658 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



diameter, and with a draw-tube). The fine adjustment moves the 

 entire body by means of a micrometer-screw at the loicer end, and 

 within the bend of the limb, and is claimed to be " practically 

 frictionless, acting on rollers, and perfectly free from lateral move- 

 ment." The mirror slides upon a radial arm that swings laterally in 

 a travelling zone in a metal disk, the centre of which is in the plane 

 of the object. For opaque illumination the mirror-bar can be swung 

 above the stage. The wheel of diaphragms fitting beneath the stage 

 is mounted on a jointed arm allowing it to be turned aside clear 

 of the stage opening, a fixed stop ensuring its being in the axial 

 position when so required. The circular stage (i inch thick), with 

 standard screw in central opening, has spring clips, which may be 

 used under the stage when great obliqiaity is required. A sliding 

 substage to be attached to the mirror-bar can be substituted for the 

 accessory tube. 



Baker's Students' Stephenson's Erecting Binocular Micro- 

 scope. — This instrument (Fig. 142) consists of the stand of the small 



Fig. 142. 



" Model Histological Microscope," to which is adapted the optical 

 part of a " Stephenson's Erecting Binocular," the whole being placed 



