614 



SCIENCE 



[N. S. Vol. XLV. No. 1172 



complete devastation being to the right of 

 the center seems to be plausibly explained 

 when the agents of destruction are considered. 

 On the right of the center there is the ex- 

 plosive action due to the reduced pressure on 

 the outside of the buildings, the eastward 

 component of the counter-clockwise wind of 

 the tornado (probably over 400 miles per 

 hour), the forward movement of the storm, 

 and the west wind which was prevalent at 

 that time all working in conjunction as 

 agents of destruction; while on the left side 

 of the center the westward component of the 

 counter-clockwise wind is partially counter- 

 balanced by the forward movement of the 

 storm and the prevalent west wind. However, 

 the backward or east wind of the storm was 

 strong enough to move an eight room, one 

 story house 41 feet to the westward, others 

 shorter distances, to break elm trees 18 inches 

 in diameter and to tip over a large percent- 

 age of the monuments in a cemetery in 

 Mattoon. 



Evidence of the explosive action so fre- 

 quently stated as the principal agent in tor- 

 nado destruction is not as general as one 

 would expect. The north ends and the east 

 roofs were pulled from some houses in the 

 partially demolished districts; plate glass 

 windows were broken and had fallen out; in 

 one of the churches and a store in which 

 the glass was supported by metallic strips the 

 windows were made convex; a pump and 14 

 feet of water was sucked from a well; these, 

 and the various forms of roofing which were 

 picked off like feathers from a fowl, indicate 

 the suction action of the storm. Although 

 examples of explosion are not common, it is 

 quite probable that in and near the center of 

 the storm explosion was a big factor in the 

 preparation of buildings for the crushing ac- 

 tion of the wind. 



Blunt cedar sticks were found imbedded 

 one and one half inches in posts, and oat- 

 straws one half inch in a maple tree. Another 

 tree was decorated like an Indian's helmet 

 with feathers. Huge oak and elm trees were 

 twisted off, freight cars filled with brick were 

 upset, as were also the tank cars of the Stan- 



dard Oil Company. These and the buildings 

 moved and crushed indicate the force of the 

 wind of the storm. 



METEROLOGICAL CONDITIONS 



The Daily Weather Map, published at St. 

 Louis at seven a.m. of the date of the storm, 

 shows a well-defined cyclonic area covering 

 most of the interior lowland of the United 

 States. The isobars are oval in shape with 

 their longest axis extending north and south. 

 The isobars also show a slight bulging to the 

 south in the southern quadrant. Cloudiness 

 was prevalent over most of the Mississippi 

 valley. 



At 11 A.M.^ a thunder shower occurred at 

 Charleston. The clouds broke for a short 

 time but lights were necessary at 2 p.m., and 

 the air was exceedingly sultry and oppressive. 

 At 3 P.M. a heavy, black, nimbus cloud ap- 

 peared in the northwest, and frequent and 

 fierce fiashes of lightning occurred. Shortly 

 before 3 :45 a greenish black cumulo-nimbus 

 cloud began to tumble in from the west. The 

 wind suddenly changed from east to west 

 through the south and hail began to fall. 

 Then the hail lessened in amount and the 

 wind attained a velocity of eighty miles per 

 hour, the barometer dropped three tenths of 

 an inch but came up immediately, and the 

 temperature fell fourteen degrees. (Shown 

 by the barograph and thermograph records.) 

 Suddenly the wind lulled and flattened 

 spheroidal hail, some having a major axis of 

 2 J inches, fell until the ground was covered. 

 The hail was accompanied and foU'owed by a 

 deluge of rain. 



Although the funnel or balloon-shaped cloud 

 of the tornado was not visible to those in the 

 cities, it was seen and well described by 

 numerous individuals who were west of the 

 cities and to the right or left of the storm. 

 J. P. Carey 



Depaetment op Geography, 

 Eastern Illinois State Normal School, 

 Charleston, Illinois, 

 June 4, 1917 



1 Observations made at the State Normal School, 

 Charleston, one mile to the south of the storm 

 track. 



