Evaporation of different Liquids at their Boiling-points. 47 



given for the heats of 

 absolute value for ben- 



In the later tables the numbers 

 evaporation are calculated from the 

 zene, viz. :— L = 94«4 at 80°'2. 



Table V. records the results obtained by us for benzene, 

 toluene, metaxylene, acetic acid, and ten of the lower esters 

 prepared by Prof. Sydney Young. Each liquid is compared 

 with alcohol. 



In Table VI. we give for each liquid : — 



(A) the ratio compared with benzene ; 



(B) the value of L in thermal units at 15°; 



(C) the value of L obtained from the thermodynamic 



equation (see p. 51, infra)', 



(D) values obtained by other observers. 

 In Table VII. we give for each, 



L, the heat of evaporation; 



t, the temperature of the boiling-point ; 



M, the molecular weight; 



Tp-, the quotient of the molecular heat of vaporization 

 by the absolute temperature ; according to Trou- 

 ton's Law this should be a constant. 



9. Table V, 



No. 



Date. 



B. 



Weights evapo- 

 rated. 



Eatio 



Correctec 



weights. 



Ratio 



Mean. 



Benzene. 







Alcohol. 













1 ... 



2 ... 



3 ... 



4 ... 



May 21. 

 „ 22. 

 ,, 23. 



» 24. 



752-8 

 755-7 

 757-9 

 756-7 



16-976 

 18-662 

 19-010 

 17-098 



8-193 

 8950 

 9-150 



8-286 



0-907 

 0-906 

 0-901 

 0-905 



16976 

 18-662 

 19010 

 17-098 



7431 



8-1085 



8-244 



7-499 



0-438 

 0-434 

 0-434 

 0-438 



0-436 



Toluene. 



















5 ...1 May 28. 



6 ...| „ 29. 



763-2 



17-359 

 17-046 



7-136 

 7-040 



0-972 

 0-972 



17-359 

 17-046 



6-936 

 6-843 



0-400 

 0-401 



0-401 



Metaxylene. 



















7 ...1 May 30. 



8 ...| June 6. 



1 755-7 

 1 767-6 



16-309 

 16755 



6063 

 6150 



1031 

 1-036 



16-309 

 16-755 



6-251 

 6-3715 



0-386 

 0-380 



0-383 



Acetic Acid. 



















9 . 



10 .. 



11 .. 



June 11. 

 ,. 12. 

 „ 19. 



758-6 

 762-2 

 752-4 



19-517 

 17-033 

 19-330 



8-956 

 7-754 

 8-613 



0-980 

 0-984 

 0-984 



19-517 

 17033 

 19-330 



8-777 

 7-630 

 8-475 



0-450 

 0-448 

 0-447 



0-448 



