THE COMPOUND MICROSCOPE. 



As has been stated a magnified image is observed 

 in the Compound Microscope. Any two lenses of 

 suitable focus, placed sufficiently far apart, will attain 

 this object, and this was for years the method of 

 construction. 



In any microscope, whether simple or compound, 

 the difficulty of holding it or the object steady during 

 observation increases with the increase in magnifying 

 power, and in the compound form with only a 

 moderately high power it is utterly impossible to 

 retain sufficient steadiness to make any reliable obser- 

 vation. Mechanical contrivances therefore are a neces- 

 sity and were applied in the very earliest constructions 

 of the microscope. Even when such a luxury as an 

 achromatic lens was unknown they were all made to 

 embody the following essential parts: 



A platform or stage for holding the object. 



A means of adjustment for properly focusing the 

 lenses on the object. 



Provisions for suitably illuminating the object. 



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