L 392 ] 



About the year 1735 Mr. Hadley publiflied a very different 

 account of the origin of the trade winds. 8 Phil. TranH Abrid. 

 p. 500, which, however, has been rejeded by the moft diftin- 

 guifhed aftronomers that have fince attended to this objed, as 

 D'Alembert, fur la Caiifc des Vents. Art. 376, and 385, Gentil 

 Voy. 2 Bergman Erde Befchreib, p 91. 



According to Mr. Hadley, the air, being rarefied towards the 

 equator, is confequently invaded, in the northern hemifphere by 

 the northern,, and in the fouthern hemifphere by the, fouthern 

 colder air. 



But as the parallels of latitude enlarge as they approach the 

 equator, and as the equatorial fpace is nearly in the proportion of 

 1000 to 917, the difference of their circumference is nearly 2083 

 miles ; confequently, the furface of the globe at the equator moves 

 fo much fafter than tinder the tropics ; and hence the northern or 

 fouthern air, moving from the tropics towards the equator, rauft 

 pofTefs lefs velocity than the parts it arrives at, and, confequently, 

 appear to move in a diredion contrary to that of the earth's mo- 

 tion, which being from weft to caft, the air arriving fooner at the 

 weflern parts, will appear to move from eaft to weft, and this re- 

 lative motion being combined with that towards the equator, a 

 north-eaft wind will be produced on the north fide, and a fouth- 



eaft 



