343 
instructions contained in his ‘ Treatise on Artillery’ (Trans. R.I. A.) could 
scarcely fail to make a barrel like that of the Armstrong gun.” I will 
_ add that the peculiarities in the mounting or equipment of those guns 
7 
for field service, by which the recoil is absorbed by elastic resistance, in 
place of dead weight in the gun, &c., are clearly described in Note T, and 
elsewhere in that paper. 
The Academy will, therefore, recognise that the rights of priority 
in principles and methods, the applications of which are now changing 
the artillery and armaments of the world, offer a temptation to plagia- 
rism proportionate to the magnitude of the results arising from them ; 
and they will, I trust, excuse the length at which, in consequence of 
Captain Blakely’s first paper, read here 14th May (which, without once 
asserting boldly his own priority, left it to be inferred hereafter, and as- 
sumed it tacitly throughout), I have been compelled to assert the prin- 
ciple of “suum cuique.” 
While I assert my own rights in this matter, however, I will not 
follow Captain Blakeley in ignoring those of others. Asrespects himself, 
I have always admitted that I believed him an independent second in-- 
ventor and discoverer, and that he deserved whatever merit or rights 
such can carry. He has, however, studiously and at all times avoided 
reference to the claims of M. Thiéry, to whom I believe justly belongs 
the merit of having been the first person in point of date who proposed 
the ringed structure with initial tension, and pointed out its advantages 
in increasing the strength of artillery, in wordsthat show that he possessed 
a general notion of the principles upon which such increment of strength 
depends. In his work, entitled, ‘‘ Applications du fer aux Constructions 
de l Artillerie, par A. Thiéry, Capitaime d’Artillerie,” published at Pa- 
ris, by D’Anselin, 4to, in 1834, he has in chap. ix. p. 153, et seq., 
headed ‘‘ Canons en fonte avec enveloppe en fer forgé,”’ distinctly described 
and figured in a large lithographed plate, the application of external 
rings of wrought-iron shrunk on hot upon a cast-iron tube, to form a 
built-up gun. 
Any one who reads his pages, 155 and 156, of this chapter (in which 
he discusses the causes of the failure of certain guns, which it appears 
had been already tried in France, formed of a cast-iron barrel, round 
which the bronze envelope was cast in a fluid state, and traces it to the 
fact that the cast-iron, thus becoming heated and expanded in the cast- 
ing, was left (when the gun was completed and cold) without any initial 
tension upon it, will see that Thiéry clearly recognised this principle, 
and he puts it beyond doubt in the following passage:— 
““ Le moyen qu soffre naturellement prenuere, pour fretter un canon 
de fonte, en fer forge, serait de le recouvrir d'une série de cercles super- 
posés a chaud; les uns a coté des autres, et qui adhéreraient ainsi a cette 
bouche a feu de toute la force du restrait; force qui peut devenir excessive 
en portant a un tres haut degré la temperature du cercle en fer forge”? 
(p. 156). In fact, as respects the method and knowledge of the prin- 
ciple of ringed construction, Thiéry’s publication of 1834 embraces 
R. I, A. PROC.—VOL. VII. 3c 
