154 HOW TO SEE WITH THE MICROSCOPE. 



and attention, and that the manipulations of the same 

 are not acquired in a day. 



In iny intercourse with microscopists, I have nearly 

 always found one idea salient. The general question 

 has been and now is, * How shall we contrive to save 

 expense ; where can we buy the cheapest? " 



It seems to me that these considerations must eventu- 

 ally force the wide apertures into use. I was about to 

 say, "There's millions in it." For example, we know 

 of a microscopist who has, by purchase, from time to 

 time, acquired a batter} 7 of some 35 or 40 objectives. 

 Now, allowing the cost of these to average $10 each 

 not a high estimate the owner has thus paid out some 

 $350 or $400 for objectives alrne! While one-half that 

 money, expended in glasses of the highest apertures, 

 would have enabled our friend to have accomplished 

 any and all work that can be effected with his entire 

 battery. And unless I am greatly mistaken, the wide 

 apertures would carry the day, and with flying colors. 



This is no solitary case. We have in very many in- 

 stances been called on to select wide-angled objectives* 

 for our friends and correspondents, and in each and every 

 case there have been no exceptions we have received 

 assurances from the parties interested, that there would 

 have been money saved had the facts been known in 

 time. Says one: " My one-fifteenth that I bought two- 

 years ago is a dead letter; what shall I do with it? I 

 can't sell it for anything like what it cost, it would be 

 perpetrating a swindle !" Says another : " If I had met 

 you thirty days ago I would be a hundred dollars better 



