232 



THE CHEMICAL CONTROL OF THE DAIEY. 



There are many other machines now on the market, which in 

 general principle are much the same as the original Gaertner- 



Fig. 25.— Gerber Tester. 



Hugershoff centrifuges. Some of these are driven by a handle 

 (Fig. 25), which, by means of a worm gearing, imparts a rapid 



Fig. 26. — Gerber Tester, electrically driven. 



motion to the spindle, and this method of driving finds favour 

 with those who do not mind the extra expense. 



