This may be considered as one great and general current of the waters of the sea; and although it be not every where distinguishable, it is nevertheless every where existent, except when opposed by some particular current or eddy produced by partial and local causes. This tendency of the sea towards the west is plainly perceivable in all the great straits of the ocean; as for instance, in those of Magellan, in South America, where the tide running in from the east nearly twenty feet high, and continues flowing six hours, whereas the ebb continues but two hours, and the current is directed to the west. This proves that the flux is not equal to the reflux, and that from both results a motion of the sea westward, which is more powerful during the time of the flux than the reflux. This motion westward has been sensibly observed by navigators in their passage back from India to Madagascar, and so on to Africa. In the great Pacific, also, it is very perceivable; but the places where it is most obvious are, as it was said, in those straits which join one ocean to another. In the straits between the Maldivia Islands, in the gulph of Mexico, between Cuba and Jucatan. In the straits in the gulph of Paria, the motion is so violent, that it has received the appellation of the Dragon’s Mouth. Northward, in the sea of Canada, in Waigat’s straits, in the straits of Java, and in short, where the ocean on one part pours into the ocean on the other. In this manner is the sea carried with an unceasing circulation round the globe, and at the same time that its waters are pushed backward and forward with the tide; they have thus a progressive current to the west, which, though less observable, is not the less real. {19} CHAPTER II. THE ORIGIN OF CURRENTS THEIR VARIATION, EFFECTS, AND VELOCITY CONSIDERED. ANOTHER impulse communicated to the waters of the ocean arises from its currents. These are caused by the winds blowing for many months in one direction, which produce on an expansive ocean movements of considerable magnitude: this may be easily conceived when we observe the effects produced on our own seas by the temporary action of the same cause.