Dr. priestley has given a general though brief account of what had been done by his predecessors in this department of experimental Philosophy, and Sir John Pringle in his discourse before the Royal Society on occasion of presenting Dr. Priestley with the Copley Medal in 1772 has entered expressly, and more fully into the history of pneumatic discoveries. The same subject was taken up about three years after by Mr. Lavoisier still more at large, in the introduction to his first Vol. of Physical and Chemical Essays, of which a translation was published by Mr. Henry of Manchester in 1776. It is unnecessary to detail here what they have written on the history of these discoveries. It may be observed that no mention is made by any of these gentlemen of an experiment of Mr. John Maud, in July 1736, who procured (and confined) inflammable air from a solution of Iron in the vitriolic acid. Inflammable air had been procured from the White Haven coal mines, and exhibited to the Royal Society by Mr. James Lowther, but I do not recollect any notice of its having been collected from a solution of metals in acids, and its character ascertained before Mr. Maud's experiment; for Hales, though he procured both inflammable and nitrous air, did not examine their properties.