398 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



small howitzers behind. They had then been in nse for a con- 

 siderable time. They were fast sailers, very strong built, and 

 quite small. These gun-boats now to be constructed should be 

 small ; the machinerj^ should be small and entirely under the 

 water. It is a most dangerous thing for a gun-boat to have its 

 machinery injured. Paddle wheels would be exposed ; but the 

 screw being under the water is safe. 



Mr. Montgomery was of the opinion that gun-boats should not 

 be made too light, but should have good sea going qualities and 

 should be able to stand the recoil of the gun. They shotild be 

 prepared for all emergencies and equally adapted to all. It is 

 unnecessary however that the}^ should draw more than seven or 

 eight feet. 



Mr. Garbanati. — I should think it would be better not to build 

 all upon one model. We shall need very few out at sea, but shall 

 want them to advance up rivers, and to go especially into such 

 places as only vessels of light draught can enter. 



Mr. Babcock stated that there were now two guns of very great 

 size at Portress Monroe; one called the "Floyd," of 15 inches 

 bore, made of cast iron; and the other the "Union," the largest 

 rifled gun ever built, being 14 inches in diameter. 



JVew subject. — The subject selected for the next meeting, w^as 

 " Steel guns, and the preparation of the material." 



Adjourned. 



American Institute, Polytechnic Association, 1 



June 27, 1861. \ 

 Prof. Cyrus Mason in the chair. 



self-clearing cartridge cases. 



Mr. Stetson exhibited drawings illustrating two constructions 

 of metallic cartridge cases for ordnance. 



If the cartridge case is made of any kind of cloth, there is a 

 difhcultyof the most serious character arising from the inflamed 

 material remaining in the gun, and prematurely igniting the 

 next charge. A metallic case is, also, a more perfect protection 

 against moisture or accidental injury to the cartridge ; and is, 

 therefore, better than cloth, if it can be made to clear itself 

 from the gun. But the back of the case is apt to stay in the 

 gun. The first new construction was that patented by Mr. 



