Biography provided by the Metropolitan Museum of Art)
 
In late 1853, at a time when experimental variations on processes were proliferating at a dizzying pace, Teasdale presented his thoughts “On the Waxed-paper Process” to the members of the Leeds Philosophical Society. He was only twenty-two at the time, but, as noted in his obituary, “from boyhood his mind showed a scientific bent.” The chart that Teasdale published in connection with his talk was the first tabulation of the various formulas and a courageous attempt to make sense of the process. Teasdale joined the fledgling Photographic Society and was briefly active in photographic publishing. As a civil engineer he could not resist the lure of major public works projects, and he soon moved to India to take a job on the railways. In 1858 he married his English fiancée in the Bombay Cathedral, but, tragically, she died in childbirth. Although the experience in India profoundly influenced him, and, as his obituary commented, “even up to his death he preserved the habit of thinking in Hindustani,” he returned to his native village of Headingley, near Leeds. He retired there sometime in the 1860s. It was also remembered that in Leeds, as “the doyen of local scientists, Mr. Teasdale was well known and welcomed wherever men of science most do congregate.” Teasdale developed new types of microscopes and was the driving force behind the reestablishment of the Leeds Astronomical Society in 1892. “His love of science amounted to a passion. His home . . . was a veritable treasure house of scientific apparatus, works of art, interesting curios. . . . In astronomy and photography he found his chief delights. In photography he was among the pioneers.”