Blasius.l -l-O-^ [MayC, 



summer of 1886, it is hoped that, by means of signals, hundreds of lives 

 and much valuable property will be saved." 



The summer of 1886 has passed ; can it be said that this hope is realized ? 

 Has the Signal Service saved a single life or any property by its tornado 

 predictions? 



Mr. Eddy tells us that the "invariable location south-east of the storm- 

 centre is one of the main peculiarities of tornado development upon which 

 the predictions depend." And yet to this same peculiarity, with its expla- 

 nation, I called attention as earlj^ as 1852, and again in 1875, in the pub- 

 lication of my work on storms already referred to, and I urged it on the 

 Signal Service Bureau during a personal visit to Washington at that time. 



Mr. Eddy also says: "When the conditions are unfavorable for the 

 development of tornadoes, there are no unusual contrasts of tempera- 

 ture, the areas of warm and cold air neither great nor well defined north- 

 ward and southward, the winds are variable and not very strong, and the 

 distribution of pressure is about normal." All this can be found in my 

 work on "Storms," published in 1875 — why is it put forward as a new 

 discovery in 1886 1 



Indeed, it was only after the publication of that work that the Signal Ser- 

 vice Bureau began to note the difference of temperature in air-currents — 

 to which I had called attention — and made various and important changes 

 in its method of prediction. But when Lieutenant Finley puts forth as a 

 discovery of his own, the fact that tornadoes are caused by "two opposing 

 air-currents of different temperatures and moisture," it seems a little sin- 

 gular, in view of my communication of the same fact to the Academy of 

 Science in Boston, in 1851, its publication in 1852, and again, in 1875. 



As to the prediction of tornadoes by the Signal Service, it can never be 

 done with any certainty, except in so general a waj^ as to be valueless. If 

 any one has mastered the principles of atmospheric disturbance — and 

 they are not so difficult — he will be able to judge for himself as to the 

 probability of tornadoes being imminent in his locality ten times as well 

 as the Signal Service can ever tell him. Just where the tornado will 

 strike, and its path is a narrow one, no man can tell until within a few 

 minutes of its passage. 



Mr. Eddy says: "That during 1884, 3228 predictions ■?^^?ifavorable to 

 tornadoes were made, and of these 3201 were verified." But what a sim- 

 ple matter it is with the most ordinary knowledge and circumspection to 

 say that tornadoes will not take place, when the dark clouds of the south- 

 east storm give ample notice when there is a possibility of their happen- 

 ing? If we have a southeast storm we may or may not have tornadoes ; 

 but if we have 7iot a south-east storm, then we have no tornadoes. 



As to the prediction of a tornado itself, jNIr. Eddy cites that which 

 passed over Camden and Philadelphia, August 3, 1885, as " one of the best 

 illustrations of the advance made in definiteness in predictions ;" and he 

 further says : "The chart used by Lieutenant Finley shows that torna- 

 does were predicted and their location marked upon the map for the State 



