On the Edulcorat'ion ofFi/h-O'il. ill 



which, as was above explained, the principal foetor refides, 

 if the quantity added be large, and an intimate commixture 

 be made of them by (tirring them together for a confiderable 

 time: this only partially removing ihofe heterogeneous pu- 

 trefcent fdbftances, the remaining part foon acquires the fame 

 ftate, and the oil again grows foetid, though not to the fame 

 degree as before. 



VV^ater is, however, a neceflarv medium for the aftion of 

 falls and the feparation of alkaline earths and calces of metals 

 when they are employed for the edulcoration of oils, as will 

 appear from a confideration of my proceires. 



Aiv edulcorates oil by carrying off the mofl putrid part?, 

 which are neceflarily extremely volatile. It may be made 

 to a6t on them either by fimple expofure of them to it with 

 a large extent of fnrface, or by forcing it through them by 

 means of ventilators, as has been praftifed by fome dealers; 

 but is now, I believe, negletled on account of their finding 

 the improvement of oils by it not adequate to the trouble, as 

 the gelatinous matter and bile, not reduced to a certain de- 

 gree of putrefaftion, being left behind, putrefy again to nearly 

 the lame degree as before. 



It appears from thefe fcveral obfervations, that the cheapefl 

 ingredients which can be ufcd for the edulcoration of traiji- 

 oils are lime and chalk, which may, with the addition of a 

 proper quantity of folution of fea fait or brine, be made t<? 

 procure a feparation of them from the oils, according to pro- 

 cefs the firli;, fo as to anfwer for fome purpofes; that the lix- 

 iviate fait is the mofl; powerful purifier of oils, and, with the 

 aflil^ance of chalk and brine, will, without heat, according 

 to proccfs the fecond, efl'ecl a very confiderable degree of 

 edulcoration ; and that lixiviate fait ufed with heat, with the 

 addition of lime and chalk, to fave a part of the quantity 

 which would ollierwife be necellarv, and of brine to procure 

 a quick feparation, will perform an edulcoration fufficient fgr 

 all commercial jjurpofes, according to procefs the third j but 

 that calcined lead and the ochrous earth of iron may, per- 

 haps, be applied in fome cafes with advantage^ where th'i oil 

 is not dcfigned for efculcnt ufe. 



PROCESS THE FIRST. 



For purifying Fijh-Oil in a moderate Degree, and at a very 



little Expcnje. 



Take an ounce of chalk in powder, and lialf an ounce of 



lime flaked by expofure to the air; put them into a gallon 



of llinking oil, and, liaving mixed them well together by 



6 liirring, 



