On the Edulcorat'wn of Fijh-Oil. I09 



with them, either cold or hot, that the feparatlon is difficult 

 to be effected even with the addition of brine; and the oil, 

 when a hirge proportion of it is ufed, can fcarcely be at all 

 brought from its concreted to a fluid ftate but bv an equiva- 

 lent large proportion of lixiviate fait : the ufe of lime, there- 

 fore, alone is improper, or even in a great proportion with 

 other ingredients. But when oul.y a leHer degree of edulco- 

 ration is required, a moderate quantity, conjoined with an 

 equal or greater weight of chalk, which affiles its feparatioa 

 from the oil, mav, on account of its great cheapnefs, be em- 

 ployed very advantageoufly : it will in this cafe admit of pre- 

 cipitation from the oil by the addition of brine. It mav be 

 alfo expediently ufed when lixiviate fait is employed with 

 heat for the nioft perfeft purification of oils; for it will in 

 that cafe give room for the diminifhing of the quantity of lix- 

 iviate fait, though the projwrtion be neverthelefs fo reftrained 

 as not to exceed what the proportion of lixiviate fait { juft re- 

 quifitc for the edulcoration) can feparate from the oil. 



Chalk has an abforbing power fimilar to lime, but in a lefs 

 degree, on the putrid iubltance of oil : it docs not, however, 

 combine fo Ilrongly with the oil as to relift feparation in the 

 fame manner, and is therefore very proper to be conjoined 

 either with lixiviate falts or lime, as it renders a lefs quantity 

 of either fufficient, and indeed contributes to the feparation 

 of the oil from them. 



Magnefia alba, or the alkaline earth, which is the bafis of 

 the fal catharticus, and the fingular earth which is the bafis 

 of alum, both have an edulcorating power on foetid oils, but, 

 like lime, have too Itrong an attrail-tion with them to be fe- 

 parated ib as to admit of the redudtion of the oil from the 

 concreted Hate to which they reduce it; and therefore, as 

 they are not fuperior in efficacy to lime and chalk, but much 

 dearer or more ditficult to be obtained, thcv may be rejefted 

 from the number of ingredients that are proper for the puri- 

 fying of oils, with a view to commercial advantages. 



Sea fait has an antiieptic power on the mixed iolid parts of 

 animals; but ufed alone, or dillblved in water, it does not 

 appear to lellen the putrid fbetor of oils, but, on the contrary, 

 rather incrcafcs it. If after their commixture with it they 

 are fubjected to heat, it rather depraves than improves the 

 oils; but though by its own innnediate aiilion on them it 

 conduces fo little to the edulcoration of oils, yet it is a me- 

 dium for the feparation of water and the alkaline fubllances 

 requifite to be employed to that end. It is of great utility in 

 the cdulcorative procelfes ; for when alkaline lalts or earths 

 combine with the water necelVary to their action oa tlie oijs, 



or 



