ZOOLOGY AND BOTANY. MICBOSCOPY, ETC. 

 Fig. 12?. Fig. 124, 



795 



Fig. 125. 



objects were viewed on "sliders" passing througli a bent staple on 

 either side of the under face of the base, the instrument being directed 

 to the source of light. For viewing 

 opaque objects, some such method as 

 that shown with Campani's Micro- 

 scope (above quoted), was probably 

 employed. 



Dentist's Examining Glass. — In 

 Mr. S. S. White's Catalogue of 

 Dental Materials,* we find an ex- 

 amining glass figured, consisting of 

 a low-power lens (fig. 125), mounted 

 in a metal ring, hinged on a socket 

 that slides on a rod terminating in 

 a spiral, by which it is carried on 

 the finger in examining teeth, &c. 

 In practice we should expect the difficulty of holding the lens steady a 

 great drawback to its utility. 



Bausch and Lomb Optical Co.'s 

 "Watchmaker Glass.'' — The Bausch and 

 Lomb Co. have obtained a patent for the 

 application of a spiral spring to a watch- 

 maker's glass to encircle the head and thus 

 keep the lens in position. We are unable 

 to say how far this arrangement has been 

 found to be of practical utility, nor can we 

 trace its origin with certainty. We have, 

 however been informed that such a device was in use in the last century, 

 if not earlier. 



* Philadelphia, 1877, p. 227. 



