PROCESS OP EXTRACTING OIL. 401 



The copper is filled within two or three inches of 

 the top, a little space being requisite to admit of 

 the expansion of the oil when heated ; and then a 

 brisk fire is applied in the furnace, and continued 

 until the oil begins to boil. This effect usually 

 takes place in less than two hours. Many of the 

 fritters or fcnks float on the surface of the oil before 

 it is heated, but after it is " boiled off," the whole, 

 or nearly so, subside to the bottom. From the time 

 the copper begins to warm, until it is boiled off or 

 ceases to boil, its contents must be incessantly 

 stirred by means of a pole, armed with a kind of 

 broad blunt chisel, to prevent the fenks from ad- 

 hering to the bottom or sides of the vessel. When 

 once the contents of the copper boil, the fire in the 

 furnace is immediately reduced, and shortly after- 

 wards altogether withdrawn. Some persons allow 

 the copper to boil an hour, others during two or 

 three hours. The former practice is supposed to 

 produce finer and paler oil, the latter a greater quan- 

 tity. The same copper is usually boiled twice in 

 every twenty-four hours, Sundays excepted. Sup- 

 posing the copper to be filled at four in the morning, 

 it is generally brought to boil by half-past five, 

 and boiled off at half-past six or seven. It then 

 stands to cool and subside, until about two o'clock 

 in the afternoon, when the " bailing" process com- 

 mences. One of the backs or coolers having been pre- 

 pared for the reception of the oil, by putting into it a 

 vo]-. II. c c 



