Influence of Atomic Weight. 463 



p. 308) that those metals with the highest melting-point have 

 also the greatest constant of capillarity in the solid state ; but 

 if any connexion exists between the capillarity and chemical 

 composition of liquid inorganic bodies, it is an extremely com- 

 plicated one, and very difficult to trace. Grueront (Compt. 

 Rend, lxxxiii. p. 1291), however, has recently shown, as 

 regards homologous series of liquid organic compounds, that 

 the coefficient of capillarity decreases as the quantity of G 

 increases. This he has proved in the case of the fatty acids, 

 the ethyl ethers of the fatty acids, and the acetic ethers, 

 thus : — 



Coefficient of Boiling- 

 capillarity. point. 



Formic acid, CH 2 2 115*0 101 



Acetic „ C 2 H 4 2 160-5 118 



Propionic acid. C 3 H 6 2 189*0 141 



Butyric „ ' C 4 H 8 2 129*5 162 



Valerianic „ C 5 H 10 2 92*3 175 



Caproic „ C 6 H 12 2 64*0 205 



Ethyl formate, CoH 6 2 542-0 54 



„ acetate, C 4 H 8 2 450*3 74 



„ propionate, C 5 H 10 2 360*3 100 



„ butyrate, C s H 12 2 297*0 119 



„ valerate, C 7 H 14 O s 241*3 134 



Methyl acetate, C 3 H 6 2 534*5 56 



Ethyl „ C 4 H 8 2 450*3 74 



Propyl „ C 5 H 10 O 2 362*8 102 



Butyl „ C 6 H 12 2 305*3 116 



Amyl „ C 7 H 14 2 230*2 140 



Formic and acetic acids, however, are exceptions to Guerot's 

 law, which he attributes to possible impurities in the speci- 

 mens examined. He also points out that the coefficients of 

 capillarity of the ethers are very much higher than those of 

 the alcohols or acids which give rise to them. 



In the last column of the above Table I have added the 

 boiling-points of the respective liquids; and it will be seen 

 that, with the exception of acetic and formic acids, the coeffi- 

 cients of capillarity diminish as the boiling-point increases. 

 Also, if we compare together an acid with the isomeric ethers, 

 we find that the same rule holds o-ood : thus : — 



