THE TECHNOLOGIST. [April 1, 1864. 



426 THE MANUFACTURE OP VEGETABLE OILS. 



and falls over into perforated troughs placed to receive it Through the 

 perforations a considerable quantity of oil oozes, and this, being con- 

 sidered purer than that which is obtained by expression, is conveyed to 

 a cistern set apart for the purpose. The paste is next put into a 

 jacketted kettle, that is, one surrounded by a hollow chamber into 

 which steam is injected for the purpose of heating it. Within this 

 kettle is an agitator or stirrer, so that all the paste is in turn brought 

 to the heated surface and raised to an even temperature. Having re- 

 mained in the kettle six minutes, it is collected in woollen bags, about 

 eighteen inches long and six inches wide, each bag is placed between 

 four layers of press hairs (a kind of horse-hair mat), and eight of them 

 being thus prepared, they are ranged in two perpendicular rows between 

 four grooved shelves of a hydraulic press. The pumps worked by the 

 steam-engine are set in motion, and a pressure of 400 tons is speedilv 

 realized. The oil being expressed, runs into an underground tank, the 

 bags are then withdrawn, and on being removed the residue presents 

 itself in the form of what is known as linseed cake. These cakes are 

 placed in a rack to cool, when they become so hard as not to be easily 

 broken ; they are then orderly stacked, and from time to time sent 

 away in waggons or barges to supply the cattle-food market, for which 

 purpose the cake is in great request. 



A quarter of linseed, which only undergoes one pressure, yields an 

 average of 120lbs. of oil and 35 cakes of nutritious food, each weighing 

 8-lbs., or an aggregate of two hundred weight and a half. Rape seed, 

 which is twice ground and pressed, yields per quarter from 881bs. to 

 90lbs. of oil at the first, and from 60lbs. to 701bs. at the second pressure. 

 Of those two kinds of oil-producing seeds upwards of 600,000 quarters 

 are annually imported, and this mill alone works up 35,000 quarters per 

 annum. Calcutta, Bombay, and Kurrachee are the great emporia for 

 these seeds, and it is a remarkable fact that, whereas the last-named 

 place, when it fell into the hands of the British, in 1839, consisted of 

 only about fifty wretched huts, inhabited by fishermen ; it is now a 

 thriving port, and one of the principal outlets for the oil-producing 

 seeds of India. 



After the oil has remained a few days in the receiving cistern the 

 parenchymous matter subsides ; it is then pumped into vats for a second 

 settling, after which it is barrelled and conveyed to the Refinery. This 

 is situated about a quarter of a mile down the Blackwall line, of which 

 property it occupies nine arches in its rear. The premises are very large, 

 and are used not only for refining vegetable but also animal oils. The 

 casks of unrefined oil are hoisted to the upper floor by means of a crane 

 worked by steam. Along this floor a large vat, capable of holding ten 

 tons, is extended. It is lined with copper ; is fitted with a horizontal 

 agitator or fan ; and is called the reception rat. Into this receptacle 

 tive tons of rape oil are decanted, an equal quantity of water is added, 

 and the whole treated by chemical process. The agitator is set in motion, 



