RECENT EXPERIMENTS ON FOG-SIGNALS. 279 



gunpowder, had slight advantage over 1 pound of gun-cotton detonated 

 in the open ; while the 12-pound howitzer and the 18-pounder were both 

 beaten by the gun-cotton. On the 2d of May, on the other hand, the 

 gun-cotton is reported as having been beaten by all the guns. 



Meanwhile, the parabolic muzzle gun (Fig. 3), expressly intended for 

 fog-signaling, was pushed rapidly forward, and on the 22d and 23d of 

 March, 1876, its power was tested at Shoeburyness. Pitted against it 

 were a 16-pounder, a 5|-inch howitzer, Impound of gun-cotton deto- 

 nated in the focus of a reflector, and 1^ pound of gun-cotton detonated 





Fig. 3. Gun-Cotton Slab (lj- lb) detonated in the Focus of a Cast-ieon Keflector. 



in free air. On this occasion, nineteen different series of experiments 

 were made, when the new experimental gun, firing a 3-pound 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 found to be the same. Fired in the focus of 

 the reflector, the gun-cotton clearly dominated over all the other sound- 

 producers. 1 



The whole of the observations here referred to were embraced by an 

 angle of about 70, of which 50 lay on the one side and 20 on the other 

 side of the line of fire. The shots were heard by eleven observers on 

 board the Galatea, which took up positions varying from 2 miles to 13^- 

 miles from the firing-point. In all these observations, the reenforcing 

 action of the reflector, and of the parabolic muzzle of the gun, came into 



1 In this case the reflector was fractured by the explosion, but it did good service after 

 fracture. 



