1898.] MICROSCOPICAL JOURNAL. 193 



hitherto been used for correcting chromatic aberration ; 

 also a new apparatus for furnishing parallel rays for 

 monochromatic light of great intensity, and I am satis- 

 fied that ten million diameters can easily be photographed. 



Can a second microscope be used to view the magnified 

 result of a first microscope so as to give details which the 

 lens of highest power would not give singly? It is 

 necessary to prove this, because it is widely taught that 

 to get greater magnification and detail than a given lens, 

 say a one-sixth inch objective, we must use a smaller 

 lens, for example an eighth-inch, and get nearer the object. 

 That this is not true I can demonstrate. 



If the widely accepted theory be true, the only way by 

 which I can get a better magnification than with a one- 

 twelfth inch objective is to use a l-16th inch, with greater 

 aperture because among other things no other lens would 

 be smaller and nearer the object. But instead, I took a one- 

 sixth inch objective for the first microscope, and a two- 

 thirds inch objectivefor the second microscope,Hnd focussed 

 the objective of the second instrument upon the focal 

 plane of the image in the ocular of the first instrument, 

 the outer lens of the ocular having been removed, and then, 

 to the ocular of the second instrument, I adjusted my pho- 

 tomicrographic camera, and the^result was the magnifica- 

 tion greater than a one-sixteenth inch lens, and. more de- 

 tail far beyond any 24th inch objective. 



This proves that with two lenses low down in the Series 

 — a two-thirds and a sixth — I have obtained a better re- 

 sult than with an expensive sixteenth. 



Then I tried a still lower lens in the second instrument 

 — an inch lens — and a twelfth in the first instrument. I 

 used shortest tube-lengths and two-inch oculars, and the 

 result is the magnification is nearly 10,000 diameters. 



So far I have demonstrated that better work can be 

 done with low power lenses by using a double-micro- 

 scope than with the highest power lenses, if but a single 



