PROCEEDINGS OP THE POLYTECHNIC ASSOCIATION. 451 



ment with the Acquia Creek batteries, in which the United States steamer 

 Pawnee participated, a small rifle gun was used on board that vessel, 

 which is probably the first instance where rifled ordnance was used by the 

 forces of the United States against an enemy. The thirty-pounder Parrot 

 gun was probably first used at the first battle of Bull Run. During the 

 summer of 1861 a number of eighty-pounder rifles were manufactured at 

 the Washington Navy Yard on tlie plan and under the superintendence of 

 Admiral Dahlgren. The one-hundred-pounder Parrot gun was first used at 

 the siege of Yorktown and on board the steamer Westfield in the opera- 

 tions of Admiral Farragut on the Mississippi river. Heavy rifled guns 

 were mounted and used in Fort Pickens during the two bombardments of 

 the rebel positions at Forts McRae and Barrancas, and Pensacola Navy 

 Yard. Since then they have come into general use both afloat and ashore, 

 and have been increased in size from the light field gun, throwing a projec- 

 tile of ten pounds in weight, to the enormous " Swamp Angel" now in bat- 

 tery on Morris Island, which sends a bolt weighing three hundred pounds 

 to a distance of ten thousand five hundred and sixty yards, or six miles. 



Thus it will be seen that in the short space of thirty-one months an en- 

 tire revolution has taken place in the character of ordnance used both in 

 naval and military operations; and where, in 1861, high authority stated that 

 a bombardment of Charleston from Fort Sumter was an impossibility, now 

 is it not only possible, but we can with case, at a distance far greater, not 

 only destroy Charleston, but compel the enemy to abandon any position he 

 may take a mile beyond it. Indeed, a trial was recently made of a new 

 piece of ordnance called the Ferris gun, and the report states that a range 

 of nine miles was obtained. If this is the case an enemy's ship luill be xoilhin 

 range before her hull is in sight above the horizon; for, on account of the cur- 

 vature of the earth, the hull of one ship does not come in sight of a person 

 on the deck of another, until within a distance of seven miles. 



Such is the range being obtained, that we may expect in a little while 

 to be bombarded successfully by guns entirely removed from sight and out 

 of hearing; enabling us to obtain a knowledge of the enemy's position only 

 from the direction in which the projectiles come. Verily, we live in a won- 

 derful agel 



Ocean Navigation. 



Mr. Benjamin Garvey. — Mr. Chairman, the subject of ocean navigation 

 is one that is attracting considerable public attention, it is one that is par- 

 ticularly interesting to us from the fact that our commerce is seriously 

 threatened, and may eventually be driven from the sea, if immediate steps 

 are not taken to remedy existing defects. This nation will not permit its 

 commerce to be run down with impunity. To enable us to maintain our 

 maritime position it is necessary that we should have vessels of greater 

 speed than those now in use, and at the same time by having iron sides, be 

 capable of standing battering for hours. That is what we want, monitors 

 that can be depended on for speed the moment it is wanted. What is to 

 be avoided as much as possible is what is termed pneumatic resistance. 

 When a vessel moves through the water the pressure on its sides forms 

 part of the resistance to be overcome; to partly obviate this our American 



