DESCRIPTION OF THE ACHROMATIC MICROSCOPE. 109 



the phial-bolder the plant may be of a size sufficient to 

 live for months, during which it is ever ready for exami- 

 nation without any preparation whatever. 



In a microscope of the common construction, if the 

 magnifier or object-glass should be accidentally brought 

 into contact with the object, when it is placed on the slip 

 of glass used for the purpose, it is very liable to be de- 

 stroyed. In this we perceive another advantage of the 

 phial-holder; for the spring, in this case, behind the 

 vessel, would yield, and thus prevent the injury. 



Fig. 21. 



Fig. 21 represents the microscope with the body e, n, 

 in a horizontal position. The stage is removed, and the 



