100 Prof. Treadwell’s Improvements in Cannon. 
made his own in 1855,—he being, as we must suppose, ignorant 
of what Mr. Treadwell had done thirteen years before. T 
statement of Mr. Anderson (witness before the Commons’ Select 
Committee), made before the Institute of Civil Engineers im 
1860, is equally explicit as to the nature and value of this method 
of constructing cannon. And, finally, the high estimate of its 
importance abroad is shown not only by the honors and emolu- 
ments conferred by the British government on the re-inventor, 
but still more by the actual adoption of this gun as the most ef 
ficient arm yet produced. For it must be borne in mind that 
the faults or failures, complete or partial, of the Armstrong and 
similar guns, are not of the cannon itself, as originally construct- 
ed, but of breech-loading contrivances, of the lead coating of the 
projectile, or of other subsidiary matters. oa 
That our colleague’s original invention, the value of which is — 
now so clearly established, should have been so generally un- 
acknowledged by inventors abroad is his misfortune, not his fault. 
For, not only were his guns made and tested here, and their 
strength as clearly demonstrated before 1845 as they have been 
since, not only was a full account of the process and of the re- 
sults published here in that year, buta French translation of his 
pamphlet was published in Paris, in 1848, by a professor in the 
school of artillery at Vincennes, and Mr. Treadwell’s patent, 
with full specifications, was published in England before Sir 
William Armstrong began his experiments. 
The difficulties to be overcome in making such a gun,—great 
at all times, as Sir William Armstrong and Mr. Anderson testify, 
—were far greater in 1842 than in 1863. These difficulties were 
mainly, if not wholly, in welding large masses of wrought iron 
in the shape of tubes or cylinders. It is for overcoming these 
difficulties that this medal is bestowed, and especially for the 
means and appliances by which this difficult mechanical achieve? 
ment was effected in the furnace “ by the agency of fire.” Bee 
An incidental but noteworthy part of the improvement was 
e com the second improvement in the construction 
of artillery, the invention of the hooped gun. a 
This is not always clearly distinguished, even by those occl- 
pied with the subject, from the gun formed of coiled rings. Bub 
a simple statement will bring into view distinctly the new pri — 
ciple of strength here introduced, eee oe 
If an elastic hollow cylinder be subjected to internal fluid — 
pressure, the successive cylindrical layers of the material com- 
posing it, counting from within outwards, will be unequally dis- 
tended, and the resisting efficiency of the outer layer will be less 
