Dalton, John

From HydroWiki

Life and Work

John Dalton (September 6, 1766 – July 27, 1844) was born at Eaglesfield in Cumberland, England. He was the son of a Joseph Dalton and Deborah Greenup and one of six children. His early education was originally by his father, but he also attended the Pardshaw Hall School. Between when he was twelve and fifteen years old he opened a small school in Eaglesfield. In 1781 he gave up his school to move to Kendal to be an assistant school teacher, where he met John Gough, whom he referred to as an intimate friend and adviser for eight years. After three to four years, he became the principal at the boading school in Kendal and then continued in that capacity for eight years. On March 24th, 1787, he began a diary which he called Observations upon the Weather and continued it until his death. He constructed his own thermometer, barometer, and hygroscope to make measurements. In 1793, he moved to Manchester to New College, where he served six years as a tutor in mathematics and natural philosophy. After that, he was employed as a private and public teacher of Mathematics and Chemistry in Manchester.

Although John Dalton is highly credited for his advances in atomic theory, he also contributed greatly to hydrology through the understanding of the global hydrological cycle. In 1793, he published Meteorological Observations and Essays, which included essays on the quantity of rain and dew, on the power of fluids to conduct heat, maximum density of water, heat and cold produced by condensation and barefaction of air, constitution of mixed gases, force of steam, evaporation, and expansion of gases by heat. While other scientists speculated about the process of evaporation and precipitation, these essays were the first to offer a mathematical and scientific explanation. Among many observations, he was the first to determine the dew point and explained that the cause of rain was the lowering of the atmospheric pressure. His ability to have these findings is due in large part to his own observations. His observations included pressure, temperature, humidity, rainfall, height of clouds, thunder-storms, hail showers, winds, snow, frost, and magnetism. His investigative methods and tools advanced the observational tactics of hydrology. Although John Dalton did not term the words “hydrologic cycle,” his investigation into the relationships between precipitation, evaporation, and seasonal fluctuations serve as the backbone for modern-day hydrology. Forty-One years after publishing this paper he printed a second edition, where he accounted for improvements in his observational tools and additional data from his diary.

Portrait

References

Dalton, John (1834). Meteorological Observations and Essays, 2, Manchester: Harrison and Crosfield. Henry, William C. (1854). Memoirs of the Life and Scientific Researches of John Dalton. London: Cavendish Society. Millington, John Price (1906). John Dalton. London: J. M. Dent & Company.