200 EBB AND FLOW. 



the open sea, the motion of the air is best perceived ; and 

 where the air itself, as well as heaven, revolves in a larger 

 circle, and therefore more rapidly, that a perennial and 

 gentle breeze blows from east to west, insomuch that those 

 who wish to use the south west wind often seek and avail 

 themselves of it outside the tropics. Consequently this 

 motion is not extinguished, but becomes languid and ob 

 scure, so as to be scarcely perceptible outside the tropics. 

 Yet even outside the tropics, in our own part of the globe, 

 Europe, at sea, in serene and peaceful weather, there is ob 

 served a certain wind, which is of the same species ; we 

 may even conjecture that what we experience here in Eu 

 rope, where the east wind is sharp and dry, and, on the 

 contrary, the south west winds are cherishing and humid, 

 does not depend merely on the circumstance that the one 

 blows from a continent, the other from the ocean, but on 

 this, that the breath of the east wind, since it is in the 

 same train with the proper motion of the air, accelerates 

 and heightens that motion, and therefore disperses and 

 rarifies the air ; but that of the west wind, which is in the 

 contrary direction to the motion of the air, makes it re 

 bound upon itself, and become inspissated. Nor ought 

 this to be neglected, which is admitted into the number of 

 common observations, that the clouds which are in motion 

 in the upper part of the air generally move from east to 

 west ; while the winds about the earth s surface generally 

 blow at the same time the contrary way. And if they do 

 not this always, the reason is this ; that there are some 

 times opposite winds, some acting on the high, others on 

 the lowest, exhalations. Now those blowing on high, if 

 they be adverse, confound the real motion of the air. It is 

 sufficiently clear, then, that the motion is not confined 

 within the limits of heaven. 



Then follows in order the second inquisition : Whether 

 the waters move regularly from east to west. Now when 

 we speak of waters, we mean those accumulations or masses 

 of waters which are such large portions of nature as to 

 have a relation of harmony to the fabric and system of the 

 universe. And we are fully of opinion that the same motion 

 is natural to, and inherent in, the body of waters, but is 

 slower than in the air; though, on account of the grossness 

 of the body, it is more palpable and manifest. Of this we 

 shall content ourselves with three selected from many ex 

 perimental proofs, but these weighty and marked ones, 

 which prove that this is so. 



