PROCEEDINaS OF THE POLYTECHNIC ASSOCIATION. 575 



of the boat, and have them to pass along the sides, where they are con- 

 tinually exposed to cold water. 



Mr. Geo. Bartlett. — We have spent three evenings here lately listening 

 to a discussion on the armor of the gun-boat Essex, that was clad with 

 an inch of India rubber, over which was placed an inch thick iron 

 plate. I see by an official report, that a trial of this plan has lately been 

 made at Washington. The target was formed of two inches of sheet rub- 

 ber, and two inches thick of iron plate, which was backed with seven inches 

 of pine, and placed against a bank of solid clay. The gun was placed 

 seventy-four feet from the target, and the ball from an 11-inch gun fired at 

 it which went through the target and sixteen feet into the bank of clay. 



Ocean Currents. 



The subject for the evening was here taken up. 



Kev. Charles G. Adams, of Manhattanville, read a paper on the origin, 

 extent and operations of the gulf stream, which occupied about an hour. 

 After alluding to the fact that Dr. Franklin first directed attention to the 

 action of the gulf stream, and giving briefly his own and other views as to 

 its origin, he presented an interesting account of the Antarctic current, 

 which moves from the south into the Indian ocean, passes between Mada- 

 gascar and the eastern coast of Africa, doubles the Cape of Good Hope, 

 moves northward along the coast of Guinea, afterwards unites with cur- 

 rents from the north, and moves westward on the equator until it reaches 

 the American continent, where it separates into two streams, one passing 

 southward and the other northward. After receiving the waters of the 

 Amazon and Orinoco, the north stream enters the Gulf of Mexico, and, mak- 

 ing a complete circuit, emerges between the Keys of Florida and Cuba, and 

 again moves northward. The reverend gentleman stated that he had resi- 

 ded for a long time in Florida, and had daily watched the action of the 

 stream, noted its high temperature, and observed the vast deposits thrown 

 up by it. After relating his personal observations, he proceeded to give 

 his theory of the action of ocean currents, which differs widely from the 

 opinions of eminent geologists, in making these currents the principal 

 cause of the formation of islands and continents. His remarks were listen- 

 ed to with respectful attention by many who could not accept his deduc- 

 tions, and at the close he received general applause. 



Mr. Nash followed, giving some geological objections to the theory of the 

 lecturer. Prof Everett and Dr. Parmelee took exception to some chemical 

 statements. Mr. Enos Stevens did not believe the rotation of the earth 

 was the cause of the equatorial currents, and alluded to the demonstra- 

 tions of Laplace upon this subject. 



The Chairman remarked that this association desired facts more than 

 theories. The phenomena relating to ocean currents, presented by the lec- 

 turer, are of very great interest, and in this connection he would allude to 

 the observations of the equatorial current of the Pacific, made by Lieut. 

 Bent, U. S. N., several years since. There is a vast movement of waters 

 extending from the Tropic of Cancer, on the north, to Capricorn, nearly 

 3,000 miles. It sweeps westward until it is split into innumerable streams 



