74 ADAMSON MACHINE. 



is taken up. In this particular machine the water is 

 supplied to the ram cylinder by means of a set of pumps, 

 which can be worked by uower, or manually through the 

 large hand wheel shown in the illustration. The water 

 tank from which the pumps draw their supply is shown at 

 G, and the pumps are immediately at the back of the ram 

 cylinder. At the end of a test the ram is restored to its 

 initial position by the heavy balance weight shown hanging 

 from the chain, trie water being allowed to escape from the 

 cylinder into the tank. 



Two side rods I connect the ram with the left-hand grip 

 box or crosshead H. The left-hand end of the specimen 

 L is held in this box by means of steel wedges. The cross- 

 head itself slides on the upper planed surface of the bed. 



The right-hand end of the specimen L is held in the 

 wedges of a second grip box K, which is connected by a 

 horizontal link with the Iqwer knife edge of the first lever, 

 a steel plate attached to the link resting against the knife 

 edge itself, which is embedded in the lever. In order that 

 there may be no sliding friction between the crosshead K 

 and the bed of the machine, the whole weight of the cross- 

 head and its link is carried by four radial links R, R. This 

 precaution is necessary because it is desirable that the only 

 force registered by the weighing levers shall be the pull 011 

 the specimen. The first lever has its two arms at right 

 angles, and these two arms have a ratio of 10 to 1 ; 

 the second lever is a straight one, also with a ratio 10 to 1 ; 

 the third is straight, with a 12 to 1 ratio ; and the upper- 

 most or fourth registering lever is straight, with a 

 ratio of 12 to 1. The first three levers are shown dotted 

 in the figure. 



The total leverage of this system of compound levers is- 

 therefore 



10 x 10 x 12 x 12| = 15,000 

 1 T T "T^ 1 



so that to have a maximum load of 100 tons on a 

 specimen it is only necessary to apply to the end of 

 the last lever 



. 



At the end of this lever is a suspending link on 

 which loose weights can be hung. These loose weights 

 are each of the value of 3 lb., the equivalent pull on the 



