370 



Production of Olefines from Paraffin. [Mar. 9, 



tainty arising from the probable disturbing causes at the first magnetic 

 station. 



It is hoped that a second series of observations at the new station will 

 throw greater light on the fact of the sun's influence on terrestrial mag- 

 netism, by either confirming the results obtained above, or by adding fresh 

 weight to the conclusions arrived at by the President of the Royal 

 Society. 



II. "Preliminary Notice on the Production of the Olefines from 

 Paraffin by Distillation under Pressure." By T. E. Thorpe, 

 Ph.D., Professor of Chemistry in Anderson's University, Glasgow, 

 and John Young. Communicated by Professor Roscoe, P.R.S. 

 Received February 2, 1871. 



When paraffin is exposed to a high temperature in a closed vessel, it 

 is almost completely resolved, with the evolution of but little gas, into 

 hydrocarbons which remain liquid at the ordinary temperature. 



This reaction will undoubtedly afford the most important insight into 

 the constitution of this body. 



Accordingly we have repeated this conversion on a large scale, and from 

 about 3^ kilograms of paraffin melting at 44°* 5 C. (prepared from shale) we 

 have obtained nearly four litres of liquid hydrocarbons. This mixture of 

 hydrocarbons commences to boil at about 18° C, but the quantity coming 

 over below 100° C. is comparatively small ; by far the greater portion 

 boils between 200° and 300°. A preliminary separation shows that the 

 four litres are made up of hydrocarbons boiling 



litres. 



Between 200° and 300° 2*7 



„ 100° and 200° 1-0 



Below 100° 0*3 



4-0 



Up to the present we have principally occupied ourselves with the investi- 

 gation of the fraction boiling below 100°, and have obtained conclusive 

 evidence that it is mainly composed of olefines, the proportion of members 

 of the C w II 2re -f-2 series being but small. By repeated fractionations over 

 sodium we obtained perfectly colourless liquids boiling about 35° and 65°, 

 which were attacked by bromine in the cold with the greatest energy. On 

 adding the bromine slowly and in minute drops, and carefully cooling the 

 hydrocarbon by a mixture of snow and salt, scarcely a trace of hydro- 

 bromic acid was produced. The portion boiling at 36° may be either 

 amylhydride or amylene, or a mixture of both ; the avidity with which 

 the bromine combines with it shows that the latter body must be present in 

 considerable quantity. As soon as the drops of bromine permanently 



