ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



673 



Beck's Mineral Microscope. — This (fig. 115) was devised by the 

 late Mr. R. Beck for rapidly looking over large pieces of rocks. The 

 body-tubes and pillar of a binocular Microscope are attached to a flat 

 horizontal bar which is passed through longitudinal apertures in two 



Fig 115. 



standards which rise from a large wooden base. The ends of the bar 

 project sufficiently to allow of its being moved by the hands from 

 side to side and from back to front, so that the Microscope can be 

 passed over a large rock placed on the base. The latter is 11 in. x 

 10 in., and the bar is 6 in. above it. 



Deutgen's Micrometer-Microscope. — This Microscope (fig. 116) 

 was devised and constructed in 1845 by Herr H. Deutgen, of 

 Groningen, for the physical laboratory of the University of that city. 



The peculiarities are (1) the application of the Turrill system of 

 mechanical stage, which had only then been recently invented by 

 Ser. 2.— Vol. VI. 2 Y 



