22 THE STRUCTURE OF 



to any amount of pressure thought necessary, 

 (Fig. 10.) This is a very important instrument 

 for examining minute Crustacea, animalcules, 

 zoophytes, and other living and moving objects, 

 especially when they live in water. 



Fig. 10. Animalcule Cage or Live Box. 



In the use of the cage and the slide, care must 

 be taken not to break them by turning the object- 

 glass down upon them. It is sometimes a difficult 

 thing, when the object-glass has a focus of not 

 more than a quarter or eighth of an inch, to adjust 

 it to exactly the point at which the object is best 

 seen, by means of the coarse handles on the rack- 

 work. For this reason the Microscope has been 

 provided with a fine adjustment, by which the 

 object-glass is moved down on the object in a 

 much slower and more gradual manner, and the 

 destruction of an expensive objective glass is often 

 thus prevented. 



The picture of the object brought to the eye in 

 the Compound Microscope is always the wrong end 

 upwards. That is, the picture is always the reverse 

 in the Microscope to what it is with the naked eye. 

 You need constantly to be aware of this, especially 

 if you are going to dissect an object under the 

 Microscope, as your right hand becomes left, and 

 your left right. The observer, however, soon gets 

 accustomed to this, and it creates no difficulty ulti- 

 mately. But science constantly attends on the 



