278 FRAGMENTS OF SCIENCE 



Meanwhile, the parabolic-muzzle gun, expressly in- 

 tended for fog-signalling, was pushed rapidly forward, 

 and on March 22 and 23, 1876, its power was tested at 

 Shoeburyness. Pitted against it were a 16-pounder, a 

 6^-inch howitzer, 1% Ib. of gun-cotton detonated in the 

 focus of a reflector (see annexed figure), and 1% Ib. of 

 gun-cotton detonated in free air. On this occasion nine- 



-> 



Fie. 8. Gun-cotton Slab (1^ Ib.) Detonated in the Focus of a Cast-iron Reflector 



teen different series of experiments were made, when the 

 new experimental gun, firing a 3-lb. charge, demonstrated 

 its superiority over all guns previously employed to fire 

 the same charge. As regards the comparative merits of 

 the gun-cotton fired in the open, and the gunpowder fired 

 from the new gun, the mean values of their sounds were 

 the same. Fired in the focus of the reflector, the gun- 



