PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 517 



engineer was greater than the Almighty and the General together. But that 

 exploit finished the services of that engineer with Uncle Sam; he could not 

 get any further employment in the service after that. Uncle Sam is always 

 very considerate; he never undertakes any enterprise, without giving his 

 enemy due notice, and he seems unwilling to undertake any movements 

 until the advantages at least seem to be balanced on both sides. 



Mr. Meissner. — I have made experiments in Washington with India rub- 

 ber, and have seen a ball go through tlnck plates and thin ones. There 

 was no trouble in piercing the India rubber one inch thick; we tried the 

 pure rubber, and had it mixed with cloth. I had twelve balls pass through 

 my target. 



Mr. Bartlett. — I would like to know if there is any engineer's report of 

 the doings of the Essex, and at what angle she was fired at ? I have not 

 the least doubt but that the inch plates of iron, and India rubber, can be 

 easily penetrated. 



Mr. Dibben. — From the position of the works which the Essex had to 

 operate against, I am of the opinion that any one of the monitors would 

 have stood more than six vessels of the Essex pattern. There is no diffi- 

 culty in firing a ball through an inch of iron at an angle of forty-five 

 degrees; the angle makes very little difference, unless there is a low velo- 

 city. These exploits of the Essex were confined to very poor forts; but at 

 Charleston they had everything prepared, and they had the best English 

 guns, which were served with precision and vigor. These guns were 

 obtained through the blockade runners; and some of the guns taken from 

 vessels trying to run the blockade and sent to this city, on the ends being 

 cut off to make breech loaders, showed them to be of a very fine quality, 

 and the ends looked like silver. 



Dr. Stevens. — All our gunboats are only an experiment, and the Essex 

 was poorly adapted for one; she was nothing but a ferry boat run across 

 the Mississippi, and built out west; she had to be put in fighting trim in 

 a short time; she was under the batteries at Vicksburg for six hours; she 

 destroyed several batteries below Vicksburg, and some of the shots received 

 by the Essex were point blank. I think she has done more execution than 

 all the others. 



The Chairman. — It will be remembered that at Charleston our vessels 

 had to stand the fire of five different forts at the same time, and at very 

 short range. As to India rubber, it should be recollected that it is incom- 

 pressible; that is, its atoms merely change their position by compression. 



Dr. Parmelee. — I should like to ask Mr. Meissner if the India rubber closed 

 up after the ball passed through it ? 



Mr. Meissner. — The shot made a large hole in the rubber, which imme- 

 diately closed up again. 



"The Manufacture of Sugar at the North," was selected as the subject 

 for discussion at the next meeting. 



Adjourned. John W. Chambers, Secretary pro tern. 



