Popular Science Monti dy 



755 



by the explosion. The pressure exerted by 

 the most powerful high explosives has been 

 estimated to be about 500,000 pounds to 

 the square inch. Consequently, were the 

 whole molten interior of the earth to be 

 replaced with dynamite and detonated, the 

 explosion that would follow would not lift 

 the earth's crust. The superincumbent 

 weight of the earth's crust is greater than 

 would be the pressure exerted by the 

 dynamite. 



When one of our big twelve-inch cannon 

 is fired, the projectile, weighing a thousand 

 pounds, has a muzzle energy, stated in 

 mechanical terms, of about fifty thousand 

 feet tons; that is to say, its energy is equal 

 to fifty thousand tons falling from a height 

 of one foot — energy enough to lift two 

 25, 000- ton battleships to the height of one 

 foot. 



Waters Which Exert a Pressure as 

 Great as Dynamite 



, Mother Earth is 



the greatest of all 

 explosive manufac- 

 turers. Water seep- 

 ing down into the 

 earth's crust and 

 trapped in large 

 quantities in the 

 neighborhood of 

 volcanoes some- 

 times becomes 

 heated to high in- 

 candescence — 

 heated until it is 

 no longer w'ater or 

 steam, but mingled 

 oxygen and hydro- 

 gen, far above the 

 temperature of 

 their dissociation — 

 under a pressure 

 so great that they 

 occupy a space no 

 larger than did 

 the original ,-^^t^ 

 water; 



consequently the entrapped waters exert a 

 pressure as great as the strongest dynamite. 



The most notable volcanic explosion that 

 ever occurred in historic time was when 

 that old extinct volcano, Krakatoa, in the 

 straits of Sunda, that had been sleeping 

 for thousands of years, was literally blown 

 into the sky by the pressure of the pent-up 

 gases beneath it. 



This great eruption occurred in 1883. 

 More than sixty thousand persons were 

 killed. The captain of a tramp steamer 

 saw a very strange disturbance in the sea, 

 in the direction of the old mountain. 

 Taking his glass he saw a perfect Niagara 

 of water pouring into an enormous fissure 

 that had opened in the earth. He was 

 struck with consternation, and rightly 

 imagining that something ver>' serious was 

 likely soon to happen he put on all steam 

 to escape, and luckily he had reached a 

 point which enabled him to survive the 

 effects of the awful blast when it came. 



The Fissure Which Swallowed a Niagara 



The vast mass of water which had 

 tumbled into the bowels of the earth was 

 immediately trapped by the closing of the 

 great fissure down which it had poured.; 

 The water was quickly converted by the 

 intense heat into a veritable high explosive, 

 with the result that the massive mountain 

 was literally blown bodily skyward, and 

 fell in huge fragments into the surrounding 

 sea. The shock was so great that it was 

 felt clear through the earth, and an immense 

 tidal wave was set going which encircled 

 the earth. The opposing portions of the 

 great wave, meeting in the lower Atlantic, 

 flowed up even to the coast of France. An 

 atmospheric wave passed around the earth 

 three times. The amount of volcanic mud 

 that was discharged from the mountain 

 during the eruption was more than the 

 muddy Mississippi discharges into the Gulf 

 of Mexico in two hundred years. 



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Sixty twelve-inch naval guns, loaded with several hundred pounds of explosive each, could 

 be fired by electricity one after the other while grandfather's clock is making one tick 



