128 
THE MANUFACTURE OF VEGETABLE OILS. 
chinery of forty-five horse power. With the exception of the workmen’s meal-times and 
Sundays, it is always at work night and day. From the engine-room the visitor is con¬ 
ducted to the manufactory, where, as soon as he can recover from the irritation in the 
eyes produced by the volatile oil escaping from the heated and bruised seed, the whole 
process presents itself before him. 
The grain is received from the upper floor into a hopper , in which is a screen, the agi¬ 
tating of which removes all foreign substances, and suffers the seed alone to pass through 
its meshes. This falls between two faced, hollow, iron cylindrical rollers, Which are 
heated by steam, and which as they revolve crush, or, as it is termed, open the grain. 
Thus opened, it is thrown on to a steel plate calf ,J fixed on a bed of solid masonry, which 
is constantly traversed by a pair of edge-runners, weighing from eight to nine tons, and 
travelling at the rate of sixteen revolutions per minute. They revolve in a strong 
framework attached to a vertical axis, which also, by means of a large cog-wheel at the 
top, which engages a wheel upon the main shaft, revolves slowly. A double motion is 
thus given to the grinders or edge-runners, one on their own axis and one on the iron 
plate, which we may consider the nether mill-stone. A raised border or rim prevents the 
seed from escaping from the plate, and the paste is brought regularly under the stones 
by means of rakes or sweeps attached to the vertical framework, and revolving with the 
runners on the surface of the plate. When the grain has been sufficiently ground, the 
paste is brought to an open portion of the rim, and falls over into perforated troughs 
placed to receive it. Through the perforations a considerable quantity of oil oozes, and 
this, being considered 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 jacketed 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 remained 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 speedily 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 120 lbs. 
of oil and 35 cakes of nutritious food, each weighing 8 lbs., or an agregate of two hun¬ 
dredweight and a half. Rape seed, which is twice ground and pressed, yields per quarter 
from 88 lbs. to 90 lbs. of oil at the first, and from 60 lbs. to 70 lbs. at the second pres¬ 
sure. Of these 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 the 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 parenchymatous 
matter subsides; it is then pumped into vats for a second settling, after which it is bar¬ 
relled 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 
vat. Into this receptacle five 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, and 
after four or five hours the oil becomes thoroughly washed, its impurities having been 
removed. The agitation is then stopped, and the water and bleaching ingredients are 
allowed to subside. The oil is next drawn off into the boiling vat on the next story. 
This vat also is lined with copper, fitted with fans or agitators, and a coiled perforated 
