HIGH EXPLOSIVES. 501 



explosive as Maximite has an enormous advantage over explosives 

 heretofore in use. 



CURIOUS PROPERTIES OF MAXIMITE. 



Maximite cannot be exploded by ignition. If a store-house filled 

 •with this material were set on fire, there would he no danger of ex- 

 plosion. Melted cast iron may be poured upon a mass of Maximite with- 

 out the least danger of exploding it. When heated, it melts, and if the 

 heating be continued, it will evaporate like water, without producing an 

 explosion. Lyddite, the high explosive adopted by the British Govern- 

 ment, is said to be simply picric acid. This substance is melted for fill- 

 ing the shells, which are preliminarily heated to about the fusion point 

 of the material to prevent too rapid setting. The melting point of 

 picric acid is 122° C. The melting point of pure Maximite is exactly 

 one-half of that of picric acid. That is to say, it is 01° C. The low 

 melting point of Maximite enables it to be fused over the ordinary 

 water bath, but owing to the impossibility of exploding it by heat, 

 the water bath is not used, for it may be melted over an open fire in the 

 same manner that asphalt is melted in the street cauldrons, and with 

 equal safety. It is not necessary to heat the shells beforehand when 

 filling them with Maximite. 



On the other hand, great care has to be taken in the fusion of 

 picric acid, because, if it becomes ignited in quantity before fusion, 

 while in granular form, it will detonate, and also if it be heated very 

 much above the fusion point, it will detonate. 



The high fusion point of picric acid renders it necessary to em- 

 ploy a special lining material for protecting the shells against the 

 erosive effect of the acid, while Maximite has very much less erosive 

 action upon metals, and owing to its low fusion point an ordinary coat- 

 ing of shellac or similar sid)stanee is all that is necessary to protect the 

 shells. 



It has been found from the experiments made by the Government 

 that, although a high explosive may be so sensitive as to safely with 1 

 stand the shock of acceleration in the gun. it may still be dangerous to 

 fire, owing to the rapid rotation given to the projectile by the rifling of 

 the gun, which is a rate of about 7,000 turns a minute. As a result, the 

 projectile revolves upon the explosive before the latter has time 

 fully to participate in its rotation. The great heat generated by this 

 friction is apt to set fire to the explosive, causing a detonation. 



Maximite requires so little heating for fusion that there is but 

 slight contraction of the molten substance in reaching the point of 

 solidification or freezing point. Maximite, furthermore, possesses the 

 peculiar quality of expanding on solidifying, in the same way that 

 Mater does on freezing. This causes it to set very firmly upon, and to 



