DEDUCTIONS AND REMARKS. 141 



Thus we find that theory harmonizes perfectly with fact, both as it respects the 

 direction and the constancy of the winds regarded as systems. Let us now examine 

 a few minor details. 



1. The facts mentioned in our fifteenth deduction have long been known, and 

 have been usually, and I suppose correctly, accounted for by ascribing them to the 

 rarefaction of the air over the Great Desert. Some additional facts, confirmatory 

 of this idea, will be mentioned as we proceed. 



2. The winds at the stations in South-western Asia, having of themselves but a 

 feeble tendency to flow in one direction rather than another, owing to their prox- 

 imity to the dividing line between two systems of winds, appear to be controlled 

 entirely by the strong local influences to which they are subject, and for which that 

 region is remarkable. This may account for their irregularity, alluded to above 

 in our sixteenth deduction. 



3. May not the less progressive motion of the wind in Europe than in the United 

 States (mentioned as our eleventh deduction), be accounted for by the higher tem- 

 perature of the former ? Just as a burning building increases the strength of the 

 wind on the side from which it blows, and diminishes it on the opposite side. 



when it passes tte same parallel on its return toward the equator. Now, colder air occupies less space than 

 warm air, and therefore the current of air flowing from the pole to the equator is narrower than when it 

 flows from the equator to the pole. If the beds in which these opposite currents flow are shifting ones, 

 the same station will necessarily be oftener in a southerly than in a northerly current (in the northern 

 hemisphere), and the proportion of southerly wind will in the course of a year exceed that of the northerly. 

 Moreover, the southerly winds bring with them a quantity of vapor, with which they are continually 

 parting in the form of rain and other precipitations; the returning northern dry winds do, indeed, bring 

 back the same mass of air, but without its aeriform companion, which, having now assumed the form of a 

 liquid, no longer contributes to raise the column of mercury in the barometer." 



On considering the above-described alterations to which the atmosphere is subjected, on its passage from 

 and return to the equator, we see that throughout the temperate zone the mean direction of the wind may 

 be from the equator, converted by the rotation of the earth into a south-westerly direction in the northern, 

 and a north-westerly in the southern hemisphere. 



Professor Loomis seems to view the subject in a similar light. (See his articles on the Meteorology of 

 Hudson, Ohio, published in the American Journal of Science and Arts.) 



