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John Henry Dallmeyer

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DALLMEYER, JOHN HENRY (183o-1883), Anglo-Ger man optician, was born on Sept. 6, 183o at Loxten, Westphalia, the son of a landowner. On leaving school at the age of 16, he was apprenticed to an Osnabruck optician, and in 1851 he came to London, where he obtained work with an optician and later with Andrew Ross, a lens and telescope manufacturer. After a year spent in a commercial post, he was re-engaged by Ross as scientific adviser. He married Ross's second daughter, Hannah, and in herited, at Ross's death (1859), a third of his employer's large fortune and the telescope-manufacturing portion of the business. Turning to the making of photographic lenses (see PHOTOG RAPHY), he introduced improvements in both portrait and land scape lenses, in object-glasses for the miscroscope and in con densers for the optical lantern. In connection with celestial photography he constructed photo-heliographs for the Wilna ob servatory in 1863, for the Harvard college observatory in 1864, and, in 1873, several for the British Government. Dallmeyer's instruments took the highest awards at various international ex hibitions, and he received many honours from governments and learned societies. He died on board ship, off the coast of New Zealand, on Dec. 30, 1883.

His second son, THOMAS RLTDOLPHUS DALLMEYER (1859 1906), introduced telephotographic lenses into ordinary practice (patented 1891), and wrote a standard book on the subject (Tele photography,

optician and lenses