In 1774, Susan Mason was a twelve-year-old girl living in Salem. In mid-November her father, David Mason (1726-1794), was secretly commissioned by the Massachusetts Provincial Congress to gather and prepare artillery in case the people had to confront the royal army in Boston. Mason had been the founding captain of Boston's militia artillery train, but had moved out to Salem for better business prospects in the mid-1760s.
The small cannons that Mason gathered were useless until they were mounted on carriages and equipped with all the tools and supplies needed to fire them, including the cloth sacks of gunpowder called "cartridges." Susan remembered how her father recruited all the seamstresses in the family to supply those:
My father…engaged my mother, tho in feeble health, to cut out 5,000 of these cartridges, and set my eldest sister and myself to make them, and I well remember being lock’d up in a chamber while at work for fear our prying mates or Neighbors should discover our employment.That's from a memoir that Susan Mason, later Susan Smith, wrote out for her nieces and nephews in 1842; it was published in the Essex Institute Historical Collections in 1912.
Later that year an antiquarian interviewed widow Smith, and the notes from that conversation are now part of the Shaw Family Papers at the Library of Congress. They tell the same story this way:
My father fearing to let more into the secret than was absolutely necessary engaged my mother to cut 5000 of these cartridges & set my sister & myself to make them, and we were often locked up in a chamber, for fear some of our prying mates or neighbors should find out the nature of our employment & undoubtedly the first (of such) instruments for the defence of our national liberty was made by my sister & myself.