xvi WINDS OF THE GLOBE. 



a resultant the same as that for the month or season 1 The former may be regarded 

 as tlie wind that would exist if the surface of the earth were homogeneous, and 

 the sun ever over the equator; and the hitter as that which is due to the change of 

 temperature in the diflcrent parts of the year, in connection with the cliaracter of 

 the neighboring regions, chiefly with respect to land and water. These deflecting 

 forces, which are found almost everywhere, I denominate monsoon wJlHences, and 

 where they are so great as to decidedly control the direction of the current, the 

 resulting winds are tlie well-known monsoons. 



4th. What relation exists between the direction of the wind and the pressure 

 of tlie atmosplicre 1 Or, what winds arc, on an average, attended by a rise in the 

 barometer, and w^iat by a fall, and at what average rate ? 



5tli. Also what connection exists between the direction of the wind and the 

 pressure, temperature, and humidity of the atmosphere, the state of the sky, and 

 the amount of rain-fall ^ 



"These are not the only questions of interest connected with the study of the 

 winds (for their relations to hygienic and agricultural considerations merit close 

 investigation), but they are the only ones to whicli I have given much attention. 

 And, as to the latter, my investigations have been confined chiefly to the point 

 first named in it. 



"The proper scientific investigation of each of these questions is comparatively 

 of recent date, extending back not much furtlicr than the year 1830. Vast 

 collections of observations on the Avinds had been made previously, which are now 

 of invaluable service under the improved methods of studying them ; and some of 

 the more obvious phenomena, such as the ' trade winds,' monsoons, and regions of 

 calms, were well known. But the usual, and indeed the only method of discussing 

 observations of the winds, was to sum up the number that was observed from each 

 of the several points of the compass, to regard that direction which afforded the 

 largest sum as the prevailing direction, and to make no account of the rest. This 

 method often served to point out the geographical features of the surrounding 

 country, rather than to afford any information of value in regard to the real 

 question discussed. It was about the year 1836, perhaps a little earlier, that the 

 idea of resolving the traverse of the winds on the principle now so familiarly 

 known as Lambert's formula, first occurred, nearly simultaneously, to Prof. Kaemtz 

 in Europe, and to Prof Loomis and myself in this country, to each without the 

 knowledge of the others. [This method is fully described and the formulae stated 

 in the Preface to this work.] 



"My first efforts were directed to the winds at Dartmouth College, New Hamp- 

 shire, as then reported monthly in the Vermont Ghronide, 1836, and having soon 

 afterward removed to Ogdensburg, New York, I applied the method to the winds 

 there, as recorded momentarily by a self-registering vane that I had constructed 

 for the purpose. The results at the latter place were published in the annual 

 report of the Regents of the University of the State of New York for the year 

 1 838. 



"In the year 1824, the Legislatiire of New York had made an appropriation for 

 establishing a system of meteorological observations at diff'erent academies in the 



