22 SATURATED STEAM, AND OTHER VAPORS. 



SULPHUR DIOXM>K. AMMOXIA. 



log p = a 6a" cf log p = a ba* c/J" 



a = 5.6663790 a = 11.5043330 



6 = 3.0146890 6 = 7.4503520 



c = 0.1465400 c = 0.9499674 



log a =1.9972989 log a = 1.9996014 



log/? = 1.9872900 k>g/J = 1.9931*: 



n = t + 28 n = t + L'_' 



Limit*, -28, +62. Limits, -22, +82. 



Unfortunately the heat of the liquid and the total heat for these sub- 

 stances have not been determined. We have, however, eomc of the 

 properties of these substances in the gaseous state or more properly in the 

 state of superheated vapors. 



Now, it has been shown by Zeuner that superheated steam may have iU 

 properties represented by the equation 



in which ;> is the pressure in pounds on the square foot or kilograms on 

 the square meter, v id the volume of a pound in cubic feet or of a kilogram 

 in cubic meters, and T is the absolute temperature. The constants have 

 the following values when calculated from the properties of saturated 

 oteam: 



French units, . . . , 5 = 51.3 C=198 a = f 

 English units, .... 5 = 93.5 C=971 a = i. 



It was first proposed by Ledoux to find similar equations to represent 

 the properties of superheated sulphur dioxide and ammonia, and to use 

 such equations for calculating approximate tables of the properties of these 

 vapors when saturated, just as the tables of the properties of saturated 

 steam had been nsed in establishing the equation for superheated steam. 



In the TJifi of Ihe Steam-engine by the author, pages 452 



to 459, this calculation has been carried out with the best ascertained 

 properties of the superheated vapors of sulphor dioxide and ammonia with 

 the following results: 



SULPHUR DIOXIDE. AMMONIA. 



French units, pv *= 14.5 T- 4Sp'* pv = 54.3 7^-142^ 

 English units, pv = 26.4 T - 184/-* pv = 99 T- 710/>1 



The application of these equations to the vapors when saturated give* 

 the following results: 



