208 



THE BOOK OF THE LANDED ESTATE. 



back again. L D D are parts which are moved by the revolving of the 

 flywheel, and press the lower part of the jaw C forward. In fig 79 is 



shown an end elevation. K shows the 

 driving-wheel, on which is fixed the belt 

 from the engine ; H H the flywheels ; G 

 the crank ; FF the lever; C the upper part 

 of the movable jaw; and L L the screws, 

 the raising or lowering of which alters 

 the mouth of the jaws accordingly. Fig. 

 80 is a plan of the machine. A shows 

 the fixed jaw, C C the movable one, B B 

 tapering check-pieces to hold the mov- 

 able jaw in its place. The movable jaw 

 C is fluted to fix into corresponding ones in the fixed jaw. The shaft G 

 has two flywheels H H, one on each side, and also a driving-pulley K. 



Fio. 80. 



Its motion is in this way: Every turn of the shaft causes the moving 

 jaw to advance at its lower end about three-eighths of an inch and 

 return, and so on to and fro ; and there being a considerable slope 

 between the jaws, as shown in fig. 78, the stones fall down gradually as 

 the jaw recedes, and the jaw of course crushes them in returning each 

 time until they fall out at the mouth. The jaws can be shifted so as 

 to break the stones different sizes. A proprietor of iron-works informed 

 me that he has one in use which breaks stone to the size of road-metal 

 for about 3d. per ton ; this includes the feeding of the machine and 

 the cost of engine-power, but not of quarrying the stones. When the 

 jaws are fixed so as to break stones which will pass through a ring of 

 two inches, it will crush about ten tons per hour. This cost does not 

 include any interest on the cost of the machine ; and it must be kept 



