Henry Rowland

Henry Augustus Rowland achieved high recognition as expert on electricity. He was born in Honedsdale, Pennsylvania in 1848 as the son of a Protestant clergyman, who had descended from a long line of theologians. Rowland entered the ministry school of Yale University but rebelled against family expectations to pursue religious studies. Excited by doing experiments in chemistry and electricity, he left Yale to attend the Rensselaer Polytechnic Institute. He earned a degree in civil engineering in 1870 and worked as a railroad surveyor and as a teacher at the College of Wooster in Ohio. Two years later, he returned to Rensselaer Polytechnic to teach physics, and threes years after that, he accepted a chair at Johns Hopkins University.
Rowland's research helped to demonstrate that electric currents are the source of magnetic fields, to determine the value of the Ohm (a unit of electrical resistance), and to show that specific heat (the ability of a substance of absorb heat as measured by the increase in temperature per unit of heat absorbed) varies with temperature. He became well known internationally as a scientist when he invented a new spectral grating that automatically focused light. This spectrograph, which was more accurate than previous ones, won Rowland a gold medal at the 1890 Paris Exposition. Rowland used this invention to make the most precise measurements of the spectral lines (unique characteristic colors of light given off by specific atoms) in sunrays coming from the Sun. He was elected to the National Academy of Sciences, to the Royal Society of London and to the French Academy of Sciences. As vice president of the American Association for the Advancement of Science, he advocated investment in pure science in spite of his own success in applied physics. In 1899, Rowland became the first president of the American Physical Society. He died in 1901.

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