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Originally appearing in Volume V07, Page 772 of the 1911 Encyclopedia Britannica.
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JOHN HENRY DALLMEYER (183o-1883), Anglo-German optician, was born on the 6th of September 1830 at Loxten, Westphalia, the son of a landowner. On leaving school at the age of sixteen he was apprenticed to an Osnabruck 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 corrrespondent 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 making of photographic lenses (see PHOTOGRAPHY), he introduced improvements in both portrait and landscape lenses, in object-glasses for the microscope and in condensers for the optical lantern. In connexion 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. Dall'meyer'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 188o 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 the 3oth of December 1883. His second son, THOMAS RUDOLPHUS DALLMEYER (1859-1906), who assumed control of the business on the failure of his father's health, was principally known as the first to introduce telephotographic lenses into ordinary practice (patented 1891), and he was the author of a standard book on the subject (Telephotography, 1899). He served as president of the Royal Photographic Society in 1900-1903. DALL' ONGARO, FRANCESCO (1808-1873), Italian writer, born in Friuli, was educated for the priesthood, but abandoned his orders, and taking to political journalism founded the Favilla at Trieste in the Liberal interest. In 1848 he enlisted under Garibaldi, and next year was a member of the assembly which proclaimed the republic in Rome, being given by Mazzini the direction of the Monitor oiciale. On the downfall of the republic he fled to Switzerland, then to Belgium and later to France, taking a prominent part in revolutionary journalism; it was not till 186o that he returned to Italy, where he was appointed professor of dramatic literature at Florence. Subsequently he was transferred to Naples, where he died on the loth of January 1873. His patriotic poems, Stornelli, composed in early life, had a great popular success; and he produced a number of plays, notably Fornaretto, Bianca Capello, Fasma and Il Tesoro. His collected Fantasie drammatiche e liriche were published in his lifetime.
End of Article: JOHN HENRY DALLMEYER (183o-1883)
DALMATIA (Ger. Dalmatien; Ital. Dalmazia; Serbo-Cro...

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