124 OF THE NATURE of the tides.

of the sea was the effect of its respiration : men,and other creatures, he conceived to be insectswhich feed upon this animal; bushes and treesthe bristles on his back ; and the water of seasand rivers a liquid which circulates in his veins,Galileo, Descartes, and even Kepler, have,however, expressed themselves more philosophi-cally upon this subject; but the first who clearlypointed out the cause of the phænomenon, andshewed its agreement with the effects, was N ew-ton. To a genius like his, enterprise and disco-very were recreation. The moon he presentlysaw was the principal agent which produces thesemotions; and, by applying his new principles ofgeometry and attraction, he soon shewed themanner in which they are effected, To followhim through all his calculations and enquiries,would be to perplex the subject instead of eluci-dating it. Not to insist, therefore, upon abstruseinvestigations, which are intelligible only to ma-thematicians and philosophers, I shall , begin bydescribing the most obvious facts, and afterwardsshew their conformity with the theory he hasestablished.

The ocean, it is well known, covers more thanone half of the globe; and this large body ofwater, is found to be in continual motion,ebbing and flowing alternately, without theleast intermission. What connection these mo-tions have with the moon, we shall see as

we