420 



MR. J. H. BRINKWOETH ON THE SPECIFIC HEAT OF STEAM AT 



correction of O'l per cent, per centimetre has been applied to the results calculated as 

 above in order to reduce them to the values corresponding to a pressure of one 

 atmosphere. The variation of the specific heat with temperature, indicated by the 

 experiments made with different values of dO, was directly measured in the case of 

 each calorimetric arrangement in the following manner. With a constant value of 

 the flow a series of .experiments was made in which only the value of d6 was 

 changed. The observations made in the case of two such experiments with the 

 medium flow are given (fig. 9). 



In the results quoted, the observed values of CE/QcZ0 have been corrected to 

 correspond to an infinite value of the flow and the pressure correction has been applied. 

 These corrected values of CE/Q dO are the values of the mean specific heat S m . The 



2030^ 



2020 



ZOIO 



2000 



1995 



Fig. 9. 



relationship existing between the values of S m and dd is well represented by the 

 equation previously given. Similar experiments have been made with both the 

 maximum and minimum flows and the observed temperature variation found in each 

 case agrees with that given above. In some experiments a more rapid variation of 

 the mean specific heat with temperature, in the neighbourhood of the cold temperature, 

 has been indicated, but with small values of dd, the experimental errors are magnified, 

 and in consequence, the straight line relationship has been applied to all the observa- 

 tions. The temperature variation of the specific heat at the constant pressure of one 

 atmosphere as calculated from equation (7) gives dS/de = -O'OOIO or S = S c -0'0010 d6 

 where S e is the actual specific heat at the temperature d. Hence the observed 

 coefficient is double that deduced from theoretical considerations. The experimental 



