earth science

Jacques Triger

Jacques Triger is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Jacques Triger rather than just read about it. In short: Jacques Triger (10 March 1801 – 16 December 1867) was a French geologist who invented the "Triger process" for digging through waterlogged ground using a pressurised caisson. Triger was also deputy director of coal mining operations in Chalonnes-sur-Loire (Maine-et-Loire).

Key takeaways

Jacques Triger belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Jacques Triger to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Jacques Triger from memory before moving on to harder problems.

Reference excerpt

Jacques Triger (10 March 1801 – 16 December 1867) was a French geologist who invented the "Triger process" for digging through waterlogged ground using a pressurised caisson. Triger was also deputy director of coal mining operations in Chalonnes-sur-Loire (Maine-et-Loire).

Biography Triger was born in Mamers, Sarthe, France, on 10 March 1801. He studied at La Flèche and then in Paris, where he met Louis Cordier in 1825. Cordier was an eminent French geologist, who taught Triger his first lessons in geology, where he quickly took interest in the technical challenges of this industrial sector. At 32 years old, together with skilled managers, Triger developed new industries in Sarthe and Mayenne. In this period, he developed and launched three coal mines, a paper mill and a sawmill. In 1833, Triger was left by the woman he intended to marry. This plunged him deeply into his work: the production of gravel from dolomite rock, the construction of public fountains in Mamers and the detailed study of phreatic groundwater tables near Le Mans. In 1834, Triger started the study and geological investigation of his region – Sarthe and Mayenne. These investigations and discussions with Louis Cordier drove him to Anjou (Maine-et-Loire), where coal was craft-mined. Thus, in 1839, Triger began to look at the Loire river and the way to reach solid rock underneath about 20 meters of waterlogged soil. After reading many articles on compressed air, he was convinced that he could use it to help dig through this layer of soil. He did not rely directly on the idea of using compressed air, but on the invention of the airlock – to pass from the pressurized zone of the caisson to the zone of atmospheric air pressure, and especially in finding a practical way to utilize the technique on an industrial scale. With the financial and administrative support of Emmanuel de Las Cases, five steel shaft linings were drilled by this invention, which was subsequently adapted and applied to dig foundations, bridges and many tunnels. Helped by a liking for travel, Triger gradually established the first geological map of Sarthe County. After more than 20 years of research, the document was presented in 1853 at the Geological Society of France. The topographic background, support of the geological layers were designed by Triger himself. To design this document, he had to study all the fossils in his county and deal with some of the mysteries at that time, such as the structure of the Cretaceous terrain of Maine or the study of the Silurian-Devonian-Carboniferous lands in the west part of France. Triger wanted the designation of the geological strata to be borrowed from paleontology (fossil names). He saw in this new system "the precious advantage of a universal language that one would understand everywhere, without comments and which would easily help the geologists from all regions of the globe to communicate". Triger would come to constitute regular geological cross-sections of the eastern France. This work was carried out by a team of geologists directed by Triger: geological sections from Paris to Brest, from Le Mans to Angers, from Paris to Rennes, and from Vendôme to Brest. Triger was also a paleontologist, part of the first team to excavate the archaeological site of Roc-en-Paille (Chalonnes-sur-Loire, Maine-et-Loire). His very large collection of rocks, fossils and minerals is now displayed at the Museum of Natural History in Angers. He collected many fossils, many of which carry the name "trigeri" in honor of Triger's efforts as a collector. On 16 December 1867, Triger died from a heart attack after a meeting at the Geological Society of France, where he served for 35 years. Triger's name is one of the 72 names inscribed on the Eiffel Tower.

References

External links A. Banyai: A great invention with built-in hazards (1975) A french article on J. Triger written by François Martin, for Tunnel et Ouvrages Souterrains (2004). More information about his local contribution in Chalonnes-sur-Loire.

Illustrations

Worked examples

Example 1 — a first encounter with Jacques Triger

Start with the simplest possible case. Write down what Jacques Triger claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Jacques Triger before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Jacques Triger ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Jacques Triger

In research: Jacques Triger appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Jacques Triger in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Jacques Triger is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1801 births, 1867 deaths, French geologists, so understanding it makes those chapters shorter.
In everyday life: Look for Jacques Triger outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Jacques Triger in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Jacques Triger means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Jacques Triger out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Jacques Triger in simple terms?

Why does Jacques Triger matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Jacques Triger?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Jacques Triger.