ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



1047 



than the old forms of lantern Microscopes. It has a large rotating 

 diaphragm forming an entirely open stage, which greatly facilitates 

 the manipulation and gives a clean sharp edge to the disc. By a 

 prism the image can he thrown down on paper for drawing. Any 

 good Microscope objectives can be used. 



For high power work it cannot of course compare with the 

 Wright and Newton lantern Microscope. 



Leeuwenhoek's Microscopes. — Leeuwenhoek, it will be remem- 

 bered, published nearly the whole of his microscopical investigations 

 through the medium of the Eoyal Society, and yet, beyond the occa- 

 sional statement by himself that his observations were made with 

 simple Microscopes, nothing appears to have been definitely known 

 by his contemporaries regarding their actual construction. The 



general impression during his lifetime seems to have been that he 

 utilized lenses consisting of spherules of blown-glass. At his death 

 (1723) he bequeathed to the Eoyal Society a cabinet containing 

 twenty-six of his Microscopes (now lost), and these were reported 

 upon * somewhat vaguely by Martin Folkes, Vice-President of the 

 Eoyal Society, who appears not to have directed his attention 

 minutely to their construction. 



In 1740 these Microscopes were examined and described f to the 

 Eoyal Society by Henry Baker, F.E.S., whence it appears that the 

 magnifiers were not spherules of blown-glass, but bi-convex lenses 

 having worked surfaces, and that they ranged in power from 1/5 in. to 

 1/20 in., magnifying from 40 to 160 diameters. No figure of any of 

 the instruments was however published until 1753, when Baker { 

 issued two outline drawings representing both sides of one of them 



* Phil. Trans., xxii. (1723) pp. 446-63. t Ibid., xli. (1740) pp. 503-19. 



I •Employment for the Microscope,' 1st ed., 1753, pp. 434-6, pi. xvii. 

 figs. 7 and 8. 



