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XCIII. On the Expansive Force of Steam at different Tem- 

 peratures. By Philip Taylor. 



To the Editors of the Philosophical Magazine and Journal. 



M Bromley, Middlesex, Dec. 26, 1822. 



UCH interesting discussion having lately 

 taken place on the expansibility of steam, I shall feel pleasure 

 if I can in any degree contribute toward a more correct know- 

 ledge of the physical properties of this important agent. 



Some years since, I proposed a safe and simple mode by 

 which the heat of compressed steam might be employed, to any 

 extent, in various manufacturing processes. 



In this application of steam, it became necessary to deter- 

 mine what precise temperature would result from its different 

 degrees of compression ; for in many cases it was desirable to 

 employ it as the medium for conveying heat to solutions of 

 saline substances and sugar, which require high degrees of 

 heat for their ebullition. 



Finding that my practical results did not accord either with 

 the experiments given by other writers, or with the theories 

 deduced from them, I was led to form a Scale (Plate VI.) which 

 might show the expansive force consequent on each degree of 

 temperature, from 212° to 320° Fahr. 



As this Scale was intended to exhibit the force of steam above 

 the point at which the atmospheric pressure balances it, I have 

 placed my zero at 212°, and given the forces produced by each 

 addition of temperature in inches of mercury; and in order 

 that it might be rendered more convenient for use, the divisions 

 ai*e reduced to one-fourth of their actual magnitude. I have 

 also in another column given the pressure on a square inch at 

 each degree of temperature — assuming that 2^^, inches of mer- 

 cury of sp. gr. 13*50, are equal to one pound per square inch. 



The rapidly increasing series of the forces compared with 

 the regular increments of heat, is at one view exhibited on this 

 Scale, in a manner which I hope will be interesting to the man 

 of science, and useful to those who are like myself engaged in 

 the practical aj^plication of the force and heat of steam. 



This Scale was formed by the means of an apparatus likely 

 to render my experiments as correct as any can be, which de- 

 pend on the indications of thermometers ; but I have hitherto 

 hesitated in publishing it, from its great variance with those 

 Tables already given by men of science. 



Repeated experiments having led me to believe that my re- 

 sults are correct, I send it for your insertion : — at the same 

 time I wish to observe, that I have not endeavoured to make 



it 



