thecarriage, and in its consequences must seriously affect the interests of the United States. For in bidding for a contract upon a road so much travelled as this, the bidder would undoubtedly be greatly influenced by thé 'advantages which a contract would-give him in the conveyance of passengers, as his carriages, when carrying the mail, are entitled to go free. But if they, and they alone, are to be subjected to this burdensome and unequal toll, it is obvious that he must seek to reimburse himself, by enlarging his demand upon the government. Indeed, if this system of levying toll can be sustained, the mischief may not stop .here; and'it will be in the power-of any one of the states through which the road passes so to graduate the tolls as to drive all passengers from the mail-stages into other lines, and by that means compel the United States, contrary to their wishes, and contrary to the'public interest, to transport the mails in vehicles in which no passenger would travel.

Nevertheless we do not mean to deny the right of the state to impose a toll upon passengers in the mail-stages, provided, the power is exercised, in a manner and upon principles, consistent with the spirit and meaning of the argument by which the road was transferred to the care of the states. On the contrary, in the case of Searight v. Stokes and others, we have already said that such a toll may be lawfully collected. But as no toll on passengers had been proposed by the. law of Pennsylvania, the opinion,' on that occasion,' is expressed in general terms, as to tíre right; the case then under consideration, not calling upon the court to speak more particularly upon the subject. The Ohio law, however, brings the. question directly before us, and makes it necessary to state inore, fully and precisely the opinion of .the court.

The true meaning of the compact we understand to be this. The carriages carrying the mail, with their passengers, travelling in the known and customary manner, were to pass toll free, as well as other vehicles laden with the property of the-United States and the persons employed in their service, as mentioned in the proviso hereinbefore recited; and the road was to be kept in repair by.the •■revenue derived front the tolls specified in the Ohio law, according to the rates, there.set forth, provided they should prove to be sufficient for the. purpose. No toll was at that time proposed upon/ passengers many vehicle,, and passengers in the mail-stage there-" fore ha¿ no• pepuliar privilege in going free,-and merely passed along the road upon-the same terms with fhose who were travelling in Other carriages. Andas the compact contains no stipulation for the exemption of travellers'-in the mail-stages, the general government " can.demand no Nadvaritages in their behalf, which are not extended do .passengers in other vehicles. Rut'they have a right to insist.that the\equality upon this subject, which- the law of Ohio originally proposed, shall still be 'maintained; that the privilege and advantages intended to be secured to the carriages conveying the mail, over those granted to other vehicles, shall be preserved in substance and reality as well as in form; and that the passengers in the mail-stages shall not.be selected and set apart, as the especial objects upon which burdens are to .be laid, and.to which travellers, in other . carriages are not.to'be subjected.

If, therefore, the revenue from the road, according' to the rates originally agreed on, was found to be inadequate, then the state had undoubtedly a right to increase the rate on "any thing before subject to toll; or might, if it was deemed more advisable, leave the tolls as they stood, and charge in addition to them a toll' on passengers. And if instead of selecting the persons travelling in the mail-coaches, áñd laying the burden exclusively upon them, all passengers in vehicles of any .kind had been equally charged, the real and sub- ' stantial advantages and privileges to Which the United States are entitled under the agreement would have'been preserved, and the equality in relation to passengers originally existing betwéen the mail-coaChes and other carriages would not have been disturbed. And it is in this manner-only,, in our judgment, and as a toll in addition to that specifically stated in "the contract, and imposed equally-upon passengers in every description of vehicle, that persons travelling in the mail-stages can be lawfully charged, without first obtaining the assent of Congress.

The 15th section of the law of 1831 has been relied on in the argument, as reserving to the state the right to make any alteration it might afterwards think proper without regard to the interest of the general -government. It is true that this section begins with a declaration that it shall be lawful for the Genéral Assembly at any future session, without the assent of Congress, to change, alter, or amend the act. .But this clause evidently relates -to the various provisions made in the law for tile collection'and disbursement of the money arising from the tolls proposed to be charged. The United States could have no interest in these details, and they were therefore properly retained in the hands of the state. And so in' regard to the privilege of passing free on certain occasions, given by the-law, it is undoubtedly in the power of the state, if it thinks proper, to revoke it, since the exemption was a mere voluntary act, founded. on no valuable consideration, but growing out of what was then supposed to be a just and liberal policy, which the state could afford to exercise; but which it had the right to change whenever it was deemed necessary to do so. But a full and valuable consideration' had been paid, by the United States for the privileges reserved to them, and they were a part of the contract which transferred the -road to the care of the state. And this being the case, 'the section in question cannot by any sound rule of construction be regarded as inconsistent with the contract contained in-another part of the same law.,, and qs placing the rights secured to one party entirely at the discretion and the control of the other. The reservations of power to the state, evidently relate to subjects in which the general government had no separate interest; and they would have, been altogether unnecessary and useless if the state had not considered the preceding part of the law as the proffer of a com-1 pact which was to be obligatory upon it; if assented to by Congress.

There is a clause in-the law. of 1837, which would appear, to distinguish between the mail-stages, in relation .to toll, where more than one mail passed along the road on the. same day. Upon this point it may be proper to say, that, in the opinion of the court, it Tests altogether in the discretion of the postmaster-general, where the power has been conferred on him by Congress, to determine at what hours the mail shall leave particular places and arrive at others; and to determine whether it shall leave the same place only once a day or more frequently. Upon this point his decision is absolute, when the discretion is committed to him by the laws of the United States, and cannot be controlled by a state or by the courts. And in the ■ case of Searight v. Stokes and others, when, the court speak of abuses by the contractors in the number of carriages employed, and of thp right of -the court to enforce the compact, i.t will, be seen by a reference to the opinion,- that it is confined to cases where the mail-bags, directed to leave the post-office at the same time, are unnecessarily divided among a number of carriages in order to evade ■ the payment of toll’; and the opinion expressed on that occasion by ’ the coiirt does not apply to stages leaving the post-office with mails at different hours, in obedience to the orders of the department. In the latter case.it is immaterial whether the mails are light or heavy. .The postmaster-general'is, upon this subject, the proper and only • judge of what the public interest and convenience requires, and his decision cannot be questioned by the courts.

The provision upon this subject, however, appears to have been intended to guard against -abuses by contractors, rather than to interfere with the powers of the postmaster-general. And in regard to the toll imposed, as hereinbefore mentioned, if it is necessary for the support of the road, it is in the power of the parties to the compact to modify it at tbeir pleasure, and to give the state the power it has .exercised. But according to the terms of the contract; as it Was originally, made, and. still stands, the toll upon passengers in the mail-stages, laid in the manner hereinbefore stated, cannot law-, fully be demanded, and the judgment of ike state court must therefore be reversed.

Mr. Justice 'DANIEL.

From the decision just pronounced on behalf of the majority of the court, I am constrained to dissent. - Upon the principles involved in the decision, so far as they, have been assumed as the foundation of rights in the federal government, or in the postmaster-general as its agent or representative, independently of any agreement with the state; of Ohio, my opinion has already been declared. That opinion was expressed on a similar point arising in the case of Searight v. Stokes et al., during the present term*; it is unnecessary, therefore, on this occasion to repéat it. With respect to- the compact which' is said to have been made between the federal government and the state of Ohio, by the act of Congress relinquishing the control of the. Cumberland road to the state, and 'by the act of the Ohio legislature, ■ assuming the control arid management of that road, it has not to my mind been shown'that this compact has. in any respect been violated by the state. A cursory view of the' legislation, both by the-state and by Congress, will establish the very converse-of any such infer-' ence. That the several proceedings on the part of the state steer entirely clear of collision with the letter of that compact, has not, So far as I have heard, been even disputed. The statute of Ohio, passed on the 4th 'of February, 1831, after several' provisions — 1st, investing the governor of the state with power to take--under his care-that portion of. the Cumberland road comprised within the liinits of the state; 2dly, prescribing .'the rates of .toll to be collected; .3dly, laying down regulations for the police of the road; contains in the second proviso of the 4th section the. following enactment: “ Provided also, that no toll shall be received or collected for the passage of any .stage or coach carrying the United States mail, or horses bearing the same, or any wagon or carriage lad en with the property of the United States, ^or any cavalry or other .'troops, arms or military stores belonging to the same, or to any of the states of the union; or any person- or. persons on duty'in the military service of the United States/&c., &c.” The. 15th section of the same law is in the following words: “ That it shall be lawful for the General Assembly at any future session thereof, without the assent of Congress, to change, alter, or amend this act; provided that the same shall not be so changed, altered, or arriended, as to reduce or increase the fates of toll hereby established, below or above a sum necessary to defray the expenses incident to the preservation and repair of the said road, to the erection of gates and toll-houses thereon, and for the- payment of the fees or salaries of the superintendent, the collectors of'tolls, and such other agents as may be necessarily employed in' the preservation and repair of the same, according to the true intent and meaning of the act.” The act of •'Congress of the 2d of March, 1831, (4 Story’s L. U. S. p. 2250,) is nothing more than a literal recital of the law •of Ohio-, and an entire and unqualified assent to, and adoption, of, that law. These statutes comprise* all that has been ever done by the state and federal governments, which amounts to any thing in the nature of an agreement or compact between them in reference to the Cumberland. road. Let us now inquire what it is that, by reasonable and proper construction, these'laws import? And it should, in their examination, ever be borne in mind, that whatsoever the law of Ohio, has.ordained in reference tó its subject matter; whatever rights or powers it has claimed for the state in’regard to it, the act of Con- ■ gress-has unconditionally recognised the whole. The second pro- . viso of the 4th sectión, already'quoted,«contains no stipulation'that-ordinary travellers or passengers, or any others-indeed, or any de- ■ scriptions of property, save those expressly enumerated in the proviso., shall pass upon the road free of toll. •' It concedes to the fede- . ral government that stages carrying the mail, i. e. the carriages and .' the ■ horses necessary for' their use, and the mail itself, should not pay toll; but with respect to private travellers, and to everything, within or without those carriages, the law- is entirely silent. By what correct implication, then,'can the power of the state to levy tolls on travellers.in such carriages be taken away. I can conceive of no implication tending to such a result, which would not obviously do violence, to the language of the statute, as it would to every ¿orrect rule of construction^ and to every intendment consistent with the natural and plain objects of the law. The fact-that •the state has exacted tolls on passengers in the stages carrying the mails, only beyond- a certain number of carriages so employed, can by no-correct reasoning .affect the right of the state in this matter, however, it might be received as a.measure either of policy or liberality ; for having the power ¿bsolutely 'to exact tolls of all travellers on the„road hot exempted- by the proviso,- this power carried 'with it, by every sound rule of logic', the right to discriminate be-, tween the subjects of her power. She had then a perfect right to declare .that travellers in specified carriages carrying the mail should ■ pass free of toll, and that those transported in other vehicles, although bearing the mail, likewise should be subjected to the payment of toll. Such a regulation the state had the power to enact, had -it -been the dictate of mere caprice. A correct apprehension, however, of her policy and ■ interests in reference to this road, and in reference'to the accommodation of the public, will develope a more enlarged and more equitable motive for the measures adopted by the .state--showing those measures.to have been produced • fry the force of supervening circumstances. It cannot be denied, that in assuming the management of this road, the purpose of the state was to maintain and preserve it as a commodious highway. By the title qf the law passed for its assumption, viz., “ An act for. the pre-. servation and repair of the United States road,” as well as by every clause and provision of that law, this object is clearly evinced. It is equally undeniable, that the means in contemplation for the accomplishment of this object were the usual and natural means by which artificial highways are supported, viz.: the tolls ■ collectable on travellers and on property transported upon it. The concession to the federal government of the free passage -of a portion of its mails over this road, and of the vehicles in which they might be carried, was an act of fairness and liberality which should not be made the pretext for abuse and monopoly, such as must, if permitted, dry up . the source whence the means of maintaining the road are to be derived, and which would opera.te for the exclusive advantage of the favourites of such monopoly, and for the serious injury of the public. To guard against consequences like these, the power reserved by the-15th section of the law of Í-1831 was retained by the'state, a power xpressly recognised to Its full extent by the act of Congress adopting the former law; and it can as little be doubted, that, in the practical experience of those consequences,.and in the intention of applying a remedy for them, the law of Ohio of March - 9th, 1838, and the‘order of the Board of Public -Works of the same state, had their origin.

But it is argued that the exaction of tolls on travellers in stages carrying the mails, would be a violation of the compact between the two governments, because it wovdd enhance the demands of- contractors for transporting the mail, and thereby become a fax upon the federal-treasury, aua in the same degree an impediment to the conveyance of the mails. It is á sufficient reply to. such an argument to,remark, that neither the law of Ohio nor the act of Con-, gress adopting that law, stipulates any exemption from tolls on travellers, but the exemption is limited'to carriages only; and it is an inflexible rule of contract, too familiar to be commented on here, . that neither party, singly, can superadd a term or .condition to. a contract completed. This argument is therefore utterly without force, even if the effects it seeks to deduce could be demonstrated. It is'fallacious too in' another respect. The monopoly in support pf which it is adduced, by enabling thé mail contractor to drive off all competition, whilst it puts it in his power to withhold the .tolls by payment of which the road would be supported, enables, him to practise the very extortions upon the government which . fair competition would be the surest means of preventing. But conceding, for thp moment, that a denial to the contractor of the privilege now contended for, might enhance the price of transporting the mails, the question still very properly arises, whether.this effect (were the language of the law even doubtful) would justify, the extension to him of such a privilege ? A just view of the legislation of both the state, and federal governments, and of the obvious purposes of that legislation, must compel a negative answer to this) question. The purposes designed by this' legislation were the preservation and repair of the National road. Such are the objects announced, no,t only in the titles of the laws themselves, but provided for in all their enacting sections ; and the quo modo declared by these enactments is the levying of tolls. Is it then reasonable or logical, or rather is it npt inconsistent and contradictory, to attempt to deduce from them; conclusions which fall not within their terms, but which go to defeat every end which must-have been within the contemplation of the parties.; for which indeed these enactments all profess to have been made. Is not this attempt in violation of all rules foj the construction either of statutes or' contracts,' which always preserve the main and obvious intentions of legislators or of contracting parties, to the exclusion of minor though seemingly contradictory considerations ?. But the language of these laws is by ho means equivocal. Except for the exemption contained in the.sécond proviso of the 4th section of the Ohio statute of 1831, all mails and the carriages in which they are transported, the-troops, arms, and property of the United States of every description, would have been subject to the payment of tolls; and the exemption can be extended no farther than the plain and natural import of the language of that-proviso will justify.

Again, it has been said, that the exaction of tolls from travellers in the mail-stages would be a. violation of the contract, because by such a demand travellers would be excluded .from those stages, and that the safefy. of the mails would be endangered by this exclusion; it being assumed by this argument that the travellers are to constitute a guard to the mails. To this seemingly strange and farfetched. argument, it might be sufficient to answer, as was done to the former, that no stipulation for the transportation of such a guard, (if by any violence to language ordinary casual wayfarers could be so dehominated,) is contained in the contract; and that the attempt thus to introduce any such stipulation or engraft it upon that contract, is a palpable and unwarrantable interpolation upon its terms and its objects. In the next place, the propounders of this argument may be challenged to show either the duty or the willingness of such travellers, to hake upon themselves the hazards, the trouble, or the responsibilities of guarding the United States mails. With equal cogency may those who thus reason be called upon to prove, that amongst tlie promiscuous multitudes who travel in stages, there may not be comprised those who roam the country with the viéw of committing depredations, and from yffiose designs, the safety of the mails may be most endangered.

Upon a full consideration of this case, I am brought to conclude, that the acts of. the legislature of Ohio, subsequent in date "to the 2d of March 183.1, and the proceedings of the. Board of Public Works of that statej founded upon those statutes, áre in violation of no principle or right guarantied by the -Constitution of the United States, nor of any acts, of .Congress passed in pursuance thereof; nor of any contract at any time existing between the state of Ohio and the federal government. I am farther of opinion, that the aforesaid laws of Ohio' were on the contrary designed, and are of a tendency, fairly and justly, to distribute the foils collectable within her limits, on the road in question, so as to make them properly' subservient to the view's of the federal government and of the governmént of Ohio, at the times of passing of the .state law of February 4th, T831, and the act of Congress of the 2d. of March,. 1831; and in conformity with the express language of those laws; and to prevent unwarrantable monopoly, and serious if not fatal detriment to the road. I think that the decision of the Supreme .Court.of Ohio, being a correct exposition - of the laws, designed to ■ effect these important objects; ought.therefore to ne affirmed.