text:
Black Tom explosion

The Black Tom explosion was an act of sabotage by agents of the German Empire, to destroy U.S.-made munitions that were to be supplied to the Allies in World War I. The explosions occurred on July 30, 1916, in New York Harbor, killing as many as 7 people and wounding hundreds more. It also caused damage of military goods worth some $20,000,000 ($0 million in 2024 dollars). This incident, which happened prior to U.S. entry into World War I, also damaged the Statue of Liberty. It was one of the largest artificial non-nuclear explosions in history.

Black Tom Island
The term "Black Tom" originally referred to an island in New York Harbor next to Liberty Island, named for a "dark-skinned" fisherman who inhabited the island for many years. The island was artificial, created by land fill around a rock of the same name, which had been a local hazard to navigation. Being largely built up from city refuse, it developed a reputation as an unseemly environmental hazard. The island was the site of two different explosions. The first occurred on January 26, 1875, when an accidental explosion in a powder factory killed four people. The more famous and deadly explosion occurred on July 30, 1916. By 1880, the island was transformed into a 25 acre promontory, and a causeway and railroad had been built to connect it with the mainland to use as a shipping depot. Between 1905 and 1916, the Lehigh Valley Railroad, which owned the island and causeway, expanded the island with land fill, and the entire area was annexed by Jersey City. A 1 mi-long pier on the island housed a depot and warehouses for the National Dock and Storage Company. Black Tom Island is now part of Liberty State Park.

Black Tom was a major munitions depot for the northeastern United States. Until April 6, 1917, the United States was neutral in respect to World War I and its munitions companies earlier in the war could sell to any buyer. Due to the blockade of Germany by the Royal Navy, however, only the Allied Governments were able to purchase American munitions. As a result, Imperial Germany sent spies to the United States to disrupt by any means necessary the production and delivery of war munitions that were intended to kill German soldiers on the battlefields of the Great War.

Explosion
On the night of the Black Tom explosion, July 30, 1916, about 2000000 lb of small arms and artillery ammunition were stored at the depot in freight cars and on barges, including 100000 lb of TNT on Johnson Barge No. 17. All were waiting to be shipped to Russia. Jersey City's Commissioner of Public Safety, Frank Hague, later said he had been told the barge was "tied up at Black Tom to avoid a twenty-five dollar charge".

After midnight, a series of small fires were discovered on the pier. Some guards fled, fearing an explosion. Others attempted to fight the fires and eventually called the Jersey City Fire Department. At 2:08 am, the first and largest of the explosions took place, the second and smaller explosion occurring around 2:40 am. A notable location for one of the first major explosions was around the Johnson Barge No. 17, which contained 50 tons of TNT and 417 cases of detonating fuses. The explosion created a detonation wave that traveled at 24000 ft/s with enough force to lift firefighters out of their boots and into the air.

Fragments from the explosion traveled long distances: some lodged in the Statue of Liberty, and other fragments lodged in the clock tower of The Jersey Journal building in Journal Square more than 1 mi away, stopping the clock at 2:12 am. The explosion was the equivalent of an earthquake measuring between 5.0 and 5.5 on the Richter scale and was felt as far away as Philadelphia. Windows were broken as far as 25 mi away, including thousands in Lower Manhattan. Some window panes in Times Square were shattered. The stained glass windows in St. Patrick's Church were destroyed. The outer wall of Jersey City's City Hall was cracked and the Brooklyn Bridge was shaken. People as far away as Maryland were awakened by what they thought was an earthquake.

Property damage from the attack was estimated at US$20000000 1916. On the island, the explosion destroyed more than one hundred railroad cars, thirteen warehouses, and left a 375 by crater at the source of the explosion. The damage to the Statue of Liberty was estimated to be US$100000 1916, and included damage to the skirt and torch.

There were several reported fatalities in the explosion: the barge captain, Jersey City Police Department officer James F. Doherty, Lehigh Valley Railroad chief of police Joseph Leyden, and ten-week-old infant Arthur Tosson. One contemporary newspaper report estimated as many as seven deaths in the attack. Immigrants being processed at Ellis Island had to be evacuated to Lower Manhattan.

Investigation
Soon after the explosion, two watchmen who had lit smudge pots to keep away mosquitoes were questioned by police but the police soon determined that the smudge pots had not caused the fire and that the blast had likely been an accident. President Wilson remarked of the incident that it was "a regrettable incident at a private railroad terminal", and Edgar E. Clark of the Interstate Commerce Commission was dispatched to investigate.

Soon afterward, a Slovak immigrant named Michael Kristoff was suspected, Kristoff would later serve in the United States Army in World War I, but admitted to working for German agents (transporting suitcases) in 1915 and 1916 while the U.S. was still neutral. According to Kristoff, two of the guards at Black Tom were German agents.

It is likely that the bombing involved some of the techniques developed by German agents working for Ambassador Count Johann Heinrich von Bernstorff, who acted covertly as a spymaster while using German Foreign Office cover, and Captain Franz von Rintelen of the intelligence wing of the German Imperial Navy, using the cigar bombs developed by Dr. Walter Scheele. Von Rintelen used many resources at his disposal, including a large amount of money. Von Rintelen used these resources to make generous cash bribes, one of which was notably given to Michael Kristoff in exchange for access to the pier. German intelligence operatives Kurt Jahnke and Lothar Witzke were then suspected, and are still judged as responsible legally. It is also believed that Michael Kristoff, a 23-year-old Austrian immigrant who had served in the U.S. Army, was responsible for planting and initiating the incendiary devices that caused the explosions.

Additional investigation by the Directorate of Naval Intelligence also found links to some members of the Irish republican Clan na Gael organization and far-left organizations. Irish socialist and labour union leader James Larkin asserted that he had not participated with sabotage, but admitted to having encouraged work stoppages and strike actions in munitions factories, in an affidavit to McCloy in 1934.

The United States did not have an established national intelligence service, other than diplomats and a few military and naval attaches, making the investigation difficult. Without a formal intelligence service, the United States only had rudimentary communications security and no federal laws forbidding espionage or sabotage except during wartime, making the associations with the saboteurs and accomplices almost impossible to track.

Aftermath
This attack was one of many during the German sabotage campaign against the neutral United States, and it is notable for its contribution to the shift of public opinion against Germany, which eventually resulted in American approval for participating with World War I.

The Russian government sued the Lehigh Valley Railroad Company operating the Black Tom Terminal on grounds that lax security (there was no entrance gate; the territory was unlit) permitted the loss of their ammunition and argued that due to the failure to deliver them the manufacturer was obliged by the contract to replace them.

After the war, the Lehigh Valley Railroad, advised by John J. McCloy, sought damages against Germany by the Treaty of Berlin from the German-American Mixed Claims Commission. The Mixed Claims Commission declared in 1939 that Imperial Germany had been responsible and awarded $50 million (the largest claim) in damages, which Nazi Germany refused to pay. The issue was finally settled in 1953 for $95 million (interest included) with the Federal Republic of Germany. The final payment was made in 1979.

The Statue of Liberty's torch was closed to the public after the explosion, due to structural damage. Access was not opened even after the 1984–1986 restoration which included repairs to the arm and installation of a new gold-plated copper torch.

Kurt Jahnke escaped capture. He later served as an Abwehr agent during World War II. Jahnke worked as intelligence advisor to Walter Schellenberg. He and his wife were captured by Soviet SMERSH agents in April 1945 and interrogated. In 1950, Jahnke was put on trial as a spy, found guilty, and executed the same day.

Witzke was arrested at the Mexican border on February 1, 1918, near Nogales, Arizona. Officials were not prosecuted for the bombing, but prosecuted him as a spy. A military court at Fort Sam Houston found him guilty of espionage and sentenced to death by hanging. While in custody, he tried to escape twice, once succeeding, albeit he was recaptured the same day. On November 2, 1918, Witzke's death sentence was approved by the Department Commander. However, he was not executed due to the November Armistice. In May 1920, President Woodrow Wilson commuted Witzke's sentence to life in prison. In September 1923, Witzke, due to heroic conduct in prison and pressure for his release by the Weimar Republic, was pardoned by President Calvin Coolidge, and deported to Germany. Upon his arrival, Witzke was awarded the Iron Cross, First and Second Class, by the Reichswehr. Witzke later joined the Abwehr, and after World War II, lived in Hamburg. He was a monarchist who represented the German Party in the Hamburg Parliament from 1949 to 1952. Witzke died in 1961.

Kristoff was arrested by the Jersey City police on suspicion of involvement in the blast, but later released due to a lack of evidence. Over the next several years, he drifted in and out of prison for various crimes. Kristoff died of tuberculosis in 1928.

Legacy
The Black Tom explosion resulted in the establishment of domestic intelligence agencies for the United States. The then Police Commissioner of New York, Arthur Woods, argued, "The lessons to America are clear as day. We must not again be caught napping with no adequate national intelligence organization. The several federal bureaus should be welded into one and that one should be eternally and comprehensively vigilant." The explosion also played a role in how future presidents responded to military conflict. President Franklin D. Roosevelt used the Black Tom explosion as part of his rationale for the internment of Japanese Americans after the attack on Pearl Harbor in 1941. In an interview with Jules Witcover, McCloy noted that as assistant secretary of the navy for President Wilson, Roosevelt "knew all about Black Tom". At the time President Roosevelt said to him: "We don't want any more Black Toms".

The incident also influenced public safety legislation. The sabotage techniques used by Germany, and the United States' declaration of war on Germany, resulted in the creation of the Espionage Act, which passed by Congress in late 1917. Landfill projects later made Black Tom Island part of the mainland, and it was incorporated into Liberty State Park. The former Black Tom Island is at the end of Morris Pesin Drive in the southeastern corner of the park, where a plaque marks the spot of the explosion. A circle of U.S. flags complements the plaque, which stands east of the visitors' facility.

The inscription on the plaque reads: Explosion at Liberty!

On July 30, 1916 the Black Tom munitions depot exploded rocking New York Harbor and sending residents tumbling from their beds.

The noise of the explosion was heard as far away as Maryland and Connecticut. On Ellis Island, terrified immigrants were evacuated by ferry to the Battery. Shrapnel pierced the Statue of Liberty (the arm of the Statue was closed to visitors after this). Property damage was estimated at $20 million. It is not known how many died.

Why the explosion? Was it an accident or planned? According to historians, the Germans sabotaged the Lehigh Valley munitions depot in order to stop deliveries being made to the British who had blockaded the Germans in Europe.

You are walking on a site which saw one of the worse [sic] acts of terrorism in American history.

A stained-glass window at Our Lady of Czestochowa Catholic church memorialized the victims of the attack.

title: Black Tom explosion


text:
Fluid and crystallized intelligence

The concepts of fluid intelligence (gf) and crystallized intelligence (gc) were introduced in 1963 by the psychologist Raymond Cattell. According to Cattell's psychometrically-based theory, general intelligence (g) is subdivided into gf and gc. Fluid intelligence is the ability to solve novel reasoning problems and is correlated with a number of important skills such as comprehension, problem-solving, and learning. Crystallized intelligence, on the other hand, involves the ability to deduce secondary relational abstractions by applying previously learned primary relational abstractions.

History
Fluid and crystallized intelligence are constructs originally conceptualized by Raymond Cattell. The concepts of fluid and crystallized intelligence were further developed by Cattell and his former student John L. Horn. Most of the intelligence testing had mainly been focused on children, and young adults. Cattell and Horn wanted to see how intelligence changed and developed when aging took place on an individual. They realized that while some memories and concepts remained, others diminished. Thus, there was a need to delineate two types of intelligence.

Fluid versus crystallized intelligence
Fluid intelligence (gf) involved basic processes of reasoning and other mental activities that depend only minimally on prior learning (such as formal and informal education) and acculturation. Horn notes that it is formless and can "flow into" a wide variety of cognitive activities. Tasks measuring fluid reasoning require the ability to solve abstract reasoning problems. Examples of tasks that measure fluid intelligence include figure classifications, figural analyses, number and letter series, matrices, and paired associates.

Crystallized intelligence (gc) includes learned procedures and knowledge. It reflects the effects of experience and acculturation. Horn notes that crystallized ability is a "precipitate out of experience," resulting from the prior application of fluid ability that has been combined with the intelligence of culture. Examples of tasks that measure crystallized intelligence are vocabulary, general information, abstract word analogies, and the mechanics of language.

Example application of fluid and crystallized abilities to problem-solving
Horn provided the following example of crystallized and fluid approaches to solving a problem. Here is the problem he described:

"There are 100 patients in a hospital. Some (an even number) are one-legged but wearing shoes. One-half of the remainder are barefooted. How many shoes are being worn?"

The crystallized approach to solving the problem would involve the application of high school-level algebra. Algebra is an acculturational product.

$$x + 1/2*(100-x)*2$$ is the number of shoes worn, where $x$ equals the number of one-legged patients. $$100 - x$$ equals the number of two-legged patients. The solution boils down to 100 shoes.

In contrast to the crystallized approach to solving the problem, Horn provided a made-up example of a fluid approach to solving the problem, an approach that does not depend on the learning of high school-level algebra. In his made-up example, Horn described a boy who is too young to attend secondary school but could solve the problem through the application of fluid ability: "He may reason that if half the two-legged people are without shoes, and all the rest (an even number) are one-legged, then the shoes must average one per person, and the answer is 100."

Relationship to Piaget's theory of cognitive development
Researchers have linked the theory of fluid and crystallized abilities to Piaget's theory of cognitive development. Fluid ability and Piaget's operative intelligence both concern logical thinking and the "eduction of relations" (an expression Cattell used to refer to the inferring of relationships). Crystallized ability and Piaget's treatment of everyday learning reflects the impress of experience. Like fluid ability's relation to crystallized intelligence, Piaget's operativity is considered to be prior to, and ultimately provides the foundation for, everyday learning.

Measurement of fluid intelligence
Various measures have been thought to assess fluid intelligence.

Raven's Progressive Matrices
The Raven's Progressive Matrices (RPM) is one of the most commonly used measures of fluid ability. It is a non-verbal multiple-choice test. Participants have to complete a series of drawings by identifying relevant features based on the spatial organization of an array of objects and choosing one object that matches one or more of the identified features. This task assesses the ability to consider one or more relationships between mental representations or relational reasoning. Propositional analogies and semantic decision tasks are also used to assess relational reasoning.

Woodcock–Johnson Tests of Cognitive Abilities, Third Edition
In the Woodcock–Johnson Tests of Cognitive Abilities, Third Edition (WJ-III), gf is assessed by two tests: Concept Formation and Analysis Synthesis. Concept Formation tasks require the individual to use categorical thinking; Analysis Synthesis tasks require general sequential reasoning.

Concept Formation
Individuals have to apply concepts by inferring the underlying "rules" for solving visual puzzles that are presented with increasing levels of difficulty. As the level of difficulty increases, individuals have to identify a key difference (or the "rule") for solving puzzles involving one-to-one comparisons. For more difficult items, individuals need to understand the concept of "and" (e.g., a solution must have some of this and some of that) and the concept of "or" (e.g., to be inside a box, the item must be either this or that). The most difficult items require fluid transformations and cognitive shifting between the various types of concept puzzles that the examinee had worked with previously.

Analysis–Synthesis
In the Analysis–Synthesis test, the individual has to learn and orally state the solutions to incomplete logic puzzles that mimic a miniature mathematics system. The test also contains some of the features involved in using symbolic formulations in other fields such as chemistry and logic. The individual has presented a set of logic rules, a "key" that is used to solve the puzzles. The individual has to determine the missing colors within each of the puzzles using the key. Complex items presented puzzles that require two or more sequential mental manipulations of the key to deriving a final solution. Increasingly difficult items involve a mix of puzzles that requires fluid shifts in deduction, logic, and inference.

Wechsler Intelligence Scales for Children, Fourth Edition
The Wechsler Intelligence Scales for Children, Fourth Edition (WISC-IV) is used to have an overall measure in cognitive ability with five primary indexing scores. In the WISC-IV, the Perceptual Reasoning Index contains two subtests that assess gf: Matrix Reasoning, which involves induction and deduction, and Picture Concepts, which involves induction.

Picture Concepts
In the Picture Concepts task, children are presented with a series of pictures on two or three rows and asked which pictures (one from each row) belong together based on some common characteristic. This task assesses the child's ability to discover the underlying characteristic (e.g., rule, concept, trend, class membership) that governs a set of materials.

Matrix Reasoning
Matrix Reasoning also assesses this ability as well as the ability to start with stated rules, premises, or conditions and to engage in one or more steps to reach a solution to a novel problem (deduction). In the Matrix Reasoning test, children have presented with a series or sequence of pictures with one picture missing. Their task requires the child to choose the picture that fits the series or sequence from an array of five options. Since Matrix Reasoning and Picture Concepts involve the use of visual stimuli and do not require expressive language, they have been considered to be non-verbal tests of gf.

In the workplace
Within the corporate environment, fluid intelligence is a predictor of a person's capacity to work well in environments characterised by complexity, uncertainty, and ambiguity. The Cognitive Process Profile (CPP) measures a person's fluid intelligence and cognitive processes. It maps these against suitable work environments according to Elliott Jaques's Stratified Systems Theory. Fe et al. (2022) show that fluid intelligence measured in childhood predicts labor market earnings.

Factors related to measuring intelligence
Some authors have suggested that unless an individual is truly interested in a problem presented on an IQ test, the cognitive work required to solve the problem may not be performed owing to a lack of interest. These authors have contended that a low score on tests that are intended to measure fluid intelligence may reflect more of a lack of interest in the tasks than an inability to complete the tasks successfully.

Development across life span
Fluid intelligence peaks at around age 27 and then gradually declines. This decline may be related to local atrophy of the brain in the right cerebellum, a lack of practice, or the result of age-related changes in the brain.

Crystallized intelligence typically increases gradually, stays relatively stable across most of adulthood, and then begins to decline after age 65. The exact peak age of cognitive skills remains elusive.

Fluid intelligence and working memory
Working memory capacity is closely related to fluid intelligence, and has been proposed to account for individual differences in gf. The linking of working memory and gf has been suggested that it could help resolve mysteries that have puzzled researchers concerning the two concepts.

Neuroanatomy
According to David Geary, gf and gc can be traced to two separate brain systems. Fluid intelligence involves the dorsolateral prefrontal cortex, the anterior cingulate cortex, and other systems related to attention and short-term memory. Crystallized intelligence appears to be a function of brain regions that involve the storage and usage of long-term memories, such as the hippocampus.

Research on training working memory and the training's indirect effect on fluid ability
Because working memory is thought to influence gf, then training to increase the capacity of working memory could have a positive impact on gf. Some researchers, however, question whether the results of training interventions to enhance gf are long-lasting and transferable, especially when these techniques are used by healthy children and adults without cognitive deficiencies. A meta-analytical review published in 2012 concluded that "memory training programs appear to produce short-term, specific training effects that do not generalize."

In a series of four individual experiments involving 70 participants (mean age of 25.6) from the University of Bern community, Jaeggi et al. found that, in comparison to a demographically matched control group, healthy young adults who practiced a demanding working memory task (dual n -back) approximately 25 minutes per day for between 8 and 19 days had significantly greater pre-to-posttest increases in their scores on a matrix test of fluid intelligence. There was no long-term follow-up to assess how enduring the effects of training were.

Two later n-back studies did not support the findings of Jaeggi et al. Although participants' performance on the training task improved, these studies showed no significant improvement in the mental abilities tested, especially fluid intelligence and working memory capacity.

Thus the balance of findings suggests that training for the purpose of increasing working memory can have specific short-term effects but no effects on gf.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Fluid and crystallized intelligence


text:
A83

A83 or A-83 may refer to:
 * A83 motorway (France), a road connecting Nantes and Niort
 * A83 road (Scotland), a major road in Scotland

title: A83