then highly explosive, and may be used in that state; but, to increase its explosive power, it is dipped in a weak solution of nitrate of potash, and, lastly, dried in a room heated by hot air, or steam, to about one hundred and fifty degrees Fahrenheit. The advantages and disadvantages of this substance have thus been stated by professor Brande:--“The disadvantages are, that the effects are less regular than those of gunpowder; that it is more dangerous, because inflaming at a lower temperature; that it does not take fire when compressed in tubes; that it burns slowly in all kinds of cartridges; that guns and pistols must be altered to admit of its use; that it is not adapted for the use of the army; that the barrel of the gun is moistened by the water produced during combustion. The advantages, on the other hand, may be stated as follows:--Its extreme cleanliness, leaving no residue after combustion; its freedom from all bad smell; the facility and the safety of its preparation; the possessing treble the force of gunpowder; its explosion producing no smoke, and less noise than that of gunpowder; its filamentary nature admitting of its being used over head in mining operations; its not being liable (as a granulated substance is) to the accidents of leakage; its occasioning very little recoil.”--Every benevolent mind must wish to hear no more of “the confused noise of battle and of garments rolled in blood;” and that the time may soon arrive when men shall “beat their swords into ploughshares, and their spears into pruning-hooks;” when “they shall learn war no more,” but yield themselves heartily and devotedly to the benignant sway of the Prince of peace. There seems, however, no reason to conclude that gun-cotton will be employed for any hostile purpose, the Board of Ordnance having definitely decided against its adoption in the military and naval services. The principal objection to it is, the very low temperature at which it explodes. The mere heating of a gun, from a number of charges successively fired, has been proved sufficient to cause an instant explosion of gun-cotton.