8G KANSAS CITY REVIEW OF SCIENE. 



The present annual product of the world is therefore about 50,000 tons It 

 is principally used in Asia for the tinning of copper, and in Europe and America 

 for the tinning of iron. The manufacture of alloys is believed to consume a 

 minor portion only. — Eng. and Mining Journal. 



THE GAMGEE PERPETUAL MOTION. ; 



BY B. F. ISHERWOOD, CHIEF ENGINEER NAVAL DEPARTMENT. 



[Chief Engineer Isherwood recently made a report to the Secretary of the 

 Navy on the Gamgee perpetual motion, from which we make the following ex- 

 tract. The invention will finally, of course, rest on its actual merits :] — Ed. 



From obs.ervations made by Professor Gamgee in the experimental working 

 of this machine, he deduced the possibility of what he terms a zeromotor, in 

 which, by means of properly adapted apparatus invented by himself, the heat in 

 water or other objects at ordinary atmospheric temperature may be utiHzed to 

 vaporize liquid ammonia under very considerable pressures, but within the control 

 of known means of retention. The high pressure gas thus obtained being used 

 with the greatest practicable measure of expansion on a working piston generates 

 power, becoming by that very expansive use greatly refrigerated and diminished 

 in- bulk, and partially liquefied at the end of the stroke of the piston, when it is 

 exhausted and then returned by a method invented by Professor Gamgee, to the 

 ammonia boiler whence it came. The cycle is thus a closed one ; no material is 

 lost, and no heat is rejected in matter leaving the engine. The work done by the 

 engine is due to the difference in bulk of the material when it enters and when it 

 leaves the boiler, that difference being caused by the heat derived from water or 

 other natural objects in the ammonia boiler and from the refrigeration resulting 

 from the transmutation of a portion of this heat by the engine into the mechanical 

 work performed by the latter. That this difference of bulk exists is indisputable, 

 and if the proper mechanism can be contrived to utilize it, the idea of the zero- 

 motor becomes realized. It will be observed that this power has not been ob- 

 tained from artificial heat produced by the combustion of fuels, but from the heat 

 of natural objects at ordinary atmospheric temperatures, and therefore costing 

 nothing in money. This is made possible by the fact that liquid ammonia gasifies 

 under considerable pressure at ordinary atmospheric temperatures, the sole diffi- 

 culty in constructing the zeromotor being to find the means of economically con- 

 densing the gas after it has been used Qn a piston. Were it not for the refrigera- 

 tion due to the expansive working of the gas, the condensation would have to be 

 obtained by the application, externally to the condenser, of artificially produced 

 cold, and the zeromotor could not be made a commercial success. It is only by 

 obtaining the lower limit of temperature from the action of the engine itself, while 

 the higher limit is furnished without money cost by natural objects at atmospheric 

 temperatures, that commercial success becomes possible. 



