752 A MEMOIR OF ELIAS LOOMIS. 



hours at each e<iuiiiox and each solstice. This storm fell partly upon 

 one of these term days. Prolessor Loomis set to work to collect all the 

 nieteorolofiical observations made during the week of the storm that he 

 could obtain from all i)arts of the United States, and from some stations 

 in Canatla. The discussion resulting therefrom was read in March, 

 18-iO, before the American rhilosophical Society at riiihidelphia. 



Let us for a little while consider the amount of knowledge of the facts 

 about storms in our possession in 1840, the date when this memoir was 

 read and an abstract of it published in rhihulelphia. Franklin had 

 noted the motion of storms from southwest to northeast. He said :* 

 "Our northeast storms in North America begin first in point of time in 

 the sonthwest parts, that is to say, the air in Georgia, the farthest of 

 our colonies to the southwest, begins to move southwesterly before the 

 air of Carolina, which is the next colony northeastward ; the air of 

 Carolina has the same motion before the air of Virginia, which lies still 

 more northeastward ; and so on northeasterly through Pennsylvania, 

 New York, New England, etc., quite to Newfoundhuul." Kedfield had 

 traced several storms along the West India Islands northwesterly un- 

 til about in the latitude of 30^ their course was turned quite abruptly 

 and they swept oft" northeasterly along the Atlantic coast toward and 

 even past Newfoundland. Espy found some storms moving easterly or 

 south of east from the Mississippi to the Atlantic. 



lirandes had announced as a law that the wind in storms blows 

 inward toward a center, but his law was an induction from a small 

 number of observations. Dore had contended for a whirling motion. 

 Redfield advanced facts to show that the winds blew in circles anti- 

 clockwise around a center that advanced in the direction of the preva- 

 lent winds, and with him agreed Eeid, Piddington, and others. Espy, 

 agreeing with Braudes, claimed that the observ'ations in the various 

 storms showed a centripetal motion of the winds toward a ce ;ter if the 

 region covered by the storm was round, and toward a central line if 

 the storm region was longer in one direction than in another. Espy's 

 conclusions were intimately connected with his theory that in the center 

 of the storm there w as an upward motion of the air, and that the con- 

 densation of vapor into rain furnished the energy needed for the con- 

 tinuation of the storm. The rival theories of Redfield and Espy were in 

 sharp contest on several points, but the main contention was around 

 this central (juestion: Do the winds blow in circular whirls or do they 

 blow in toward a center? New York State was (!ollecting observations 

 from the academies. The American PliiIos()i)hical Society and the 

 Franklin Institute, aided by an appropriiition from the State of Penn- 

 sylvania, had united in an effort to learn the facts and the true theory 

 of storms. 



Under such circumstances the thorough discussion of a single violent 

 storm was likely to add materially to our knowledge. The treatment 



"Letter to Alexander Small, May 12, 1760. 



