ON CONSTRUCTING STANDS OF MICROSCOPES. 165 



tubes is a novelty produced by Mr. Pritchard expressly 

 for his diamond and sapphire instruments. 



I therefore conclude that the principles, at least, of the 

 best possible construction for the mechanical part of 

 microscopes, may be defined. I have attempted to re- 

 duce them to practice in an instrument the patterns of 

 which 1 have executed with my own hands, and Mr. 

 Pritchard has made a mechanical drawing of it, which 

 he will describe in the next chapter, under the title of 

 my Operative Aplanatic Engiscope. Before, however, the 

 description proceeds, I must beg a boon of my readers 

 and the microscopic world at large, viz. to permit me 

 to supplant the term Compound Microscope by the word 

 EXGISCOPE, which seems to me more apposite. 



It is derived from two Greek words, lyyCc, near, and 

 ffKovlw, to view, and therefore well expresses an instru- 

 ment for viewing close objects, or for viewing objects 

 closely, and is in strong contradistinction to the term 

 telescope, derived, as my readers well know, from reXoc, 

 an end or distant limit, and vKoirlta, and therefore denoting 

 an instrument for viewing distant objects. The term 

 microscope, derived from /m'poc, small, and O-KOTTCW, sig- 

 nifies an instrument for examining small objects, which 

 is perfectly correct also, but in bad contradistinction to 

 the telescope, which would have to be named megala- 

 scope, to oppose it (from ptyas, great, and o-jcoTn-'w,) which 

 expression would be perfectly accurate when applied to 

 the telescope, for it views very large objects, such as the 

 totality of a planet or the sun, &c. Now a compound 



