610 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



Berger's Fine Adjustment. — Fig. 115, from Messrs. Zeiss'* new 

 Catalogue, shows the action of this fine adjustment more clearly than 

 the illustration previously published in the Journal for 1898, p. 585, 



fig. 99. 



iS:t-«%isi-dl 



Fig. 115. 



Zeiss' Small Mineralogical Stand.j — This model (fig. 116) is 

 numbered IX 1 ' in the Catalogue ; it is not inclinable, and possesses 

 rack-and-pinion coarse adjustment. The tube, which is not provided 

 with draw-tube, carries on its upper extremity a divided circle and a re- 

 movable analyser. At the lower end are two sliding carriers and a 

 centring appliance. One of these carriers bears a second analyser, 

 while the other is available for a quartz or other crystal plate for inser- 

 tion above the objective. The polariser is combined in a sliding 

 sleeve with a condenser system of 1 • N.A. The upper lens of this 



* Fig. 19, p. 44, of Zeiss' Catalogue. 



t Catalogue, English edilion, 1902, pp. G8-71, fig. 34. 



