50 



gun cotton, was not so much heated as after thirty rounds 

 with powder. 



(6.) Gun cotton is perfectly uninjured by moisture, and 

 may be kept wet or stored in water for any length of time. 

 This is a very great advantage over gunpowder, as even 

 when heat is applied to the wet gun cotton it smoulders 

 gradually away as it dries. 



A ton of wet gun cotton has been treated experimentally 

 with the above harmless results. 



(7.) It has been seen that gun cotton fired in an open 

 space burns quickly and quietly away. Even a large disc of 

 compressed gun cotton which I light burns rapidly and 

 evenly away, but the same weight fired in a closed space 

 would produce disastrous effects. Thus so small a quantity 

 of gun cotton as five grains, placed in a soda water bottle, 

 loosely closed by a cork, and fired by a galvanic current, 

 produces a loud explosion and drives the cork out violently. 



Similarly firing twenty grains of dry gun cotton, sealed 

 up in a glass flask and ignited by a galvanic current, a con- 

 siderable explosion is obtained, and on lifting up the wooden 

 safety cage all that remains of the flask is a heap of fine 

 glass dust, showing clearly the force of explosion of even a 

 small quantity of cotton when fired in a closed space. 



The explosion of one cubic inch of gun cotton in a 

 closed space gives by calculation a pressure of log tons on 

 the square inch, as compared with a pressure of 40 tons 

 yielded by powder. In order to obtain the full explosive 

 force of gun cotton, it was in all earlier experiments con- 

 fined in strong cases in order that the flame of the portion 

 first ignited might raise the temperature of the rest to the 

 point of explosion. The discovery by Mr. E. O. Brown, 

 that unconfined gun cotton might be exploded by detona- 

 tion opened a new career to this substance. 



In order to explode the cotton a detonating fuze is 

 placed in its substance in a hole drilled to receive it. This 

 fuze consists of a tube of quill or metal containing fulminate 

 of mercury, on passing a galvanic current through the 



