323 
Blakely’s diagrams, in which it is shown that the removal of some of 
the inner rings would add largely to the total strength ; it is to be ob- 
served, however, that this removal of inner rings would also add ina 
still higher ratio to the interior diameter, and that the pressure which is 
proportional to this diameter would be increased more than the strength; 
but if the space now occupied by these inner rings was accurately filled 
by longitudinal bars or voussoirs analogous to Mr. Mallet’s blocks, the 
inner diameter would be restored to its former magnitude, while the in- 
creased strength resulting from equalization of tension would be retained. 
Robert Mallet, C.E., F.R.S., made some remarks on Major Blakely’s 
paper.* 
CAPTAIN BLAKELY’S REPLY.} 
Mr. Cuarrman,—I regret that the time of the Academy has been 
taken up this evening in hearing a discussion on a question which must 
be quite without interest for it,—that of the priority of discovery by Dr. 
Hart or myself of the method now almost universally adopted for mak- 
ing cannon. About three years ago, to the best of my recollection, I first 
heard of Dr. Hart’s investigation; and, although two years had then 
elapsed since my actually making several cannons on the system in ques- 
tion, and the mortars made by Mr. Mallet on Dr. Hart’s suggestions had 
not even then been fired, yet, hearing it stated that Dr. Hart had pro-. 
posed the system before I did, I wrote to ask him whether this was or 
not so. I mentioned to him when I had discovered the thing, when I had 
first urged Government to try it, and when I had myself put it into prac- 
tice. Dr. Hart’s reply was, that he had not turned his attention to the 
matter till some months after I had actually made the guns. Not only, 
Sir, did Dr. Hart tell me this, but Mr. Mallet coroborated what he said. 
The date then given for Dr. Hart’s discovery was, I think, July, 1855. 
If the date given to-night, namely, ‘early in 1854,” is correct, he was 
in the field before me, “and I shail cheerfully acknowled ge that he was 
so, if on further reflection he is of opinion that, when the: circumstances 
were recent, he was mistaken, and that he can now remember them 
enough to correct his mistake. This matter Dr. Hart alone can decide; 
I hope he will do so. I think, Sir, that, having finally communicated 
with him and Mr. Mallet on the subject of priority, and having received 
definitive confirmation from both three years ago, I have reason to be 
much surprised at the tone of Mr. Mallet’s remarks to-night, from which 
it would be difficult to gather that, if I entertained mistaken notions 
about priority, I did so in consequence of having been misled by himself. 
In my paper to-night, I distinctly acknowledged that the principle was 
first publicly advocated in this room by Mr. Mallet in June, 1855. So 
much for priority of discovery and priority of publication: I shall be quite 
content to have carried out the system in practice on several cannon, not 
only years before Mr. Mallet. made his mortar, but months before he 
* (Mr. Mallet was unable, through absence, to furnish any memorandum of his remarks, 
which are, however, contained in his subsequent communication (June 11) to the Aca- 
demy.—Ep. } 
t [This reply is here printed from a memorandum furnished by Captain Blakely.— Ep. | 
