ZOOLOaY AND BOTANY, MIOROSOOPY, ETC. 

 Fig. 54. 



307 



%--il 



decrease the light. The higher the cells, and the deeper therefore 

 the immersion of the elements (carbon and zinc It z), the greater the 

 illumination. The wires pass out through ccl. At e r 

 a cover can be introduced to prevent the fluid spilling ^^<^- ^^• 

 when carried. The whole measures 8 in. X 9 in. x 3 in. 

 As we have recently * dealt somewhat fully with 

 the advantages of electrical illumination for microsco- 

 pical work, it is unnecessary to recapitulate them here, 

 but we may mention that Dr. M. Flesch records f some 

 further experiments both with arc and incandescence 

 lamps, and commends the steadiness of the light and 

 the very perfect manner in which colours are shown, 

 differences of tint hardly appreciable by daylight being 

 readily discriminated with the electric light. 



Swifts' Sheep-Scab Microscope. — This (fig. 55) was 

 constructed by Messrs. Swift for a microscopist who 

 desired to examine the scab in sheep without having to 

 approximate his face too closely to the diseased portion 

 of the animal. It would of course be found equally 

 useful in the case of examinations of other contagious 

 or disagreeable diseases. 



* See this Journal, iv. (1884) p. 966. Cf. also ii. (1882) p. 419. 

 t Zeitschr. f. Wiss. Mikr., i. (1884) pp. 561-3. 



X 2 



