112 HOW TO SEE WITH THE MICROSCOPE. 



lenses will show, and that if one takes a higher power 

 that will show the images, he will find, by comparison, 

 the higher power will be the more difficult to manage. 

 The whole question tums upon results ; if you are con- 

 tent with medium images, use medium or low-angle 

 objectives; if you train your eye for fine images, you 

 must use high-angled objectives." 



In 1876, Dr. J. Gr. Hunt, of Philadelphia, a widely 

 known and expert microscopist, after having given the 

 new American objectives of medium power close study, 

 writes as follows ; and believing that the doctor's letter 

 will be found of general interest, we give it entire* 

 The glass he makes reference to was a Tolles tenth : 



" I can now report to you that the one-tenth you 

 sent me is grand. It contains more good qualities than 

 are to be -found in many first-class lenses perfect 

 mechanical workmanship, large field, gives sharp image 

 on the margin of field, decision of definition leaving- 

 nothing doubtful or foggy, equal penetration with reso- 

 lution; thus being superior for his tological work. 



I could engrave it all over with marks of 

 admiration. . . . For the best work of 

 the botanist or histologist it has a definition which can 

 be retained, with an amplification such as I have not 

 seen in any one twenty-fifth or one-fiftieth that has come 

 under my notice. ... I see in its con- 

 struction more finger skill, more time and conscious 

 brain patience than mathematics. Hence its charac- 

 ter; it has no precedent, but is wholly original, and 

 unlike any other ma&e, English or continental." 



