ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



279 



MICKOSCOPY. 



o. Instruments, Accessories, &c* 

 (1) Stands. 



Bausch and Lomb Optical Co.'s Petrographical Microscope. — This 

 instrument, fig. 40, was founded on suggestions of Dr. G. H. Williams, 

 Associate Professor of Mineralogy and Inorganic Geology in the Johns- 



Fig. 40. 



Hopkins University.f The general form of the stand is the Bausch 

 and Lomb Optical Go's "Model" Microscope, J with their watchspring 

 fine-adjustment, and the mechanical stage described in this Journal, 1887, 



* This subdivision contains (1) Stands; (2) Eye-pieces and Objectives; (3) Illu- 

 minating and other Apparatus ; (4) Photomicrography ; (5) Microscopical Optics 

 and Manipulation ; (6) Miscellaneous. 



t Cf. Amer. Journ. Sci., xxxv. (1888) pp. 114-7 (1 fig.). 



X It can also be applied to the " Universal " and " Professional " forms. 



