ZOOLOGY AND BOTANY^MICROSCOPY, ETC. 



639 



pin stops, one being adapted for dry objectives, the other for immersion 

 lenses. The Plate Condenser, shown in fig. 100, is adapted for dry 

 objectives, and may be used without special adaptation on any Micro- 

 scope, and is clamped to the stage by ordinary stage clips. The Universal 

 Condenser (fig. 101), with wheel diaphragm, may be placed upon any 

 square or round Microscope stage, and is available for use with oil- 

 immersion and dry lenses. The wheel diaphragm furnishes a means of 

 appropriately stopping down the pencil of light and also of conveniently 

 moderating the light furnished by different sources of illumination and 

 of facilitating the transition from dark-ground to ordinary illumination. 

 The plate is attached to the stage by means of two screws. This type 



Fig. 103. 



may also be procured fitted with an iris diaphragm. The Reflecting 

 Slide Condenser is shown in fig. 102. It is mounted upon a stout glass 

 plate which serves as a carrier, and is available for use with any Micro- 

 scope. A circle ruled with a diamond upon its surface facilitates the 

 operation of centring. The Swing-out Reflecting Condenser is shown 

 in fig. 103. It is alternatively available as an Abbe condenser and as 

 a dark-ground illuminator, the latter condition being obtained by 

 swinging-out the lower lens L 2 and swinging-in the centre pin stop B. 

 It may be used with either dry or oil-immersion lenses. Fig. 104 shows 

 a chamber for the transfusion of liquids. It is available only for use 



