100 PROF. C. H;i:\vi:X JKNKIN AND MB. P. R. PYE ON THE 



Tin- ..Iflervations on which CAILLETKT and MATHIAS' smooth curve is founded lie 

 erratically and at considerable distances from the curve. The curve is clearly 



rrn Hi-nils below 20 C. 



It will be noted that our values agree very closely with CAILLETET and MATHIAS' 

 from -20 C. to + 10" C. Our curve also lies almost exactly parallel with AMAGAT'S 

 curve and KUENEN and ROBSON'S theoretical extension of it. The agreement between 

 our curve, the observations, and the theoretical curve is a confirmation of the accuracy 

 of the shape of our L curve. 



The inaccuracy of our pressure-temperature curve, due to the presence of '11 per 

 cent, of air, referred to on p. 69, introduces an error into our values ofd p/dO which 

 probably does not exceed 2 per cent. If this were allowed for, it would raise our 

 specific- volume curve by 2 per cent., and bring it closer to KUENEN and ROBSON'S. 

 Tin- value of V does not enter into the construction of our 00 diagram. 



Joule-Thomson Effect. (Fig. 9.) 



No experiments on the Joule-Thomson effect for liquid C0 2 appear to have been 

 published. Figures for comparison might be deduced from MOLLIER'S I<f> diagram (3), 

 but that would be beyond the range of this paper. It is not easy to say what effect 

 the presence of the trace of air may have on these results. 



Dilatation and Elasticity of liquid C0 2 . 



As has been explained, the results of the Series V. experiments were not sufficiently 

 concordant to warrant the publication of values of the dilatation and elasticity 

 derived from them, though they are accurate enough to determine the values of $<f> 

 between the constant-pressure curves and the limit curve on the 6<f> diagram. The 

 confirmation of BEHN'S densities, shown in fig. 11, must not have much weight 

 attached to it for the same reason. 



The only results previously published are a single curve at 13'l C., given by 

 ANDREWS (14), and three curves given by AMAGAT(5) at C. +10 C., and +20 C. 

 We have failed to fit ANDREWS' curve on our figure, but AMAGAT'S curves are shown 

 for comparison in fig. 11. ANDREWS suggests that the curvature of the lines near 

 the saturation pressure may be due to the presence of air. 



0$ Diagram. (Fig. 12.) 



As stated at the beginning of this paper, the primary object, for which all the 

 quantities already discussed were measured, was the construction of a 00 diagram for 

 comparison with MOLLIER'S. 



It may be useful to recapitulate here the steps in the construction of the two 

 diagrams. Fig. 12 was drawn as follows : 



