THE MICROSCOPE. 
. -*- 
CHAPTEB VI. 
83. His object-glasses. Messrs. Smith and Beck’s microscope : 84. Their 
largest and most efficient instrument.—85. Their smaller microscope. 
—86. Their object-glasses.—87. Yarley’s microscope. M. Nachet’s 
microscope : 88. Their adaptation to medical and chemical purposes. 
■—89. Multiple microscopes.— 90. Double microscope.—91. Binocular 
microscope.—92. Triple and quadruple microscopes. 
83. With his largest and best instruments, Mr.„ Boss supplies 
four eye-glasses and eight object-glasses, by which thirty-two 
varieties of power and illumination may be obtained. The object- 
glasses vary from two inches to a 12th of an inch' in focal 
length, and from 12° to 170° in angular aperture. The following 
Lardner’s Museum of Science. a 81 
No. 116. 
