246 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



mirror is variable, and a catch-spring marks the position of 45°. The 

 projection and objective support slides between guides fixed to the base- 

 board. The preparation-stage is adapted for the largest preparations, 

 and the objective is focused by rack-and-pinion. The drawing-board 

 is 40 X 50 cm. and the reflecting-mirror 20 x 28 cm. Microplanar 

 projection objectives are recommended. The best source of light is a 

 Nernst lamp with automatic regulation. The luminous intensity is 

 about 700 candle-power with 110 volts ; and 1400 candle-power with 

 220 volts. In the absence of electricity an incandescent gas-lamp is 

 recommended. 



Colour-disks for Microscope Condensers.* — R. Cleminson has 

 invented a simple means of applying colour-disks to an ordinary con- 



£ 



±-j+ 



Figs. 51, 52. 



denser so that the colours may be readily changed or varied. In the 

 accompanying illustrations fig. 51 is a side elevation, and fig. 52 a plan 

 view of a condenser of well known type provided with the colour-disks ; 

 a is the condenser itself secured to an arm b, carried by a tube or 

 sleeve c, which latter is adjustably mounted upon a rod d supported 

 by the base-plate e, while / represents strips of variously coloured 



* English Mechanic, lxxxviii. (1908) p. 368 (2 figs.). 



