538 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



ready, and is perfectly safe, and when gas is employed for 

 heating, requires only two feet per hour. Externally, it is 

 cylindrical in form, widening at one end conically, and placed 

 at an angle of forty-five degrees, and turns on supports, a con- 

 ical toothed wheel on the top converting the motion into 

 horizontal or vertical. 8 C^May 29, 1873, 173. 



THE GUNPOWDER PILE-DRIVEK. 



The gunpowder pile-driver, with regard to its efficiency 

 and economy as compared with the ordinary pile-driver, was 

 recently the subject of a paper before the American Society 

 of Civil Engineers. The apparatus had been employed on a 

 line of sheet piles for a reservoir dam in the valley of Parson- 

 age Creek, Long Island. The character of the w^ork was, 

 from the nature of the soil to be penetrated, very difficult. 

 The opinion expressed by the engineer having the work in 

 charge was to the effect that when the resistance is slight the 

 machine may be economical, but when, as in this case, it re- 

 quired three hundred blows from cartridges costing two and 

 a half cents each to force a pile down fifteen or sixteen feet, 

 it can not be so considered. The gas from the explosions 

 cuts passages in the ring at the end of the piston, thereby 

 greatly lessening the power of the machine. Other difficul- 

 ties exist, such as the heating of the gun and the enlargement 

 of the bore ; and finally, from the bending of the piston, the 

 machine ceases to work. 



There is great diversity of opinion among engineers con- 

 cerning the economy of this highly ingenious apparatus, and 

 reliable statistics, based upon the results of actual practice, 

 such as those presented in the special case above named, will 

 be very useful. 



TURBINE AVIND MOTOR. 



Attention is called, in the German Architectural Magazine^ 

 to a so-called wind-turbine, or horizontal wind-wheel, near 

 Riesa, moving about a vertical axis. It has a diameter of 

 about 17 feet, height of 10.2 feet, six curved paddles, and 

 eight movable guide curves, and makes ten revolutions per 

 minute, even while running a saw, cutting a plank over three 

 inches thick. It would probably make twenty revolutions 

 without work, and with a good wind would furnish about six 



