JOURNAL 



OF THE 



ROYAL MICROSCOPICAL SOCIETY. 



JUNE, 1907. 



TRANSACTIONS OF THE SOCIETY. 



Y.—An Early Criticism of the Abhc Theory. 

 By J. W. Gordon. 



{_Read February 20, 1907.) 

 Plates XII. and XIII. 



On reading my copy of the December Journal 1 find myself 

 referred to in a paper presented to the Society on October 17 

 last by Mr. A. E. Conrady, and as I may have unintentionally 

 appeared wanting in courtesy to the Society in general and to the 

 author of the paper in particular, inasmuch as I took no part in 

 the discussion, I will ask leave to explain that my silence was only 

 due to the fact that I was wholly unaware of what was proceeding ; 

 it not having occurred to the author of the paper to give me notice 

 that I should be put on my defence. 



The point made against me is that my criticism of the Abbe 

 theory contained in a paper read before the Society in June, 1901, 

 and printed at page 353 of the volume for that year of the 

 Society's Journal had been anticipated by a certain Professor 

 Altmann twenty years before and answered in effect l)y Professor 

 Abbe in his paper " Uber die Grenzen der geometrischen Optik." 

 I appreciate that Mr. Conrady has absolved me from the necessity 

 of showing that I did not borrow from Altmann's paper, but it is 

 not altogether irrelevant to what I have to say if I mention that I 

 have never seen that paper, and I had never even heard about it 

 until some six months ago when I read in Abbe's Collected Works 

 the above-mentioned paper on the limits of geometrical optics. 



With regard to the matter of substance, I have to point out 

 that between Altmann's paper and mine there is — to judge from 



June 19th, 1907 T 



