John Henry Dallmeyer
Encyclopedia
John Henry Dallmeyer 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 lens
es, 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 connexion with celestial photography he constructed photo-heliograph
s 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 and Royal Photographic societies. 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.
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Optics
Optics is the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light...
, was born at Loxten, Westphalia
Westphalia
Westphalia is a region in Germany, centred on the cities of Arnsberg, Bielefeld, Dortmund, Minden and Münster.Westphalia is roughly the region between the rivers Rhine and Weser, located north and south of the Ruhr River. No exact definition of borders can be given, because the name "Westphalia"...
, the son of a landowner.
On leaving school at the age of sixteen he was apprenticed to an Osnabrück
Osnabrück
Osnabrück is a city in Lower Saxony, Germany, some 80 km NNE of Dortmund, 45 km NE of Münster, and some 100 km due west of Hanover. It lies in a valley penned between the Wiehen Hills and the northern tip of the Teutoburg Forest...
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 lens
Photographic lens design
The design of photographic lenses for use in still or cine cameras is intended to produce a lens that yields the most acceptable rendition of the subject being photographed within a range of constraints that include cost, weight and materials...
es, he introduced improvements in both portrait and landscape lenses, in object-glasses for the microscope
Microscope
A microscope is an instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy...
and in condensers for the optical lantern. An important invention was the Rapid Rectilinear
Rapid Rectilinear
-External links:*...
camera objective. In connexion with celestial photography he constructed photo-heliograph
Heliograph
A heliograph is a wireless solar telegraph that signals by flashes of sunlight reflected by a mirror. The flashes are produced by momentarily pivoting the mirror, or by interrupting the beam with a shutter...
s for the Wilna observatory in 1863, for the Harvard College Observatory
Harvard College Observatory
The Harvard College Observatory is an institution managing a complex of buildings and multiple instruments used for astronomical research by the Harvard University Department of Astronomy. It is located in Cambridge, Massachusetts, USA, and was founded in 1839...
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 and Royal Photographic societies. 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
Thomas Rudolphus Dallmeyer
Thomas Rudolphus Dallmeyer , English optician, was the son of John Henry Dallmeyer who ran an optics business.He assumed control of the business on the failure of his father's health, was principally known as the first to introduce the telephoto lens into ordinary practice , and he was the author...
assumed control of the business on the failure of his father's health.
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