CH. //] LABORATORY MICROSCOPES 71 



FIG. 70. Krauss 1 Method of 

 Marking Objectives on a Revolving 

 Nose- Piece. 



As seen in the figure, the equiv- 

 alent focus of the objective is en- 

 graved on the diaphragm above the 

 back lens and may be very readily 

 seen in rotating the nose-piece. This 

 is of great advantage, as one can see 

 what objective is coming into place 

 without trouble. It is also an ad- 

 vantage in showing where each ob- 

 jective belongs when the microscope 

 comes from the ma n ufacturers. The 

 method is coming into general use. 



FIGURES OF LABORATORY AND HIGH SCHOOL 

 MICROSCOPES 



In order that teachers and students may get a good general idea of the appear- 

 ance of microscopes of various makers for high school and advanced laboratory 

 work a few pictures are appended of the microscopes most used in the United 

 States. This has been rendered possible by the courtesy of the manufacturers or 

 importers. The microscopes are arranged in alphabetical order of the makers. 



Laboratory microscopes which will answer nearly all the requirements for 

 work in Biology, including Histology, Embryology, Pathology and Bacteriology, 

 are listed in the makers catalogs at about $100.00. The less expensive micro- 

 scopes shown are listed at $25 to $45. There is usually a discount of 10% or more 

 from these prices. Fortunately in the State of New York the State pays half for 

 high school apparatus, so that there is no reason why every high school should 

 not be properly equipped with microscopes of a good grade. To avoid misunder- 

 standing it should be added that the quality of the oculars and objectives on the 

 high school microscopes figured is the same as for the best laboratory micro- 

 scopes. The mechanical work also is of excellent quality. 



During the last ten years great vigor has been shown in the microscopical 

 world. This has been stimulated largely by the activity in biological science and 

 the widespread appreciation of the microscope, not only as a desirable, but as a 

 necessary instrument for study and research. The production of the new kinds 

 of glass, (Jena glass), and the apochromatic objectives has been a no less potent 

 factor in promoting progress. The student is advised to write to one or more of 

 the opticians for complete catalogs. (See list, p. 2 of cover). 



