548 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



cule of vapor was many thousand times that of an atom of ether. 

 Magnus shows this remark is only true in regard to fog or foggy 

 vapor. By means of his very delicate thermo-multiplier he found 

 the heat radiated by certain gases and vapors, at about 230° C, 

 which is proportional to their absor})tive power, to be as follows: 



Dry atmospheric air, 3 m. m. 



Air after passing through water 3 to 5, m. m. 



Air after passing through boiling water. 20 M. m (the maximum). 

 Air through water boiling so strongly 

 as to produce visible fog at the radi- 

 ating point 100 M. M. 



This was the result of a gradual increase of heat. Eadiation of 

 carbonic anhydride (garet), from 100 to 120 m. m. Common illu- 

 minatinjj gas about the same. 



Mr. Norman Wiard exhibited and explained the action of the 

 Prussian needle gun, Spencer's repeating gun, and Sharpens 

 breech-loader ; after which he presented the following paper : 



Breech Loaders and the Prussian Needle Gun. 



At the beginning of the late war, the highest position in our 

 ordnance department was occupied by an officer who believed 

 and asserted, " that a Harper's Ferry model smooth-bore musket, 

 with buck and ball,- was the best arm and ammunition for infantr3^" 

 He considered the Springfield rifle an innovation, ^nd expected 

 the experience of a war would condemn it. While such views 

 were extant, in the department charged with procuring arms for 

 troops, it was, of course, impossible to introduce any improve- 

 ments; and the policy thus inaugurated prevailed nearly through- 

 out the Avar — during which time, however, a large number of 

 breech-loading arms were invented and offered to the government. 



Ofiicers, in command of troops in the field, noticing that muz- 

 zle-loading muskets were disabled after about twenty rounds, 

 because they would become so foul that the next cartridge could 

 not be got down, united with the inventors :u laying the question 

 before President Lincoln, who attempted, by giving an order to 

 the ordnance department, to have the troops supplied with breech- 

 loaders; but was deterred when shown that no such arms were on 

 hand, and that a sufficient number could not be procured withiu 

 a reasonable time. In the meantime the ordnance department 

 continued to urge the manufacture and purchase of muzzle- 

 loaders. 



