1826.] Mr. Scanlan on a Volatile Oil from Soap Ley. 327 



also soluble in alcohol, and is again separable by water; it 

 readily and entirely evaporates, leaving no stain on paper. It 

 is little inflammable, depositing abundance of carbon, as it 

 burns : the colour of its flame is pale green.* It is soluble in 

 caustic ammonia ; it dissolves camphor. 



Nitric acid did not inflame it, but produced increase of tem- 

 perature ; and in one instance changed the colour to a beautiful 

 pink. Oxalic acid is formed by the action of nitric acid upon it. 



All the iodine I have prepared from soap ley is contaminated 

 with this substance, even when well washed with water, dried on 

 blotting paper, and exposed for some time to the air. 



In forming hydriodate of iron with iodine of my own prepara- 

 tion, in order to make hydriodate of potash,! had always observed 

 a smell closely resembling water recently distilled from horse- 

 radish, and an oily appearance on the neck of the flask, which 

 was not the case with iodine bought of Messrs. Herrings and 

 Burbige, London. 



To ascertain the cause of this difference, I submitted eight 

 troy ounces of iodine, prepared by myself, with iron filings and 

 water, to distillation in a retort, and obtained about thirty or 

 forty drops of a heavy oil, diftering from that first obtained in 

 its colour, which was somewhat deeper, and in smell and taste, 

 both of which were like horse-radish, though not quite so pene- 

 trating. A similar quantity of London iodine did not even 

 flavour the water distilled in the experiment. 



From the foregoing it appears, that th^re must be some great 

 difference between our ley and that of England and Scotland, 

 which probably may be accounted for by the fact, that the soap- 

 boilers here use large quantities of fat, partially decomposed in 

 the roasting of meats, i\\ fabricating their soaps ; which to those 

 who prepare muriate of potash from soap ley, is a source of 

 annoyance, hindering the free crystallization of the salt, after it 

 has arrived at a certain density. 



I can in no way account for the formation of this oily sub- 

 stance, unless it be, that the partially decomposed animal matter 

 above-mentioned enters into some peculiar sort of combination 

 with the hydriodate in the kelp ley, and is subsequently further 

 decomposed by the sulphuric acid, used in eliminating the 

 iodine. If to the concentrated soap ley boiling, a considerable 

 excess of sulphuric acid be added, there separates a black sub- 

 stance, of the consistency of pharmaceutical extract, which, 

 when heated by itself, melts and puffs up, and when cold is 

 brittle like pitch, not unlike the substance which results from 

 the decomposition of alcohol by sulphuric acid, in making 

 sulphuric ether, and perhaps attributable to changes not very 

 dissimilar. 



Very complicated eflects seem to be produced by the action 

 * Not unlike chloric ether. 



