ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



95 



Watson's New Standard Electric Lamp.* — This lamp (fig. 16), 

 which is intended for Microscope work, has a 16 candle-power incan- 

 descent burner, with frosted glass bulb. It is carried on a lacquered 

 brass standard, and, by means of a movable double arm, is adjustable in 

 all directions. The bulb is inclosed in a nickelled reflector of parabolic 

 shape, Avhich has the simultaneous advantage of shielding the eyes and 

 concentrating the light on the Microscope mirror. It can also be sup- 

 plied with a special hood and iris diaphragm. 



Fig. 16. 



Small Electric Light for Photomicrography.! — W. Scheffer's 

 first experiments were with a cravat-pin, which held a small electric 

 lamp, lighted by a dry cell of American make. He then constructed 

 a small lamp (fig. 17), in which the carbon filament lay as near as 

 possible to the glass, so that the whole lamp might be brought into 

 close proximity to the under side of the object-slide. The filament, 

 magnified ten diameters, is shown more completely in fig. 18. The 

 length of the filament (a, fig. 17) is 1 mm., the thickness 0*1 mm., and 



* W. Watson & Sons' Catalogue, 1902-3, p. 116. 



t Zeitschr. wiss. Mikr., xviii. (1902) pp. 405-8 (3 figs.). 



