Bengal: saltpetre
A seventeenth-century army increasingly relied on gunpowder, and the production of that vital resource required three mineral ingredients - charcoal, sulphur and saltpetre. Of these, the two minority ingredients were charcoal, which could be obtained readily wherever there were trees, and sulphur, which was mined in many places and was fairly cheap. However, three-quarters or so of the mix was taken up by saltpetre, the mineral potassium nitrate. Saltpetre forms naturally in small quantities in some locations, but for regular supply it had to be 'farmed' by heaping animal dung with earth in large beds that were then treated with urine for a period of months. Bacterial action produces potassium nitrate, which with the right technique can be refined to a relatively pure crystalline product.
The Mughal army was as gunpowder-based as the European armies. At the start of the sixteenth century the technologies were very similar, with European powers making …