"It appears from these essays, which are not new productions, but tracts of near a hundred and fifty years standing, that the chemical experiments and discoveries, which have lately made so much noise in England and France, were long since made and exhibited by a provincial physician of Perigord. It is true that the main object of these essays, when first published, was to account for the additional weight of metals by their passing through the fire. The fact was known to Boyle and others, who imputed it to the weight deduced from heat; as Buffon hath done long since, imputing gravity to fire. Dr. Rey, however, so long ago as the year 1630, attributes such additional weight to the condensed, or fixed, air; which attaches itself to the calcined substance, and that in proportion to the division of its parts.—It is farther remarkable, that, in a small tract annexed to these essays, the present Editor gives us an account of a method, used upwards of fifty years ago, to pour fixed air out of one vessel into another; which is the very same made use of by Dr. Priestley, Lavoisier, and other modern experimentalists.—A considerable part of the volume contains the learned correspondence that passed between the author, Dr. Rey, and the celebrated Father Mersenne."