MECHANICS AND USEFUL ARTS. 21 



water-line, the reaction of which upon the water propels it for- 

 ward in a direction opposite to the jets. 



The accounts of the performance of this vessel in October last 

 gave rise to a good deal of discussion in the leading engineering 

 papers as to the value of this means of propulsion as shown by 

 the trial and as indicated by theory, and the general conclusion 

 arrived at by those who took part in it was that it was very 

 wasteful of power. Since then further experiments have been 

 made and slightly better results obtained. The nozzles which, 

 on the former trip, were placed so as to discharge the water 

 into the air above the level of the external water, have now been 

 arranged so as to deliver below the water-line, thus avoiding the 

 loss of power in lifting the water through a vertical distance, and 

 no doubt-checking somewhat the velocity of escape of the water. 



Admiral Elliott, in a paper read before the Institution of Naval 

 Architects, came out very strongly in favor of the " Water witch " 

 principle as the future motive-power for ships of war. He was as 

 strongly sustained in the ensuing discussion by Sir Edward Bel- 

 cher, and by Mr. Scott Russell, while Mr. Reed, Chief Constructor 

 of the Navy, and others, opposed. Mr. Russell predicted that 

 with time and perseverance the plan would certainly succeed in 

 the end, and supersede the screw for the purposes of warfare. 

 The official result of the trial of the " Water witch " with the 

 "Vixen" seems to show that with a very crude and wasteful 

 arrangement of her water jets, wasting power both in lifting 

 and short turns of the water ejected, she did quite as well as 

 the steamer, making 9 knots with 750 indicated horse-power. 

 At a subsequent trial with deeper draft she did better, and * the 

 results, bad as they are," says " Engineering," have led to san- 

 guine predictions as to the final success of the jet system." 



NEW WATER PROPELLER. 



Mr. James Parker describes in " Engineering" for Jan. llth; an 

 apparatus for propelling vessels by steam without an engine. 

 The steam is issued in extremely small jets, each shooting into 

 the centre of an open pipe a quarter of an inch in diameter, con- 

 ducting into a hot-water chamber, into which the jet carries with 

 it a current of compressed air. This compressed and heated air 

 is admitted upon the surface of the water in closed tanks, by the 

 ordinary slide valve, and its force is employed to eject the water 

 through propelling pipes on the plan of the " Waterwitch" above 

 described. The steam and compressed air may also be driven 

 into a dry hot receiver and thence used in a large cylinder engine. 

 The contrivance is a modification of the caloric or hot-air engine. 



TELOUYNAMIC TRANSMISSION. 



This name is given to a system of transmitting power to in- 

 credible distances, perfected, after many years of baffling experi- 

 ment and endeavor, by M. G. A. Him. It is applied to distribute 

 the power of the Falls of Sohaflhausen throughout the mami- 

 fac tu riii" 1 district around, and is in use in more than 400 of 



