some Thermodynamical Relations. 

 C 2 H 6 



43 



15. Alcohol and Oxygen. 

 taken as correct. c = — -00040075. 



Temperatures of alcohol 



Pressures. 



Ratios. 



Absolute temperatures 

 of Oxygen. 



From observed 

 temperatures. 



Smoothed. 



Eecalculated. 



Observed. 



millim. 



300 



400 



500 



600 



700 



800 



1000 



1500 



2000 



3000 



5000 



10000 



15000 



20000 



30000 



40000 



3-£ 

 3-6 

 3-5 

 31 

 31 

 31 

 3^ 

 3-4 

 Si 



s-: 



35 



331 

 332 



S123 

 '800 

 f 024 

 )848 

 1662 

 1098 

 5824 

 J189 

 5698 



3-940 



3-913 



3-894 



3-879 



3-861 



3-848 



3-824 



3-780 



3-7485 



3-694 



3-621 



3-514 



3-441 



3-388 



3-300 



3-240 



83-7 



85-9 



87-6 



89-1 



904 



91-6 



93-7 



97-8 



100-8 



105-7 



112-8 



124-0 



131-8 



137-9 



1479 



155-6 



920 



93-5 



970 



1000 



105-5 



113-9 



125-7 



1330 



138-1 



147-1 



*154-2 



The absolute temperatures of oxygen recalculated from the 

 smoothed ratios with alcohol agree well with those calculated 

 from the ratios with water. It was thought worth while to 

 compare these temperatures with those of sulphur, oxygen 

 being the most and sulphur the least volatile of all the sub- 

 stances examined. 



* The last pressure, 40,000 millim., is a little above tbe critical point, 

 but sufficiently near to allow of tbe continuation of tbe vapour-pressure 

 curve without sensible error. This was done instead of calculating the 

 absolute temperature of alcohol corresponding- to 38600 millim., the 

 critical pressure of oxygen. It is to be remarked that the last two or 

 three points representing the experimentally determined vapour-pressures 

 of oxygen at the highest temperatures lie a little above the curve which 

 was drawn. If more weight had been given to these points, the agree- 

 ment between tbe observed and recalculated numbers would have been 

 much closer. Thus Olszewski gives 154°-2 as the absolute temperature at 

 the critical pressure 38600 millim., whereas from the curve this would be 

 the temperature at 40000 millim. If the curve were raised so as to pass 

 through the point representing the observed critical pressure and tempe- 

 rature, the exterpolated temperature would become 155° # 3, or only o, 3 

 lower than that recalculated from the smoothed ratio. 



In any case, the agreement seems to be close enough to show that the 

 equation R' = R-j-c [t'—t) holds good up to the critical point. 



