272 THE MICROSCOPE AND ITS LESSONS. 



three years before, have thought such impossible. "A 

 quarter of a century " ago leads us to the year 1866, and, 

 amongst the many interesting memoranda of my common- 

 place books, I find the following: "Mr. Powell" (of 

 "Powell and Lealand," one of the best of microscope- 

 makers in the world) "told me, Nov. 5, 1859, while 

 showing me the smallest lens of his one-sixteenth object- 

 glass, which he then charged 16 16s. for, that its 

 diameter was only the twenty-fifth part of an inch, and 

 that such a lens could be ground to such a mathematical 

 nicety that it would distinctly present the object to 

 the eye when magnified, with the fifth eye-piece, 4800 

 diameters which is, in fact, twenty-three millions and 

 forty thousand times, superficial measurement. The 

 material he used was chiefly foreign glass, very pure, 

 and when brought over, about the size of a cheese-plate, 

 three-quarters of an inch thick, each cake cost 11." 

 Subsequently, the same celebrated makers exhibited what 

 the Journal of the Microscopical Society for February, 

 1864, in a report of the president's address, called "a 

 triumph of artistic skill," in which the one-sixteenth 

 glass of 1859 had grown to a twenty-fifth, the magnify- 

 ing power greatly exceeding that of their greatest figure 

 of five years previous ; and the same authority then said, 

 " We cannot doubt that the wonders of creative benefi- 

 cence will be developed in proportion to our extended 

 means of investigation, and we can fully testify to having 

 repeatedly seen, under this objective, evidences of 

 structure that are, under ordinary powers, utterly in- 

 distinguishable." 



These prophetic words were uttered about a quarter of 

 a century ago ; since then the one-twenty-fifth has, by the 

 same firm, grown to a one-fiftieth object-glass, and the cost, 

 as compared with that of the previous lens, risen from about 



