PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 485 



Mr. Rowcll. — Oh, no, not impossible. 



Mr. Dibben. — Yes sir, impossible. 



Mr. Geo. Bartlett. — General Rosecrans, one of our most successful gen- 

 erals, tried various experiments in order to produce a lamp that would 

 burn without a chimney, and he was not successful; he had to use a chim- 

 ney some two inches high. 



The regular subject for the evening, "Harbor Defence," Avas then 

 taken up. 



Mr. Geo. Bartlett. — When the question of harbor defence was agi- 

 tated, some months since, there were various plans presented to the 

 city; the most prominent of these was that of Commodore Yanderbilt, 

 which consisted of sinking rafts at the narrow channels in the lower bay; 

 the rafts were to be bolted together in a peculiar manner, so that they 

 would have to be removed one by one, and sunk at the most narrow en- 

 trances; this plan met with much favor at the time. 



The Chairman. — It was known that the governor had purchased a large 

 quantity of timber for this purpose, and this no doubt was a very good 

 plan for an emergency. 



Mr. Geo. Bartlett. — I perceive that thej'^ are putting small cannon into the 

 forts in the lower hixj, while the experience of the past does not warrant 

 the use of small caliber; their introduction in such places seems strange; 

 the affair at New Orleans has fully demonstrated that small guns are use- 

 less in stopping even wooden vessels, and they are therefore of very little 

 use in harbor defence; those I have seen are from 42 to 64-pounders. 



Mr. Dibben. — The plan of Commodore Vanderbilt is a very practicable 

 one as far as it goes; the sinking of bulkheads at the Narrows, with float- 

 ing gates to be placed at narrow openings for the passage of small vessels, 

 will answer very well; the rafts should be sunk so as not to be seen at 

 low water; this will answer very well in keeping the enemy from coming 

 up to the city by water, but at the same time we are blockading our own 

 ports, and in that case we are half starved; this blockading the harbor is 

 simply to put ourselves on short allowance. These rafts will have to be 

 made very strong and fastened securely, so that they will stand the cur- 

 rent, but it can be done. There is in the St. Lawrence river bulklieads 

 similar to those proposed, and they stand the current of seven miles an 

 hour very well, even in the depth of winter. But this plan protects only 

 particular points, while others equally accessible are open to the enemy; 

 a hostile arm}' can land at the south side of Long Island and cross by land 

 to the city; there are very good harbors in the lower bay, where a navy 

 could anchor in safety. We have, therefore, Long Island and New Jersey 

 to put in thorough defence, which would require time and a vast outlay. 

 The best defence of the harbor, and which would overcome most of these 

 difficulties, would be the construction of a ram, of great speed and strength; 

 but a million and a half is not enough; this sum would go but a short way 

 in building forts and mounting them with guns; how much more so then 

 should rams cost, that answer the double purpose of a fort and a ram — a 

 floating battery? a million of dollars is not enough, or near enough; if a 

 ram was built to cost two and a half million dollars, that would have a 

 speed of 25 miles an hour, it would sink the best navy in the world, and 



