Note 217 — MINERAL POISONS.

A very large quantity is annually prepared from the sublimate which collects in the chimneys and flues of the smelting works and burning houses in Cornwall. We have examined samples prepared according to the improved process of Dr. Edwards, and found them to be perfectly free from foreign admixture: a fact of much greater importance than the reader may at first imagine. Those who require farther information upon this subject may consult a paper in the first volume of the Transactions of the Royal Geological Society of Cornwall, by J. H. Vivian, Esq. entitled “Observations on the processes for making the different preparations of Arsenic, which are practised in Saxony.”