1>()PULAR ERRORS ABOUT GREAT MAGNIFICATION. 5 



inagiiii'viiig power ns is done by instrimu-nts of 

 Ix'tter construction. The best and most expensive 

 .uhisses will not only bear long tubes, but also eye- 

 pieces of high power, without any practical diniinu- 

 tio!i of the accuracy of their operation, and this is 

 a great convenience in natural history investiga- 

 tions. To obtain it, however, requires such perfec- 

 tion of workmanship, as to be incompatible with 

 cheapness. An experienced operator will not be 

 satisfied without having an object-glass at least as 

 liigh as a quarter, that will bear a second eye- 

 piece, but beginners are seldom successful with a 

 higher power than one of half-inch focus, or there- 

 al)outs, and before trying this, they should familiarize 

 themselves with the use of one Avith an inch focus. 

 It is a popular error to suppose that enormous 

 nuignitication is always an advantjige, and that a 

 microscope is valuable because it makes a flea look 

 a.s big as a cat or a camel. The writer has 

 often smiled at the exclamations of casual visitors, 

 who have been pleased with his microscopic etforts 

 to entertain them. ''Dear me, what a wonderful 

 instrument; it must be immensely powerful;" and 

 so forth. These ejaculations have often followed 

 the use of a low power, and tlieir authors have 

 been astonished at receiving the explanation that 

 the best microscope is that which will shew the 

 most with the least mairniiication, and that ac- 



