MECHANICS AND USEFUL ARTS. 101 



ciated, there is no necessary connection between these conditions. 

 In the monitors the deck is as tight us the bottom, and the only 

 openings to the interior are through towers which the waves can- 

 not enter. Such vessels rise well to the sea, and with such towers 

 as those of the "Dictator" can encounter with safety the heaviest 

 waves; the voyages of the "Monadnock" round Cape Horn, and 

 of the " Miantonomoh " across the Atlantic, show their seaworthi- 

 ness. Their reputed want of liveliness is a material advantage in 

 any vessel requiring to take aim with heavy guns, since it must 

 make the aim more sure. 



BEEBE INERTIA FUZE. 



It has long been considered desirable to have a fuze for spheri- 

 cal shot so arranged that the shell should explode at the instant of 

 impact, but hitherto without success. With elongated shells there 

 is no difficulty, as they are almost sure to strike point foremost. 

 With spherical shells, owing to their rotation during their entire 

 flight, it is quite uncertain which part of the shell will strike first ; 

 consequently the fuze cannot be fixed at any given point that will 

 insure its explosion. In a fuze recently invented by Major W. S. 

 Beebe, U. S. A., this difficulty seems to have been overcome. His 

 fuze is not dependent on its arrangement previous to firing, but 

 the explosion of the charge in the gun having released it, on the 

 impact of the shell the inertia of the fuze sets it end on, and thus 

 secures ignition. The fuze being used with a solid screw plug in- 

 creases the force of the explosion of the bursting charge in the 

 shell, and is neither dependent on the flash of the gun for ignition, 

 nor is it liable to extinction from any cause. 



It is very simple, consists of only two parts, can be quickly ad- 

 justed, and" is less expensive than most fuzes now in use. To avoid 

 premature explosion, the great danger in fuzes of this class, it is 

 designed to be carried separately, and is quickly applied when 

 needed. From numerous experiments, it has been ascertained that 

 this fuze ensures explosion of the shell upon impact with earth and 

 ice ; yet it can be used in ricochet firing over water. The success 

 of the 15-inch Rodman gun, and the efficiency of spherical shell in 

 smooth-bore guns, will be greatly increased by this invention, 

 which secures impact explosion, a great advantage hitherto ex- 

 clusively belonging to rifle projectiles. 



STORAGE OF GUNPOWDER. 



The usual construction of powder magazines is with thick walls 

 and a bomb-proof roof, even in forts never intended to resist a 

 siege. The damage caused by the explosion of such a maga- 

 zine would be great in proportion to the mass of its materials and 

 the increased force of the explosion of powder when confined ; the 

 lighter, therefore, the magazines are constructed the better, the 

 lighter materials being less destructive than heavy fragments. 

 The higher magazines are built from the ground the better, the 

 explosion in that case having less effect upon adjoining objects. 

 Whatever be the strength or weight of the sides, the roof should 



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