YOL. LXXVI.] PHILOSOPHICAL TRANSACTIONS. * 7^ 



VI. Observations on the j^ffinities of Substances in Spirit of Wine. By John 



Elliot, M.D. p. 155. 



In Mr. Kirwan's papers on the attractive powers of the mineral acids, it is 

 shown that metallic calces have stronger attractions to those acids, than alkalis 

 and earths. The following experiments not only confirm this doctrine, but also 

 a position that I have lately ventured to advance,* " that certain decompositions 

 will take place in spirit of wine, which will not at all in water, nor in the dry 

 way.** I have shown, that if expressed oil be mixed with slaked lime into a paste, 

 * so as to form calcareous soap, and mild alkali be added, the latter will not de- 

 compose the former, either in water or by fusion. But that if spirit of wine be 

 substituted for water, an alkaline soap and mild calcareous earth will be formed. 

 As sea salt contains the fossil alkali, and as by the table of affinities acids have 

 stronger attraction to metallic calces than to alkalis, I concluded, that if sea 

 salt were added to a metallic soap, a similar double decomposition would take 

 place. 



To try this, I took some diachylum, which had been bought at Apothecaries- 

 Hall, and added to it sea salt ; then covered them to a sufficient height with 

 spirit of wine, and set the bottle over the fire. Soon after they had boiled, the 

 decomposition of the diachylum began to be apparent. When the boiling had 

 continued some time, I removed the vessel from the fire, and after it had stood a 

 few minutes, decanted the clear liquor while hot ; then evaporating it, obtained 

 a true alkaline soap. The residuum of course contained a quantity of calx of 

 lead, combined with marine acid. But much of the diachylum remained either 

 wholly or partly undecomposed : I therefore added more sea salt and spirit of 

 wine, and obtained a further yield of soap. But though much sea salt remained 

 behind, diachylum was still found in the residuum. I found indeed, that if the 

 ingredients were previously freed from their water, the process succeeded to 

 somewhat better advantage. 



From 5 oz. of diachylum I did not get quite 3 oz. of soap. This soap was 

 likewise soft, and contained a portion of oil not combined with a sufficient quan- 

 tity of alkali. The oil I suppose had existed in a similar state in the diachylum : 

 and I remarked, that as the spirit evaporated, it gave out the true soap first, the 

 unsaturated oil not till afterwards; so that the latter might easily be obtained 

 separate from the formefr. If too much salt was employed, much of it was 

 taken up by the liquid, and communicated to the soap, at least if the ingre- 

 dients had not been previously deprived of their water. To separate this salt I 



* In an Appendix to the 2d edit. •£ the " Elements of the Branches of Nat. Philos. connected 

 with Medicine." — Orig. 



