FERREL, William, scientist, born in Bedford, now Fulton, County, Pennsylvania, 29 January 1817. He studied at Marshall, now Marshall and Franklin, College, and was graduated at Bethany College in 1844. In 1857 he became assistant in the office of the "American Ephemeris and Nautical Almanac," which place he retained for ten years. Subsequently, until 1882, he held a special appointment in the U. S. coast survey for the discussion of the tidal observations. In 1882 he was made assistant, with the rank of professor, in the signal service bureau, where he remained until October 1886, after which he made Kansas City, Missouri, his home. He invented the maxima and minima tide predicting machine, which is now used by the coast survey in predicting tides. A full description of this machine is given in Appendix 10 of the "Report of the Coast and Geodetic Survey" (1883). Professor Ferrel has received honorary elections to Austrian, English, and German meteorological societies, and in 1868 was elected to membership in the National academy of sciences. His contributions to science include "Motions of Fluids and Solids relative to the Earth's Surface" (1859);" Determinations of the Moon's Mass from Tidal Observations" (1871); "Converging Series expressing the Ratio between the Diameter and the Circumference of a Circle " (1871); "Tidal Researches" (1874); "Tides of Tahiti" (1874); " Meteorological Researches," Parts I. (1875), II. (1878), and III. (1881); "Temperature of the Atmosphere and the Earth's Surface" (1884); and also "Recent Advances in Meteorology," being Part II. of the "Report of the Chief Signal Officer" (Washington, 1883).