ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



371 



drilling a hole in the ocular just above the diaphragm. The aperture 

 should be of such size that it will admit the passage of a medium-sized 

 pin (about 3 cm. long) to serve as indicator. 



(3) Illuminating and other Apparatus. 



Pfeiffer's Hot-Air Chamber.*— This apparatus, made by C. Reichert, 

 is seen in fig. G5. It is intended for the heating of the whole Micro- 

 scope. It is fitted with a thermometer and a gas thermo-regulator. 



"' 



Fig. 65. 



Reichert's New Achromatic Condenser.| — This illuminating 

 apparatus has an aperture of 1*30, and as will be seen from the illnstra- 



* C. Reichert (Vienna) Catalogue No. 25 (Mikroskopie, 1904) p. 53, fig. 266. 

 t C. Reichert's Catalogue, No. 25 (1901) p. 13. 



2 C 2 



