124 THE AMERICAN MONTHLY [July 



zones ; but the best of them reveal a marvellous standard 

 of approach to this ; and with that we find ever associ- 

 ated an increase of that practicable cone of heterogeneous 

 light which we have found so all-important to true con- 

 tours. And with this we get further revelation. More min- 

 uteness we do not indeed get; for that we can look only to the 

 1-63 lens. But we have a world of structure to learn yet, 

 within the resolution of our present lenses ; and for that 

 we are only waiting better condensers and better correc- 

 tion. It was only recently that the protoplasm so long 

 written about as " structureless jelly," yielded up some at 

 least of its marvellous and minute structure, which can 

 only be seen by English wide-cone methods, with one of 

 the exceptionally-perfect objectives here referred to ; 

 whose significance, however, as we have seen, is not yet 

 recognized on the Continent as it is in England, and even 

 here only by the few. It may be beyond us to-day to 

 discover the minute departures from type which cause 

 the superiority of the few phenomenal lenses : it is no 

 easy thing to ascertain precisely what it is, in a lens one 

 of whose components may not exceed a hemisphere 1-16 

 of an inch in diameter. But the superiority is there ; it 

 has been attained; and we may cherish reasonable hopes 

 of such discovery. We may anticipate that the present 

 rarest excellence may be reached yet as a standard, more 

 generally procurable by the scientific investigator; that 

 the very best of all may even be further improved in 

 correction in some degree. If it be so, such advances 

 will not be barren of results in research. The microsco- 

 pist may yet hope and take courage. 



Personal.— Prof. W. A. Rogers died at Waterville, 

 Maine, March 1, 1898, aged 61 years. He had been pro- 

 fessor of physics and astronomy in Colby University since 

 1886 but expected to remove to Alfred University the 

 Iresent spring. 



