Emmanuelle Regagnon

/ Olivier Barge

The city plan as an information system: the example of the Middle Islamic city of Qalhât (Oman)

Keywords: information system, archaeological survey, update, reliability, Qalhât

The approach used for the making of elevations at the archaeological site of Qalhât (Oman) with the help of a DGPS and aerial photos demonstrates the efficiency of the methods and also how the archaeologist should use resulting plans as an information system. The results produce a system which takes into account the heterogeneity and the gaps of information which are inherent in archaeological data.

In addition the qualification of the information obtained in the field produces a reliability map. While the geomatic tools offer flexibility for the composition of the cartography, they also offer the possibility of intuitive perspectives: they allow to capture archaeological reality of the town with the prospect of dissemination to a wider public, as well as a scientific approach.

Introduction

For ten years French archaeology has been developing the use of GIS tools, but they remain marginal.

Archaeologists are familiar with data sets (Joliveau, 2005), being obliged to save information that tends to disappear because of human activities or are destroyed by investigations themselves (excavations). Thus archaeologists have always been producers of maps and plans. There are several possible reasons for the reluctance to use GIS tools. Procedures for obtaining plans or maps have already been in existence for a long time, and were giving satisfaction. Moreover, common logic itself leads to produce detailed inventory maps, more than thematic maps. Thus automatic mapping capabilities of GIS have not been motivating their adoption. Similarly, ways of spatial analysis initiated by geographers, taken over by English and American archaeologists in the 1970s [START_REF] Clarke | Spatial Archaeology[END_REF][START_REF] Hodder | Spatial analysis in archaeology[END_REF] had only few echoes in France. Although there have been notable exceptions (Van der Leeuw et al., 2003), the potential of GIS for that purpose has not been fully understood. This statement must be moderated: since the early 2000s, the community of French archaeologists using GIS has been expanding. This movement was accompanied by the creation of exchange networks, like the ISA network (Spatial Information and Archaeology, http://isa.univ-tours.fr/), which helped archaeologists to meet and share experiences [START_REF] Barge | L'utilisation des systèmes d'information géographique appliquée à l'archéologie française[END_REF], Rodier , 2011).

On the site of Qalhât, our work was influenced by particular conditions, which led us to develop new methods.

Qalhât is one of the most famous cities of the Middle Islamic Period, located at the tip of the Arabian Peninsula in the Sultanate of Oman (Fig. 1). Extending over a surface of 35 hectares, the site is located at the foot of high mountains, in front of the Indian Ocean. In addition to these natural protections, it is surrounded by large fortifications, protecting the city and its port. A. Rougeulle opened several excavation fields, which brought answers to questions of chronology, material culture and trade networks. The building of a GIS was also one of the main objects of the project but the large size of the site and the difficulties of ruins interpretation forbid to use traditional methods of mapping for studying the urbanism network of Qalhât.

To map the city including topographic data and a drawing of each building, we used a composite method based on the use of aerial photographs and Differential GPS. Especially, the map was considered mainly as an Information System, structured in a GIS. The main principle was to gather raw data in the field, and from them to construct a model able to evolve according to the advances of research. Conceived in that way, the information system not only allows to generate several types of cartographic representations of the site, but also enables evaluation of the reliability of raw data and provide transparent interpretations.

Acquisition methods

A Differential GPS was used to determine the layout of visible structures. This was easy in sectors of low concentration. However, in the central quarters of the city, remains were too entangled, and looked just like huge humps of stones (Fig. 2). But often, what seems incomprehensible seen on the ground appears more clearly seen from the sky. For this reason a camera carried aloft by a kite was used, operating by remote control to take aerial pictures (Sanz, Barge, 2005). Markers were set on the ground, easily visible on pictures, for enabling georeferencing. Through photo-interpretation, we were able to outline visible buildings, although sometimes only roughly. In a second time we verified these determinations on the ground. In many cases, elements that were not linked on the ground appeared to be parts of similar structures when mapping with GPS (Fig. 3). This composite method enabled the city map to be completed step by step. In comparison with the use of a tachometer, that is traditionally employed, aerial photographs allow to progress from general network analysis to particular spacing identification. Then GPS allows a geographic representation of these interpreted remains. It has the advantage of being coupled with a field notebook where a description of each element can be recorded (for example the width of a wall and the size of its stones, Fig. 4). Indications that add to the reliability of the element and that can be mapped. The use of a field notebook allows the map to be instantaneously drawn in the field following the process of seeing and describing structures, a valuable aid that cancels the necessity of a preliminary sketch.

Moreover, traditional method of archaeological mapping saw the plan as a drawing. There was a single reading of the terrain, given as exact, and this reading was frozen in the result. Here instead, we generate a raw data set from which it is possible to create several interpretative maps leading to in a living information system.

Data structuration

On the field, with the GPS, walls and edges were recorded to enable delineation of buildings. Edges are suggested by indications such as a break in the slope or a change in the texture of the soil. These traces are not necessarily joined. A point "id_space" taken in the centre of the outlined space enables recording of the type of space and its height in relation with the whole building.

Besides, traces seen in the aerial photos, once validated, are assigned to a feature class, called "bld_pict".

Again, a point "id_space"in the center of each outlined space will be taken to record information about it. All these elements are assigned to a feature dataset called "raw data" (Fig. 5). These are crude field data, which will not be modified. They will be used to feed other feature classes called "spaces" which belong to a feature dataset called "model": the latter can evolve. It will enable the outline of polygons that are integrated with their attribute data of the identifier "id_space" (Fig. 6).

Several contiguous spaces form a building to which a number is assigned. Terraces are particular spaces that may be situated within a building (they are private) or outside a building, (where they are public). These terraces play a large part in city spaces; they often were built to adapt to natural relief. The adjoining of these polygons is perfectly respected in a topology (streets for example which are connected in a network).

Map and its reliability

The information system structured in this way enables production of a city map, first according to the canons of archaeological plan. But the functionalities of symbol tools also enable production of other representations: the type of spaces identified in the field, or the functions determined by the archaeologist (Fig. 8).

The information system also allows for an estimation of the reliability of the plan. We have seen that some areas are simple and clear, whereas others are complex and hardly read. We have also used different feature classes, which reflect a reality that is well known, that is sometimes only probable, or that is even sometimes only "possible".

There are two types of lines picked up with the GPS to define the buildings: walls and edges, the latter being less reliable.

There are also edges drawn on the basis of aerial photos, verified on the ground. For these, three levels of validity could be distinguished. In level 3, the geo-referencing of the photos is satisfactory and the traces are coherent with observation on the ground, giving a comparable reliability to that of "walls". In level 2, traces visible on aerial views are less easy to be read on the field. The level of reliability matches that of "edges". In level 1, traces could not be clearly verified, mainly because of the difficulty of reading the vestiges on the ground.

Thus from the point of view of reliability, a correspondence between the two types of lines ("walls" and "edges") can be established, with 3 levels of reliability (3, 2 and 1).

A regular grid measuring 20 m per cell is then applied to the map. In each square, the accumulated length of the three types of traces is calculated, and the percentage of each type in each square is established. This enables sorting of the squares: Those in which level 1 traces are predominant, Those in which level 2 traces are predominant, Those in which level 3 traces are predominant,

Those that contain only level 3 traces.

In this way a scale of increasing reliability based on 4 levels can be obtained and mapped (Fig. 7). The result corresponds well to the complexity of the terrain in that it can be understood intuitively.

This map enables the archaeologist to know the level of reliability he can attribute to the plan according to the sector being investigated.

Fig. 1 -

 1 Fig. 1 -General view of the site of Qalhât

Fig. 2 -

 2 Fig. 2 -Left: View from ground level of the city center. Right, aerial photography showing two kinds of building's organisation: on the left, with loose planning, on the right, densely built (city center).

Fig. 3 -

 3 Fig. 3 -Work on city center step by step: first, aerial kite view, geo-referenced. 2, with DGPS, street recording. 3, the visible structures on the picture are digitalized. 4 and 5: back on field, control points, validation or correction of each structure's map. 6: taking points "id_space" in each space delineated.

Fig. 4 -

 4 Fig.4-Field notebook on the Trimble DGPS: each entity is described inside a data dictionary before designated.

Fig. 5 -

 5 Fig. 5 -Data structuration: a first DDB contains exclusively the raw datas

Fig. 6 -

 6 Fig. 6 -Data structuration: the second DDB outcome from de field datas is an interpretation

Fig. 7 -

 7 Fig. 7 -Reliability of the raw datas

Acknowledgements

The Qalhât project is led under the authority of the Ministry of the Heritage and the Culture of the Sultanate of Oman, with material and financial supports from Oman, the French Ministry of Foreign and European Affairs and CNRS-UMR 8167. The cartographic study was realized with a sponsorship of the Total Group which we thank. We also thank our laboratory Archéorient (UMR-5133 CNRS). At last, we thank A. Rougeulle for her enthusiasm and her infallible precision and perception of the ruins of Qalhât.

Information system and its uses

The information system can also be used in other ways: without being a GIS specialist, the archaeologist can undertake an exploratory approach to the data by activating the display functions.

In this way, it is possible to develop the plan (Fig. 8). Interpretation also applies in the field. In this case, there is no longer recourse to the elements that led to the choices made; however, the attribute data recorded on the ground can be displayed when the recorded traces are doubtful (Fig. 9). In the same way, it is possible to modify or refine the plan, based on work carried out on a finer scale -excavation plans or plans of the buildings studied. The information system also enables proposition of 3D representations of the site. As we have roughly recorded on the ground, the relative height of each outlined space -0 for the open spaces, 1 for the spaces whose cover of collapsed debris indicate a closed structure, 2 when the collapsed debris reaches a height indicating the existence of several storeys -, this height can be expressed by extruding volumes based on polygons. Images of the site can thus be obtained, quite rough graphically, but enough for a not specialist to have an idea of the medieval city (Fig. 10, Fig. 11). Indeed, it is not easy for a visitor to see any representation based on a field of ruins. Those views propose a representation that agrees with the information system, and thus with the state of the research (Fig. 12). But these 3D representations go beyond being just useful for communication with the public. They can be used to back up scientific discussion, or even to stimulate constructive criticism; this enables understanding of the archaeological realities from an angle that is closer to intuitive perception. The hypothesis is that the 3D representations are perceived more rapidly and that they illustrate more concretely the urban plan reconstructed by the field work; thus they enable scientific discussion to be supported by evidence that is more easily perceptible, even dynamic, whereas the reading of a plan, even for an archaeologist, remains a technical approach and involves an abstract perception of the city. In this scientific framework, as many views as models may be proposed, scenarios may be built and hypotheses put forward.

It's the same way for the updates of the data according to the advance of the knowledge of the site. So, it is easy to integrate the new plans of excavations which sometimes modify determinedly the aspect of buildings such as they had been perceived the first time. These data are added in the raw data of ground, and allow the elaboration of new models. Thus the transparency of the elaboration of the new plan from the raw data is always preserved.

Conclusion:

The survey method followed in Qalhât presents several significant advantages for archaeology.

The first of these advantages is the implementation of smaller time frames, thus reducing the cost of prospections. For instance, here, five weeks were enough to cover the site and its surroundings (about 60 ha). Moreover, apart from the Differential GPS, it requires a very inexpensive hardware for its implementation.

The second is to offer a new approach to the survey methods traditionally used in archaeology, at almost any scale. The whole point is to design from the outset the plan as an Information System structured in a GIS. Thus, several city map can actually be built, but this approach leads to a living tool that opens up to other types of uses. According to us, the interpretation of raw data transparent, unlike the implicit production plans, constitutes a great advance scientifically speaking. Finally, the updating and refining knowledge can always be included in the database and are, for archaeologists, a valuable support for reflection and sharing the progress of their work.

The potential use of this information system can be evaluated in the long term. Indeed, besides being a tool to the archaeologist, it has a place in the development of the site: this is a complete map database, useful for example in terms of tourism development plan of the site, in direct connection with the Omani authorities. It can also be used to produce images for explanatory scientific popularization: thematic plans, views and even videos bridleways.


Jean-Charles Quinton

Laurent Goffart

Active Neural Field model of goal directed eye-movements

Introduction

For primates (including humans), interacting with objects of interest in the environment often involves their foveation, many of them not being static (e.g. other animals, relative motion due to self-induced movement). Eye movements allow the active and continuous sampling of local information, exploiting the graded precision of visual signals (e.g., types and distributions of photoreceptors). Foveating and tracking targets thus requires adapting to their motion.

Simulation Results (vs. experimental)

We here relied on a simplistic learning rule (the center of mass of the neural activity during the trial drives the adaptation of the projection eccentricity) and oculomotor commands (neural field to motor map). The computational model made it possible to replicate neurophysiological findings in presence of rapidly moving targets (Bourrelly et al., 2016).

This research has received funding from the French program "investissement d'avenir" managed by the National Research Agency (ANR), from the European Union (Auvergne European Regional Development Funds) and from the "Region Auvergne" in the framework of the IMobS3 LabEx (ANR-10-LABX-16-01), as well as from the LabEx PERSYVAL-Lab (ANR-11-LABX-0025-01).

Considering the delays involved in the transmission of retinal signals to the eye muscles, a purely reactive schema could not account for the smooth pursuit movements which maintain the target within the central visual field. Internal models have been posited to represent the future position of the target (for instance extrapolating from past observations), in order to compensate for these delays. Yet, adaptation of the sensorimotor and neural activity may be sufficient to synchronize with the movement of the target, converging to encoding its location here-and-now, without explicitly resorting to any frame of reference (Goffart et al., 2017).

Oculomotor muscles

Retinal projection

Committing to a distributed dynamical systems approach, we relied on a computational implementation of neural fields to model an adaptation mechanism sufficient to select, focus and track rapidly moving targets. By coupling the generation of eye-movements with dynamic neural field models and a simple learning rule, we demonstrated how different eyemovements and the synchronization with rapidly moving targets could be generated from a single dynamical system without explicit encoding of the target location (Quinton & Goffart, 2018). Qualitatively different behaviors corresponded to attractors (e.g., smooth pursuit as a fixed point attractor).

[ 1 ]

 1 Quinton, J-C. and Goffart, L. (2018) A unified neural field model of the dynamics of goal-directed eye movements. Connection Science, 30(1):20-52. [2] Goffart L, Bourrelly C & Quinet J. (2017) Synchronizing the tracking eye movements with the motion of a visual target: basic neural processes. Prog Brain Res 236:243-268. [3] Bourrelly, C., Quinet, J., Cavanagh, P., & Goffart, L. (2016). Learning the trajectory of a moving visual target and evolution of its tracking in the monkey. Journal of neurophysiology, 116(6), 2739-2751.

•

  Distributed neuro-inspired model • Catch-up saccades reduced and smooth pursuit velocity increased • No encoding of future locations of the target (here-and-now at best) • Neural projections not matching the target frame of reference


est destinée au dépôt

Influence of eye-movements on multisensory stimulus localization: experiments, models and robotics applications

  Mathieu Lefort, Jean-Charles Quinton, Simon Forest, Adrien Techer, Alan Chauvin, Marie Avillac To cite this version: Mathieu Lefort, Jean-Charles Quinton, Simon Forest, Adrien Techer, Alan Chauvin, et al.. Influence of eye-movements on multisensory stimulus localization: experiments, models and robotics applications. Grenoble Workshop on Models and Analysis of Eye Movements, Jun 2018, Grenoble, France. , pp.1. hal-01894621v2


Fluctuat… Ford

Madox Ford's Urban Psychogeography

Georges Letissier

The Latin verb fluctuat triggers a constellation of meanings relating to Ford Madox Ford in various ways. The metonymic association with sea-crossing immediately springs to mind and, with it, the silhouette of the author landing at Cherbourg on returning from New York to collect funds for the transatlantic review. Besides, the undulating movement of choppy seas emblematises the fate of the review, as documented by Bernard J. Poli, [START_REF] Bernard | Ford Madox Ford and the Transatlantic Review[END_REF] which encapsulates on a reduced scale and within a much shorter time span Ford's own destiny, marked by turns of fortune, alternations between periods of depressionprobably originating in low self-esteem -and moments of exhilaration entailed by the prospect of new literary ventures.

The harsh judgments of a highly respected father taunting his son by referring to him as 'the patient but extremely stupid donkey' 2 may at least partly account for the writer's suicidal impulses, when he conveyed his innermost emotions through the persona of a character who felt 'naked beneath the pitiless stars.' [START_REF] Ford | The Heart of the Country[END_REF] By contrast, when the time had come to launch the transatlantic review, the emotional low tide yielded to sheer enthusiasm when Ford became convinced that war destructiveness was about to be defeated by the energy of the collective, creative Zeitgeist:

All this clamorous life seemed to call for its organ.… […] It was not merely Paris that was alive to the Arts: it was the whole world. […] It was the real reaction from the war; the artist making the claim for glory as against the glory of the warrior. Mars was to be disgruntled. [START_REF] Ford | It Was the Nightingale[END_REF] Ford was writing from the crest of a wave of artistic creativity which he meant to encourage.

Fluctuat is of course the first word of the Paris motto inscribed on the city's coat of arms. Ford evinced a marked interest in cities' emblems as metonymic condensation for everything a city stood for at the sensorial and emotional level. Speaking about Avignon in Between St. Dennis and St. George, he alludes to the wind element as a fit symbol for the papal city:

The emblem indeed of the proud city of Avignon is a medieval head with wild hair blown straight back from the forehead and face, since Avignon is the city of the mistral. [START_REF] Ford | A Sketch of Three Civilisations[END_REF] Paradoxically for a landlocked city, Paris, or rather Lutetia, is associated with the water element since the blazon features a ship tossing on rough seas. This stems from the fact that it was the river Seine boatmen's corporation that had ruled the city's trade since Roman times. There is actually an analogical link between the image perennially attached to the city: fluctuare and the writer's own plight. This could be illustrated through an anecdote that is an allegory of the writer's predicament. In Joseph Conrad: A Personal Remembrance Ford relates how his close friend evoked the solitude of the man of letters:

You write and write, Conrad said, and no one understands, either what you're trying to say or how much blood and sweat you have put into the work. It's as if you had rowed about all your life in a huge river in dense fog. You row endlessly without ever seeing a signal light on the invisible banks to indicate whether you're going upstream or drifting with the current. [START_REF] Ford | A Personal Remembrance[END_REF] Writing is fluctuare, either floating with a set purpose or drifting.

Fluctuare may also express a particular way of subjectively responding to outer stimuli: lines, colours, movements impressing on the retina an image that is not fixed but vacillating. Much has been written on impressionism and it might be worth noting that metaphors of liquidity are often used to call up the specificities of a mode of perception blurring the demarcating lines between inner consciousness and outer phenomena:

In addition to the permutations of limited points of view, one of the primary characteristics of much impressionist work is that distinctions and boundaries between subject and object or between an object and another are fluid as an observer perceives an object in the context of a seamless flow of experience. [START_REF] Peters | Conrad and Impressionism[END_REF] From fluctuare to fluere (to flow) stretches the whole continuum between artistic experience and aesthetic reception.

Paris features little in Ford's novels, beyond passing allusions, such as to Tietjens's wedding in Paris, [START_REF] Ford | Some Do Not[END_REF] so it is necessary to turn to what some would call the author's lesser writings to see how the French capital is pictured. As a matter of fact, Ford does not endorse the traditional hierarchy between fiction as the highest expression of creative talent as opposed to the more pedestrian essay-writing and journalism: 'You should never say to a novelist that you prefer his "serious" writings to his fiction, though I find that such few novelist friends as I have always say that to me' ( IWN 25). No easy dichotomy can indeed be drawn between creative imagination and autobiography where Ford is concerned. A perfect illustration of this fluctuating perception tugged between the 'here and now' and the 'there and then', which has been tagged as 'time shifts' in the case of fiction-writing, is not difficult to find in It Was the Nightingale. It is hardly worth recalling, for a start, that the whole train of recollections is reassembled from a present affording a privileged vista over a sea which Ford favoured over all the others: 'I nearly always write in my dressing gown and slippers. I am doing it at this momentin a room that looks over the Mediterranean.…' (IWN 139). Thomas C. Moser shows how the view of the sea, however distant on the horizon, is liable to provide a form of relief to the agoraphobic Ford: 'no landscape is restful […] unless the horizon is somewhere broken into by the line of the sea'. 9 'Broken into' is the key expression given that the sea line is most likely to be undulating.

In Chapter One of It Was the Nightingale, it is from within this fluctuating frame that Ford reminisces a single event that soon divides itself up into a twin one. The binary rhetoric of the extract reflects the wave-like motion of a mental image that fails to stabilise into a distinct, well-fixed recollection. It all starts with a factual, seemingly objective remark: 'The last time I saw him was on the quai Malaquais' (IWN 19).

Ford remembers seeing the Anglo-Irish novelist George Moore loitering somewhere between the Pont des Arts and the Pont du Carrousel near the bookstall holders (les bouquinistes): 'before the old books, under the grey benches of the plane trees, above the grey Seine' (IWN 19). The precision of the remembrance, isolated from the stream of shifting memories, soon gives way to a nearly spectral vision: 'His pale eyes were unseeing in his paler face' (IWN 19). 'Pale eyes' is of course an odd combination so that the initial realism of the recollection is soon dispelled. Moreover, the pale/paler polyptoton seems to erase George Moore's image almost at the same moment as it calls it up, a fact which is borne out by the proximity between 'I saw' and 'his eyes were unseeing'. So the boundary line between the perceiving subject and the perceived object becomes flimsy since both are involved in an act of perception which finds itself denied just as it is mentioned. Indeed, it clearly transpires that Ford is in the process of losing track of this visual trace that keeps receding further and further. The pendulum movement of the wavering image is rendered through assonances: 'quai'/'Malaquais', and the near homophone 'seen'/'Seine'. The duality involved in the tension between presence and absence, through the waning recollection of a man on the brink of death, is redoubled by the allusion to another death superimposed on the former. Indeed Ford, from the peace and quiet of his Provence abode, is simultaneously recalling the very circumstances in which he had been apprised of another death, that of his friend John Galsworthy, from a newspaper headline. One death was to follow hard on the heels of another, as only the week before George Moore had passed away.

The whole passage is therefore caught up in a fluctuating movement between flashes of memory, summoning up two antithetical figures who were both to some extent Ford's tutelary literary figures. Memory does not fix itself on either one or the other but swings to and fro between one and the other and the text is, as it were, lexically and stylistically saturated by this mnemonic flux and reflux. To set the scene of this gloomy late January evening, Ford chooses to translate word for word the typically French expression 'between dog and wolf', meaning at nightfall, but no sooner are the words introduced than they take on another meaning, as if they were caught in a semantic vortex. [START_REF] Sara | s discussion of this phrase in her essay: 'Dowell and Dopamine: Information, Pleasure and Plot', in Ford Madox Ford's 'The Good Soldier[END_REF] Indeed, Galsworthy is the dog, metonymically because he owned a black spaniel, but also metaphorically on account of his obstinacy or doggedness. Moore, for his part, is the wolf, because he is as fast and lonesome as Galsworthy is painstaking and sociable. So, the sense of place is seminal for Ford and, in his mental recollection of this late wintry evening in a Parisian café, the printed letters on the newssheet announcing Galsworthy's demise soon shift on to the sea-like Kentish countryside which the writer of The Forsyte Saga had cherished: 'dull green hop-lands rolling away under the mists of the English North Downs' (IWN 18). And, eventually, in a see-saw, syntactic movement calling up the waves through hypotyposis, Moore and Galsworthy succeed each other in the ebb and flow of Ford's recollection: 'Sexagenarian greynesses [standing for the books Moore had beheld on the stalls from Quai Malaquais] as, when I saw the news of the other death, my eyes rested on thirty year old Kentish greennesses' (IWN 19). The chiasmic balance between the odd plural forms, greynesses/greennesses, points to the fusion between the two memories before they fragment into many colour shards as may be seen on a mottled sea.

Ford's impressionist vision of Paris is, as has been briefly suggested, emblematized by the first word inscribed on the city's device: fluctuat, which the prolific writer was subsequently to use, together with a sailing ship, as a crest for the transatlantic review in 1924. So the fates of the city and of the review that was born in it and could only have been born in it, because Paris was the capital of artistic creation, as Ford insisted, were jointly sealed:

The transatlantic review arose almost accidentally, though I have said that when I had been passing through Paris on my way to the Riviera an idea had passed through my mind. It was a vague sense rather than an idea.… It seemed to me that it would be a good thing if someone would start a centre for the more modern and youthful of the art movements with which in 1923 the city, like an immense seething cauldron, bubbled and overflowed. (IWN 248) This suggests the tight bond between on the one hand literature and art and, on the other, place, both being so closely bound up that Ford repeatedly expressed his experience of the city by using the very narrative tools that he had purportedly designed for his fiction, and conversely more often than not perceived the city through the lens of textual memory. So Ford's Paris, a hotbed of intense artistic creativity and the founding site of a review largely dedicated to literary productions in all its guises, is a textual palimpsest. In a number of different pieces, the writer worked out what amounts to an epistemological compromise between essay writing, autobiographical records and geography. Ford himself was perfectly conscious of the potential hybridity of his writings, when for instance in It Was the Nightingale he claims that he 'was not completely unaware of Paris's geography' (IWN 191). What he means through this statement is that he was alive to the feuds and conflicts of interest between rival reviews in the Parisian context: Mercure de France, Nouvelle Revue Française and all those who, like André Gide, had their own axes to grind. However, since only a few lines before, he had also evoked the hill Montparnasse through the lines of Livy or Cicero, this urban geography may also be construed as a treasure trove of textual gems: 'the slopes of Mount Parnassus, which is one of the Seven Hills of Paris' (IWN 181). In any case, this is the projection of a man's personal culture onto the Parisian urbanscape.

Even if the term psychogeography may seem slightly anachronistic when dealing with Ford, as is shown below, the very idea of intercrossing radically different approaches such as human geography and a phenomenological, subjective relation to a historicised space is perfectly in line with the author's versatile cast of mind. Indeed, some of the associations he claimed for himself might have appeared as maverick to some of his contemporaries. Didn't he praise the merits of part-writing, part market-gardening in It Was the Nightingale? In order to apprehend Ford's multifaceted take on Paris, this chapter will start with a brief review of the tenets of psychogeography before turning to Ford's diachronic outlook on Paris.

Ford and Psychogeography

Psychogeography is an intricate appellation that can be envisioned from either the French cultural background or the English one. Prior to applying the notion to Ford it is probably safe to set out the premises of this interdisciplinary field of study. The term 'psychogeography' derives from the Lettrist and Situationist internationals from the late 1950s and 1960s. The word originally had a certain anti-establishment ring to it which is of course sharply at odds with both Ford's Tory political leaning and his conversion to Roman Catholicism on 7 November 1892 (Moser 8). It emanates from the Parisian post-war neo-Marxist avant-garde and was glossed by Guy Debord, one of its champions, as 'the study of the precise laws and specific effects of the geographical environment, whether consciously organised or not, on the emotions and behaviour of individuals'. [START_REF] Debord | Introduction to a Critique of Urban Geography[END_REF] This idea of emotional response ties in harmoniously with Ford, unlike the political agenda that the French Situationists also hastened to propound in their eagerness to usher in radical transformations to the city environment. As Debord remarked: 'from any standpoint other than that of police control, Haussmann's Paris is a city built by an idiot, full of sound and fury, signifying nothing' (ICUG 6). In actual fact, Ford could not agree more, even if he did not go as far as to contemplate razing it to the ground and, admittedly, with the English writer the diatribe is less vitriolic than in the case of the Gallic philosopher. 'I detest the Quartier de l'Étoile […] I dislike all the boulevards built by Hausmann and his imitators' (IWN 232) asserted Ford, although he had no intention whatever to set forth new plans for a renewed urban programme.

On the other side of the Channel, psychogeography has already a fairly long history of its own, given that it emerged some ten years after its French counterpart and the least that can be said is that it is still very active right now. Will Self, the English novelist, has published for years now a column in The Independent, and in 2007, he released in book form a selection of these articles illustrated by the cartoonist Ralph Steadman. According to Self, psychogeography is linked to the physical activity of walking, in an age when the geographic contact with space has been somehow lost, due to an unprecedented proliferation of faster and faster means of communication. As Self explains, walking 'blows back the years, especially in urban contexts. The solitary walker is, himself, an insurgent against the contemporary world, an ambulatory time traveller'. [START_REF] Self | Will Self: On "Psychogeography" and the Places that Choose You[END_REF] Walking features prominently in Ford's exploration of Paris and needs to be investigated as lying somewhere between Benjaminesque ludic flânerie and the kind of spatio-temporal liberation induced by 'dérive' or 'drifting', as theorized by Debord. The close connection between geography and literature has been manifest ever since the term 'psychogeography' was first introduced in Britain. Indeed, it was used specifically in relation to London writers like Peter Ackroyd, Michael Moorcock or Ian Sinclair, who by excavating the city's hidden past and investigating its more cryptic aspects, cultivated a form of urban mysticism. Ackroyd quotes Ford's The Soul of London in his London: The Biography to underscore the tentacular presence of the London underground on the collective imaginary of true Londoners. [START_REF] Ackroyd | [END_REF] Even if the author of The Good Soldier lived a few decades before the inception of what became known as psychogeography, there is no doubt that he belongs in some way to a lineage of literary walkers, including among others Daniel Defoe, Thomas de Quincey or Arthur Machen. How might a typically Fordian take on Paris, bearing the mark of the writer's own idiosyncratic impressionism, derive from such perambulating, is an issue that needs exploring. Four points will now be considered in turn; first it will be shown that Ford's vision of the French capital is inflected by the passage of time, so that he may be regarded as an 'ambulatory time traveller' to take up Self's previous remark. Then Ford's Paris is perceived through a kaleidoscopic montage of other metropolises like New York and London, as will be argued in a second part. A third will focus more specifically on literary Paris whilst a few concluding remarks will be dedicated to the trope of the mirror with a view to initiating some reflections on Ford's urban aesthetics.

Plays on Temporal and Spatial Perspectives

Ford's preface to Jean Rhys's The Left Bank and Other Stories 14 is a long meandering text in which Paris is hardly the point; the crux of the matter is the writer's celebration of Rhys's innate instinct for form and her commitment to rendering passion in a context of darkness and degradation. For all the exceptional gifts which Ford recognises in this young, rather inexperienced writer, he nonetheless points to what could be a weakness in a less talented author: the total absence of a sense of place. In a delicate manner, he condones this negligence which is nothing compared to Rhys's talents but insists, however, on the fact that publishers and readers do expect topographical data. So the preface opens on a long, nearly incidental development on Paris which may be taken as an instance of urban pyschogeography.

The lineal, peripatetic journey anticipates what the French writer Julien Gracq does with the city of Nantes in The Shape of a City. [START_REF] Gracq | La forme d'une ville[END_REF] The expression 'the shape of a city', quoted in the book's epigraph, comes from Baudelaire's 'The Swan' and refers to Paris: 'The shape of a city, as we all know, changes more quickly than the mortal heart':

Comme je traversais le nouveau Carrousel. Le vieux Paris n'est plus (la forme d'une ville Change plus vite hélas! Que le coeur d'un mortel);

As I was crossing the new Carrousel.

-Old Paris is no more (cities renew, Quicker than human hearts, their changing spell). [START_REF] Baudelaire | Le cygne[END_REF] The English translation elides the nominal reference to 'the shape of a city', but without losing anything of the mood of nostalgia that is conjured up. This affective and temporal perspective is present in Ford's preface to Rhys's collection of short stories. The evocation is indeed anchored in the writer's biography and filiation, and is suffused with his own emotions and sentiments. There are at least three perceptible temporal strata: the first one corresponding to 1926, the time when the preface which is largely drawn from A Mirror to France was written; the second one which is steeped in childhood memories expressing mostly detestation for the Hausmannized Quartier de l'Étoile; and the third one delving deeper into a past that is merely touched upon. In the early nineties when Ford was barely twenty he used to visit a painter, a friend of his grandfather's, 'in the small village of studios that is next door to the Santé prison' (Reader 239), therefore in the vicinity of the Montparnasse area. The old artist had known the Latin Quarter in the days of Henry Murger, the author of Scenes of Bohemia which would be immortalized by Giaccomo Puccini's opera. This temporally distant Paris going back to the 1830s is only known to Ford by proxy, through stories whose actual contents are left tantalizingly pending. They nevertheless add their touch to the memory kaleidoscope of the Left Bank, which Ford as a boy recalled as projecting a yellow purplish haze.

Added to the time shifts, preventing any freezing of Paris in a stable, mental image, the second striking feature is the compartmentalization of space into discrete areas rendered through separated paragraphs and self-contained narrative units. The antithesis between the Left Bank and the Right Bank is brought to the fore. In the former 'no winds have ever entered' (Reader 238), while the latter is said to be 'stony and infested with winds' (Reader 236); the coldness of the stately stone buildings of the financier quarter stands in sharp contrast with the patina covering the walls in the less affluent Left Bank district. Yet, beyond the close attention paid to minute details in a way reminiscent of the Pre-Raphaelite painterly techniques, is Ford's skill in enlarging the perspective of his urban investigation, from locally confined observation to panoramic extension, from the anecdotal incident to the general rule of principle, and from deeply personal recollections to extrapolations of universal laws and so forth. Clearly, the dynamics of the whole preface which, despite the want of a plot, achieves some sort of suspense, stems from the unpredictable modification of stances adopted by Ford. To put it differently, the geography is shape-shifting and correlatively the mental image keeps changing.

The more pedestrian level, so to speak, is afforded by perambulating, a standard practice amongst psychogeographers. But, in a typically Fordian manner, walking is not concerned exclusively with the onward, linear progression of a single man recording his impressions along the way. It is confronted with an aporetic experience -aporetic in the etymological sense of an impassable passage -because, somehow, the walker is hampered in his progress, so the action of walking is not completed. There are two reasons to account for this: first because Ford has come to realize from the Left Bank 'how minutely little one can know even of one street thickly inhabited by human beings' (Reader 237-8). Secondly, a walk from the Île St-Louis to the Observatoire provides one with the odd sensation, frequent in dreams though, of exerting oneself to the utmost of one's capacity to no avail: 'the impression of long walks with the legs feeling as if you dragged each step out of sands …' (Reader 238). Strikingly enough, Ford, like Charles Dickens, evokes the of the desert to describe urban experience, Paris for the former and London for the Victorian novelist. The point of the parallel is radically different however. In Our Mutual Friend, the Holloway district is compared to 'a tract of Suburban Sahara' [START_REF] Dickens | Our Mutual Friend[END_REF] because drought and the all-contaminating dust from the production of tiles and bricks connote the spiritual emptiness which Modernists like T. S. Eliot saw as signs of an encroaching wasteland. Ford, for his part, sees the Left Bank as 'a vast, sandy desert, like the Sahara' (Reader 237), not to underline its barrenness or spiritual void, but to suggest the opposite: that, owing to the proximity of the Sorbonne and the Beaux Arts, 'it is the region of Pure Thought and the Arts' (Reader 237). What he intends to do probably is to hoist up the Left Bank to the unreal, or surreal level of unfathomable wonder. Hence, the choice of inflated rhetoric with the mounting crescendo conveyed by means of anaphora: 'like the Sahara … but immense. More immense than the world of Europe, more immense than even Australia, which Australians tell me is the largest continent of the world' (Reader 237).

Such elevation of a Parisian district to the magnitude of a whole continent is no mere literary fireworks though. Ford's purpose is to endow the Parisian Left Bank with a universal dimension. 'The Rive Gauche is French' (Reader 237), granted, but from this factual geographic given, Ford extrapolates a whole theory of Left Bankism, as it were, from 'the Left Bank -to the Left Banks of the world' (Reader 243). In other words, a specific Parisian district becomes paradigmatic of city areas all around the world, given over to unruled, creative pursuits, usually related to art. Ford, whose admiration for Rhys at that time was not purely intellectual, commends her attraction to the Left Banks the world over, by founding his argument on his immediate surroundings of a much beloved Parisian area with 'its gaols, its studios, its salons, its cafés, its criminals, its midinetteswith a bias of admiration for its midinettes and of sympathy for its law-breakers' (Reader 244). The description of the Paris Left Bank thus becomes an artistic manifesto surreptitiously denouncing a smug, bourgeois attitude towards creation: 'with its perennial bias towards satisfaction with things as they are' (Reader 244). To put it in a nutshell, Paris through its Left Bank comes to represent the epitome of what art should be about.

The cleft between the Left Bank and the Right Bank, which Ford compared to the Mappin Terraces, those artificial mounds erected in London Zoo to keep wild beasts at some safe distance from visitors, marks the unbridgeable gulf between internationalism and cosmopolitism. The Quartier de l'Étoile is plagued by the 'cosmopolitan-sordid, marble-begilded' 18 sort of veneer that threatens to reduce all the different cities in the world to a condition of lacklustre, nondescript sameness. Ford articulates what amounts to an ethical message on the new trend in urbanism. The message is all the more poignant as it originates in the city which he probably holds as the most unique. The onslaught against the Right Bank is indeed scathing as if it had somehow betrayed the ideal of a congenial lifestyle; the Hausmannized district of Paris is branded as 'never soft, […] never warm', worse still as 'incapable of mellowing like the wines they serve you in all the Hotels Splendides et des États-Unis of the Sleeping-car world […] incapable of supporting as the refrigerated meat that in those establishments you must eat' (Reader 236). This comospolitism is flavourless and stultifying and the harbinger of a bland global village. In sharp contrast, what marks off the Left Bank is its fruitful internationalism, summarized by the Latin phrase 'E Pluribus Multa', 19 which Ford uses as epigraph to the third section of It Was the Nightingale. The seething, clamouring and roaring Rive Gauche: 'Paris gyrated, seethed, clamoured, roared with the Arts' (IWN 259) then suggests an image of Paris as a crossroads of multiple cultural influences which Ford values highly.

Kaleidoscopic Montage

Ford is a nomadic writer, often on his way to somewhere else. This sense of itinerancy is reflected in his fiction writing. The Good Soldier for example captures something of this urgency when Dowell confesses his impatience at missing trains and deplores the fact that '[t]he Belgian State Railway has a trick of letting the French trains miss their connections at Brussels'. [START_REF] Ford | The Good Soldier[END_REF] Ford's representation of Paris is influenced by this constant habit of travelling. Paris is often on the way between two destinations: it is either time to drift through Provence northwards to Paris (IWN 225) or to get back to Paris before proceeding to Mr Belloc's county of Sussex (IWN 232). Even the idea for the transatlantic review seems to have sprung up almost by chance as Ford was only passing through Paris on his way to the Riviera. This image of transience and transitoriness to which Paris is invariably attached colours the vision of the French capital. Moreover, Paris is seldom perceived as isolated, but as caught in an interplay with images of London and New York, so that ultimately Ford propounds a kaleidoscopic montage of the modern metropolises of the twenties.

The First World War, or Armageddon, is a decisive chronological break in Ford's sense urban temporality, and this applies equally to Paris and London. In It Was the Nightingale the writer insists on the devastating consequences of the air raids on London: 'the baptism of fire' (IWN 82). Such tragic events are bound to leave scars and, through his mental trick of connections, Ford establishes a parallel between, on the one hand, the flippant, frivolous comportment of Parisians before the siege of 1870-71 and their grimness immediately after and up to 1914, and on the other hand, the sadness that prevailed in London in the war and post-war period: 'War-time England had been like a lunatic asylum' (IWN 54). When he was demobbed in 1919, Ford thus returned to a London that he felt he no longer belonged to: 'When I went to London after that it would never be "back to London"' (IWN 64). The city's motto: '"Domine dirige nos…."-"Lord guide us"' (IWN 64) hardly made sense in an alienating urban environment prolonged by sprawling, meaningless suburbs. What the first section of It Was the Nightingale records could be probably construed as post-traumatic stress disorder, not because the writer expresses his own fears as a result of the temporary memory loss that he suffered after fighting in the trenches, but on account of the very narrative structure harping obsessively on the decision to leave London once and for all. Indeed, the experience of losing one's bearings in one's own city of birth appears to be just as harrowing as the one of risking one's life day in day out on the front line.

What would be analysed as progression d'effet in fiction writing -'a narrative […] gathering momentum, as each word adds to the cumulative effect of the whole, and as each incident contributes to the inevitable outcome' [START_REF] Saunders | A Dual Life[END_REF] is used in It Was the Nightingale to probe a consciousness in the throes of working out a momentous decision: that of leaving London. The moment is first dramatized by the impossibility of fixing a date precisely: 'A few days lateror a few days beforefor I am hazy as to this chronology […] Just after that earthquake, I paused with one foot off the kerb at the corner of the Campden Hill waterworks' (IWN 15), then, some fifty pages later, the same obsession recurs with a tentative effort to situate the episode in time, as if to mark a definitive change in the novelist's relation to the city: 'It was in that way I should still have written of this city of my birth until I stood on that kerb in Campden Hill, say on the 1st March, 1919….' (IWN 64). Finally, some twenty pages after, the same allusion to the momentous episode is reintroduced: 'But on that Campden Hill kerb that day […] many things were opened to me' (IWN 84) followed shortly after by the so-called coup de canon, a double-barrelled one to boot: '…. This then was the last of England, the last of London….' (IWN 86) and '… At any rate I saw, standing on that Campden Hill kerb, that as far as London was concerned there was nothing to do but to get out or go under!' (IWN 88). The urban topography is paramount, the epiphanic moment coming as it does, precisely as Ford is standing on a kerb and about to proceed to cross the street. What should have been a quick, spontaneous action is protracted over nearly seventy pages. The same technique of progression d'effet correlated with urban topography, again involving street crossing, occurs when Ford fortuitously encounters his younger brother Oliver in, of all places, a road refuge on the Boulevard Saint Michel (IWN 248-9, 255, 259). The punctilious details of urban locale, superimposing London and Parisa kerb in London Campden Hill and a traffic refuge on the Boulevard Saint Michel -act as momentous triggers in Ford's psyche.

Paris, London and New York overlap in Ford's psychogeography, as if the writer himself were the perfect example of the homo duplex which he describes in the following terms: 'a poor fellow whose body is tied in one place, but whose mind and personality brood eternally over another distant locality' (IWN 197). Ford, indeed, sees New York through the lens of Paris, and Paris whilst roaming in London. London is constantly offered to exploration, as is clear from The Soul of London, whereas it is possible to keep a bird's eye view of Paris as it is neatly divided up in well-demarcated arrondissements. New York is not America because she is the negation of nationality and the expression of an ideal vaster and more humane than the country of George Washington as a whole could ever stand for. Conversely, Paris is infinitely more French than much of France (IWN 197). So, in his writings on Paris, Ford evinces this capacity for duplicate cerebration which Ford said the New York Times spotted in his novels and praised him for (IWN 143). Thus whilst reflecting that Paris frightens a little and that London saddens him immensely, Ford may find himself fancying that he is crossing Sheridan Square. This superimposition of coterminous urban experiences calls up an effect of intensification and entitles Ford to the status of modern expatriate.

Subterranean Work and Volcanic Eruption

Ford tends to idealise the natural propensity of the French to turn to literature, going as far as to speak of an unparalleled intimacy. It is especially striking that a whole chapter dedicated to the English novel should be headed 'Towards Flaubert'. [START_REF] Ford | The English Novel: From the Earliest Days to the Death of Joseph Conrad[END_REF] In establishing a distinction between the 'nuvvle' telling stories 'more or less rattling in which the characters were as sharply differentiated into sheep and goats' [START_REF] Ford | A Critical Study[END_REF] and the novel of aloofness with its Flaubertian pursuit of the mot juste, Ford tipped the scale in favour of the French style, to the detriment of Anglo-Saxondom. The fact that the English author's relation with Paris is closely linked with the destiny of a review, the transatlantic review, is evidenced by the common motto between the city and the twelvenumber publication. The context is crucial to understand the interrelationship between history, place and art. On the French literary scene, the early 1920s were characterized by impassioned Gallic feuds. In It Was the Nightingale Ford mentions Proust's demise in November 1922 as casting a pall of grief on the Parisian population. He somehow dramatizes the picture by claiming that the whole city was in mourning, that every taxi driver on being hailed by someone dressed in black would immediately take the darkly-attired person to the place where the great man, namely Marcel Proust, lay in state. Then Ford embarks on a panegyric of the French novelist, which is perhaps slightly over the top at this stage, as it was not before Proust's death that his works reached a comparative degree of fame. The lyrical flight warrants attention in its own right however, because it establishes an interesting parallel between psychogeography and literary reception. In a subtle way, Ford suggests that Proust may still not have enjoyed any large scale celebrity but that he is nevertheless a major literary figure, whom one has to reckon with. To convey this paradox, he places on a military pedestal the valetudinarian man of letters, who was not even drafted on account of his poor health, by calling him the 'Unknown Soldier of the literature of the decade' (IWN 179). The gist of the argument is to draw an analogy between the obscure, solitary task of the writer and the equally strenuous exertions of the anonymous French people who, unbeknownst to all, contributed to the victory over the Prussians. The terms used are 'subterranean' and 'subterraneously': the country had a sense of the subterranean and ignored strivings of that steadfast personality [Proust's] […] indeed, he had been the personification of the obscure beings who, working subterraneously with small spades in hidden tunnels, had saved France for the world. (IWN 179) Not only is the connection between pen and spade, which Ford as a gardener praises, clearly stated but literary fame is called up through geographic metaphors of mining and excavation and underground exploration. Incidentally, the spatial slant is worth noting in a writer who was liable to think literary history in terms of geo-cultural areas of influences by pointing to the 'Nordic-Mediterranean contest' in The March of Literature for instance. 24 To dramatise the French literary scene, framing the publication of the transatlantic review, Ford does not hesitate to evoke Proust's death simultaneously with Anatole France's, though a two-year gap actually separates the two: November 1922 and October 1924. [START_REF] Max | essay in this volume on Anatole France's importance to Ford[END_REF] The decision to create proximity between the two events is in keeping with Ford's dual turn of mind but it also serves to heighten historical tension: 'At the same time Paris was preparing the paroxysm of hatred that attended the hideously stage-managed last hours of Anatole France' (IWN 178). The enforced parallel both sets up the volatile context and adumbrates the destiny of the transatlantic review that was fated to be tugged apart between the young and the so-called conservatives. In his study, Bernard J. Poli points out that Ford was to be accused of holding a reactionary position in the highly polemical context of Anatole France's death (Poli 127). In fact, it is astonishing to realize how dependent on the French (that is, to a large extent, the Parisian) cultural context the destiny of the review proved to be. Even if lack of funding eventually tolled the knell for the publication, the rift between a younger generation of French intellectuals close to the Surrealists and a former generation willing to preserve the legacy of highly respected figures percolated through the Anglo-French American review. It all culminated with the publication of Le Cadavre (not the exquisite cadaver) but the rotten corpse, a deliberately provocative and most outrageous firebrand, which sent shock waves through French public opinion. When obituary columns in newspapers, ranging from the right-wing Le Figaro to the left-wing L'Humanité, unanimously extolled the memory of Anatole France, a collective manifesto signed jointly by all the members of the surrealist group, among whom were Paul Éluard and Philippe Soupault, who had both collaborated to the transatlantic review, drew an obnoxious portrait of Anatole France, posthumously accusing him of having been no more nor less than a fraud. It started with the blunt assertion that France was a plain, ordinary man, before charges of scepticism, irony and even cowardice were levelled at him. It was wondered whether there might not be a link to be found between 'France', the patronym, and vestigial traces of conservatism that sometimes passed for the 'French' spirit. André Breton provokingly issued a refusal to grant a proper burial certificate and went on by rejoicing over the fact the year 1924 had seen Loti, Barrès and France die, respectively the moron, the traitor and the cop. And to top it all, Breton brazenly asked the question: have ever slapped a dead man's face?

All these events are reported in It Was the Nightingale, but in A Mirror to France published in 1926, Ford had already written about this spate of incidents which is symptomatic of a country whose cultural life, centred as it is on one single metropolis, happens to be riven by aesthetic and political differences. Some of the vitriolic power of the Surrealists' devastating attack is palpable through Ford's words: Anatole France, going to his grave with Republican honours, was to the Young a hideous figure; the honours bestowed upon him a menace for the world. He stood for scepticism such as was born in tranquil and be-statued gardens a little before the French Revolution; but he stood also for laziness, for indifference, for, even, wealth! [….] He represented a school of French thought that we, the outside world, consider to stand for France, but that is now, if not gone for ever, at any rate submerged beneath desperate waves. (MF 97-8)

Gallia mergitur, Anatole France's death was the pretext to engulf a certain France. Under these circumstances, Ford could only steer a conciliatory course by praising the lionized author of the Third Republic who was now mercilessly reviled. He indeed praised the late writer's stylistic merits but without antagonising the talented, albeit pressing, members of the young, who made no secret of their attraction to the iconoclasm of the nascent Surrealist movement (Poli 123). Indeed, the absence of any outstanding literary figures on the French literary scene left room for creative impulses, unhindered by towering tutelary authors: 'The level of literature and the Arts is in France always amazingly high, though from time to time there will be no great outstanding figure. That was the case in the days of the transatlantic review' (IWN 315). Unfortunately it was already too late for the transatlantic review: '"Nec mergitur"-"and it does not sink." … It was not to be' (IWN 237).

Loose, Slippery Geographies: Mirroring and Space Shifting

The trope of the mirror is seminal in Ford's writings and provides an objective correlative to the subtly nuanced theory of impressionism. In this sense, the mirror would be to Ford what the window is to Henry James in the House of Fiction. 26 The first pages of A Mirror to France set out the premises of what Ford defines as 'the purest, the most will-less impressionism' (MF 18) in his rendering of France, and by the same token of Paris. By endorsing the function of a mirror, the writer first bestows encomiums on a country, this is the meaning of 'Mirror to rather than of France' (MF 7). He also allows for the many variations and sometimes major differences that mirrors of all shapes and conditions may reflect. In other words, the same geographic reality can be projected with significant alterations according to the state of the mirror. Specular reflections proffer different images of the same, seemingly objective outer data. Ford then proposes to efface himself, to get back into his box, as he puts it humorously, whilst adding that this authorial absence will by no means entail a stable, transitive and utterly objectified counterpart for the real. Indeed, the surrender of the author's willpower to the mirror is bound to bring to the fore the sheer diversity and ever fluctuating shapes of reflected images apparently taking a life of their own on a looking glass 'as will-less, really as any rolled surface of quicksilver, as true and no doubt, as misleading' (MF 9). This is the quicksilver, in other words the fickle and wavering, image of Paris which the eponymous mirror reflects.

Shifting mirroring effects first result from the reintroduction of nearly the same text, with minor inflections, from one work to another. Thus the wreaths of immortelles laid at the foot of the Statue of Strasbourg on the square of the Concorde are first evoked in Between St. Dennis and St. George, published by Hodder and Stoughton in 1915 to reappear in the introductory section of A Mirror to France in 1926, which incidentally also bears the title "Between St Dennis and St George". [START_REF]Alexandra Becquet whose erudition on Ford has been an invaluable help[END_REF] From the version written in war time to its post-war revision the mirrored image undergoes variations. Likewise the Left Bank preface to Rhys's collection of short stories in 1927 is not strictly identical with the chapter bearing the same title in A Mirror to France; the former is meant to be read as part of a literary essay paying homage to a young, promising novelist and the latter as an ethno-methodological inquiry probing into the unwritten codes that pertain in social relationships, here with the French.

As L. L. Farrar Jr. convincingly argues, although Between St. Dennis and St. George may be seen plainly as a piece of wartime propaganda it nevertheless 'take[s] us to the origins of [Ford's] fiction and seem[s] to support the contention that the artist reveals himself in his lesser as in his greater works'. [START_REF] Farrar | The Artist as Propagandist[END_REF] In his reflection on Germany, France and England, Ford does not merely gather up documentation; his remarks are of course founded on historical sources -Quellen; but it is through the writer's individual mental camera that the psychology of each individual country is reconstructed. Thus, collating two versions of Ford's childhood memories of the wreaths of immortelles ends up producing the same effect as the plates of composite photographs. The 1915 text is overly praising French military efforts and evincing confidence in the possibility of winning over the enemy: 'The most militant concrete phenomenon that has ever moved me in France was the brown, faded and rustling wreaths of immortelles […] There are of course, other atmospheres of other militarisms that one may recapture from place to place all over France' (BSDSG 19). The 1926 version is, to all intents and purposes, imbued with a lingering sense of nostalgia:

Before that the most concrete military phenomenon that ever moved me in France for actual warfare had in it so little of the military and the pompous!was the brown, fading and rustling wreaths of immortelles crepitating in the chilly winds round the statue of Strasbourg in the Place de la Concorde [….] There are of course other atmospheres of other militarisms that the boyish mind could recapture from place to place all over France to-day even. (MF 22) The truth of the impression has to be negotiated in the shift between two reflections held by two temporally distant mirrors. It lies in the gap between the child's perceiving eye and the adult's mind's eye. The persistent image fixed on the retina is that of the well-named immortelle, as if the colour imprint had not faded long after the flower had wilted. But the pictorial image fixe, by punning on idée fixe, is framed in a totally different mindset in the piece of propaganda and in the travel essay. So, eventually what remains is a mental picture of Paris which is submitted to mood swings. The 'bluish and […] silvery pinpricks' (MF 8), which Ford mentions on the surface of a looking glass as potentially interfering with the reflected image would be here the state of mind of the author, passively recording: 'will-less […] as any rolled surface of quicksilver' (MF 9), however from within the frame of a subjectively inflected mindscape.

The mercurial picture of Paris that emerges from Ford's oeuvre is therefore the result of successive reappraisals and revisions on the author's part. There are, to quote another example, marked variations between 'Rive Gauche' and 'The Left Bank Again', two successive chapters from A Mirror to France, both evidently referring to the same quarter but through a different lens. The first one is permeated by the flavour of bohemianism, conjured up through the list of names of callings and trades, sometimes in French like the section's chapter. Within roughly a square mile there may be found the buzz of friendly conversations in a tight-knit community living on the margin of the impersonal Right Bank, and possibly of modern economy, as in a rural village. In this respect, the Rive Gauche may be seen as epitomizing all that is identified as typically French:

For you get here, concentrated, the efficiency, the personal dignity, the regard for the métier, the seriousness, the frugality and the terre à terre, cheerful, usable philosophy that account for the fact that only in France can a Paris of the Other side be a very extended affair. (MF 69) In this area the gulf between the poor and the less poor is somehow unacknowledged and the only potential source of misunderstanding is linguistic, such as when a French person proficient in English translates 'good enough' by 'shabby genteel', a gross misapprehension as Ford subsequently argues at some length (MF 81-2). The second part of the diptych dedicated to the Left Bank in A Mirror to France is dystopian in sharp contrast with the first. The possibility that there might some bitterness in Ford's return to a much beloved place, crystallising all that he had idealized previously, cannot be dismissed totally; there is the mark of this world weariness or Weltschmerz expressed in the adverb again: 'The Left Bank Again'.

Still in the revised version is there the same admiration for the French people's passion for art and culture, for what was designated as 'the region of Pure Thought and of the Arts!' (MF 63) in the previous twin chapter. Yet a prevailing mood of doom and gloom has set in. Now the booksellers' rows on the bank of the Seine look morbid as if thought were wrapped up in a shroud in a bibliophilic grave (MF 92). The writer's judgments have now become harsh, and the 'Jeunes', who had been treated with a certain paternal understanding before, now take the flak from his criticism: there is no strong current amongst the French young of to-day and, were I to have to put a name to any French movement that at all predominated amongst the Jeunes of the Latin Quarter, I just could not […] I can perceive no general direction in it all. (MF 96 -7) Even Montparnasse is shown to have lost its former convivial atmosphere and the warmth, and celebratory ambience that once reigned, has given way to 'inexpressive saturnalia with an ever present undercurrent of hatred' (MF 108). Worse still, in his diagnosis of what has become of Montparnasse, Ford is led to register all the early symptoms of the plague of modern tourism, including the foreigners' quest for the cheapest, loose morals while abroad, and the dishonesty of waiters always ready to swindle and of tight-fisted hotelkeepers always on the look-out for easy preys. The genuine sense of internationalism that had been the hallmark of the quarter has been replaced by clannish groups of foreigners teaming up according to their nationality. In this Babel of modern times, foreigners are looked down on by the local denizens: 'We are the invaders' (MF 109). And, as is almost invariably the case, some make themselves heard more than others: 'You have cafés full of Swedes, Finns, Letts, Danes, Polish and Russian refugees, amidst whom the Americans make so much noise that you would imagine the whole population came from New York or the Middle West' (MF 107). So much for cultural diversity! In this general linguistic rivalry, the selfwithdrawing British cut a pitiful figure: 'the numerically preponderant English are so nationally glum and taciturn that you would think there were none there' (MF 107).

Conclusion

Ford's psychogeography is coloured with his impressionism: it is steeped in a subjective vision oscillating between changing frames of mind. In a self-penetrating assessment of his skills, the author finds the very words to account for this deeply personal stance: 'For, though my heart, I assure you, is in the right place, alas, my geography is the weakest part about me, and without maps I have not the remotest idea where any […] places are' (MF 86). It may sound like a paradox that a novelist giving such insightful descriptions of the places he travelled to and valuing the sense of place as crucial to artistic production should have expressed such low self-esteem about his skills as a geographer. But of course what Ford had in mind was a scientific approach to geography of the type that may be found in ordnance survey maps. What he could offer instead is an alternative mapping of the type which is propounded by those who promote psychogeography as another means of relating to space. The thing is that, with or without maps, Ford succeeded in projecting his own, subjective geography on Paris. The Left Bank in this idiosyncratic reconstruction of territorial limits marks the ultimate Northern


Active Multisensory Perception and LearnIng For InteractivE Robots

Mathieu Lefort 1 , Jean-Charles Quinton 2 , Marie Avillac 3 and Adrien Techer 1,3 Abstract-The AMPLIFIER (Active Multisensory Perception and LearnIng For InteractivE Robots) project (2018-2022) will study how multisensory fusion and active perception can influence each other during the developmental sensorimotor loop of an autonomous agent. Psychophysics experiments will provide insights on how active perception may influence multisensory fusion in human. Using neural fields, a multiscale computational neuroscience paradigm, we want to model the behavioral observations in order to transfer and to extend the extracted functional properties to social robots. Especially, we target to provide more natural interactions with humans by allowing the robot to have a better understanding and more appropriate contextual reactions to its environment.

I. CONTEXT AND OBJECTIVES OF THE PROJECT

An embodied agent senses its environment and the consequences of its performed actions through various channels.

They provides many kinds of information related to different perceptual dimensions and environmental conditions to the agent. Thus, to obtain a consistent perception of its surrounding world, the agent has to merge these data. This multimodal merging plays a key role in human perception by improving for instance reaction times, detection thresholds or the learning of stimuli (see [START_REF] Welch | Handbook of perception and human performance[END_REF] for a review). Some sensors may intrinsically have a better performance at some tasks (e.g. a camera has a higher spatial resolution than a microphone). However, the relevance of each sensor in the perception also depends on the current stimuli (a blurred visual stimulus may in some cases be less precise than an auditory localization). So, to generate a multisensory perception, the agent has to solve autonomously two intertwined problems:

• Identification: what stimuli are related to the same environmental event?

• Fusion: what is the relevance of each of these stimuli in this event perception? The identification problem is related to the detection and learning of previously encountered spatio-temporal cooccurrences. Perception may even be defined as experiencing sensori-motor contingencies [START_REF] O'regan | A sensorimotor account of vision and visual consciousness[END_REF]. Piaget, by studying the assimilation-accommodation process (i.e. adapting the perception to the environment model while adapting the *This project is funded by the Auvergne Rhône-Alpes Region. name.surname@univ-lyon1.fr model to the stimuli) during infant's development, showed that sensori-motor behavioral abilities are appearing in some incremental way [START_REF] Piaget | La naissance de l'intelligence chez l'enfant[END_REF]. More precisely on the multimodal identification ability, it seems to quickly appear during the development, as also observed at the neuronal level [START_REF] Wallace | Development of multisensory neurons and multisensory integration in cat superior colliculus[END_REF]. In machine learning, the study of multisensory representation learning is currently an emerging active field, mainly focusing on image matching with written or oral word/sentence (see [START_REF] Zheng | Methodologies for cross-domain data fusion: An overview[END_REF] for a review).

Concerning the fusion problem, some psychophysics experiments showed that humans are able to fuse information in a Bayes optimal way [START_REF] Ernst | Humans integrate visual and haptic information in a statistically optimal fashion[END_REF]. This means that the weight of each modality is proportional to its precision, i.e. the inverse of its perceived variance. This Bayesian behavioral model can also be extended in a hierarchical architecture to take into account the identification of the relevant modalities [START_REF] Körding | Causal inference in multisensory perception[END_REF]. However, little is known on how an agent can autonomously weight the modality in the perception. It seems that this weighting is updated online by getting more information from the environment, as it decreases progressively when no more cue is provided, similarly to a Kalman filter [START_REF] Smeets | Sensory integration does not lead to sensory calibration[END_REF].

Sensori-motor theories [START_REF] Mossio | Action-dependent perceptual invariants: From ecological to sensorimotor approaches[END_REF], which are based on evidences from neuroscience, psychophysics and philosophy, claim that acting plays an important role in this process. This was studied through active perception and predictive coding, yet mainly in monomodal contexts. For instance, saccades can be used to more accurately locate targets [START_REF] Ko | Microsaccades precisely relocate gaze in a high visual acuity task[END_REF], with fixations bringing targets in the foveal region of the retina, thus refining the sampled information. Friston develops these ideas in a probabilistic implementation of predictive coding [START_REF] Friston | Action understanding and active inference[END_REF] that relies on the free energy principle, which is tightly connected to surprise minimization. This minimization can be achieved by adapting the model (adjusting predictions) or by acting to change the situation (consequently adjusting the stimulation).

Based on this body of evidences, we want to study in this project whether and how active perception plays a role in the multisensory fusion and reciprocally how multiple modalities can improve the selection of action, e.g. related with perceptual attention.

II. CONTENTS OF THE PROJECT A. Psychophysics experimental protocol

Our experiments are based on the setup used to test the ventriloquist effect [START_REF] Alais | The ventriloquist effect results from nearoptimal bimodal integration[END_REF], where human participants must locate stimuli defined by audio and visual information, whose spatial localization can be either congruent or incongruent. The paradigm allows to test the weighting of modalities in the localization process. To study the influence of active perception on multisensory fusion, we will test whether the ventriloquist effect is moderated by the active perception capabilities of the participant. Operationally, we will compare two experimental conditions, one where saccadic movements are permitted, and one where they are not (relying on eyetracking techniques). While manipulating the spatial discrepancy between the modalities and other independent variables qualifying the stimuli (e.g., eccenticity, presentation time), we will measure their influence on the visual-auditory interactions. Dependent variables include the explicit location reported by the participant (e.g. by pointing), the location of the visual stimulus on the retina (post-saccade) and the detection threshold. Depending on the obtained results, this experience will be extended to a developmental perspective, by comparing results on various age populations, and to other modalities, especially visio-tactile integration.

B. Computational neuroscience modeling

The neural field paradigm [START_REF] Amari | Dynamics of pattern formation in lateral-inhibition type neural fields[END_REF] is based on a neuronal modeling with a mean field approach while also explaining some saccadic phenomenons at a behavioral scale [START_REF] Quinton | A unified neural field model of the dynamics of goal-directed eye movements[END_REF]. By providing decentralized spatial competition/fusion, it can be combined with the learning of topologically aligned multisensory representations to obtain identification of relevant modalities in perception [START_REF] Lefort | Somma: Cortically inspired paradigms for multimodal processing[END_REF]. We want to extend this last architecture by introducing fusion capabilities in neural fields.

In the superior colliculus, a multisensory subcortical structure related to saccadic movement, visual representations rely on a log-polar encoding with a magnified central area [START_REF] Taouali | A parsimonious computational model of visual target position encoding in the superior colliculus[END_REF]. Thus, central visual stimuli should induce wider neuronal activation than peripheral ones, that should lead to a higher influence of this stimulus in the neural field. Then, following a saccade bringing the target in the central visual field, the visual stimulation should have an higher influence in the multisensory perception. This dynamics will be modeled and tested against the collected psychophysics data.

C. Social robots interactions

Grounding on previous data and models, we will apply our approach to multimodal perception in a social robotics context 1 . When a robot interacts with humans in a crowded environment, it must be able to precisely locate persons and objects based on several cues (e.g. voice or sound, shape or movement). To succeed in correctly interacting with humans for extended periods of time while sticking to predefined scenarios, the robot must keep the attention of the individuals while reaching specific configurations, themselves usually defined by a multisensory conjunction of features.

For this purpose, we will combine multimodal integration with a form of predictive coding. Neural field models can indeed encode predictions, at both the continuous sensorimotor level [START_REF] Quinton | A unified neural field model of the dynamics of goal-directed eye movements[END_REF] and the more abstract discrete level [START_REF] Sandamirskaya | An embodied account of serial order: How instabilities drive sequence generation[END_REF]. Additional flexibility can be added by dynamically chaining predictions (i.e. performing inference in a continuous or discrete space), for instance relying on a D* algorithm [START_REF] Quinton | Multilevel planning and control for robotic manipulation[END_REF]. Predictive multimodal primitives will thus be combined 1 in collaboration with Hoomano (hoomano.com) to generate more complex behaviors, and the system will simultaneously adjust primitives parameters and select action to minimize prediction error and uncertainty [START_REF] Friston | Action understanding and active inference[END_REF]. In a later step, to learn these primitives in an unsupervised way, we will adopt a constructivist and developmental approach, abstracting from the flow of sensorimotor signals and building on earlier results [START_REF] Lefort | Multimodal space representation driven by self-evaluation of predictability[END_REF], [START_REF] Mazac | On bootstrapping sensorimotor patterns for a constructivist learning system in continuous environments[END_REF].

1 LIRIS,

 1 SMA team, CNRS UMR 5205, Claude Bernard Lyon 1 University, Lyon University, F-69000, LYON, France name.surname@univ-lyon1.fr 2 Laboratoire Jean Kuntzmann, ProbaStat / SVH team, CNRS UMR 5224, Université Grenoble Alpes, F-38401, GRENOBLE, France quintonj@univ-grenoble-alpes.fr 3 Lyon Neuroscience Research Center, Brain Dynamics and Cognition Team, INSERM UMRS 1028, CNRS UMR 5292, Claude Bernard Lyon 1 University, Lyon University, F-69000, LYON, France

ACKNOWLEDGMENT

The authors want to thank the CNRS' Interdisciplinary Mission which funded the APF 2 (Active Perception For Autonomous Predictive Fusion) project that bootstraps the AMPLIFIER one by implementing the preliminary studies.