science

John Henry Dallmeyer

John Henry Dallmeyer is a 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 John Henry Dallmeyer rather than just read about it. In short: John Henry Dallmeyer (6 September 1830 – 30 December 1883), Anglo-German optician, was born at Loxten, Westphalia, the son of a landowner. On leaving school at the age of sixteen he was apprenticed to an Osnabrück optician, and in 1851 he came to London, where he obtained work with an optician, W Hewitt, who shortly afterwards, with his workmen, entered the employment of Andrew Ross, a lens and telescope manufacture…

Key takeaways

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

Reference excerpt

John Henry Dallmeyer (6 September 1830 – 30 December 1883), Anglo-German optician, was born at Loxten, Westphalia, the son of a landowner. On leaving school at the age of sixteen he was apprenticed to an Osnabrück optician, and in 1851 he came to London, where he obtained work with an optician, W Hewitt, who shortly afterwards, with his workmen, entered the employment of Andrew Ross, a lens and telescope manufacturer. Dallmeyer's position in this workshop appears to have been an unpleasant one, and led him to take, for a time, employment as French and German correspondent for a commercial firm. After a year he was, however, re-engaged by Ross as scientific adviser, and was entrusted with the testing and finishing of the highest class of optical apparatus. This appointment led to his marriage with Ross's second daughter, Hannah, and to the inheritance, at Ross's death (1859), of a third of his employer's large fortune and the telescope manufacturing portion of the business. Turning from astronomical work to the design and making of photographic lenses, he introduced improvements in both portrait and landscape lenses, in object-glasses for the microscope and in condensers for the optical lantern. An important invention was the Rapid Rectilinear camera objective. In connection with celestial photography he constructed photo-heliographs for the Wilna observatory in 1863, for the Harvard College Observatory in 1864, and, in 1873, several for the British government. Dallmeyer's instruments achieved a wide success in Europe and America, taking the highest awards at various international exhibitions. The Russian government gave him the order of St Stanislaus, and the French government made him chevalier of the Legion of Honour. He was for many years upon the councils of both the Royal Astronomical Society and Royal Photographic Society. About 1880 he was advised to give up the personal supervision of his workshops, and to travel for his health, but he died on board ship, off the coast of New Zealand, on 30 December 1883. His second son, Thomas Rudolphus Dallmeyer assumed control of the business on the failure of his father's health.

References

External links Works by or about John Henry Dallmeyer at the Internet Archive

Illustrations

Worked examples

Example 1 — a first encounter with John Henry Dallmeyer

Start with the simplest possible case. Write down what John Henry Dallmeyer claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In 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 John Henry Dallmeyer 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 John Henry Dallmeyer 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 John Henry Dallmeyer

In research: John Henry Dallmeyer appears in 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 John Henry Dallmeyer 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: John Henry Dallmeyer is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1830 births, 1883 deaths, German emigrants to the United Kingdom, so understanding it makes those chapters shorter.
In everyday life: Look for John Henry Dallmeyer 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 John Henry Dallmeyer in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what John Henry Dallmeyer 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 John Henry Dallmeyer out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is John Henry Dallmeyer in simple terms?

Why does John Henry Dallmeyer matter?

Because it connects several 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 John Henry Dallmeyer?

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 John Henry Dallmeyer.