180 



Prof. Sydney Young on the 

 Table XXI. 



£■ with Mean Ratios of 



Comparison of Values of 7™ 



Molecular Volumes at corresponding Pressures, 



Substances compared. 



T p' 



T' X f 



Mean Batios of 

 Molecular Volumes. 



Percentage 

 difference between 

 highest and lowest 

 of the three values. 



Liquid. 



Saturated 

 Vapour. 



CeH-Cl/CgH-F 



1-1308 



11974 



1-2884 



1-0589 



1 1394 



1-0760 



•9351 



•9861 



1-2771 



1-0468 



•5203 



•6537 



•8533 



•8303 



1-2564 



1-6401 



1-3054 



1-1246 



1-1802 



1-2772 



1-0495 



11358 



1-0822 



•9439 



1-0195 



1-2793 



10342 



•4228 



•6153 



•7995 



•6342 



1-4534 



1-8890 



1-2999 



1-137 



1-189 



1-282 



1-047 



1-132 



1080 



•946 



•993 



1-282 



1-038 



•507 



•676 



•859 



•593 



1-329 



1-693 



1-274 



11 



1-5 



0-9 



11 



0-7 



06 



1-2 



34 



0-4 



1-2 



231 



9-9 



7-4 



40-0 



15-7 



15-2 



2-5 



C fi H°Br/C n ILF 



C H I/C H.F 



C 6 H Br/C 6 H 5 C1 



C 6 H,°I/0 6 H 5 C1 ... 



C C H I/O e H.Br , 



C H /(LH-F 



CCl./CL-tLF 



SnCL/C.JELF 



(0 2 H 5 ) 2 O/C 6 H 5 F 



CH 3 OH/C 6 H.F 



C 2 H 5 OH/C 6 H 5 F 



C,H 7 OH/C 6 H 5 F 



CH,COOH/C 6 H 5 F ... 



C 2 H 5 OH/CH 3 OH 



C3H-OH/CH3OH 



C 3 H 7 OH/C 2 H 5 OH 



For the halogen derivatives of benzene 



p=p'. 



It will be seen that the differences between the three values 

 are not very great, except in the comparisons of the three 

 alcohols and acetic acid with fluorbenzene, and of ethyl and 

 propyl alcohol with methyl alcohol. In the other cases, 

 including the comparison of propyl with ethyl alcohol, the 

 relation 



V 

 V 





may be considered as approximately true with the limitations 

 already stated. 



The two substances — methyl alcohol and acetic acid, and 

 to a small extent ethyl and propyl alcohol — are clearly ex- 

 ceptional in their behaviour, and it is of interest to note, in 

 comparing these substances with fluorbenzene, that while 

 with acetic acid the ratios of the molecular volumes both of 

 liquid and saturated vapour are very low, with methyl alcohol 

 it is only in the liquid state that this is to be observed. This 



