ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



241 



be a position-screw to prevent impact of the objective on the prepara- 

 tion. The author thinks, however, that there is much to be said in 

 favour of a fixed tube and a movable object-stage, inasmuch as two 

 tubes might then be fixed, for high and low powers respectively. Such 

 tubes would be best placed at opposite ends of a diameter of the 

 rotatory disk. 



Bausch and Lomb's Pocket Dissecting Microscope Stand S.* — 

 In designing this little instrument, fig. 44, compactness and con- 

 venience of carriage have been especially borne in mind. A stage 

 attached firmly to the under side of the reversible cover holds the 

 mirror set at the proper angle, together with a glass stage and a 



Fig. 44. 



post for carrying the lens. A black and white metal plate is sup- 

 plied with each instrument, and is to be placed over the mirror, 

 according as a black or white background is desired. The lens is 

 adjustable for focus on a metal post, and can also be used as a hand 

 magnifier. The box is of mahogany, 45 x 65 x 102 mm., and can be 

 easily carried in the pocket. The post and lens are removable, and fit 

 in the box. The cover slides in a groove ; when right side up, it closes 

 the box ; when under side up, after insertion of the metal post in its 

 opening, the dissecting Microscope is ready for use. 



Bausch and Lomb's Compound Erecting Body.f — This instrument 

 (fig. 45) is intended for use as a dissecting Microscope. By means of 

 two double-reflecting prisms the image from the objective is inverted, 



* Bausch and Lomb Optical Co., Rochester, N.Y., Catalogue, Microscopes and 

 Accessories, p. 49. t Tom. cit., p. 57. 



