the diligent discharge of his duties had risen to the rank of lieutenant in the 1st dragoons, when he was led in 1842 by a trifling accident to the study of chemistry. Not long after, it was decided to alter the facings of the cavalry from crimson to orange, and the young lieutenant laid before the authorities a method of changing the colour by a simple chemical process. His proposition was adopted, and the department thereby saved 100,000 francs. M. Niepce de Saint-Victor received only a small pecuniary reward, but he had secured official notice, and the way was smoothed for his future career. In 1845 he obtained a lieutenancy in the municipal guards, his object being a permanent residence in Paris, and access to its facilities for scientific research. Photography was at this time attracting much attention, and Niepce de Saint-Victor resolved to devote himself specifically to the study of photographic chemistry, and the connected branches of science. His immediate purpose was to continue and perfect the discoveries of his uncle, M. Nicéphore Niepce, who, though not the first to obtain images of objects by the sun's rays on a prepared surface, was perhaps the first to fix permanently the images obtained in the camera. Joseph Nicéphore Niepce commenced his laborious experiments in 1813, his aim being to obtain on a metal plate the images of the camera, and then by chemical means, without the employment of a graver, to produce an engraving that should be capable of yielding impressions like a plate engraved in the ordinary way. For this purpose he used plates of polished copper, tin, and ultimately silver plates covered with a film of varnish of asphaltum (bitume de judée). He obtained very remarkable results, and his process, which he termed Heliography, is asserted by his nephew (Traité Pratique de Gravure Heliographique, 8vo, 1856), to have been the starting point of photography. But Nicéphore Niepce was only partially successful. He came to England in 1827, and exhibited the results of his experiments at the Royal Society. His specimens excited a lively interest; but as he refused to divulge the process by which they were obtained, the society declined to report upon them, and he returned, bitterly disappointed, to Paris. Soon after this he found that M. Daguerre, the inventor of the diorama, was engaged on similar investigations, and in 1829 the two experimentalists entered into partnership. Before, however, enough had been done to make their process commercially available, M. Niepce died (July, 1833), and M. Daguerre eventually directed his attention chiefly to obtaining portraits and views, calling his process the "Méthode Niepce perfectionée," though it soon came to be generally known as Daguerreotype. M. Daguerre had abandoned the use of M. Niepce's vehicle asphaltum, but M. Niepce de Saint-Victor when he commenced his photographic studies at once recurred to it, and it has played an important part in all his heliographic experiments. His earliest papers on photography, one of which was an account of his discovery of a method of obtaining photographs on glass, the other on the reproduction of figures by vapours of iodide, &c., were read to the Academy of Sciences, October 25, 1847. Whilst busily occupied in following up these investigations, he was surprised by the revolution of February, 1848. His little laboratory was destroyed, and he was dismissed from his employment. Still he continued his experiments, and in the following year presented to the Academy a second memoir on photography on glass. In July he was restored to his position in the army; a few months later he was made captain of dragoons; and in April, 1849, transferred as captain to the republican guard of Paris. He now pursued his researches with renewed ardour. His brilliant discoveries began to attract general attention. In 1849 he was created knight of the legion of honour, chef-d'-escadron in 1854, and finally commandant of the Louvre. M. Niepce de Saint-Victor's discoveries and researches extend over nearly the whole range of photography. It must suffice now to indicate briefly the character of a few of them. The most important relate to photographic engraving; the production of photographic images in their natural colours; and, as mentioned above, photography on glass, one of the most fruitful discoveries yet made in photography. Photographic engraving was, as we have seen, a sort of family possession. M. Niepce de Saint-Victor commenced by adopting and improving his uncle's method. His first paper on the subject was read before the Academy in May, 1853, almost contemporaneously with the publication of Mr. Talbot's experiments in London. M. Niepce de Saint-Victor has since continued to pursue the subject—still employing a varnish of asphaltum as his base—till, as he believes, he has succeeded in making it commercially available. In his treatise on heliography (1856), of which the title is quoted above, he gives the most detailed directions for photographic engraving on steel or copper, and prefixed to the work is a good untouched portrait of the author; generally, however, it is found necessary to go over the plate with the graver. By a modification of the process he engraves the surface of marble, &c., so as to produce, when the lines are filled with mastic, zinc, or other coloured substances, a kind of mosaic applicable to many ornamental purposes. The obtaining of photographic figures in their natural colours, or Heliochromy, was also one of the visions of M. Nicéphore Niepce. Other photographers during his life, and more after his death, including Sir J. Herschel, Herr Böttiger, and M. Ed. Becquerel, pursued the same fascinating object, but with very partial success. M. Niepce de Saint-Victor improving on the method of M. Becquerel has, we believe, obtained clearer images than any other operator, and he has succeeded by exposing the images in a solution of chloride of lead, in rendering the colour at least partially permanent. M. Niepce de Saint-Victor believed he had ascertained that, under certain circumstances, light became absorbed or latent. The announcement in the autumn of 1858 of this supposed faculty excited great interest among scientific men. The experiments were repeated on all hands with varying success. After a time it was found that similar effects could be produced by heat, &c., and the actual law of the phenomenon seems not yet to have been evolved. The papers of M. Niepce de Saint-Victor up to 1855 were published in a collected form under the title of "Recherches Photographiques," to which was prefixed a memoir of the author by M. E. Lacan, and at the end were Considerations by M. E. Chevreul. His subsequent researches have mostly appeared in the photographic and scientific journals of Paris. To the International Exhibition of 1862 M. Niepce de Saint-Victor sent heliographic steel plates and proofs untouched by the graver; photographs on glass; photographic engraving on marble; monochrome photographs on paper obtained by cyanide of potassium and oxalic acid, azotate of uranium, &c.; and heliochromes, or photographs in their natural colours.—J. T—e.
NIEREMBERG, Johannes Eusebius, of Tyrolese descent, was born at Madrid in 1590, and educated at Salamanca. He joined the Jesuits in 1614, and became eminent as a scholar, and professor of natural history at Madrid. He was very popular as a spiritual adviser. He wrote many works in Latin and Spanish, some of which were extensively read. He died in 1658.
NIEUHOFF, Jan van, born at Usen in Westphalia in 1630, entered at an early age the service of the Dutch West India Company, and after passing some years in Brazil transferred himself to the Dutch settlements in the East Indies, and was employed by the company as one of their principal agents at Batavia. This was in 1654; two years afterwards Nieuhoff was despatched with two others to China to obtain from the emperor the same commercial privileges which were enjoyed by the Portuguese. Nieuhoff and his companions reached Pekin, and had an interview with the emperor Chun-Chi, but the result was not what they desired. Of this embassy Nieuhoff wrote an account, which was translated into English by Ogilvy, 1671. He was subsequently governor of Ceylon. Returning from Holland, where he was obliged to answer some charges brought against him by the council of Batavia, he touched at Madagascar, and was there lost, 29th September, 1672.
NIEUWENTYT, Bernard, a Dutch physician, mathematician, and theological writer, was born at Wastgraafdyk in 1654, and died at Purmerend on the 30th of May, 1718. He wrote a treatise, once popular, on natural and revealed religion. His mathematical writings consist to a great extent of objections to the differential calculus, which were of service to science by calling forth replies from Leibnitz and John Bernoulli.—W. J. M. R.
NIEUWLAND, Peter, a Dutch poet and mathematician, was born at Dimmermeer, near Amsterdam, on the 5th of November, 1764, and died at Leyden on the 14th of November, 1794. He was the son of a master-carpenter; and in his childhood was a prodigy of precocious talent and learning in languages and mathematics. After acting for a time as assistant to Zach the astronomer at Gotha, he returned to Holland, and was appointed professor of nautical astronomy at Amsterdam, and a member of the Dutch board of longitude, which offices he held from 1789 till 1794. He was then appointed professor of natural philosophy, astronomy, and mathematics, at Leyden;
