CARNON, a stream and a village in Cornwall. The stream runs 4 miles south-eastward, down a valley, to the head of a creek of Falmouth harbour, 4 miles N of Falmouth. Great tin stream works were carried on at its mouth, over a space 300 yards wide, upwards of a mile long, some distance into the bed of the estuary, and banked round to keep off the water; but have been abandoned. The village stands a short way up the stream; and has extensive works for preparing arsenic from arsenical pyrites.

(John Marius Wilson, Imperial Gazetteer of England and Wales (1870-72))