552 TRANSACTIONS OF THE AMERICAN INSTITTUE. 



64. Capt. Blakely says of this accident: " x\.t this round the four bolts 

 gave way — the four united being equal to a solid bar the size of the bore. 

 The rest of the gun was uninjured. * * * I had this gun re-made with 

 four bolts of the best charcoal iron, but they, too, broke without injury to 

 the tubular part." — Paper read by Capt. Blakely be/ore the United Service 

 Institxdion, England; vol. Ill, Journal. 



65. There is no way to account for this, except by the extension of the 

 length of that part of the gun sustained by* the bolts, by heat; if the 

 pressure of tlie powder had broken the bolts, the whole breech would have 

 been shot away. It is satisfactory to us in this manner to learn that in 

 England they do not know the cause of the failure of guns; we may thus 

 now far excel them, if we utilize the knowledge we have. 



66. The inner tube of the Whitworth gun shown in General Gilmore's 

 report, increased in length one inch (shown marked a b on cut 9), by the 

 heat communicated to it,, and closed the vent. If the bands had been 

 fastened by screw-threads, as recommended by Prof. Treadwell and hj 

 General Gilmore, the bands would have parted transversely, as did the 

 bolts of the Blakely gun. 



67. Tliere are two views of this gun in General Gilmore's book, a slight 

 mark on the reinforce would lead tis to suppose the reinforce had been 

 cracked transversely. It is strange that the other view should be one of 

 the opposite side of the gun, and that nothing should be said of the crack. 



68. A three hundred pounder Armstrong gun, in which the breech piece 

 was inserted by screw threads within the principal reinforce band abutting 

 against the inner tube of steel, was burst by the lengthwise expansion of 

 the inner tube, pushing out the whole breech, breaking the reinforce band 

 transvertely (cut number 10.) Compare this example with the Whitworth 

 gun shown in General Gilmore's report, and with those Parrotts thai have 

 failed at the breech (see cut eleven), and see the analogy. 



69. An Armstrong gun, a banded tube, failed by the breaking of the 

 outside band. If the pressure of the powder had broken it the parts would 

 have been thrown off" with projectile force. (See cuts 12 and 13.) 



70. Here we have five guns, exhibiting the effect of the expansion of 

 the inner metal of guns by heat of the powder to the extent of rupturing 

 them, and the most astute of our ordnance officers will find it difficult to 

 account for the result in any other manner. 



71. In the face of these well attested principles, so thoroughly known 

 to practical founders, the Ordnance Bureau act on the erroneous idea that 

 guns burst from the explosive force of the gases only, and give their atten- 

 tion in the fabrication to counteracting this supposed difficulty; hence the 

 further they proceed in this direction, the wider they are from the mark. 



72. They do not seem to know that the heat engendered from the burning 

 gases of gunpowder has any effect upon the gun. 



73. No little amount of surprise is expressed by inexpert persons that 

 the acknowledged difficulty of making large guns is not overcome by using 

 strong materials, as, for instance, wrought-iron or steel in the place of 

 cast-iron. Ordnance officers excuse this discrepancy on the plea of the 

 imposibility of perfectly welding large masses, and no other reason is given, 

 and often speak of the " mysterious force" of gunpowder. Professor Tread- 



