OF THE FIXED OILS IN CONTACT WITH SULPHUR. 



867 



into the receiver, and at the same time sulphuretted hydrogen passes in torrents 

 through the alcohol ; it there deposits a certain quantity of oil, and on escaping, 

 maybe kept burning during the whole operation, with a flame eight or nine inches 

 high. The principal difficulty of this process consists in regulating the heat, so 

 as to keep up a steady action. If the heat be allowed to fall, the contents of the 

 balloon become so viscid, as inevitably to boil over ; and at the same time too 

 high a temperature causes the whole action to go on with excessive violence. I 

 have generally operated on quantities of three pounds, each of which requires a 

 complete day for its distillation, during which time the operator must never leave 

 it, but constantly attend to the regulation of the heat, and the gradual addition 

 of sulphur in small quantities. When a quantity equal to about half the oil em- 

 ployed has distilled over, the remaining mass becomes excessively viscid ; and just 

 at this point the balloon frequently cracks, the contents escape, and the whole 

 catches fire, and blazes off with a bright yellow flame, and smeU of sulphurous acid. 

 The product of this distillation, which exactly resembled that of the pure 

 oleic acid, was rectified, and the crystals which deposited from the latter portions 

 were expressed and purified by successive crystallizations in alcohol. They then 

 presented all the characters of margaric acid, and gave the following results of 

 analysis : — 



) 5-275 grains of the acid gave 

 14-558 . , . carbonic acid, and 

 5-919 ... water. 



(6-358 grains of the acid gave 

 17-578 . . . carbonic acid, and 

 7-212 ... water. 



Which gives the following results per cent. — 



100-00 100-00 100-00 



3325-0 



These results agree completely with the formula for margaric acid, and were far- 

 ther confirmed by the analysis of its silver salt and ether. 



4-648 grains of the silver salt gave 1-325 of silver = 28-53 per cent. 

 7-926 grains of the silver salt gave 2-284 of silver = 28-70 per cent. 

 The calculated result for margarate of silver gives 28-65 per cent. 



VOL. XVI. PABT III. , 5 A 



