782 Tkaxsactions of the American Institute. 



of the hole has not been ascertained. These curious results led 

 Melsen to try the experiment of shooting through a pane of glass. 

 He ascertained that contrary to the general belief, a very high velo- 

 city of the ball, as well as a very low velocity, shattered the glass, 

 while a medium velocity made a smooth, round hole. 



FIRING THROUGH GLASS. ^ 



An animated discussion arose in relation to the last item. Dr.\ 

 Vanderweyde said he believed that too great a velocity is apt to 

 break the glass. He had seen the experiments of firing through 

 glass often tried, and they have generally failed. A ball fired at 

 a speed greater than eleven hundred feet a second, would have a 

 vacuum behind it. He had a pane of glass in which a conical hole 

 was cut clean thi'ough it by a piece of slate blown from the roof of 

 this Institute during a gale of wind. 



Dr. Warren Rowell stated that, in his boyhood, he had thrown 

 marbles through panes of glass, making holes a little larger than 

 the marbles. 



]VIr. G. Harding remarked that, at the second Bull Run battle, a 

 ball passed through his shelter tent, and then through a pane of 

 glass, without shattering the glass. 



Dr. Edwards said he had seen a clean hole made in a pane of glass 

 by a canister shot, during the riots in this city. But it should be 

 remembered that it is only a peculiar kind of glass that will do 

 this. The temperature of the atmosphere at the time of the experi- 

 ment is also an important consideration. 



Dr. L. Feuchtwano;er stated that while in a Hudson river rail* 

 road car, a pebble was thrown through a pane of glass, making a 

 round hole, and then striking him in the eye. 



Dr. Vanderweyde related a similar incident occurring on the 

 Philadelphia railroad — the stone being thrown clean through the 

 glass, and then striking a mirror and shattering it. 



Dr. L. Bradley remarked that the cutting through a pane of 

 glass by a ball, might be due to the high velocity of the ball push- 

 ing the air before it. 



Dr. Vanderweyde read an article, translated b}- himself from the 

 German, on " Filtering Sirups." 



ABBREVIATIONS IN WRITING. 

 Mr. S. "W. Powell explained his method of abbreviations in 

 writing, together with his own improvements and additions. It is 

 not a system of phonography, but a more or less limited series of 



