Physical Properties of analogous Organic Compounds. 189 



This law is confirmed by ail known observations. The 

 following specific volumes of the combinations of acetic acid 

 (A.), formic acid (B.), and benzoic acid (C.) with water («.), 

 oxide of aethyl (/3.), and oxide of methyl (y.), result from the 

 observations which follow: — 



A. B. C. 



a.... 709 Mollerat. 467 Liebig. ? 



/3....1243 Liebig. 1020 ... 1794 Dumas. 



y....l012 Dumas. ? ... 1558 



and the observations give the boiling points in centesimal de- 

 grees for the same compounds :— 



A. B. C. 



a.... 120° Liebig. 99° Liebig. 239°Liebig. 



/3.... 74 ... 53 ... 209 Dumas. 



y.... 58 Dumas. ? 198 ... 



If we designate the specific volumes or the boiling points 

 of the compounds A + «, A + /3, A + y .... by (A + «) 

 (A + /3) (A + y) . . . , we find that within the limits of the 

 errors of experiment, 



(A + «)-(A + /3) = (B + «)-(B + /3) 

 (A + /3)-(A-f y) = (C + /3)-(C + y) 

 (A + «)-(B + «) =(A + /3)-(B + /3) 

 (A+/3)-(C + /3) =(A + y)-(C + y), &c. 



This law may be specially applied to single cases and rules 

 advanced for certain compounds which could be proved by 

 numerous observations. I will here enumerate some few cases 

 which frequently occur. 



I. " The specific volume of a hydrated acid (A + H- O) is 

 534 smaller than that of the corresponding aethyl compound 

 (A + AeO)." To prove this and the following laws, I will 

 give a table of the compounds, containing the formulae, the 

 atomic weights, the observed specific volumes and densities, 

 and those calculated after the above laws. 



In the following table therefore the observations of the hy- 

 drated acid have always been placed first, and from the spe- 

 cific volume of the hydrated acid resulting from the observed 

 specific weight, the specific volume of the aethyl compound is 

 obtained by the addition of 534. If the atomic weight of the 

 aethyl compound be divided by this calculated specific volume, 

 we obtain the calculated specific weight, and the agreement 

 between the latter and that observed shows the correctness of 

 the law. 



