THE MICROSCOPE. 201 



B. & L., I N. A. 1.43; B.&L.,£ N.A. 143; Spencer | N. A. 1.38, and 

 Spencer ^ N. A. r.25. The light is condensed upon the front 

 and radiated. Some strike the slide at more than 41 and enter 

 the objective as very oblique light. I. E. S. evidently believed it 

 to be genuine central light, but I can very easily demonstrate that 

 it is not. He said that his Tolles' -fa also does it. 



Very truly, 



A. Y. Moore. 



Boston, March 29, 1883. 

 My Dear Sir: 



Your favors of the 2 1 st to hand in due time. Certainly the 

 large N. A., A, Y. Moore, adduces is not needed to show the brilliant 

 lineation by central sun light, rather in the way, rather outside of 

 what is reflected from the slide, lower surface totally, and reaching 

 the balsamed object. I enclose your drawing and have 

 pencilled the directions, first and secondary reflections of the ray. 

 It is, you see, possible, but the film is, I suppose, of flatter curves than 

 you have drawn. 



You ought to announce the discovery, for it is a discovery, and 

 I think very neat. As to its being a taking piece of apparatus, if 

 made, I am somewhat doubtful. I wonder where you find the 

 people who refuse to see the lines of A. pellucida, I thought the 

 species extinct. If I get leisure to afford it I may try something. 

 You plan should go well, with room to place the apparatus, a 

 conical front. I think a balsam angle of 90 would do fairly. 



I am, very truly yours, 



R. B. Tolles. 



THE RESOLUTION" OF AMPHIPLEURA PELLUCIDA— 

 A REPLY TO DR. DETMERS. 



BY A. Y. MOORE. 



THROUGH the kindness of the editor of this journal, I have 

 been permitted to read the proof sheet of the foregoing article 

 by Dr. H. J. Detmers, and as some very peculiar ideas — ideas which 

 seem totally opposed to facts or reason — are embodied in the 

 article, I desire to say a few words upon the subject. 



Dr. Detmers makes. the statement, without qualification, that 



