278 KANSAS CITY REVIEW OF SCIENCE. 
per square foot. The pressure of wind at different velocities is something like 
this: Two pounds per square foot for a velocity of twenty miles per hour, eight 
pounds for forty miles, eighteen pounds for sixty, thirty-two for eighty, ete. Sey- 
enty-two pounds for twenty-four hours would be three pounds per hour, equal to 
about twenty-five miles. Now, although twenty-five miles is accounted a fairly 
strong wind, it cannot be doubted that above the earth and free from obstruc- 
tions, the velocity is greatly above this with a change of barometer of an inch. 
It seems hardly too much to calculate it as three or even four times as great. A 
scale might be constructed something like this: 
Pressure of the wind above a place, free of obstructions, when the barometer 
at the surface was between 
29.00 and 30.00 inches—2 pounds to the square inch. 
28.00 66 29.00 6¢ Sl 5 (a4 66 66 66 
27.00 66 28.00 6é ks 7 (a4 66 66 66 
ZO OOM 27 hOO Vi memi its 3°Ti ti es ne ee 
PSO) 99 ACO 7° —ALEXey 8 ee os ae 
2ANOOM Nn 2 5e OO cat 1 © hwy: BG oe ue 
23.00 66 24.00 66 —-T. 00 66 (74 66 (a3 
22.00 < 23.00 3 —o go 6é aC iG 0G 
ZiT OOM) 2/2 OOM ONO Tl oe G6 6G 
ZONCOM e LOLOO ee Ou] Qin le a se Se euCs 
This may be an exaggerated scale but, the principle seems to be correct. 
That the pressure of an elastic medium like the atmosphere would be very ex- 
cessive in the high regions of the scale and of much diminished power in the 
lower, seems natural to conclude. Imagine how weak the force of the wind that 
corresponded to a pressure of mercury one inch in height, for while one inch of 
mercury weighs as much as another the wind producing power of the air at dif- 
ferent pressures must vary. 
Seemingly opposed to such a scale is the fact that the measure of the wind 
does actually correspond nearly with the barometric change. Take an actual 
case: At 6:00 a. m., June 6th, the barometer read 28.986, equal, we will say, to 
a pressure of 2086.56 pounds per square foot. At 6:00 a. m., June 7th, the 
barometer read 29.882, equal to a pressure of 2151.36 pounds per square foot, a 
difference of 64.8 pounds; about 2.6 pounds to the hour for twenty-four hours, 
about twenty-three miles. Though variable, of course the wind record from 6:00 
a. m., June 6th to 6 a. m., June 7th, was 426 miles or about eighteen miles per 
hour, equal to a pressure of 162, a loss of five miles per hour, though as the wind 
was variable, running up at one time to thirty-eight miles, this loss may be excused 
or laid to natural obstructions at the place of observation. But it will be seen 
by looking at the scale of pressure and velocity that a running up of the force to 
forty or fifty miles quickly exhausts the pressure which the change of an inch im- 
plied. Besides which, this would not explain variations in force which occur at 
different portions of a storm’s progress, while the barometer change remains 
nearly uniform. 
