Here too. Scattered all over this area.
Keep your powder dry.
( What does that even mean ?)
Dates back to muzzle loaded weapons. Powder was carried separate until poured into the muzzle and tamped down with a ball prior to firing.
Getting water into the powder was a very bad thing. Hard to pour, fires/explodes unevenly or not at all, etc.
Hence, "keep that **** DRY!"