186 Messrs. Thorpe and Young on the Combined Action 



III. 5*13 grms. of the hydrocarbon after repeated distillation (21 times) 

 required 1*54 grm. of bromine, or 100 grms. would require 30 grms. 



3. In the hope of throwing some light upon the constitution of the 

 solid paraffins, we have repeated this process of transformation into 

 liquid products upon a large scale. The paraffin employed was obtained 

 from shale ; it melted at 46° and solidified at 43°, and had a specific 

 gravity of 0-906 at 13°, when solidified under an extra pressure of 

 0*75 millim. of mercury*. 



It was burnt with copper oxide in a stream of oxygen, with the follow- 

 ing results : — 



I. 0-2980 grm. paraffin gave 0-9293 grm. carbon dioxide and 0-3980 grm. 

 water. 



II. An unknown quantity gave 1*4245 grm. carbon dioxide and 0-6060 

 grm. water. 





I. 



II. 



Mean. 



Carbon 



.... 85-05 



85-23 



85-14 



Hydrogen 



14-84 



14-77 



14-81 





99-89 



100-00 



99-95 



* Considerable discordances exist in the state- 

 ments by various observers of the specific gravities 

 of the solid paraffins. These differences are doubt- 

 less due more to the difficulty of obtaining the bodies 

 perfectly homogeneous after melting than to any 

 great variations in their true specific gravity. When 

 a piece of ordinary paraffin is examined, it is seen to 

 be made up of an infinite number of small cavities ; 

 and however carefully it may be cooled after melting, 

 the interstices are invariably present. From this 

 circumstance it is obvious that any attempt to deter- 

 mine the real specific gravity of this body would give 

 too low a result. By solidifying the paraffin under 

 pressure, the formation of the cavities may be, to a 

 great extent, obviated. We have effected the solidi- 

 fication in the apparatus figured in the margin. 

 Mercury was first poured into the tube up to the 

 level A B, the bottom end of the tube being securely 

 plugged by a cork C. The wider portion D of the 

 tube was then filled with the melted paraffin, and 

 a well-fitting caoutchouc cork fastened down by wire 

 into the opening, care being taken to exclude all 

 bubbles of air. Mercury was now quickly poured 

 into the longer limb of the tube until it stood about 

 0*8 m. above the level of the metal in the wider tube, 

 and under the pressure of this mercury the paraffin 

 was allowed to solidify slowly. By withdrawing the 

 cork C, the mercury could flow out, and on warming 

 the sides of the tube the plug of paraffin was easily 



detached. Thus solidified, the body was almost entirely free from cavities, and portions 

 perfectly homogeneous were easily found ; these had a specific gravity of 0*906 at 13°. 



