saltpetre
/sɔːltˈpiːtə
/ /sɒltˈpiːtə/(US saltpeter)
noun
Another term for potassium nitrate.Glauber created a mixture of saltpeter, lime, phosphoric acid, nitrogen and potash which was the first completely mineral fertilizer....
- The leachate was collected and then chemically converted to true saltpeter, potassium nitrate, by mixing it with a solution of potash.
- The salt most used is common salt, sodium chloride, but saltpetre (which consists of potassium nitrate and sodium nitrate) has similar effects.
Origin
Late Middle English: from Old French salpetre, from medieval Latin salpetra, probably representing sal petrae 'salt of rock' (i.e. found as an encrustation). The change in the first element was due to association with salt.