62 ANNUAL OF SCIENTIFIC DISCOVERY. 



of the time is employed in boring holes, and the remainder in charging and 

 blasting; hence, accelerating the former operation is an immense advantage. 

 The perforators have another advantage : in a place where three couples of 

 miners would hardly find room, eighteen perforators may be set to work ; so 

 that, by these ingenious contrivances, as well as by others for clearing away 

 the rubbish, the perforation of the tunnel may be effected in six years instead 

 of thirty-six. The air that has been employed as a motive pOAver is used to 

 feed the gallery; but when the latter shall have reached a considerable depth, 

 it will require 85,924 cubic meters of air per twenty -four hours to replace that 

 which has been vitiated by respiration, torches, and gunpowder; and this 

 quantity, in the form of 14,320 cubic meters of air condensed to six atmos- 

 pheres, the reservoir can furnish. A new and curious fact has been observed 

 during these works, viz., that when the air, condensed to the degree above 

 mentioned, is shot into the gallery from the machine, any water happening to 

 be near the latter suddenly congeals, although the ambient temperature be 

 about eighteen degrees, centigrade (seventy-two degrees Fahrenheit). Hence, 

 when a large mass of compressed air is driven into a gallery situated at 1,600 

 meters below the outer surface of the earth, and where, consequently, the 

 temperature must be about 100 degrees Fahrenheit, the dilation of the com- 

 pressed air produces a diminution of temperature sufficient to counterbalance 

 the excess alluded to. The progress now making per day in boring is three 

 meters on each side of the mountain, or six meters per day in all. 



ELASTIC BALL-VALVE PUMP. 



This pump, patented in 1857, by Mr. A. Tower of New York, was devised 

 for the purpose of being, at the same time, a lift and force-pump, and a fire- 

 engine. It consists of two cylinders, standing vertically on a bed-plate, 

 between which is an air reservoir, and on the top of which are cast two pro- 

 jections, used as bearing for the working-beam or brake. There is a hollow 

 plunger in each cylinder, connected from its bottom with the brake, and mov- 

 ing through an ordinary stuffing-box, which is so placed that, by turning a 

 few screws, it may be made tighter without stopping the pump. There is 

 one valve-seat directly under each cylinder, and two in the air reservoir, all 

 of which are raised a few inches above the flat surface around. Over each 

 seat stands an India-rubber ball, about two inches in diameter, which is 

 prevented from falling sideways, or rising too high, by being inclosed in a 

 wire cage. Every solid particle which is earned through the valve falls by 

 its own weight by the side of the elevated seat, and cannot, henceforward, 

 choke the pump ; and the few particles Avhich may be arrested in their pas- 

 sage, when the ball comes suddenly down, get imbedded in the India-rubber 

 which closes around them, and do not interfere with the action of the valve. 

 This pump is capable of pumping a mixture of grain and water made in 

 the ratio of three quarts of corn to each gallon of water. The working 

 beam is properly moulded for the insertion of levers at each end. When it is 

 advisable to work the pump by steam power, one of the levers is taken 

 away, and a connecting-rod, with one end turned at right angles and shaped 

 like that of the lever, is substituted for it. The pump, mounted on four 

 wheels, and provided with proper hose, is turned into a small fire-engine. 



