Testing a Microscope 47 



A good idea of the comparative quality and finish can 

 often be obtained by examining some hidden or unnoticed 

 part, and observing whether the same care in finishing has 

 been exercised there as in parts that are seen. For instance, 

 if some microscopes be examined underneath the foot, they 

 will be found left in the rough as cast, and merely blackened 

 over; while another instrument will be found carefully 

 finished in that part. It would not necessarily follow that 

 the former was a bad instrument, but it would often be 

 found, if taken to pieces, that there was not a careful 

 fitting in working parts that did not catch the eye, and 

 there would be a probability of its not proving so durable 

 as the better-finished instrument. 



