104 
ELEMENTARY CHEMICAL MICROSCOPY 
The development of microscopic methods for the study and 
identification of opaque minerals ^ within the last few years has 
created a demand for inexpensive, easily transportable instru¬ 
ments of simple construction which may be carried and used 
in the field. A microscope of this sort was described by Davy 
at the August, 1920, meeting of the American Institute of 
Mining and Metallurgical Engineers. 
'Murdoch, J., Microscopical Determination of the Opaque Minerals, 1916. 
Wiley & Sons, N. Y. Davy, W. M., and Farnham, C. M., Microscopic Examina¬ 
tion of the Ore Minerals, 1920. McGraw-Hill Book Co., N. Y. 
