^6% Injljience of the Sun and Moon on the Atmofphere, 



hj rlfing and falling twice in each day, in a degree pro'por-' 

 tioned to the fiij-ypofed weekly tide. But perhaps even this 

 difference may be found to refalt from the different conlli- 

 tntion of the two fluids. The water, being of more uniform 

 denfitv and poiTe(?ing fo much greater gravity, is elevated 

 and fubfides with proportionate (^cadinefs. The air, falling 

 greatly fhort of the water in gravity, and its denfitv conti- 

 nually decreafing upwards, mu(l needs be very differently 

 afieded, If we take notice alfo of the greater eafe with 

 which the latter is thrown into currents, and lafflv of its re- 

 markable property of dilTolving mere water as it increaf^'S in 

 dctiilty and temperature, and letting it fall as it decreafes in 

 either, it will rtot feem impofllble, that the daily flux aiid 

 reflux, which is fo manifetl iti the waters, fliould be lofl; and 

 counteracted in the atmofpherc ; while, on the other hand, 

 the prngreilive incrcafc of either, through the lunar week, 

 fliouId, by the very fame caules, be fomctimes promoted and 

 rendered more confpicuous. 



It will, however, be foon enough to enter upon the theory 

 of the attnofpherical tides, when the preceding fa6ls fliall 

 have been examined, and the influence of tlie fun and moon 

 on the gravity of the atmofpherc eftablifhed, by more exlen- 

 five obfervation, Tt is for this purpofe that the fubjeft is 

 now brought forward, and the cooperation of meteorological 

 obfervcrs, in this or other countries, into whofe hands this 

 may come, is requerted. The coincidence, fo far as hitherto 

 obfcrvcd, i<5 an important faft, and ihould it be found to ob- 

 tain generally, it will necciruriiv lead to feveral important 

 confequences ; and, in the firft place, to a new atid more fa- 

 tisfaSory theory of ti>e barometer ; in confequence of which 

 that inlhnment may be more fuccelsfully applied to foretell 

 the changes of the weather. The true r^afon likewife of 

 the weather fo frequently coinciding, in-the time of its va- 

 rious alterations, with the changes of the moon (a coinci- 

 dence which has long ferved to direft the prcdiftions of the 

 almanac-makers), will be apparent, and the diligent meteo- 

 rologift will avail himfelf of it in forming probable conjec- 

 tures on the changes likely to eufue for a certain time, not 

 exceeding that which Umits the operation of the known 

 eaufe or caufes. 



P.S. That 



