An essay on dew, and several appearences connected with it

London: Taylor and Hessey, 1814. FIRST EDITION. Contemporary boards, rebacked; an uncut copy, with a presentation inscription from the author to James Johnston, Esq. on the title. First edition of this classic of meteorology, for which Wells was awarded the Rumford Medal of the Royal Society. His researches were of major importance in the development of the science of ventilation in relation to relative humidity. "It would take too much space to follow all of Wells' ingenious experiments, but his conclusions can be stated. The cooling of the Earth's surface, and of the bodies that accumulate dew, is the result of radiation to space. This radiation is always going on, but can be largely interrupted by clouds; and in the daytime it is overbalanced by the radiation to the Earth from the Sun" (Middleton). Wells had an extremely clear view of what is now called the "greenhouse effect."

Wells (1757-1817) was born in Charleston, South Carolina, but left America at the start of the Revolution and settled in London where he became physician to St. Thomas' Hospital between 1800 and 1817. "In 1812 he began to study dew with great patience . . . and in August 1814, he published his Essay on dew, called by the famous physicist John Tyndall ‘a model of wise enquiry and lucid exposition.'" (Middleton).