1887.] 1"! [Blasius. 



One of the most destructive storms this country has ever witnessed, 

 occurred on the coasts of Nova Scotia and Newfoundland, August 28, 24and 

 25, 1873, by which about 500 lives were lost and 1032 vessels destroyed, 

 including 435 small fishing schooners. The Signal Service Bureau was 

 entirely taken aback by this storm, because an "area of high pressure" 

 or an "anticyclone" had been moving from Manitoba to the coast, and 

 therefore, fair weather was to be expected. But in the weather maps 

 for several days previous could be traced the gradual advance of a 

 wave of cold air from the North — the "area of high pressure" — which 

 banking up the warmer air in its front as shown by the gradually rising 

 gradient, finally culminated in a terrific south-east storm with its centre 

 of destruction on the coast. We thus have a storm of the most violent 

 character traced on the maps of the Signal Service Bureau for several 

 days as a fair weather indicator. 



The Chief Signal Oflicer reports 80 "areas of high barometer" during 

 1884. Those occurring in the cold season mean fair weather, as they dis- 

 place the warm current which has previously discharged its moisture. In 

 the summer, however, this cool air from the North, which being heavy can 

 be identified as an " area of high pressure, " causes — in its displacement 

 of the then prevailing warm and moist air — tlie south-east storm, with its 

 tornadoes, hail-storms, cloud-bursts and thunder-storms, none of which 

 the Signal Service Bureau predicts, and which cause vastly more destruc- 

 tion than the north-east storms — the "areas of low pressure" — both from 

 their greater violence, and because they mostly occur at a season of the 

 year when the work of the agriculturist is going on and his crops — on 

 which the nation depends for its prosperity — are subject to injur^^ 



It is true that quite lately the Bureau has turned its attention to this 

 brancli of the subject, after so many years of practical neglect, and that 

 claims of considerable magnitude have been advanced as to what has been 

 accomplished and what will be accomplished, both in the way of predic- 

 tion and scientific discovery. Let us therefore examine into this a little. 



The most eminent of American meteorologists — Redfield, Espy and 

 others— agree in thinking the tornado the most instructive of all storms. 

 It is in some respects the type of our American storms, since here the op- 

 position of air-currents of different temperature and density, which is the 

 general cause of storms, is most strikingly manifested and within the nar- 

 rowest limits. 



Mr. Wm. A. Eddy, an attache of the Bureau, in The Popular Science 

 Monthly tor January, 188G, says: "During the first part of 1884, the 

 United States Signal Service began to pay special attention to the question 

 of tornado prediction. Tlie development of the science was rapid under 

 the active supervision of Lieutenant .John P. Finley, having charge of that 

 department of the service. It was found that the public interest in the 

 question was widespread, and that with the aid of voluntary reporters of 

 tornado phenomena, the possibility of saving life and property had begun 

 to crystallize into a practical scheme." He furtlier says: "During the 



