488 Messrs. T. E. Thorpe and J. Young on the Combined [June 20, 



XVIII. "On the Combined Action of Heat and Pressure upon the 

 Paraffins." By T. E. Thorpe and John Young, of the Ander- 

 sonian University, Glasgow. Communicated by Prof. Roscoe, 

 E.R.S. Received June 5, 1872. 



(Abstract.) 



The authors first refer to their preliminary communication read before the 

 Royal Society on March 9, 1871, in which they described the combined 

 effect of heat and pressure upon the solid paraffins. They showed that 

 when these substances are exposed to a high temperature in a closed vessel, 

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

 hydrocarbons which remain liquid at the ordinary temperature. In the 

 present communication they describe how this transformation may be easily 

 effected on the small scale. A few grams of ordinary paraffin are sealed 

 up in a piece of strong combustion-tubing, bent in the form of the letter \f ; 

 the tube is securely surrounded by strong wire gauze, and the limb con- 

 taining the paraffin is gently heated along its entire length in a gas com- 

 bustion-furnace. If the heat is properly regulated, the paraffin rapidly 

 distils over and solidifies in the cold portion of the tube. The gas-flames 

 are then turned down, the tube reversed, and the paraffin again distilled. 

 After a very few repetitions of this process the paraffin acquires the con- 

 sistency of butter, and the warmth of the hand is sufficient to liquefy it ; 

 and after about a dozen distillations, the greater portion of the substance re- 

 mains permanently liquid. It seems to be absolutely necessary that the 

 paraffin should thus be distilled over and condensed ; by merely heating it 

 in the tube in such a manner that the condensed vapours flow back again 

 upon the heated portion, the liquefaction is never accomplished. It appears 

 that only paraffins boiling at an extremely high temperature, and those 

 usually solid under ordinary conditions, are thus susceptible of decomposi- 

 tion. The readiness with which they yield liquid hydrocarbons appears to 

 depend upon the complexity of their constitution. 



The authors have not determined with certainty the limits of the decom- 

 position, but they find that the mixed paraffin and olefine, boiling at about 

 255°, may be repeatedly distilled backwards and forwards in a sealed y-tube 

 without suffering the slightest change. 



The authors have repeated the process of conversion of solid paraffin into 

 liquid products upon a large scale, in the hope of obtaining an insight into 

 the constitution of the higher members of the C„H 2n +2 series of hydrocar- 

 bons. The paraffin employed was obtained from shale ; it melted at 46°, 

 and had a specific gravity (when solidified under pressure) of 0*906 at 13°. 

 Its composition was : — 



Carbon. 85'14 



Hydrogen t , 14'81 



99'95 



