president's address. 21 3 



country to arouse itself to its responsibilities and obligations in 

 this direction. There are limits beyond which private enter- 

 prise cannot go. It is to German State aid that we are indebted 

 for a considerable portion at least of what has resulted to 

 microscopy by the invention of the Abbe-Schott optical glass, 

 and it is only societies like this that can know efficiently what 

 this means. 



A well -equipped optical laboratory would, I believe, in- 

 augurate a new future to theoretical and manipulative optics in 

 England, and in all probability exert a powerful influence on 

 the sciences affected by its progress. 



The practical microscopist is often struck with the singular 

 want of knowledge displayed, sometimes in the most unexpected 

 quarters, in the elements of practical knowledge concerning the 

 microscope. During the past year those who were not in posses- 

 sion of more accurate information beforehand might have come 

 to the conclusion that some sweeping advances had been made 

 in the very principles of our instrument, for in a leading scientific 

 journal published in Germany* " a new construction for the 

 microscope " was very gravely announced. It was by Dr. Lendl, 

 who pointed out that the supreme purpose of the microscope 

 having been now accomplished by the construction of immersion 

 and apochromatic systems of object-glasses, it was time to seek 

 to combine with this improved power of definition a much in- 

 creased magnifying power. 



And this charming desideratum is, he tells us, to be brought 

 about quite independently of the objective and without increas- 

 ing the power of the eye-piece, by what he designates a change 

 in the construction of the microscope. 



The e3^e-piece is removed and replaced by a second complete 

 microscope, so that the image formed by the objective is no 

 longer submitted to further amplification by the eye-piece, but 

 by this auxiliary instrument. By this means it is claimed that 

 far greater magnification in its proper sense is secured, and far 

 less light lost than with deeper eye-pieces. 



It was soon pointed out by Mr. Nelson, as it had been pointed 

 out by others, that this was only a more pretentious recurrence 

 of that optical ignis fatuus of some years ago, the Aplanatic 

 Searcher. 



* "Zeitschr. f. Wiss. Mikr.,'' viii, (1891), pp. 181-90. 



