694 



SUMMARY OF OURBENT RESEARCHES RELATING TO 



light, viz. oxy-hydrogen or electric, remove the brass tube C, containing 

 the condensing lens and draw-tube, from the mirror attachment and 

 connect to the combination stereopticon (fig. 85), using either the stereop- 

 ticon lens or Microscope as desired. The light is centered and adjusted 



Fig. 86. 



Fig. 87. 



by means of thumb-screws on the oxy-hydrogen jet. The adjustment is 

 the same as with solar light. The only change (two condensing lenses 



are used with artificial light), one of these 

 lenses is removed and only one used, and a 

 small secondary condenser placed under the 

 stage of the Microscope. With this com- 

 bination just described we can only project, 

 with transmitted light, transparent objects. 



The attachment, fig. 86, is for photo- 

 graphing and projecting objects with oblique 

 illumination, or projecting opaque micro- 

 scopic objects. It is constructed as fol- 

 lows : — To the base of the combination 

 stereopticon is clamped a triangular piece 

 of brass U, by means of thumb-screws, with 

 a slot X near its apex, to hold a movable 

 hollow pillar ^ I. This pillar is slotted on 

 one side, and has a screw and clamp G to 

 hold a perpendicular pinion P, which in 

 turn receives the stage and working part of 

 the stand ffig. 87). This is securely clamped 

 by means of the screw G, fig. 86. Ex- 

 tending through from the lower end of the 

 pillar I is a screw Ji for raising or lowering 

 the stage of the Microscope and body-tube. 

 The body-tube K of the Microscope is in a horizontal position, and the 

 stage S vertical. These arc directly in front of the condensing lens. By 



