cfOil and Water. ^^9 



oil and oily fubftances in preventing the cryflral- 

 lization of falts, and in fmoothing the waters 

 of the Tea, &c. when agitated by winds. 



The general procefs for making common fait 

 at Broitwich, we are told, by Dr. Najh in his 

 Hiftory of Worceflrcrfliire, is, firft to put a 

 little common water into the pan to keep the 

 brine from burning to the bottom : the pan is 

 then filled with brine, and a piece of refin ajbouc 

 the fize of a pea thrown in to make it granulate 

 fine. I doubted, he adds, the refin's having 

 any fuch power, but am affured by Mr. Romney, 

 a principal and obfervant proprietor, that the 

 more refin they ufe, the finer will be the grain 

 of the fait; and if a lump of the fize of two 

 walnuts were put into the pan, the grain would 

 be fo fine as not to fubfide at all. (NaJ}o\ Hift; 

 of Worcefterfiiire, vol. I. p. jco.) The fame 

 cfFed, which is here afcribed to refin, may be 

 obtained by tiie ufe of butter, tallow, and any 

 rother oily matter, which will liquefy by the 

 heat ufed in boiling the brine, and, when fo 

 liquefied, is incapable of mixing with the water. 

 In confequence of this, it forms a thin film 

 upon the furface, greater in proportion to the 

 quantity ufed. 



To the perfect cryflallization of faits, it is 

 required, that the water which holds them in 

 folution be fiowly evaporated, and that the furface 

 be cxtenfive, quite open, and expofed to the 



i^" f 4- ix^^ 



