His machine was very simple, but none the less ingenious on that account.  The cotton was placed in a trough, the bottom of which consisted of parallel rows of wire, placed like the bars in a grating, but so close together that the seed could not pass through them.  Underneath this trough revolved an iron roller, armed with teeth formed of strong wires projecting from the roller, which passed between the wire bars, and, seizing the cotton, drew it through the bars and passed it behind the roller, where it was brushed off the wire teeth by means of a cylindrical brush.  The seed, unable to pass through the bars, were left behind, and, completely stripped of the fiber, ran out in a stream through a spout at one end of the trough.  It was found that the cotton thus ginned was cleaned thoroughly,[A] and far better than it could be done by hand, and that a single man, by this process, could clean as much as three hundred pounds in a day.

[Footnote A:  The cotton for which Whitney’s machine accomplished so much, was the short staple, which is the principal product of the South.  The Sea Island cotton could not be cleaned by it, on account of the length and delicacy of its fiber; and this species, for the want of some cheap and expeditious method of preparing it, has seldom been grown to a greater quantity than fifty thousand bags of three hundred pounds each.  Consequently, it has always commanded a high price.]

The spectators were delighted with Whitney’s machine, and urged him to lose no time in putting it in the market.  They predicted an unlimited success for it, and assured the inventor that it would not only make his own fortune, but also render cotton culture the source of wealth to the South.  They did not exaggerate.  As soon as it was made known to the public, Whitney’s machine came into general use.  Planters had no longer any thing to fear from the labor and expense of preparing their great staple for market.  Whitney’s genius had swept away all their difficulties, and they reaped a golden harvest from it.  They were enabled to send their cotton promptly and cheaply to market, where it brought good prices.  With the money thus obtained they paid their debts, and increased their capacity for cultivation.  Every year the area devoted to cotton-growing became more extended, and the prosperity of the South became greater and more durable.  In 1793, the total export of cotton from the United States was ten thousand bales; in 1860, it was over four millions of bales.  Hundreds of millions of dollars were brought into the South by this invention—­so that it is no exaggeration to say that the remarkable prosperity enjoyed by the South at the commencement of our late civil war was due entirely to the genius of Eli Whitney.  This opinion is fortified by the following remarks of Judge Johnson, uttered in a charge to the jury in a suit brought by Whitney, in Savannah, in 1807, to sustain the validity of his patent: