the regular winds, and other phenomena which depend on 
‘them. 
106 Obfervations on the Flux and Reflux 
traction, the movement of an elaftic fluid would be totally 
different ffom that of a non-elaftic. Other philofophers, 
not neglecting this confideration, have believed that the 
caufes which produce the movement of the waters of the 
ocean can occafion a much greater in the aérial mafs of the 
atmofphere, and muft have a very great {hare in producing 
D’Alembert has calculated, from the theory of general 
gravitation, thofe movements which muft be produced in 
the atmofphere by the effects of the fun and moon. He 
found that from this influence a continual eaft-wind muft 
arife at the equator, and that, in the temperate zones, nat 
far from the tropics, it muft be converted into a weft-wind ; 
that on account, however, of many local circumftances, and 
other impediments which come iy the way, it cannot al- 
ways continue in the fame direction; and that the variations 
in the ftate of the barometer, which thence arife, muft be 
very inconfiderable, and almoft imperceptible, 
Bacon, Gaffendi, Defchales, Goad, Dampier, Halley, and — 
others who have written on the wind, all unanimoufly ob- 4q 
ferve, that the periods of the year moft expofed to it are the © 
two equinoxes: that florms are moft frequent at the times 
ef new and full moon, and particularly thofe which happen ~ 
near the equinoxes: that at periods, otherwife calm, a fmall — 
breeze always takes place at high water; and that a fmall 
moyement in the atmofphere- is each time perceived a little 
after noon and midnight. Now, as moft of thefe circum- 
ftances haye a great refemblance to thofe which cua A 
the flux and we of the fea, and take place at the f 4 
time; and as in this refpe&t the movement of water and Ra 
atmofphere 1 is the fame, according to Newton’s rule, that | 5 
natural effects of the like kind mutt be produced by the fame 
caufes *, both may be deduced from the fame fource. - 
From, this it appears that theory and experience coincide ~ 
to eftablith the exiftence of an atmofpheric flux and reflux, © 
and of the regular and very perceptible effects which they ~ 
produce. ‘Nothing therefare is neceflary but to deduce their — 
* Effectuum naturaliym ejufdem generis exdem aflignande funt caufla. 
phenomena — 
