On this day 250 years ago in Philadelphia, the Secret Committee of the Continental Congress entered into a contract with Thos. Willing & Robert Morris & Co. to

with the utmost speed & secrecy send a ship or vessel to some part of Europe & there purchase at the cheapest rate they can a thousand barrels of good powder, twelve good brass guns (six pounders), two thousand stand of good arms vizt. Soldiers muskets & bayonets & five thousand gunlocks double bridled, of a good quality, & in case the aforesaid quantity of powder cannot be procured . . . as much Saltpetre & Sulphur if to be had as will make as much powder as shall be deficient.

Sources: https://americanfounding.org/entries/second-continental-congress-september-27-1775/; https://www.youtube.com/watch?v=GEzhmGqlOyM

And on this day 250 years ago in York, Pennsylvania, the York County Committee wrote to the Pennsylvania Committee of Safety:

Two months ago the York committee started searching for some one to make saltpetre and found two men, Baltzer Moody and George Garver, who began the work in August. They dug in stables, outhouses, etc.; and the committee lent them money. Yesterday they delivered the 117 pounds of saltpetre that accompany this letter: they would have had more if the recent storm had not injured their earth. . . . The saltpetre is perhaps as good as that imported from Europe, and the bounty or price will presumably be the same. “A Quantity of earth is now Collecting, and we hope to see the Business prosecuted with Spirit.”

Source: https://founders.archives.gov/?q=%2227%20September%201775%22%20&s=1111311111&sa=&r=3&sr=