A must for any time traveller

Joseph LeConte, 1823-1901: Instructions for the Manufacture of Saltpetre. (Columbia, S.C.: Charles P. Pelham, State Printer, 1862.)

At the UNC Chapel Hill online library. Very cool, and if you’ve ready much time travel fiction, you’ll know exactly why this is so handy if you ever get trapped in the pre-industrial past. I love the internet.