122 Ndberfs Nineteenth Band 



Boston, Sept. 30, 1870. 



Dear Sir, — In reply to your note of inquiry concerning my ex- 

 perience wdth Nobert's test-plate, I would say that I have examined 

 the lines and witnessed their resolution on sundi-y occasions. 



I have seen the lines of the 19th band satisfactorily resolved with 

 a Powell and Lealand's ^V*^ under the skilful manipulation of my 

 friend Dr. Woodward, at the Ai-my Medical Museum, Washington, 

 D.C. I have repeatedly seen the same equally well in this city with 

 some of ToUes' excellent objectives ; I have one which with its immer- 

 sion front is a yytl' ^^^^ shows the true lines of the 19th band. This 

 is the highest power of Tolles' make with which I have seen the lines 

 in question. 



One year ago, at the Eleventh Triennial Exhibition of the Mas- 

 sachusetts Charitable Mechanic Association, the board of judges (of 

 which I was one) held several meetings to test the relative and 

 abstract merits of microscope objectives exhibited. A yxj^h. Amician 

 objective made by Tolles, and owned by Mr. Bellis, of Waltham, was 

 on exhibition, which with a B eye-piece clearly resolved the lines of 

 the 19th band of Nobert's plate, not only to my own satisfaction, but 

 also to the full satisfaction of others, among whom may be specified 

 C. K. Stevens, Esq., of this city, whose experience on this subject 

 has been quite extensive. It is proper here to observe that Mr. 

 Stevens has been an intelligent amateur microscopist for more than 

 twenty years, and has had large experience with Nobert's plates. He 

 imported a twenty-band plate some fifteen years ago for his own use, • 

 and possessed the best objectives of the most renowned makers abroad 

 and in this country. Mr. Spencer, of Canastota, N.Y., made for him 

 seven first-class objectives, on orders without limiting the price. I 

 mention these points, merely to show that Mr, S. is no novice, but 

 experienced and competent to judge, notwithstanding his modesty 

 and retii-ement has kept his name from extended publicity. As this 

 jijth objective was reported to have been in the hands of other micro- 

 scojiists of justly acknowledged eminence, who placed the 16th baud 

 " at high-water mark " in its performance, at my suggestion other com- 

 petent observers were invited to test its qualities. Among those 

 invited were Dr. B. A. Gould, ex-President of the American Associa- 

 tion for the Advancement of Science ; Dr. Walcott Gibbs, Eumford, 

 Professor in Harvard College : both of these accomplished observers 

 stated in unequivocal terms the satisfactory manner of the work in 

 fully resolving the 19th band ; Dr. Gould is now in South America, 

 but Professor Gibbs permits the use of liis letter on the occasion, 

 which reads thus : — 



Dr. Josiah Curtis, Cambridge, Oct. 18, 1869. 



Dear Sir, — In accordance with your request, conveyed to me 

 through Mr. Stodder, I called this afternoon on Mr. Tolles. With a 

 y\j^th objective and a B fjye-piece, I saw the 19th band of Nobert's 

 test-plate distinctly resolved into lines without any lateral bands or 



false images whatever Eespcctfully yours, 



Walcott Gibbs. 



