144 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1918. 



none of any practical use, can be built to withstand the violence of 

 the wind in the vortex of a well-developed tornado. Hence the only 

 resource left is to protect life and property to the best of our ability 

 and with a knowledge of the facts which have been brought to light 

 by a sane, unprejudiced, scientific study of the phenomena. Owing 

 to the varying intensity of tornado violence and of the velocity of 

 the surface winds, the damage done to different sorts of buildings 

 varies greatly. If the intensity of the storm is not sufficiently great 

 to destroy everything in its path, the damage done by the less violent 

 winds will obviously depend largely upon the strength of construc- 

 tion and upon the building materials. It was Finley's advice to 

 build " as you would without the knowledge of a tornado." He 

 found, however, that, other things being equal, a frame building 

 seems to resist destruction better than one of brick or stone. The 

 modern steel-construction buildings have some of the " elastic " 

 quality which renders frame structures safer than the more stable 

 and solid ones of stone or brick of the older style. It makes little or 

 no difference in the end whether a building is in a valley or on a 

 hill. 



In view of the property loss occasioned by tornadoes it is natural 

 that tornado insurance has become a widespread and popular method 

 of financial protection. So far, however, the business has not been 

 carried on upon a thoroughly scientific basis. Tornado insurance to 

 the amount of several hundred millions of dollars is carried, largely 

 by general fire insurance companies, and partly by local mutual 

 insurance companies. The definition of a tornado is usually crude 

 and unscientific, and there is much unnecessary confusion. It is true 

 that the more conservative companies do prohibit some " risks," 

 such as windmills, old and frail buildings, large plate-glass windows, 

 and the like. It is interesting to note the marked rise and fall of 

 the amount of tornado insurance with the occurrence in any year of 

 severe or destructive tornadoes. Closely following the St. Louis 

 tornado of May, 1896, there was an increase of tornado insurance of 

 nearly $10,000,000, and after the Omaha (Nebraska) tornado of 

 Easter Sunday, 1913, several million dollars' worth of tornado in- 

 surance was written in Omaha and the surrounding districts, which 

 were at once thoroughly canvassed by insurance agents. Many new 

 dugouts and cellar caves were built at the same time. As Prof. H. E. 

 Simpson * has pointed out, tornado insurance risks differ from 

 others in several ways, notably in the fact that there is no criminal 

 hazard present; for people can not remove, or explode, or destroy 

 their buildings for the sake of the insurance, on the plea that the 

 damage was done by a tornado. It is obviously wise to scatter 



1 II. E. Simpson, " Tornado Insurance." Monthly Weather Review, vol. xxxiii., pp. 

 534-539. (Washington, D. C, December, 1905.) A short bibliography is appended. 



