APPENDIX II 363 



Tools for the manufacture and repair of apparatus wiU be found 

 almost indispensable in the laboratory. Among the most useful are 

 round files for cork-boring and triangular ones for cutting glass, a 

 hammer, nails and brads, fine carpenter's saw, hack-saw, pliers and 

 cutting pliers, chisels, brace with bits and twist drills, annealed brass 

 wire, small soldering copper with solder and zinc-chloride soldering 

 solution. 



The Compound Microscope. — Compound microscopes and acces- 

 sories may be bought of most dealers in physical apparatus. Four 

 of the most important manufacturers are the Bausch & Lomb Optical 

 Co., Rochester, N.Y. ; E. Leitz, 30 East Eighteenth St., New York 

 City ; the Spencer Lens Co., Buffalo, N.Y. ; and C. Zeiss, represented 

 by the Bausch & Lomb Co. All send catalogues on application, and 

 all furnish instruments suitable for high-school laboratories at prices 

 ranging from $20 to $35. The microscopes of German manufacture 

 (of Leitz and Zeiss) are imported duty free for schools. 



A very brief account of the construction and use of the compound 

 microscope is given in the Manual, pp. 10-14. More details can be 

 found in Winslow's Elements of Applied Microscopy, John Wiley & 

 Sons, N.Y., or in any of the standard treatises, such as Gage's, or 

 Carpenter and Dallinger's. 



School microscopes are very commonly provided with a 2-inch 

 and a 1-inch eyepiece and a |-inch and ^-inch objective. In this 

 ease either eyepiece when used with the lower objective will give 

 a low power. The 2-iiich eyepiece with the J-inch objective will give 

 a medium power, and the 1-inch eyepiece with the ^-inch objective 

 will give a moderately high power. 



It will be found desirable to equip many if not all of the stauds 

 also with a 2-inch objective, as this gives a far better general view 

 of such objects as sections of roots or stems of seed plants, gTeen 

 algse, small liverworts, fern prothallia, and so on than can be ob- 

 tained with a hand lens. If possible, the laboratory should have at 

 least one stage micrometer, several eyepiece micrometers, and a cam- 

 era lucida. The micrometers should be kept in frequent use to give 

 the students accurate ideas of the dimensions of objects studied, 

 and the camera lucida should be used as a check on the accm-acy of 

 drawings made from the microscope without it. 



