I wish you, sir, not to show this letter nor communicate anything of its contents to any body except My Brothers and Sister, ENJOINING it on them to keep the whole A PROFOUND SECRET." * Then the national capital.
** Hammond, "Correspondence of Eli Whitney," American Historical Review, vol.III, p.99.The other citations in this chapter are from the same source, unless otherwise stated.
The invention, however, could not be kept "a profound secret," for knowledge of it was already out in the cotton country.

Whitney's hostess, Mrs.Greene, had shown the wonderful machine to some friends, who soon spread the glad tidings, and planters, near and far, had come to Mulberry Grove to see it.

The machine was of very simple construction; any blacksmith or wheelwright, knowing the principle of the design, could make one.

Even before Whitney could obtain his patent, cotton gins based on his were being manufactured and used.
Whitney received his patent in March, 1794, and entered on his new work with enthusiasm.

His partner, Phineas Miller, was a cultivated New England gentleman, a graduate of Yale College, who, like Whitney, had sought his fortune as a teacher in the South.