Manchester Memoirs, Vol. xli. (1896), No. 3. 13 



In order to make use of this formula in the reduction 

 of the experiments under consideration, all that is necessary 

 is to bring about, by means of wire-drawing, the condition 

 that T 2 ' shall be sufficiently larger than T 2 to insure that 

 the final condition approximates to that of steam gas. 

 That this difference must be more than 20°F. has been 

 shown, but it would appear that with this difference the 

 error is not great. 



To use the formula, 



is substituted for the right member of equation (6), 

 Hp-, U —, — being small, so that 



S 1 (H 1 -/j 1 )+A 1 =772< 1092+0-48 (T 2 '- 3 2°)}... (7), 



which only requires the experimental determination of 

 Ti and T 2 ' to give the value of S 1? provided that the final 

 condition is that of steam gas. 



The means of assuring the condition of Steam Gas. 



Perhaps the most important fact to which attention is 

 herein directed is that, although, as already stated, the 

 limiting relations of temperature and pressure of steam 

 gas are not known with any degree of precision, the wire- 

 drawing experiments are capable of affording simple and 

 direct evidence of the existence of such a final state. As 

 the pressure of steam is reduced by wire-drawing which 

 is gradually increased, at first, owing to the great expan- 

 sion, the temperature falls considerably, but, as the wire- 

 drawing increases, by the diminution of pressure in the 

 receiving vessel, the fall of temperature gradually diminishes, 

 until the gaseous state is produced, when the temperature 

 T 2 ' will be unaffected by still greater wire-drawing. 



2g 2g 



