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terraneous fires, which uniting their flames, neccs- 

 sarily put into fervid motion the congregated va- 

 pours of its cells, which finding no immediate outlet, 

 exert their utmost powers, till at last they force a 

 way through whatever opposes them. He says also, 

 that if the vapours be too weak to burst the barriers 

 which retain them, all their efforts end in weak 

 shocks, and hollow murmurs without any fatal conse- 

 quence, 



9. Of all the solutions that erer were attempted 

 to be given of the ebbing and flowing of the sea, the 

 most simple and ingenious, is, that of Kepler and Sir 

 Isaac Newton, it is founded on this hypothesis, 

 that the moon attracts the waters of the sea, dimu 

 Dishing the weight of all those parts of it over whose 

 zenith it comes, and increasing the weight of the col. 

 lateral parts, so that the parts airectly opposite to the 

 moon, and under it in the same hemisphere, must be- 

 come more elevated than the rest. According to this 

 system, the action of the san concurs with that of the 

 moon, in occasioning the tides ; which are higher or 

 lower respectively, according to the situation of those 

 two luminaries, which, when iu conjunction, act in 

 concert, raising the tides to the greatest height ; and 

 when in opposition, produce nearly tbe same effect in 

 swelling the waters of the opposite hemispheres ; but 

 when iu quadrature, suspend each other's force, so as 

 to act only by the difference of their powers : and 

 thus the tides vary, according to the different posi- 

 tions of those luminaries. 



10. Pliny's account agrees with this. " That great 

 naturalist maintained, that the sun and moon had a re- 

 ciprocal share in causing the tides; andafter a course of 

 observations for many years, remarked that the moon 

 acted most forcibly upon the waters, when it \vas nearest 

 totheearth,but that the effect was not immediately per- 

 ceived by us, but at such an interval as may well take 

 place between the action of celestial causes ; and the 



