412 FOODS AND FOOD ADULTERANTS. 



melted out. Another method consists in covering the tank with wood, 

 forming a chamber into which exhausted steam is introduced. Gutters 

 are provided along the railroad tracks into which the oil flows and 

 is conducted into the receiving tanks. From the receiving tanks it is 

 pumped into large receivers called scale tanks, where the crude oil is 

 weighed. 



(&) Refining process. After weighing, the oil is pumped into refining 

 kettles. These are of various sizes, the largest ones being 20 to 25 feet 

 deep and 15 feet in diameter. These tanks are furnished with steam- 

 coils for the purpose of heating the oil and with appropriate machinery 

 for keeping it in motion. A solution of caustic soda is used for refin- 

 ing. This solution is made from 10 to 28 Beaume in strength, and 

 varying quantities are used according to the nature of the oil operated 

 upon. After the addition of the caustic soda the mixture is agitated 

 for forty-five minutes and kept at a temperature of 100 to 110 F. 

 The contents of the tank are then allowed to stand six >to thirty-six 

 hours, when the solid matters, soap and substances precipitated by the 

 caustic alkali gather at the bottom. This mixture is called " foots," 

 and is used for making soap. The yellow oil resulting by this proc- 

 ess is further purified by being heated and allowed to settle again or 

 by filtration and is called summer yellow oil. Winter yellow oil is 

 made from the above material by chilling it until it partially crystal- 

 lizes and separating the steariue formed, about 25 per cent., in presses 

 similar to those used for lard. This cotton-oil stearine is used for 

 making butteriue and soap. 



(c) White oil. The yellow oil obtained as above is treated with from 

 2 to 3 per cent, of fuller's earth in a tank furnished with apparatus for 

 keeping the mixture in motion. When the fuller's earth has been thus 

 thoroughly mixed with the oil, the whole is sent to the filter press. 

 The fuller's earth has the property of absorbing or holding back the 

 yellow coloring matter, so that the oil which issues from the press is 

 almost white. This white oil is the one which is chiefly used for mak- 

 ing compound lard. 



Cotton oil is obtained from the seeds of Gossypium hcrbaccum. The 

 percentage of oil varies in the seed from 10 to 30. 



In 1882 it was estimated that the oil industry was represented by the 

 following data : * 



410,000 tons of seed, yielding 35 gallons of crude oil to the ton, are 

 14,1550,000 gallons, worth 30 cents per gallon $1,305,000 



Same amount of seed, yielding 22 pounds cotton lint to the ton, 189,090,000 

 pounds cotton, worth 8 cents per pound 721, di't) 



And yielding also 750 pounds of oil-cake to the ton (2,2-10 pounds) is 137,277 

 tons of cake at $20 per ton 2,745, ;>}ii 



7,772,140 

 Deduct the sum paid for the seed, say 4, 100, < >D 



And there remains for value gained in niauipulati > i of s:< 1 :!, (IT. 1 , 1 I'l 



'Brant. Vegetable and Animal Oils. Phil. II. ('. 1 laird &, Co. 



