PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 



399 



upper side, and a peculiar swing gate, swinging opposite to the usual 

 direction, is employed much outside of the usual one on the lower side. 

 The total addition to the length is some 50 per cent., and gained at a small 

 cost. The present practical length, i. e., the length of boat passed, is but 

 97 feet with the present locks; the length to be passed with the new gates 

 at both ends is intended to be 150 feet and some inches. 



The cost of fitting one lock with these devices would be, as estimated, 

 'about 2,500 dollars. The cost of enlarging a lock to an equal extent, byi 

 masonry, would be about ten times that amount. 



The regular subject of the evening, " Modern Improvements in Warfare," 

 being called by the Chairman, 



The Secretary introduced to the meeting Mr. Norman Wiard, widely 

 known as a successful inventor, experimenter, discoverer and manufacturer 

 of ordnance, and as the author of a series of improvements which had been 

 submitted to the attention of the government, and which he was now pre- 

 pared to place before this Association. Mr. Wiard was distinguished for 

 presenting or elaborating in drawing to thd minutest details his various 

 inventions, while many are satisfied with presenting their schemes in 

 • general and crude outline. This difference in method in every light is very 

 obvious, and it both enables and entitles Mr. Wiard's statements and sug- 

 gestions to receive careful consideration. 



Great Guns. 



Mr. Norman Wiard. — It is. a matter of public concern, that although 

 much time, money and ingenuity have been expended in eflbrts to produce 

 safe and effective ordnance of large calibers, no large gun has ever been 

 designed or made that could be pronounced entirely trustworthy, even after 

 it had been subjected to the usual test of firing, a process exposing the gnu 

 to destruction and imperiling the lives of the gunners and inspectors; for 

 after enduring any prescribed number of trial charges, there is no certainty 

 that the gun will not burst at the next round. Numerous examples could 

 be quoted to show that large guns have burst with a small charge after 

 having withstood a succession of heavy charges. 



Cast iron guns, with a tensile strength of 16,000 lbs. to the square 

 inch, have exhibited greater endurance than others of the same size and 

 model having a tensile strength of 38,000 lbs. 



Experts have found themselves unable to account for the fact that a 

 large steel gun, with a tensile strength of 120,000 lbs. to the square inch, 

 exhibited less endurance than a cast iron gun with a tensile strength of 

 but 30,000 lbs., or that the strongest metal does not make the strongest 

 gun. 



By examining the fragments of guns of ordinary forms which have been 

 burst, it will be observed that they burst in three ways: 



First. They split through the cascabel and re-enforce longitudinally to a 



point forward of the trunnions, 

 and from thence the fracture di- 

 verges to either side, leaving the 

 chase and muzzle unbroken. Some- 

 times cross fractures through 



-Tfr-S, 



