INTRODUCTION.

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1st. So early as 1787, Mr. Charles Macintosh anti-cipated the discoveries of the French chemists, Che-vreul, Braconnet, and Thenard, made in 1813, 1814,and 1815, in regard to the analogies of the chemicalcomposition of animal and vegetable substances, andthe elements into which these bodies are mutuallyresolvable. See p. 7.

2d, He, in the same year, 1787, combated the hypo-thesis of Monsieur Hellot, and of Dr. Irvine , in respectto the philosophy of dyeing, and substituted what hassince been generally admitted as the true theory of thisprocess. See p. 7.

3d. He seems thus early, 1787, to have been awareof the compound nature of the vegetable alkali, (pot-ash). See p. 8.

4th. He anticipated other chemists in a knowledgeof the properties of Saccharum Saturni, (acetate of lead,sugar of lead,) in abstracting carbonic acid from waterand atmospheric air; and of the different states ofacidification of this salt; facts of which Dalton, solate as 1807, seems not to have been cognizant. Seep. 25.

5th. Previous to 1790, he discovered and preparedthe salt termed the chlorate of potash, since used as afulminate in the manufacture of percussion powder,and patented at Vienna by Messrs. Liebig and Vee, solate as 1821. See pp. 30, 31.