ZOOLOGY AND BOTANY, MICROSCOPY^ ETC. 



271 



Fig. 42. 



The mirror has seven jointed arms, and can be used above the 

 stage for illuminating opaque objects. 



The whole instrument stands upon a strongly made tripod 15 in. 

 high with revolving top 20 in. in diameter. When at an inclination 

 of 45° the eye-piece is 3^ ft. from the floor. 



The Microscope was constructed under Dr. Deecke's supervision, 

 and from plans drawn by himself, at the " Utica Engine and Boiler 

 Works " of Mr. P. 8. Curtis, Utica, N.Y. 



Dr. Deecke also sends us a description of a stage for use in photo- 

 micrography for the purpose of rendering possible the focussing of large 

 areas of sections when low magnifying powers are used. 



An ordinary photographic lens can be successfully employed 

 instead of the microscopic objective. It gives at a proper distance, of 

 from 10 to 20 or even 40 ft, 

 from the lens, a picture of 

 excellent definition, but the 

 great difliculty is to bring 

 all parts of a field of such 

 dimensions into the proper 

 focus. Assuming that this 

 difficulty probably origi- 

 nated in slight inequalities 

 in the thickness of the 

 sections in their different 

 parts, or that it was due 

 to their position in the 

 mounting fluid between the 

 slide and the cover-glass. 

 Dr. Deecke corrected the 

 defect by constructing a 

 stage on which the speci- 

 men may be placed in any 

 desired plane slightly 

 oblique to a vertical plane 

 drawn through the centre 

 of the magnifying lens, and 

 thus arrived at results 

 which gave perfect satis- 

 faction.* 



Robin's (Chevalier) 

 Dissecting Microscope. — 



This (fig. 42) is another 



form (by A. Chevalier) of 



Prof. C. Robin's Dissecting 



Microscope, that made by MM. Nachet having been figured on p. 100, 



Vol. 11. (1882).t 



* Description supplied by Dr. Deecke. See also brief note in Proc. Amer. 

 Soc. Micr., 5th Ann. Meeting, 1882, pp. 277-9. No little credit is due to Mr. 

 G. "W. Kuffle for engraving the above woodcuts from photographs very mucb 

 wanting in clearness. 



t Cf. also C. Robin's ' Traite' du Microscope,' 1877, p. 75. 



