MICROSCOPY FOR BEGINNERS. 



CHAPTER I. 



THE MICROSCOPE AND ITS PARTS. 



Simple and Compound Microscopes. Pocket -lens. " Craig Mi- 

 croscope. "" Excelsior Microscope." Watch-maker's Glass. 

 Coddington Lens. How to Focus a Simple Lens. Parts of the 

 Compound Microscope. Draw - tube. Eye - pieces. Society - 

 screw. French Triplets. Objectives. Selecting Objectives for 

 the Beginner. Coarse Adjustment. Focussing. Fine Adjust- 

 ment. The Stage. Diaphragm. Mirror and Bull's-eye Cou- 

 densing-lens. Preparing the Object. Thin Cover-glass. Cells. 

 Cement. Dry Mounting. Needles. Dipping - tube. Bunsen 

 Burner. Evaporation from beneath the Cover. Life -slide. 

 Growing - cell. Air - bubbles. Drawing. Camera Lucida and 

 Glass Reflector. Micrometer. Measuring the Object. To as- 

 certain the Magnifying Power. Collecting-bottles. Books and 

 Magazines for Reference. 



MICROSCOPES are compound or simple : compound 

 when they consist of two or more glasses, one or more 

 being near the object to be examined, and one or more 

 near the eye of the observer ; simple when they consist 

 of but one double-convex lens to be held near the ob- 

 ject, or of two or more lenses that can be used singly or 

 all at the same time. "When thus used in combination, 

 the two or three simple lenses are not only placed close 

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