26 ANNUAL OF SCIENTIFIC DISCOVERY. 



be as elaborate and as complete as it is possible to make them. And 

 under the practical conditions of steam engineering, it is believed 

 they will indisputably set at rest the amount of gain to be obtained 

 from using steam with different measures of expansion, and also 

 determine the relative merits of different kinds of valve-gear, steam 

 pressure, etc., besides settling many incidental questions of great 

 importance. 



ON THE ECONOMY OF WORKING STEAM EXPANSIVELY. 



Steam engineers and scientists generally, have, it is well known, 

 been greatly interested of late in regard to the question of the econ- 

 omy of using steam expansively ; and during the winter of 1860-61, 

 a series of experiments were made by Mr. Isherwood, Chief Engi- 

 neer of the U. S. Navy, under the auspices of the Government, with 

 a view of testing the question. These experiments were reported in 

 the Annual of Scientific Dis:^~>v?ry for 1862, p. 25 : and in the suc- 

 ceeding article we give the English opinion of them as expressed in 

 one of the leading British Scientific journals. Some two vears ao-o, 



J v ^3 



Congress appropriated the sum of 820,000 for the further prosecu- 

 tion of this investigation, and Air. Horatio Allen of Xew York City, 

 and Mr. Jsherwood of the Navy were appointed Commissioners to 

 conduct the experiments. Committees representing the American 

 Institute of New York, and the Franklin Institute of Philadelphia, 

 were also appointed, by request from these associations, to attend and 

 counsel concerning the experiment. The result of the investigations 

 as far as they have been made public, have been furnished us by Dr. 

 Warren Rowell, Chairman of the Committee on the part of the Amer- 

 ican Institute. In a recent letter to the editor, he says : " An engine 

 was constructed in accordance with the suggestions of the best practi- 

 cal and theoretical engineers in the country. The engine frame was 

 made larsje enough to take in seven or eight different diameters of cy- 



* * 



linders in succession, and to use steam ot the same pressure and the 

 same quantity in each cylinder, the same amount of work in each in- 

 stance being put on the engine. The comparison that has been made, 

 is this. The first cylinder tried used one cubic foot of steam when the 

 piston had performed twenty-one twenty-fourths of the stroke : this 

 cylinder was then taken out of the frame of the engine, and a cylin- 

 der put in its place that held a cubic foot of steam when the piston 

 had performed sixteen twenty-fourths of the stroke ; and the Commit- 

 tee found that there was not a 'pounds difference' in the consump- 

 tion of either fuel or water in a 72 hours' experiment. This result 

 was quite unexpected, because it was thought by the Commissioners 

 and others, that if there was any possible expansive force to be ob- 

 tained, it would be between two thirds and seven eighths of the 

 stroke. 1 ' 



Another set of experiments, beiring on the same subject, are also now 

 in the course of induction by Messrs. Hecker, Watermann, Rowell, and 

 others in New York, the results of which have not a* yet been fully made 

 public; but copying from the columns of the Scientific American, we will 

 endeavor to state what is and ought to be ascertained. In a series of ex- 

 periments made by the above-named gentlemen in 1860, it was found that 

 when the steam was cut otf'at one quarter of the stroke in an unjacketed 



