Page 70 - James Rodger Fleming - Fixing the sky

Great fires and artificial volcanoes

In the closing decades of the eighteenth century in Europe, and slightly later
in Russia and the United States, serious attempts were made to broaden the
geographic coverage of weather observations, standardize their collection, and
publish the results. Individual observers in particular locales dutifully tended to
their journals while networks of cooperative observers gradually extended the
meteorological frontiers. No one, however, had yet proposed a serious scientific-
based program of weather control. James Pollard Espy (1785–1860) was a lead-
ing meteorologist of his day, the first to be employed by the U.S. government
in this capacity. Born into a farm family in Washington County, Pennsylvania,
and educated at Transylvania University in Kentucky, he worked as a frontier
schoolmaster and lawyer until he moved to Philadelphia in 1817. There he sup-
ported himself by teaching mathematics and classics part time at the Franklin
Institute while devoting his free time to meteorological research. From 1834
to 1838, he served as the chairman of the Joint Committee on Meteorology of
the Franklin Institute and the American Philosophical Society. He won the lat-
ter’s Magellenic Prize in 1836 for his theory of hail. Working with the scientific
societies of Philadelphia, Espy gained the support of Pennsylvania’s legislature
to equip weather observers in each county in the state with barometers, ther-
mometers, and other standard instruments to provide a larger, synoptic view
of the weather, especially the passage of storms. He also maintained a national
network of correspondents and volunteer observers. During this period, he
invented a “nephelescope,” an early cloud chamber, which he used in his popu-
lar lectures and, in his technical work, to calculate the amount of heat released
by condensing water vapor.
Espy moved to Washington, D.C., in 1842. In his first government appoint-
ment, as professor of mathematics in the navy, he developed a ventilator for
ships and expanded his network of meteorological correspondents. He also held
a joint appointment as the “national meteorologist” in the U.S. Army Medical
Department, a position that boosted his storm studies by providing him access to
the meteorological reports of the army post surgeons. From 1847 to 1857, his sal-
ary was provided by annual appropriations from Congress. With Joseph Henry,
he established the Smithsonian meteorological system of observers and experi-
mented with telegraphic weather reports. Several of his major reports on meteo-
rology appeared as U.S. Senate executive documents. 8
Espy viewed the atmosphere as a giant heat engine. According to his thermal the-
ory of storms, all atmospheric disturbances, including thunderstorms, hurricanes,

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