54 ANNUAL OF SCIENTIFIC DISCOVERT. 



said he thought that a note of interrogation ought to be put to what 

 Mr. Russell had said. 



The subject was considered of so much importance that the Associa- 

 tion not only reappointed the joint committee to continue the inves- 

 tigations, but passed a resolution requesting the government to investi- 

 gate the matter separately. 



Submarine Batteries, or Torpedoes. M. F. Maury, formerly 

 an officer in the United States service, who was present, re- 

 marked in the course of the above discussion, that Mr. Rus- 

 sell's report " was important as affording an element of security by giv- 

 ing the preponderance on the side of defence. Ever since steam had 

 been applied to purposes of naval warfare, it had been considered a 

 matter of very great doubt by many professional men how far ordinary 

 steamers and men-of-war, where forts were to be passed at the mouth 

 of a river, were capable of sustaining the fire of such forts and passing 

 up the river. And to show that there was ample time for them to do 

 so, they had only to recollect the fact of steamers having fought forts 

 for several hours. In the Crimea and at Charleston, the steamers 

 had remained under fire for several hours, a much longer time than 

 was necessary to enable them to pass the forts and go higher up the 

 river into a place of safety, where they could do damage to the enemy. 

 Tron-clads had rendered this much more easy than it had previously 

 been. If, then, their principal defences failed them at the mouth of a 

 river in this way, the question was whether they should not have re- 

 course to mining for the destruction of the invading vessels ? He him- 

 self had been engaged upon the subject. He found this difficulty in em- 

 ploying gunpowder, that in order to be sure of destroying the vessel as 

 she passed in a given line by means of gunpowder, the magazines must 

 be in actual contact, or very nearly in actual contact, with the side of 

 the vessel ; otherwise, the probability was that the vessel would not be 

 destroyed. Recently they had the intelligence of a vessel having had 

 a mine exploded under her on the James River. That magazine con- 

 tained several thousands of pounds of powder. The vessel did not 

 know that the mine was there ; but the mine did not destroy the ves- 

 sel. It merely threw up a column of water, which washed some of the 

 men overboard. His own conclusion was that to make sure of destroy- 

 ing a vessel after she had passed the forts, they must mine the channel 

 in such a manner that the vessel must come in contact with one or other 

 of the mines. It was found that wooden vessels to contain the pow- 

 der would not do. They would not confine the powder long enough to 

 produce a sufficient force. It was necessary to make them of stout 

 boiler-iron. It would not do to leave the magazines on the top of the 

 water, and it would not do to put them at the bottom, for then there 

 would be a cushion of water between the bottom of the ship to be de- 

 stroyed v and the magazine, which would protect the vessel. In short, 

 they had to anchor them beneath the surface with short buoy-ropes, 

 at a depth proportioned to the kind of vessel expected to come up. 

 But when they made the magazine of boiler-iron, they had to have 

 buoys to float it so large that they were always in danger of being 

 carried away by the vessels crossing the line of magazine. The plan 

 was to place those magazines in a ring in such a position that the ves- 

 sel in passing would have to come in contact with at least one and 



