52 



MKASl IIKMKNT OF THE LOAD. 



with respect to the fulcrum ; in others, generally the 

 smaller kinds, W is variable, the fine adjustments being 

 obtained by the movement of a small constant weight on 

 the lever. 



The chief example of this type of machine is to be found 

 in the Wicksteed single-lever machine, in which a large 

 moving weight is used. A number of smaller machines of 

 the same kind are constructed by various makers. These 

 machines are all vertical machines, the specimens to be 

 tested being held in an upright position. 



w 



FIGS. 19. 



II. MULTIPLE - LEVER MACHINES.- Of the second type 

 of testing machines two examples are shown in the accom- 

 panying sketch, Figs. 19. The diagram (a) represents the 

 multiple-lever machine designed by the late Mr. Daniel 

 Adamson. In this machine there are four levers, the first 

 a bell-crank lever, and the remaining three straight ones. 

 The total leverage is 15,000 to 1, so that a very small 

 moving weight on the last lever measures a pull in the 

 specimen fifteen thousand times as great. (6) is the two- 

 lever machine of Messrs. Greenwood, of Batley. Here the 

 leverage is 100 to 1, and the load upon the specimen is 

 controlled by the application of the variable and movable 



