lo8 On the Edulcoration ofFi/h-Oil. 



do not, however, equally aft on the parts of the oil on which 

 the enipyreumatic fcent depends, unlefs by the alhflance of 

 heat; for when they are commixed with the oils without 

 heat, in proportion as the putrid fmell diminiflies, that be- 

 comes more fenfibly prevalent. The ultimate aftion of lixi- 

 viate falts on animal oils, except with refpeft to the empy- 

 reunia, feems to be the fame either with or without the me- 

 dium of heat ; for the fame urinous and putrid fmell, gra- 

 dual diminution of the colour, and foetid fcent, happens in 

 one cafe as in the other, except w-ith regard to the accelera- 

 tion of the changes ; and fuch falts, where the purification 

 is required to be made in a great degree, are a ncceflary 

 means, as they are more efil-ctual than any other fubllance 

 that can be employed. 



The ufe of lixiviate falts alone is not, however, the moft 

 expedient method that can be purfued for the edulcoration ot 

 oils, for feveral reafons. If they be ufed alone, cold, in the 

 requifite proportions, they coagulate a confiderable part of the 

 oil, which will not again feparate from them under a very 

 great length of time ; and when they have defiroyed the pu- 

 trid fcent, a ftrong bitter empvreumatic fmell remains. The 

 fame inconvenience, with relation to the coagulation of part 

 of the oil, refults when they are ufed alone with heat. The 

 fuper-addition of common fait (which refolves the coagulum 

 and counterads the faponaceous power of the lixiviate fait, 

 by which the oil and water are made to combine) is there- 

 fore neceflary ; and the expenfe arifing from the larger pro- 

 portion of lixiviate fait requires it to be employed if no other 

 alkali be taken in aid, and renders the junftion of alkaline 

 earths with it extremely proper in the edulcoration of oils for 

 commercial ufes. Lime has alfo an edulcoralive power on 

 animal oils ; but it has alfo fo ftrong a coagulative aclion, 

 that the addition of a large proportion of alkaline (alts be- 

 comes, when it is ufed, neceifary to reduce the concreted oil 

 to a fluid ftate ; and therefore this iubitancc alone is not 

 proper for that purpofe. The combination of lixiviate fait 

 with lime, or the folution commonlv called foap-lve, has an 

 efte6lual edulcorative aftion on foetid oils ; but it makes a 

 troublefome coagulation of part of the oil if no common fait 

 be employed, and muft be ufed in fuch large proportion, if 

 no alkaline earth be added, as renders the method too ex- 

 penfive. 



Lime has a pov>er of combining with and abforbing the 

 putrid parts of the gelatinous fluid and bile when commixed 

 with oil, and eftefts, either with or without heat, a confix 

 (lerable edLilcoratioil of foetid oilsj but it combines fo (trongly 



wjlU 



