3134 HOW TO SEE WITH THE MICROSCOPE. 



rior defining glass I have still working distance enough to 

 illuminate my object by condensing sunlight on top of the 

 cover, thus securing exquisite definition under amplification of 

 more than 5,000 diameters. Here, again, with said l-6th, I get 

 better work than I can with any other style of glass. 



Again, should it be desirable to cross-question my specimen 

 still closer, it would become necessary to remove the l-6th and 

 substitute a bran-new l-10th not yet a month old, the master- 

 piece of a young American optician. This l-10th has also the 

 widest aperture known, combining still more exquisite defini- 

 tion with sufficient working distance to allow the use of sun- 

 light as above named, while its glorious performances by central 

 light eclipse, yea, distance the work of any low-angled glass 

 extant, this beyond the ghost of a doubt. (And right here I 

 beg Prof. Hitchcock to be lenient, and to allow me a little mar- 

 gin ; it's hard to keep cool over the central-light performance of 

 this new MOth). But, with the employment of this l-10th, we 

 get into tolerably close quarters, the " difficulty of working " is 

 enhanced. It won't do to put the screw-collar somewhere 

 between " zero " and somewhere else. And then, too, there has 

 got to be a good deal of that - w handling " attended to that 

 Prof. H. says will do so well to talk about before an audience. 

 Prof. Hitchcock here applies the great American question, and 

 asks if all this bother will pay. I reply, " Yea, verily !" 



I shall be very grateful if Prof. Hitchcock will point me to 

 glasses that will take the place of those above mentioned. It 

 has so happened that those who have thus far undertaken this 

 task (and some have traveled hundreds of miles to accomplish 

 it) have resigned their previous ideas in my favor. In fact, I 

 have scores of friends made in just this kind of a way, and I 

 hope to add Prof. H. to the list. 



Having thus given my ideas as to the nature and performance 

 of high-angled objectives, I beg to add that I see no necessity 

 for backing down from my original statements, although chal- 

 lenged by Prof. H. On the contrary, the advent of the new l-10th 

 serves to clinch the nail that I had previously well-driven home 

 with the duplex. And I now place again on record my deep- 



