The '■'■Oil Imviersion " of Carl Zeiss. 29 



grade, having a balsam angle of about 102°. I say their then 

 highest grade, as they have since brought out a ^th, and also 

 a yV^h, on a new formula having a balsam angle of near iio'^. 

 One of the objectives sent to Germany was compared with the 

 new " Zeiss Oil Immersion " by a personal friend of mine, not 

 the owner of this objective ; he pronounced it an excellent 

 glass, but, to use his own words, " a long way behind his Zeiss 

 Oil Immersion." I felt inclined to accept this decision, 

 though the Messrs Spencer assured me, that there must be 

 some mistake ; yet, from the very high reputation of M. Zeiss, 

 and especially from his connection with Professor Abbe, in 

 the production of the new objective, I was prepared to admit 

 that he had, really, made something of surpassing excellence, 

 which would easily beat any competitor. True, Mr. Dallin- 

 ger's report upon this objective showed that, upon the whole 

 the new optical wonder of Jena did not quite equal the Powell 

 and Leland " ^th new formula," but then I had not seen any 

 of these new formula objectives of the world-renowned 

 English opticians, and as the 'same able and wholly competent 

 judge had decided that Mr. ToUes' ^/^th was not quite up to 

 this " new ^th " though pressing it very closely, I felt inclined 

 to believe that, really, M. Zeiss had stolen a march on the 

 Americans. For the purpose then of satisfying myself, and 

 for the grim satisfaction of convincing the Messrs. Spencer, I 

 purchased in London a " gV^h " immersion by Zeiss, with the 

 express notice that it was to be tested against the best Ameri- 

 can objectives, and more recently induced a friend, who had 

 just received the " new oil immersion ^th " to send me that 

 for examination. The }^X\\ proved to be a good objective. I 

 did not feel like complaining that I had not the worth of my 

 money, but it was not so good an objective as I could have 

 procured from either Tolles, or Spencer, though of higher 

 numerical grade than they would have furnished for the same 

 money. It proved certainly, that M. Zeiss was an excellent 

 workman, and as I have said I did not feel disposed to think I 

 had paid too high a price, as Franklin has it, " for the whistle ; " 

 but I did expect to see something far superior to the -^^\\\ 

 when the '' oil " should arrive. This indeed proved to be the 

 case, and I have no hesitation in saying, and all who have 

 looked through it here agree with me, that up to this time, the 

 new Zeiss " ^th Oil Immersion " is the best foreign made objec- 



