One day Mrs. Greene heard some of the neighboring planters complaining of the trouble they had in clearing the cotton of its seeds. They could manage what was called the long-staple cotton by the use of a rough roller machine brought from England, which crushed the seeds, and then "bowed" or whipped the dirt out of the lint. But this would not work with short-staple cotton, the kind usually grown, and there was nothing to do but to pick the hard seeds out by hand, at the rate of a pound a day by the fastest workers. The planters said it would be a splendid thing if they only had a machine that would do this work. Mrs. Greene told them that this might not be so hard to do. "There is a young man at my house," she said, "who can make anything;" and to prove it, she showed them some of the things he had made. Then she introduced them to Eli Whitney, and they asked him if he thought he could make a machine to do the work they so badly wanted.
"I don't know about that," he replied. "I know no more about cotton than a child knows about the moon."
"You can easily learn all there is to know about it," they urged. "We would be glad to show you our fields and our picker-houses and give you all the chance you need to study the subject."
Mr. Whitney made other objections. He was interested in his law studies, and did not wish to break them off. But a chance to work at machinery was too great an attraction for him to withstand, and at length he consented to look over the matter and see if he could do anything with it.
The young inventor lost no time. This was something much more to his liking than poring over the dry books of the law, and he went to work with enthusiasm. He went into the fields and studied the growing cotton. Then he watched the seed-pickers at their work. Taking specimens of the ripe cotton-boll to his room, he studied the seeds as they lay cradled in the fibre, and saw how they were fastened to it. To get them out there must be some way of dragging them apart, pulling the fibres from the seed and keeping them separate.
The inventor studied and thought and dreamed, and in a very short time his quick genius saw how the work could be done. And he no sooner saw it than he set to work to do it. The idea of the cotton-gin was fully formed in his mind before he had lifted his hand towards making one.
It was not easy, in fact. It is often a long road between an inventor's first idea and a machine that will do all he wants it to. And he had nothing to work with, but had to make his own tools and manufacture his own wire, and work upward from the very bottom of things.
In a few months, however, he had a model ready. Mrs. Greene was so interested in his work and so proud of his success that she induced him to show the model and explain its working to some of her planter friends, especially those who had induced him to engage in the work. When they saw what he had done, and were convinced of the truth of what he told them,—that they could clean more cotton in a day by his machine than in many months by the old hand-picking way,—their excitement was great, and the report of the wonderful invention spread far and wide.
Shall we say here what this machine was like? The principle was simple enough, and from that day to this, though the machine has been greatly improved, Whitney's first idea still holds good. It was a saw-gin then, and it is a saw-gin still. "Gin," we may say here, is short for "engine."
This is the plan. There is a grid, or row of wires, set upright and so close together that the seeds will not go through the openings. Behind these is a set of circular saws, so placed that their teeth pass through the openings between the wires. When the machine is set in motion the cotton is put into a hopper, which feeds it to the grid, and the revolving saws catch the fibre or lint with their teeth and drag it through the wires. The seeds are too large to follow, so the cotton is torn loose from them and they slide down and out of the way. As the wheel turns round with its teeth full of cotton lint, a revolving brush sweeps it away so that the teeth are cleaned and ready to take up more lint. A simple principle, you may say, but it took a good head to think it out, and to it we owe the famous cotton industry of the South.