1874.] The Iowa and Illinots Tornado. 393 
air was no longer on one side of the centrifugal cloud, but 
apparently near itscentre. Hence the witnesses generally 
described the cloud as it approached, as consisting of a dark 
cloud to the north-west, a less dark to the south-west, and a 
clearer space between. In Iowa all circumstances had com- 
bined in order to render precise observation easy. In 
Illinois the very reverse was the case. I shall therefore 
treat this portion of the subject in a few general remarks. 
The tornado developed energy in this State quite as great 
as that displayed in Iowa. Its direétion of revolution was 
the same. The disposition of the ruins were precisely 
similar. It showed the same and even a greater partiality 
for water-courses, turning abruptly from its course in order 
to follow them. Its direétion varied between north-east and 
south-east, and was in the main easterly. At the moment 
when its velocity diminished, and before reaching Spoon 
River, it passed down close to the whirlwind, and even on 
its very path a perfect cataract of water. The height of the 
cloud must have been very great, for it was seen in the west 
for hours previous to its advent. There was less hail, and 
the sound was not so generally noticed as in Iowa. 
The Identity of the Tornado in Iowa with that in Illinots.— 
When lost track of, the Iowa tornado was close upon the 
Iowa river, and travelling to the south-east. Its general 
course had, however, been easterly. A very severe rain- 
storm passed over the district between its point of dis- 
appearance and the Mississippi River. ‘Trains were delayed 
by it and bridges washed away. On the Mississippi itself 
some damage was done to shipping by a violent gust of 
wind, which accompanied the rain. At Monmouth there 
was a severe thunderstorm. ‘Twenty miles to the south of 
it the tornado again struck the ground. It was at Youngs- 
town, at 5.45 P.M., or thereabout. From A. McKee’s house, 
north of Washington, Iowa, to Youngstown, is a distance of 
about 63 miles in a straight line. The tornado was at 
McKee’s house at 3.10 P.M. The difference between 
5.45 and 3.10 is 2.35. ‘The discrepancy due to longitude is 
four minutes, very nearly. The time, therefore, consumed 
by the storm in travelling from opposite Washington, Iowa, 
to Youngstown, Illinois, was two hours thirty-one minutes, 
or two and a-half hours. 63+24}=251, which is, therefore, 
the velocity of the storm, in miles per hour, in a straight 
line. The length of the journey was materially increased 
by the crookedness of the path. This brings the velocity 
nearly up to that with which the meteor traversed Keokuk 
and Washington Counties, Iowa. These facts, taken in 
