1880.] Physical Constants of Liquid Hydrochloric Acid. 119 



liquid was considered of the highest importance, as from these num- 

 bers the latent heat of transformation and other important data can 

 be easily calculated. For these reasons the gas was examined in 

 rather a different way to the acetylene, the volume to which it had 

 been compressed at the point of liquefaction (or the volume of the 

 saturated vapour) at any given temperature being first accurately 

 determined, and then the pressure increased until the condensed 

 liquid entirely filled the upper part of the tube. The volume of this 

 liquid column was then measured, so that a comparison between the 

 volume of the saturated vapour and the volume of the total condensed 

 liquid was obtained at each temperature. 



This fractional volume of the gas at the point of liquefaction was 

 determined by observing when the air manometer ceased to show an 

 increase of pressure on compressing the gas ; the volume of the gas 

 at this point being then measured, and the pressure being then 

 gradually released until the air manometer showed a slight decrease 

 of pressure, — the volume of the gas was then again measured at this 

 point, and the mean taken as the point of liquefaction. 



The results of the whole series of experiments are recorded in a 

 condensed form in the following table : — 



A. 



B. 



C. 



T>. 



E. 



F. 



4 



137 -31 



1 



38-89 



7'55 



18-18 



29 -8 



9-25 



118-96 



1 



45 '75 



7-90 



15-05 



33 -9 



13 8 



103 -50 



1 



53 19 



8-35 



12 -39 



37-75 



18-1 



91 -77 



1 



61-17 



8-74 



10-50 



41 -80 



22-0 



81-19 



1 



70-06 

 1 



9-10 



8-92 



45-75 



26 75 



69-69 



82 -94 



9-50 



7-33 



51-00 



33 '4 



55 -75 



1 



105-98 



10-12 



5-50 



58-85 



39 -4 



44-85 



1 



13T-33 



10-68 



4-19 



66-95 



44-8 



36-34 



1 



168 -67 



11 -96 



3-03 



75 -20 



48-0 



31 -33 



1 



197 -60 



12-00 



2-61 



80-80 



49-4 



27-64 



1 



22^96 



12-92 



2-13 



84-75 



50-56 



25-70 





14 -30 



1-79 



85-33 



51-00 



23-96 











