116 MR. CARL SCHORLEMMER ON THE 



as the normal paraffins and the normal alcohols and their 

 derivatives"*. 



In a paper read before the Royal Society I have already 

 pointed out that the difference between the boiling-points 

 of the lower members of these paraffins is not the same, 

 but that it decreases regularly by 4° until it becomes the 

 well-known difference of 19 , as the following table will 

 show : — 



Boiling-points. 



, * V 



Mean found. Calculated. Difference. 

 C H 4 



C 2 H 6 



C 3 H 8 ■ 



C 4 H 10 i° 



C 5 H 12 38 38 37 



C 6 H M 70 71 I 3 



C 7 H 16 99 100 



C a H ia 124 i2<; 



is I2 4 "5 



C 12 H 26 202 20, 4X19 



C 16 H 34 278 278 4XI 9 



It appeared to me of interest to compare the boiling- 

 points of other normal compounds, selecting, of course, 

 only such of which the boiling-points have been carefully 

 determined and corrected for pressure and expansion of 

 the mercurial column of the thermometer above the va- 

 pour. The result of this investigation is that in most of 

 the other series the difference between the boiling-points 

 also steadily decreases by about 2°; but I am not in a 

 position to state whether this decrease ceases when the 

 difference becomes 19 , as we do not yet know a sufficient 

 number of compounds. 



* Compare: — Lieben and Eossi on normal butyl alcohol (Ann. Chem. 

 Pharm. vol. clviii. p. 137), on normal valerianic or pen ty lie acid (Ann. 

 Chem. Pharm. vol. clix. p. 58), on normal amyl or pentyl alcohol and 

 normal caproic or hexylic acid (Ann. Chem. Pharm. vol. clix. p. 10) , Zincke 

 on otyl compounds (Ann. Chem. Pharm. vol. clii. p. 1); Franchimont and 

 Zincke on hexyl compounds (Ann. Chem. Pharm. vol. clxiii. p. 193), and 

 on nonylic acid (Deut. Chem. Gres. Ber. vol. v. p. 19). 



