120 MmiKG lOTDFSTEY. 



month of February, 1867, a cage was descending at usual speed, with thirteen 

 men, when by a singular accident the cable became detached from the lifting 

 rod of the cage. The latter stopped almost immediately, but with so little 

 shock that the men on the cage were not even led to suppose that an accident 

 had happened. The engineer, not perceiving any difficulty, continued to 

 unwind the cable, which, passing down between the cage and the side of the 

 shaft, attracted the attention of the men, who rang to stop. Another cage 

 was sent down in the adjoining compartment, when the state of the case was 

 discovered and the men relieved. 



Eccentric Safety Attachment. — Another appliance for insuring safety, 

 more common, and by some preferred to the one just described, is that known as 

 the " Eccentric." This is illustrated by drawings on Plate VIII. The gen- 

 eral form of the cage may be the same as in the case already described. The 

 contrivance for insuring safety consists in two round shafts, or rods, a, a, which 

 extend across the cage from side to side, parallel to the central cross-bar, h, of 

 the main frame. They are supported by the main frame of the cage in such 

 manner that they may revolve freely, and they extend beyond the sides of the 

 cage so that their ends are opposite the wooden guide-rods, c, c, of the hoisting 

 shaft. To each end of these two rods are attached the eccentrics, d, d, which 

 are circular pieces of cast iron, supported, as their name implies, in such 

 manner that the center of the shaft, a, or axis of revolution, does not coincide 

 with the center of the circle. That part of the circumference of the circle 

 which is nearest to the point of support is smooth, but that which is more 

 remote is furnished with teeth, so that, when the shafts, a, a, are in such position 

 that the smaller diameter of the eccentrics is turned toward the guides, they 

 may move freely, up or down, without coming into contact with the guides ; 

 but if the shafts, a, a, be turned so as to present the larger diameter of the eccen- 

 trics to the guides, the latter are grasped by the teeth just referred to. Each 

 eccentric rod is furnished with a chain, e, one end of which is fixed to the rod, 

 and, winding round it, is attached at the other end to a bolt, which passes 

 through the cross-bar, h. Between the head of the bolt and the cross-bar, a 

 strong steel spring, y^ is interposed, the tendency of which, when compressed, 

 is to cause the shaft, a, to revolve in such manner as to bring the teeth of the 

 eccentrics into contact with the guides. The chains, g, g, by which the cage 



