■62 



SCIENCE. 



[N. S. Vol. XVII. No. 419. 



As compared with this we find from the 

 last U. S. Census Report that, during the 

 ■census year 1899, there were constructed 

 in the United States 18,500 combustion en- 

 gines having a total capacity of 165,000 

 horse-power, or only about 9 horse-power 

 per engine. 



Although this country has lagged some- 

 what behind Europe in adopting large gas- 

 engines, there is evidence that this state of 

 affairs will not exist very long, for a num- 

 ber of enterprising firms are already in the 

 field prepared to build gas-engines up to 

 any required size. One firm has already 

 ■sold over 40,000 horse-power of large en- 

 gines, most of them of 2,000 horse-power 

 and several of 1,000 horse-power. An- 

 other firm has recently built two 4,000- 

 horse-power gas compressors and also a 

 number of 1,000-horse-power gas-engines. 



The use to which these large engines are 

 put is about equally divided between the 

 ■operation of blowing engines for blast 

 furnaces and the driving of dynamos for 

 general power distribution; the tabulated 

 list compiled by Mr. Humphrey for engines 

 of more than 200 horse-power shows 99,000 

 horse-power for driving dynamos for light 

 and power and 83,000 horse-power for 

 other purposes. 



While the gas-engine in the larger sizes 

 is thus used extensively for the generation 

 of electric light and poAver, a growing ten- 

 dency is observed to use the gas-engines 

 direct as motors. 



A number of railroad and other machine 

 shops have been equipped with moderate- 

 sized gas-engines suitably located about the 

 works, and in addition, thousands of horse- 

 power are used in the smaller sizes for a 

 wide variety of purposes, including vil- 

 lage water-works, isolated lighting stations, 

 and manufacturing plants of all kinds. 



With the possibilities of high thermal effi- 

 ciencies we may look with much hope upon 



the still higher development of cheap fuel 

 gas processes that will bring the gas-engine 

 into very general succession to the electric 

 motor for many purposes, for it will 

 doubtless be found that gas transmitted 

 from a central gas-making plant at a 

 manufacturing works into engines located 

 at points of use mil effect a material sav- 

 ing in the utilization of power over any ex- 

 isting methods. 



It is not to be presumed that the gas- 

 engine will displace either the electric 

 motor or the steam-engine; each has its 

 legitimate sphere of usefulness, and each 

 will be more liighly developed as the re- 

 sult of direct competition. Yet the econ- 

 omies already obtained indicate that the 

 field of the gas-engine will be extended 

 more and more into that of the steam- 

 engine and the electric motor. 



Many of the questions involved in this 

 consideration are at the present time in 

 a transitional stage. The reciprocating 

 steam-engine has reached a high state of 

 development, but it is not probable that it 

 has attained its highest degree of perfec- 

 tion. While an economy less than 9^ 

 pounds of steam per horse-power-hour has 

 been obtained, even better results may be 

 anticipated ; the use of high pressure super- 

 heated steam in compound, jacketed en- 

 gines involves more perfect lubrication, and 

 this may demand modification in existing 

 valve types; however this may be, the out- 

 look is promising for still higher efficien- 

 cies ; whether this will mean cheaper power 

 than can be obtained in other ways will 

 depend upon many conditions. 



In any case, and especially with inter- 

 mittent or variable loads, it is not so much 

 a question of maximum efficiency as it is 

 economy of operation. 



From this point of view the present ac- 

 tivity in the construction and development 

 of the steam-turbine is of interest to en- 



