Note 163 — PART SECOND. (continued 2)

If sulphur be a simple substance, as the new chemists pretend, there ought never to be any variation in its properties, except what arises from mere impurity; but the following is a remarkable instance to the contrary: Dr. Crawford (brother to the celebrated Adair Crawford) informed me, that for his oil of vitriol works at Lisburn, in Ireland, he had purchased five tons of sulphur produced from copper mines in the island of Anglesey. The sulphur looked well, and was not more impure than what he commonly used; but, on trial, the produce of acid fell so much short of what he had been accustomed to receive, that it would not afford the expense of manufacturing. An experiment on such a large scale could not be erroneous. If sulphur is a simple substance, the fact is unaccountable: if it is composed of phlogiston and acid, an over proportion of the former will easily account for it.