880 Transactions of the American Institute. 



equivalent to a fulminating powder. It is only the rapidity of the 

 burning which gives the power to dynamite and nitro-glycerine. It 

 is the difference between a push and a sharp blow of the hammer. 

 Some fifteen years ago I advised Prof. Maillefert to use fulminating 

 powders in surface blasting at Hellgate ; but he said gunpowder was 

 dangerous enough, and he was afraid to use anything stronger. How 

 the stronger materials are found much more economical, and are 

 almost universally used. Gunpowder will only blast out near the 

 bottom of the hole which is charged, but dynamite or nitro-glycerine 

 will crush the rock many inches beyond the bore. Prof. Doremus 

 has made gunpowder in a solid mass weighing ten or twenty pounds 

 to tit the bore of the gun. I do not know what was its practical 

 success. 



Mr. P. Weir represented upon the blackboard the Lyman gun and 

 the Bessemer gun. He said the Bessemer gun never was made, never 

 would be made, and never would work if it was made. The powder 

 made by Prof. Doremus' was not really solid, but was of a honeycomb 

 structure. 



Mr. J. K. Fisher — There is a superstition that it is dangerous to 

 lire a gun when the ball is not rammed home. I think it is worth 

 while to try whether leaving a sufficient place, so that there would 

 not be pressure enough to burst the gun, would not produce good 

 results. Gun-cotton, for instance, might be used with an air space. 



Mr. Green — That is out of the question. It upsets the shot and 

 deranges the particles of metal in the gun. If you should have a large 

 chamber of air, there is no material that could resist the blow. Many 

 guns have been burst in that way. 



Dr. P. II. Yan der Weyde — What Mr. Fisher proposes cannot 

 but be injurious. .When the powder commences to ignite it finds the 

 ball at rest, and should immediately act upon it, and commence to 

 set it in motion ; but if the ball is at a little distance a considerable 

 part of the powder ignites before its effect reaches the ball, and then 

 it acts with a blow. 



Mr. J. K. Fisher — I do not see w T hy there should be a blow when 

 there is a cushion of air there to prevent it. 



Mr. Raynor — It is the experience of gunsmiths that when double- 

 barreled sporting guns are sent for repair, in a large proportion of cases 

 the left-hand barrel is burst. The reason appears to be this : It is 

 most natural to discharge the right-hand barrel. The jar starts the' 

 bullet in the left-hand barrel and produces a little space behind it. 

 The right-hand barrel is loaded and fired several times, each time 



