Mr. Williams on the Constitution of the Essential Oil of Rue. 381 

 The mean of two determinations of the density of the vapour * gave, — 

 Experiment (mean). Theory C-^ H=2 0^ =4 vols. 



5-870 5-874 



The aldehyde, purified as above, was again converted into the am- 

 moniacal bisulphite, from which the oil was a second time obtained. 

 It gave on analysis, — 



Carbon 77-&7 



Hydrogen 12-93 



Oxygen 9-40 



100-00 

 It is plain, therefore, that oil of rue contains an aldehyde of the 

 formula C" H" O'^ Recent researches having demonstrated that no 

 acid of the series C° H" O^ with 22 equivalents of carbon has yet been 

 isolated, and no other derivative with a 22 carbon formula being 

 known, the author has given the name enodijle to the radical homo- 

 logous with acetyle contained in this substance. 



Enodic aldehyde is a colourless fluid of a fruity odour, quite differ- 

 ent to that of the rue plant. Its density is 0-8497 at 15°. Agitation 

 will cause it to solidify at 7° into a snow-white mass resembling cam- 

 phor. Its boiling-point is 213°. 



Rue oil yields a small portion of fluid boiling at 232°, containing 

 the aldehyde of lauric acid. It was not obtained absolutely free from 

 the first fluid. It contained : — ■ 



Experiment. CalculaJiou. 



(^bon Ts^l C^' 144 78"^6 



Hvdrogen.... 12-9 H'^ 24 13-04 



Oxygen 9-0 O" _16 8-70 



1000 184 100-00 



The oils accompanying the aldehydes, but which refuse to combine 



with the alkaline bisulphites, are of the terebinthinate class. The more 



volatile are composed chiefly of an isomer of oil of turpentine ; the less 



volatile are hydrates apparently homologous with an isomer of borneol. 



March 25. — The Lord Wrottesley, President, in the Chair. 



The following communications were read : — 



" On the Relative Power of Metals and their Alloys to conduct 

 Heat." By F. Crace Calvert, Esq., F.C.S., M.R. Acad, of Turin; 

 and Richard Johnson, Esq. 



After describing the aj)paratus employed, and the process followed 

 to determine the conductibillty of metals and alloys, the authors 

 give the chemical means by which they purified the metals used in 

 the experiments. Taking silver, which is the best conductor, as 

 1000, they have obtained the relative conducting powers of the fol- 

 lowing metals : — 



* In order to prevent oxidation of the oil, the balloons were filled with hy- 

 drogen previous to immcmion in the bath. 



