LET. VIII. OF THE NATURE OF THE TIDES. I3I.

the moon raises the waters at Z and N, theywill be depressed at H and 11 j and when they areraised by her at H and R, they will be depressedat Z and N. And as the moon passes over themeridian, and is in the horizon, twice every day,there will therefore be two tides of flood andtwo of ebb, in that time, at the interval of aboutsix hours and eleven minutes each; which isexactly conformable to theory and experience.

One great privilege of genius, seems to bethat of considering diflicult things under a pointof view which renders them more simple andperspicuous, and enables the mind to compre-hend and follow them with ease and facility.This felicity of conception was possessed byNewton in the highest degree: he always knew,in every cafe which required investigation, theproper mode of resolving the question. Geo-metry and mechanics were his favouritesciences, and, by their means, he soon con-quered every difficulty. We have seen, in thepresent instance, how easily he removed objec-tions, and reconciled apparent contradictions.The occurring of the tides at the fame placetwice a day, was made use of as an argumentagainst the truth of his grand principle of at-traction ; but this, so far from being repugnantto that doctrine, he has strewn to be a necessaryconsequence of it.

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