252 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



2. Levelling Super stage (fig. 44). — It has hitherto been usual for 

 this superstage to be made with levelling screws working from the 

 upper surface, but it will be seen that this new and improved form 

 works from the sides by means of screws operating on wedge-shaped 

 pieces of brass, which, slowly tilting, cause the upper part to tilt, and 

 reaction is obtained by springs attached to the lower plate and grasping 

 the lower one on its upper surface. 



3. Scop Bullseye Stand Condenser (fig. 45). — This is fitted with 

 centring adjustments and iris diaphragm. The lens is 2\ in. diameter,. 



Fig. 45. 



and is of a suitable power for work with a vertical illuminator. With it 

 a very small point of light of intense brilliance can be secured. 



4. Scop Bullseye with Mechanical Adjustments (fig. 46). ■ — When 

 examining metal specimens, constant necessity arises for the minutest 

 possible alteration of the position of the bullseye lens, sometimes laterally, 

 sometimes vertically. Messrs. Watson have specially constructed this 

 bullseye, which optically is the same as the preceding, to meet this 

 inconvenience. It is mounted upon a pillar, on which is a rackwork, 

 with which adjustments can be made to the finest point by turning the 

 pinion milled head. Laterally, similar slight movements can be effected 



