146 KANSAS CITY REVIEW OF SCIENCE. 



tornado with hardly an exception occurs in the afternoon, just after the hottest 

 part of the day and generally disappears before the going down of the sun. The 

 hour of greatest frequency is between three and four P. M. A tornado very 

 rarely, if ever, begins after six P. M. Understand me, a tornado commencing 

 about five P. M. may continue its characteristic violence until nearly eight P. M. 

 which only means that the tornado cloud may be traveling after six P. M. or after 

 seven P. M., but it does not develop, that is, make its appearance, for the first 

 time after those hours. Without the path of destruction, even to the shortest 

 distances, at times even along the immediate edge, the smallest objects often re 

 main undisturbed although a few yards distant the largest and strongest buildings 

 are crushed to atoms. At any point along the storm's path, where there is oppor- 

 tunity afforded the tornado cloud to display its power, the disposition of the debris 

 presents unmistakable signs of the revolving right to left action of the wind. The 

 violence and intensity of the destructive power increases directly as you pass from 

 the circumference of the storm to its centre. 



Observations with the barometer are of little practical value at any one point, 

 whether made before or after the tornado cloud has formed or while it is ap- 

 proaching. Such observations will not indicate its approach however near 

 the position of the instrument to the point of the cloud's inception. The torna- 

 do season is embraced between the ist of April and the ist of September, 

 although it can be considered unusual to record their appearance at any time 

 in the former month. The months of greatest frequency are June and July. 

 There are exceptional instances in a long series of years where tornadoes have 

 been reported in every month of the year. They may, and sometimes do occur 

 in some of the Southern States during the winter and spring months. Taking the 

 whole United States together and averaging the dates of occurrence for a long 

 series of years (nearly 90) it is found that the region of greatest frequency is the 

 Lower Missouri Valley, embracing the States of Kansas, Nebraska, Missouri and 

 Iowa. Of all the States in the Union, Kansas ranks the highest in regard to fre- 

 quency. 



Hurricanes — Although it seems hardly necessary to define the hurricane, 

 it will perhaps be well to state that as here considered it means a straight wind of 

 extraordinary velocity. They may and frequently do occur without the accom 

 paniment of any precipitation. On the summit of Mount Washington, White 

 Mountains, New Hampshire, a measured velocity of nearly two hundred miles 

 per hour has been recorded. On the summit of Pike's Peak, Rocky Mountains, 

 Colorado, a measured velocity has several times exceeded one hundred miles per 

 hour. On the coast of the Carolinas maximum measured velocities have ranged 

 from seventy-five to one hundred and sixty miles per hour. In the Eastern Rocky 

 Mountain Slope and in the l^ake Region measured velocities are sometimes re- 

 corded ranging between sixty and eighty miles per hour. This storm may be 

 known as the Blizzard of the Northwest, the Chinook of the Northern Plateau, 

 the Norther of the Southern Slope and Texas, or the Simoon of the Desert. 

 Hurricanes may occur at any hour of the day or night and in any month of the 



