The American Cyclopædia (1879)/Mayer, Alfred Marshall

MAYER, Alfred Marshall, an American physicist, nephew of Brantz Mayer, born in Baltimore, Md., Nov. 13, 1836. He was educated at St. Mary's college, Baltimore. He has occupied the chair of physics, with chemistry or astronomy, in several institutions, as follows: University of Maryland, 1856-'8; Westminster college, Missouri, 1859-'61; Pennsylvania college, Gettysburg, 1865-'7; Lehigh university, Pennsylvania, 1867-'70; Stevens institute of technology, Hoboken, N. J., since 1871. In 1863-'4 he studied in the university of Paris. At Lehigh university he superintended the erection of an observatory, from which he made a series of observations of Jupiter. He was in charge of the party sent to observe the eclipse of the sun at Burlington, Iowa, Aug. 7, 1869, and took 41 perfect photographs of the eclipse. At Hoboken he began his researches in acoustics, in which he has made his most important discoveries; among these are: the measurement of the relative intensities of sounds of the same pitch; an acoustic pyrometer; the connection of the pitch of a sound with the duration of its residual sensation; the reflection of sound from flames and heated gases; that the fibrils of the antennæ of the mosquito are its auditory organs; the mechanism of hearing in mammals; and new methods of sonorous analysis. In 1873 he was one of the editors of the “American Journal of Science and Arts,” from which he withdrew on account of weakness of sight, and visited England. Among his numerous scientific papers are: “Estimation of the Weights of very small Portions of Matter” (1858); “Lecture Notes on Physics” (1868); “Researches in Electro-magnetism” (1870 and 1873); “An Investigation of the Composite Nature of the Electric Discharge” (1874); and “Researches in Acoustics” (7 papers, 1871-'4).