174 



OBITUAEY. 



Jean Alfred Nachet. 1831-1908. 



Plate VI. 



Jean Alfred Nachet was born at Paris in 1831. In 1853 he 

 joined his father in the business, their attention being at first 

 occupied by the construction of binocular Microscopes * which had 

 just been introduced by Professor Eiddell of New Orleans. Next 

 they brought out demonstration Microscopes f which had two, 

 three or four bodies, so that more than one observer might view 

 the same object through the same Microscope at the same time ; 

 later, in 1860, an etching prism was brought out.J 



This firm's well-known Camera Lucida was designed by M. 

 Nachet, senior, in 1843, but it underwent alteration and improve- 

 ment in 1882 § and again in 1886. || There is an article about 

 cameras from the pen of J. A. Nachet in Quart. Journ. Micr. Sci., 

 viii. (1860) p. 156. 



In 1877 he brought out a dark -ground illuminator, If a variety 

 of spot lens ; and in the same year he made a large inverted 

 Microscope,** with the object-glass below the stage, the rays being 

 bent upwards into an inclined tube by a first-surface mirror ; the 

 ray-path being 3 ft. long. These tubes were of great size, in fact 

 they might have belonged to a small astronomical telescope. The 

 idea of this Microscope was to obtain both a large amplification 

 and field by means of great tube-length ; the tube was doubled up 

 to bring the focusing and various other adjustments within reach 

 of the observer. 



In 1880-1 Nachet made some penological ft (called petro- 

 graphical) Microscopes. In 1881 a spring changing nose-piece, J$ 

 and in 1882-5 some portable §§ Microscopes were introduced by that 

 firm. In 1885 he made a class Microscope || || in which all the adjust- 

 ments and movable parts could be locked up by a key. In the next 

 yearTHf we have his "Grand Modele Perfectionne." A novelty 

 is claimed for this instrument inasmuch as the fine-adjustment, 



* Quart. Journ. Micr. Sci., ii. (1854) p. 72, figs. 1-4. t Loc. cit. 



X Op. cit., viii. (1860) p. 206, 1 fig. 



§ See this Journal, 1882, p. 260, figs. 44-6. 



|| Op. cit., 1886, p. 1057, fig. 228. 



i Op. cit., 1877, p. 463, fig. 103. ** Op. cit., 1879, p. 766, fig. 1. 



tf Op. cit., 1880, p. 22S, fig. 15 ; 1881, p. 934, figs. 205-6. 

 II Op. cit., 1881, p. 661, figs. 144-5. 



§§ See this Journal, 1882, p. 99, figs. 7-11 ; 1S85, p. 700, figs. 137-8. 

 HI Op. cit., 1885, p. 514, fig. 100. ^f Op. cit., 1886, p. 837, fig. 157. 



