232 ON PLASTER! AND SOAPS. 



with litharge, hold in solution a substance, that he called the 



Svreet ptjnci- sweet principle of oils, because it has a very decided saccha- 



pco oi b. rinfi taste. But as, acrordins^ to the observations of that 



eminent chemist, the water likewise holds in solution a cer- 



Is •• not ow-ng tain quantity of oxide of lead, may it not he inferred, that 



this taste is owing to the property that metal has of impart- 



Que^tions to ins^ sweetness to n;ost of its compounds? If experience 



be aiiswcrvid. pjoye the cont'ary, would it not be interesting, to inquire 



how tins principle is formed ? what are its properties ? in 



what state the oil is left, alter having lost the principles that 



give birth to it ? whether this abstraction be indisDensable 



to the combination of oil with oxide of lead? and on the 



exj>eriments necessary in this research to establish the theory 



of one of the most important operations of pharmacy and 



the analogy of its results to alkaline soaps ? 



Such were the propositions that led to the experiments I 

 am about to describe. 

 Oil litharge ^"*^ ^ tubulated glass body I put equal parts of olive oil, 



and water litharfre, and water. To its tubulure I adapted a tube, ter- 

 tUer^ minating in a vessel of lime water ; and to its orifice a blad- 



der, to prevent the contact of air. This bladder was so 

 contrived, as to allow me to stir the matter with a spatula, so 

 The oxide as to prevent it sticking to the bottom. Having brought the 



changed yel- ^jixture to boil, I observed the oxide of lead change in sue- 

 low, andthen . „ , „ , p ,, ?. 1 

 white, cession from red to yellow, and irom yellow to white : and 



and carbonic during the experiment carbonic acid was almost always fly- 

 acid evolved, ing off. Having suffered the apparatus to cool, I examined 



the results of the experiment in succession. 

 Tiie water hjad The water, that had served as an intermedium, had a 

 te'^rl' would strong metallic taste. With the addition of yeast, and at a 

 not ferment, proper temperature, I could never biing it to ferment*. It 

 Lead precipi- formed an evident precipitate with sulphuric acid, and with 

 uted from it. hidroguretted sulphuretsf. I passed sulphuretted bidrogen 



through it, till nothing more was thrown down, and then lil» 



tered to separate the sulphuret of lead. 



• I was for a moment led into an errour, by employing yeast, which, 

 not having been washed, contiintd some iilcohol. 



_,, ,. , + I satisfievi myself by various expcrimeiii^, that it is of no consc- 



Oil dissolves ' ■' ' , ; , , r , ,, ■, 



t«^d without quence to the solution of oxiJe of lead, thai the oil or fat should be ran. 



teing rancid, eid, as Scheele supposed. 



The 



