448 



Drs. Ramsay and Young on 



but approximate corrections were introduced. It was possible 

 to read pressures to within 30 millim.on the scale employed, and 

 volume to within 0*02 cub. centim. per gram. Pressures corre- 

 sponding to even volumes were read oft', as with ether ; and on 

 mapping the isochors w T ith temperatures as abscissae and pres- 

 sures as ordinates, the resulting points lay in straight lines. The 



dip 

 values of b, i. e. of -^-, were then read off, and smoothed, 



by mapping them against the reciprocals of the volumes. After 

 smoothing, the values of a were calculated at each volume, 

 making use of the pressures previously read from the carve 

 representing isothermals. The diagram (1) on Plate X. was 

 then constructed from these smoothed values. The crosses 

 denote our readings of pressures at the temperatures chosen 

 by Andrews for his isothermals. These values of a and b 

 were then made use of in recalculating isothermals at the 

 above temperatures, and the diagram (2) on Plate X. repre- 

 sents the curves complete so far as Andrews's data allow. The 

 circles represent Andrews's actual measurements ; and it is 

 evident that no better concordance could be expected. The 

 tables which follow give the data afforded by Andrews's 

 experiments. 



Table V. 



Pressures read from Curves originally drawn from Andrews's 

 experimental data, and represented by circles in the 

 diagram (2), Plate X. 



Vol. 



Temperature. 





















0°. 



6°. 



13°-1. 



21°-5. 



31°-1. 



32°-5. 



35°-5. 



48°1. 



64°. 



100°. 



c. c. 



mm. 



mm. 



mm. 



mm. 



mm. 



mm. 



mm. 



mm. 



mm. 



mm. 



30 



11430 



11790 















14820 



16710 



25 



13480 



13830 















17500 



19860 



20 



162U0 



16570 















21450 



24300 



15 



20300 



20970 















27700 



31570 



12 



23730 



24800 















33500 



38730 



10 



26715 



28000 















38970 



45330 



8 









35340 



37560? 37800? 



38400? 



41930 



46200 



54630 



7 







35340 



38220? 



40970 '41370 



42060 



46200 



50850 



61500 



6 









41100? 



44700 145060 



46000 



51000 



56700 





5 









44100? 



48600 '49200 



50370 



56760 







4-5 











50550 '51400 



52830 



60000 







40 











52420 153430 



55140 



63500 







3-5 











54250 55260 



57240 



67000 







3-0 











55800 56700 



59130 



72400 







