He went to Savannah and searched among the warehouses and flat-boats for samples of cotton. Mrs. Greene encouraged him in his undertaking and gave him a room in the basement of her house for his workshop. Here he shut himself up with his task, and was heard early and late hammering, sawing, and filing. No one was admitted to the room but Mrs. Greene and Phineas Miller, the tutor of Mrs. Greene's children. At the outset Whitney had neither money nor tools. The money was supplied by an old college friend; the tools Whitney made himself. He could procure no wire in Savannah for constructing his machine, and was compelled to make his own, which he did with much perseverance and skill.
In 1793 the gin was sufficiently completed to convince the inventor that it would be a complete success. Mrs. Greene invited a number of distinguished planters and merchants to witness the working of the machine. The spectators were not slow in realizing the success and the significance of the invention. They saw that with this little machine one man could separate as much cotton from the seed in one day as he could separate by hand in a whole winter. With the gin the cotton grown on a large plantation could be separated in a few days; by hand, the separation would require a hundred workmen for several months.
One dark night some unscrupulous persons broke open the shed in which the unfinished machine had been placed and carried it away. Filled with rage and despair at the wrong which had been done him, Whitney left Georgia and went to Connecticut to complete his invention. But he had scarcely left Savannah when two other claimants for the honor of the invention appeared in Georgia. A few weeks later a gin very closely resembling Whitney's came out. His stolen gin was doubtless used as a model by these false claimants.
On March 14, 1794, Whitney received a patent on his gin. Phineas Miller, who had become the husband of Mrs. Greene, entered into a partnership with Whitney for managing the new invention. Whitney was to manufacture the gins in the North and Miller was to furnish the capital and attend to the interests of the business in the South. They planned not to sell machines or patent rights, but to make and own the gins, loaning them to planters for a rental of one pound in every three pounds of cotton ginned. They would have been wiser if they had manufactured and sold the machines outright. In the first place, it required a larger capital than the firm had to manufacture the necessary number of machines. In the second place, no one firm could make gins fast enough to supply the rapidly increasing demand, and consequently great encouragement was given to infringements on the patent rights. Unending troubles beset the new firm. Whitney himself was a victim to severe illness in the winter of 1794. Scarlet fever raged that year in New Haven, Connecticut, where the manufacturing was being done, and many of the workmen in the gin factory were unable to work. In 1795 Whitney was again seized with severe sickness, and to add to the vexations of the business, the books, papers, and machinery were destroyed by fire. Besides all this, rival claimants circulated a report that Whitney's gin ruined the fiber of the cotton, and that for this reason cotton ginned by the patent process was discriminated against in the markets of England. Another gin which did its work by crushing the seeds between rollers and leaving the crushed seeds in the fiber was represented as superior to Whitney's machine.