Elias Loomis (August 7, 1811 - August 15, 1889) was an American mathematician and meteorologist. From 1844 to 1860 he held the professorship of natural philosophy and mathematics in the University of the City of New York, and in the latter year became professor of natural philosophy in Yale. He published many papers in the American Journal of Science and authored textbooks on mathematics, including Analytical Geometry and of the Differential and Integral Calculus, published in 1835. His research interests, and contributions to science, were more meteorological. In February 1842, he investigated the paths of two large storms moving across the eastern half of the United States. By tracking the storms over a wide area for several days, he was able to accurately chart the storms' courses and show their meteorological changes. In two series of sequential maps he drew lines of equal deviations in barometric pressure and equal oscillations in temperature, and assigned colors to areas of clear sky, clouds, rain, snow, and even fog. In addition, he used arrows of varying length to indicate wind direction and intensity. His proposal for a system of observers across the United States and for daily weather maps was realized in the creation by Congress of the Weather Bureau of the United States Signal Service in 1870. This became the National Weather Service we know today. He died in 1889 at the age of 78.