82 On the Tides. 



appears to be contradicted by strong evidence. That the Gulf 

 stream gives the pecuhar character to the tides on the coast of 

 North America, appears certain. Where it leaves the Gulf of 

 Mexico, the rise and fall of the tides is said to be two or three 

 feet only. The tides increase with that current to the east, till 

 it rises more than twenty-five feet m Nova Scotia and Newfound- 

 land ; where that wave is wafted across the ocean to the Irish 

 and British channels, and the Bay of Biscay, of about a similar 

 height. But at St. Ubes it rises only one to two feet, and in the 

 Mediterranean sea there is no rise and fall of tides. 



If the moon were the sole cause of the rise of tides, why is it 

 not more evident in the south Atlantic, West Indies, and coast of 

 South America, where her influence ought to be the greatest, in 

 the greatest expanse of ocean ? And yet the tides there are so 

 so small they are scarcely noticed. 



It is said that the Gulf stream is caused by the effect of the 

 trade wind on the Caribbean sea, by pressing the water westward, 

 and causes the outlet at the Gulf of Mexico. That may produce 

 some eff"ect ; but can it be the sole cause of the Gulf stream ? 

 Although that stream may be swayed from its course (like a cable 

 in a stream) both north and south, by long and violent winds, 

 (as has been seen,) yet it resumes its wonted place and preserves 

 its regular course so exactly, that in approaching it in fair and 

 moderate weather in day light, by ascending the shrouds of a 

 vessel, it may be seen at a great distance, and when passing it, 

 the edge of the stream may be discerned as plainly as land from 

 water. It appears as blue as indigo, while the adjoining water is 

 of the usual green hue. The division is so exact, that it may be 

 noticed as plainly as the crack between the planks in a house 

 floor ; and yet, if you dip a bucket of water from the stream, it is 

 of similar clear and white appearance as the common ocean or 

 other water, but warmer. Why does the ocean always run swiftly 

 into the Mediterranean sea, as do the immense Danube, Nile, and 

 other large rivers ? No doubt to keep up the subterranean stream 

 which passes out of the Bay of Mexico, called the Gulf stream. 

 This sustains the usual circulation and its warm temperature and 

 throws off" an immense evaporation, as it runs towards the colder 

 region, where it is condensed to furnish materials for watering 

 the Atlantic coasts by frequent rains, without which, they would 

 be rare, and the land parched by drought. 



