"The cotton is thrown into a hopper, and, falling, is seized by the friction of the leather and drawn between the doctor knife and the leather surface. Whilst this is taking place, there is a beater knife which is reciprocated at a considerable speed and which strikes the seed attached to the cotton drawn away by the leather roller. The detached seed will then fall through a grid provided for the purpose. A single-action gin should produce about 30 pounds of cleaned cotton per hour."
Fig. 9.—Single-acting Macarthy gin.
Another gin which does considerable damage to fibre, especially if it be over-fed, is still in use in the States. This was the invention of an American named Eli Whitney, and has been named a "saw-gin."
If the reader can imagine a number of circular saws (such as are to be seen in a wood-sawing mill) placed nearly together on a shaft to form an almost continuous roller, he will have a good idea of what the chief part of a saw-gin is like.
As the cotton is fed to the machine, the saws seize it and strip the cotton from the seeds, which fall through grids placed below the saws. The cotton is afterward stripped from the saws themselves by means of a quickly revolving brush which turns in the opposite direction to the saws. This gin is best suited to short stapled cottons, especially such as are grown in the States. For the longer fibred cotton this gin is not well adapted, much injury resulting to the cotton treated by it.
After the cotton is ginned, it is gathered into bundles and roughly baled. When a sufficient quantity has been so treated, it is carried to the "compressors," where the cotton undergoes great reduction in bulk as a result of the enormous pressure to which it is subjected.
For the general reader it will scarcely be necessary or wise to describe a "cotton press" in detail. Let it suffice to say that by means of a series of levers—in the Morse Press seven are used—tremendous pressure can be obtained. Thus for every 1 pound pressure of steam generated there will be seven times that pressure, if seven levers are used. When 200 pounds pressure of steam is up, there will be 1400 pounds pressure per inch on the cotton. So great is the pressure exerted that a bundle of cotton coming to the press from the ginnery, 4 feet in depth, is reduced to 7 inches when drawn from the compressor. While in the press iron bands are put round the cotton, and readers will have frequently seen cotton on its way to the mills having these iron bands round it.
The following table shows the number of bands which are found on bales coming to England from cotton-growing countries:—