74 TECHNOLOGY. 
heretofore proved so troublesome to the miller, are by this process entirely 
removed. The preliminary soaking, which is just sufficient to moisten the 
skin of the wheat, entirely penetrates other seeds, so that they are subse- 
quently ground or crushed in the rubbers, and after being dried are blown off 
with the hull of the grain. It is said that by this process fifteen per cent. 
more flour is obtained from wheat, and at a less expense, than by the usual 
process of grinding and bolting. 
The mill-stones in use in the United States and Europe are mostly made 
of a porous silicious stone obtained from France. As this stone is not 
obtainable in masses sufficiently large to make the mill-stones in a single 
piece, they are put together in smaller pieces with cement and secured by 
iron bands. After being accurately balanced, the stones are cut upon their 
grinding surfaces, as seen in pl. 16, fig.6. The bed-stone must not only be 
adjusted level, but concentric with the axis of the spindle. To accomplish 
the first, the bed-stone rests upon a frame, r, which is adjusted by three 
screws, one under each corner. The centring of the stone is accomplished 
by means of screws working against the sides of the stone (pl. 16, jig. 6). 
The operation of the mill-bush is seen in figs. 8 and 9. This bush is of 
cast-iron, and is secured in the centre of the bed-stone. Three pieces of 
brass or wood rest against the mill-shaft, and are pressed against it by 
screws, in order to perfectly adjust the main shaft in the centre of the 
bush ; the interstices not occupied by the brass or wooden blocks are filled 
with oakum or tow saturated with oil, in order to lubricate the bearing. 
After the grain is ground, it is necessary that the flour be thoroughly cooled 
before it is bolted ; where there are no arrangements for effecting this, the 
flour has to remain twenty-four hours before being bolted. in most mills, 
however, this is accomplished by a machine, also an American invention, 
called the hopper-boy. The flour is run into a circular room, where it is 
stirred by revolving arms until it is completely cooled, when it passes imme- 
diately to the bolts, where the preparation of the flour is finished. 
V. COTTON MANUFACTURE. 
Cotton is the production of a genus of tropical plants of which there are 
many species; these again run easily into varieties, so that there have been 
enumerated over one hundred different sorts. The dwarf varieties found in 
America, India, and China grow to a height of eighteen inches to two feet ; 
the blossoms are a pale yellow and are succeeded by triangular three-celled 
seed-vessels, which gradually turn brown as they ripen, and ultimately burst 
open, exposing the cotton fibres wrapt round the seed. The shrub and tree 
cotton grow in America, the West Indies, East India, Egypt, &c., the latter 
reaching a height of from 12 to 20 feet. 
When cotton is to be spun, it is first subjected to the operation of ginning, 
to separate it from the seeds. This is performed upon the plantation where 
it is grown, as when packed with the seeds it becomes oily and soiled, and 
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