HAYES, Augustus Allen, chemist, born in Windsor, Vermont, 28 February, 1806; died in Brookline, Massachusetts, 21 June, 1882. He was graduated at Captain Partridge's military academy at Norwich, Vermont, in 1823, and then studied chemistry under James F. Dana. Subsequently he became assistant professor of chemistry in the New Hampshire medical college, but settled in Boston in 1828, where he devoted himself to chemical investigations, filling also successively the posts of director of an extensive factory of colors and chemical products in Roxbury and of consulting chemist to some of the most important dyeing, bleaching, gas, and iron and copper smelting establishments in New England. Among his early researches is that begun in 1825 for the purpose of determining the proximate composition of various American medicinal plants, which resulted in his discovery of the organic alkaloid sanguinaria, a compound remarkable for the brilliant colors of its salts. Later he conducted an elaborate investigation upon the economical generation of steam and the relative value of fuels, which, in 1838, led to a novel arrangement of steam boilers. He was the first to suggest the application of the oxides of iron in refining pigiron, and still earlier the refining of copper was, under his direction, rendered much shorter and more certain by the introduction of scales of oxide of copper. Among his other original investigations are those in relation to the chemical decomposition of alcohol by chlorine and the formation of chloroform, on the action of alcohol on the human system, on the formation, composition, and specific differences of the varieties of guano, and a memoir on the difference in the chemical constitution and action of sea waters on and below the surface, on soundings, and at the entrance of rivers, being part of an investigation executed under a commission from the navy department to examine and report on the subject of copper and copper sheathing as applied in the construction of national vessels. In 1859-'60, while investigating the water supply of Charlestown, Massachusetts, he found that the deep water of Mystic pond was far less pure than the surface water, and proved that a copper strip or wire passing vertically through two masses of water slightly unlike in composition would become polarized and exhibit electrolytic action. This mode of testing the exact limits of the impure water was applied under his direction, and a large number of observations on this and other masses of water have proved the practical value of this test. After the beginning of the civil war, Dr. Hayes called public attention to the uncertainty of the foreign supply of saltpetre and the necessity of domestic production. His efforts resulted in the manufacture of a very pure product for the navy by a novel process from sodium nitrate by the action of potassium hydroxide. Later he spent some time abroad, and on his return published a paper "On the Cause of the Color of Lake Leman, Geneva," and also one "On the Red Oxide of Zinc in New Jersey." For many years he held the of-flee of state assayer of Massachusetts, and in 1846 received the honorary degree of M.D. from Dartmouth. He was a member of scientific societies in the United States, and contributed numerous papers of technical value to their proceedings and to the "American Journal of Science."