140 Starkweather — Thermodynamic Relations for Steam, 



pressures, p^, in the fourth the fractional deviations of the 



former from 



the latter, 



and in the fifth 



a few determinations 



at low temperatures recently made 



by Juhlin.* 



T 



P 



P* 





d p, 



273-7 



4-626 



4-6 





•006 4-618 



283-7 



9-277 



9-165 





•012 9-242 



293-7 



17*632 



17-391 





•014 17*46 



303*7 



31-943 



31-548 





•013 



313-7 



55-449 



54-906 





•008 



323-7 



92-610 



91-980 





•007 



333-7 



149-40 



148-79 





•006 



343-7 



233-59 



233-08 





•005 



353-7 



354-94 



354-62 





•003 



363-7 



525-56 



525-39 





•0003 



373 7 



760 



760 









The variations are considerable, but for those at low tempera- 

 tures, an explanation has already been given, and in the middle 

 of the scale they are not more than could be ascribed to Reg- 

 nault's not correcting his thermometer to the air-thermometer. 

 Above 100° C. Regnault's gives two formulas, one for tempera- 

 tures according to the air-thermometer, the other for tempera- 

 tures by his mercurial thermometer ; below 100° this is not 

 done, the inference being that corrections were not made. 

 Now Regnault remarks! that at about 50° C. the air-thermom- 

 eter differs from the mercurial by two-tenths of a degree, 

 which would be sufficient to account for the deviations in that 

 region. The pressures are on the same side of Regnault's as 

 those of Juhlin, and agree well from 80° to 100° with those of 

 Wiebe. 



In the following table are given values of various quantities for 

 the saturation line from 0° C. to 100° C. on the basis of the formulae 

 developed in this paper, and from 100° to 200° from the for- 

 mulae adopted in the preceding article. They represent, in the 

 writer's opinion, the best determinations possible with the data 

 at hand. In the first column is given the temperature Centi- 

 grade, in the second the heat of the liquid, in the third the 

 total heat, in the fourth the latent heat, in the fifth the pressure, 

 in the sixth the volume, in the seventh the entropy of water, 

 7) Wi and in the eighth and ninth the entropy and energy of dry 

 saturated steam, rj s and e s . 



*Beiblaetter zu Wied. Ann., xviii, p. 736. 

 fComptes Rendus, lxix, p. 884, 1869. 



