Saturated Steam expressed by a New Formula, 

 By integration was obtained for value of hyp. log P, 



If we put 



we get 



logP= — {l -e—***}. 



logV = ot<f)\ogp, and p = e «<pi°gi». 



" The formula for the pressure of saturated steanibeingP = e acplo ° ? , 

 the formula for volume is ~V = e~ cc ^ >lo ^ p ; and the formula for the 

 expansive force of a unit weight of such steam is 



py = e («- «-) log /? _ e %,$ log j^ 



The value of a in the formula for pressure has been shown to be 

 •03580, which represents the rate of increase per degree (Centi- 

 grade) of the pressure at the absolute temperature 376°, or at 

 100° on the Centigrade scale. In order to represent the law of 

 volume, we have to put (for the same temperature) a y = —'03365 ; 

 and to represent the law of expansive force we have to put 

 « fl =+ -00215. We thus obtain the following expressions for 

 pressure, volume, and expansive force, reckoned from 100° Cen- 

 tigrade : — 



P = e«* 1 ^p, and log P = + -035 80 $ log p, 



y =e -cc,Qio gPf and log y= — -03365 $ log p, 



PV=gM>toM, and logPV= + -00215 log p. 



By the aid of the three foregoing equations any one of the 

 three quantities P, V, or PV may be expressed in terms of either 

 of the other two quantities. In order to express V in terms of 

 P, we obtain, by dividing log V by log P, 



logV_ * x <t> logjp «,_ -03365 



logP ~" a<j> \ogp ~"~ u~ -03580 



-•939944; 



1-06389 

 V=P 



consequently 

 and 



py__p+ -060056 



Similarly may be obtained 



P = V" 1( 

 and 



py=v- 



B2 



