ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



275 



Binocular Dissecting Microscope.* — Prof. F. C. Van Dyck de- 

 scribes a "binocular dissecting and mounting simple Microscope, made 

 of a stereoscope by turning tbe lenses end for end, and tilting them so 

 as to prevent the disagreeable convergence of optic axes, which an ordi- 

 nary ' reading glass ' necessitates. The arrangement is equivalent to a 

 reading glass cut in two, so that its parts may be set at such angle and 

 distance as prove effective. If you try it by holding a couple of stereo- 

 scopic lenses about five inches from a flower, you can prove the comfort 

 of the thing, and try, by shutting one eye, how much good the binocular 

 effect does. The aberrations are very marked, of course, but do not 

 practically annoy." 



" I have used mine," he says, " for a year or more, and find it very 

 convenient. The affair is so cheap and so easily made by any one that I 

 am inclined to publish a note on it if new, which it is, so far as I know." 



Leitz's large Dissecting Microscope. — The speciality of this 

 Microscope (fig. 41) consists in the arrangement for extending the lens- 



FiG. 41. 



holder. This is attached to a bar which slides by a small knob in a 

 grooved plate, the latter again sliding in a second grooved plate rotating 



» Queen's Micr. Bulletin, v. (1888) p. 25. 



