COKRESPONDENCE. 81 



Sciences of Philadelphia, that by taking a photograph through each 

 tube of the binocular microscope and afterwards combining these two 

 pictures by looking at them in the ordinary hand stereoscope, we should 

 secure a i)erfect and complete reproduction of the exquisite image in 

 relief obtained by the aid of double-tubed instruments, and he recom- 

 mended that the method should be tried at an early opportunity. 



COKKESPONDENCE. 



On Mr. Wenham's Keply to Db. Woodward, 



To the Editor of the ^Monthly Microscopical Journal.^ 



Boston, Mass., U.S.A., December 16, 1873. 



Mr. Editok, — I have no intention of engaging in the " battle of 

 the glasses," but as I have been conversant from the commencement 

 of the "battle" — more so probably than Dr. Woodward — with some 

 of the facts, I wish to offer in your pages a few remarks on Mr. 

 Wenham's " Eeply to Col. Dr. Woodward," printed in your December 

 issue. 



Mr. Wenham writes, " The controversy has been so long and 

 tedious, that it is not a matter of surprise that they (i. e- the points of 

 the controversy) should be forgotten." I must thank Mr. Wenham 

 for the suggestion. Let us inquire whose memory has failed. That 

 the controversy has been so long is in a measure owing to the 

 necessities of the printers, and the interposition of the Atlantic 

 Ocean between the combatants. From the time that Mr. Wenham 

 writes his optical laics, it requires three — perhaps four months before 

 a reply can be published in London. It may have been tedious to 

 Mr. Wenham to reiterate the impossibility of doing what had often 

 been done, but I can assm-e him that his efforts in the cause have been 

 eagerly looked for by microscopists at this side. 



It is certainly " a matter of surprise " that Mr. Wenham himself 

 is the one that has forgotten the subject of the controversy. " I can- 

 not think that I have anywhere stated distinctly that it was not pos- 

 sible to construct an object-glass with an immersed angle exceeding 

 82° " (December number, p. 256). In No. XXVIL, p. 118, May, 

 1871, he writes, " and whether the object is mounted in balsam or not 

 — I challenge Dr. Pigott, OR anyone else [capitals mine], to get, 

 through the object-glass with the immersion front, a greater angle, or 

 any portion of the extreme rays that would in the other case be totally 

 reflected, as NO object-glass oan [capitals mine again] collect image- 

 forming rays beyond this limit." 



That is, and has been, the question, and the whole question in con- 

 troversy. There is no allusion whatever to " reduced angle." There 

 is no intimation that Mr. Wenham had ever constructed, or dreamt 

 (which is about all that he now claims) of constructing, a lens capable 

 of such a performance, but — if words have meaning, — a distinct unqua- 



