ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 525 



The apparatus was brought from Philadelphia by Colonel G. L, 

 Tupman, E.M.A., to whom we are indebted for the diagram. 



High Magnifying Power. — The following will serve to start a 

 column of " Curiosities of Microscopical Optics ! " It is not neces- 

 sary to suppose it to be a hoax, as claims to magnifications not far 

 short of some of those described have previously been made with 

 undoubted seriousness. 



" Professor F. G. Fairfield, of New York, has, according to 

 Gaillard's ' Medical Journal,' invented a new oly'ective, giving an 

 increased magnifying power of 49 per cent. It multiplies the power 

 of the Microscope by 7 in diameter and by 49 in area. The visualiz- 

 ing power of the Microscope had heretofore been reckoned to be equal 

 to the showing of an object -rsinroo ^^ ^^ inch in diameter. That 

 was the limit to which Helmholtz attained. With Tolles' Jg-inch, 

 exhibited in the New York Academy of Science two years ago, it was 

 shown that there could be discerned an object 2^5-0-^ iro of an inch 

 in diameter. ' With the -i-inch objective or lens,' said the lecturer, 

 I am able to discern an object ^•q^^o'o 0" ^^ ^^ ^^^^^ a^^ diameter ; 

 and if I were to apply the same principle to a y^g-inch lens, I should 

 be able to discern an object, making allowance for proper diffusion 

 of light, as minute as Tg-x^o^o-o^ro ^^ ^^ ^^^^ ^^ diameter. At that 

 power it would be possible, unless the molecule of albumen be much 

 smaller than it is supposed to be, to discover and demonstrate the 

 molecular constitution of living matter.' The objective invented by 

 Professor Fairfield is composed of three minute lenses in succession. 

 After the rays have passed through the three lenses, formed their 

 image, and crossed, they are then taken up in a field-glass, through a 

 second powerful lens, cross a second time, and a second image is 

 formed from the first. The alleged result is that the penetrating 

 power is very much improved as compared with the ordinary lens, 

 whose power is actually multiplied by more than 49 per cent. The 

 lens is so minute as to be capable of being used only by the aid of 

 the electric light." * 



We may again point out that Professor Helmholtz has never 

 asserted that the tswo-^o ^^^^ ^^ ^^^ limit of visibility in the Micro- 

 scope. His researches on this subject referred to the limit to the 

 poiver of separating two portions of an object which are close 

 together. 



Fig. 126. 



Graham's Compressorium. — Fig. 126 shows this apparatus, which 

 was described, but not figured, at p. 148 of vol. iii. (1880). 



* 'British Medical Journal,' 1881, March 5th. p. 3ii3. 

 Ser. 2.— Vol. I. 2 N 



