ZOOLOGY AND BOTANY, MICKOSCOPV, ETC. 447 



is acquired by sliding the tube in a cloth-lined jacket, and a micrometer 

 screw provides the fine adjustment. The stage is fitted with an iris- 

 diaphragm, and is threaded for the addition of a substage ring to hold 

 an Abbe condenser. The tube is nickel-plated, the other brass parts 

 being lacquered. The height is 12 in., and the tube takes eye-pieces 

 and objectives conforming to Society standards. 



Grundlach Microscope, Model D H.* — This medal represents the latest 

 general stand manufactured by the Gundlach firm. Economy in com- 

 bination with excellence of workmanship has been kept steadily in view. 

 The draw-tube is nickel-plated and graduated in millimeters ; it slides 

 in a cloth-lined case. The coarse-adjustment is by diagonal rack-and- 

 pinion. The fine-adjustment is a micrometer-screw with a direct action 

 and no reciprocating parts. The pillar is hollowed out as a handle-arm. 

 The stage is 4 in. by Sh in-, and the height of the whole instrument is 

 11 in. 



Gundlach Microscope, Model D D.f — In this instrument, which 

 is meant for general microscopical work, the pillar is bent to serve as 

 a handle-arm, and the fine-adjustment is located under the pillar, where 

 the operator can reach it without disturbing his elbow-rest. The stage 

 (3| in. by 3f in.) is provided with an iris-diaphragm, and an Abbe 

 condenser can be added if desired. 



Focostat Lens.— This lens (fig. 77) was exhibited at the February 



Fig. 77. 



Meeting and was described by Conrad Beck (see Proceedings, pp, 231 

 and 232). 



(2; Eye-pieces and Objectives. 



Leitz' Double Demonstrating Eye-piece. | — This eye-piece, which 

 was exhibited by Mr. Ogilvy at the March Meeting, enables two 

 observers to view jointly an object under the Microscope. It slips 

 into the draw-tube of the Microscope like an ordinary eye-piece. The 

 field of view is common to both eye-pieces and contains a pointer which 

 either observer can direct upon any feature to which he wishes to draw 

 attention. 



* Catalogue, Gundlach-Manhattan Optical Co., Rochester, New York. 

 t Catalogue, Gundlach-Manhattau Optical Co., Rochester, New York. 

 X Leitz' Special Catalogue, 1912. 



