338 
ried out. For this and other reasons dependent upon the molecular 
properties of iron, I did not employ his mode of regulating the tensions, 
but reverted to the method of boring out each successive ring as much 
too small to go over the preceding one when both were cold, as should 
give the tension required by his calculus, and heating them all ved hot, 
before superimposing them, as proposed in the text of my paper, sections 
289 to 293. 
I mentioned this to Dr. Hart in a hasty conversation (some time in 
1856, I believe), and he appears to have quite misapprehended me, and 
supposed that I had neglected all regard to the relative tensions of the 
superimposed rings, for in a letter of his, addressed to Captain Blakely, 
and published by the latter, Appendix E of his pamphlet en Constructing 
Cannon, of 1858 (Ridgeway, London), already referred to, Dr. Hart 
does the unintentional injustice to say of me—‘‘ This caution,” namely, 
the proportioning the tensions of the successive rings to caleulation, 
«Mr. Mallet has, I believe, utterly neglected.”” ‘In this same letter, na 
previous paragraph, Dr. Hart, by a looseness of expression, I am sure 
equally unintentional, has also given ground for misapprehension; he 
says—‘‘ The construction which I proposed to Mr. Mallet when he was . 
about to make his large mortars, and which, I am sorry to see, he did 
not fully adopt, was,” &c. Now, Dr. Hart never proposed anything to 
me on the subject until long after those mortars had been designed, had 
far progressed towards completion, and after everything relating to their 
construction had been already settled by myself. 
Dr. Hart’s communication enabled me to determine the exact strain 
that each successive ring should have when in place, but did not even 
modify the practical method of obtaining such proportioned strains, 
which I had anteriorly devised, and adopted, much less suggest or deter- 
mine anything relative to their constructive detail. 
Dr. Hart has informed me that this letter was addressed as an ordi- 
nary private reply to a note from Captain Blakely, and that he gave him 
no authority to publish it. 
My paper “‘ On the Principles involved in the Construction of Artil- 
lery’”’ was read to the Academy on the 25th June, 1855, leave of Council 
having been had for its reading on the 18th of that month. Its publi- 
cation, therefore, dates from that time. Everything contained in the 
text which refers to the question before us, except words of reference 
in two or three places to Dr. Hart’s investigation in Note W added in 
the printing, was in manuscript at the time, and laid upon the table of 
this Academy ; and this was substantially the case with regard to every 
part of the paper, except the notes. Captain Blakely, however, in 
attempting to make out a later date for it, states in his second commu- 
nication, read here on the 28th May last, that ‘‘some parts of Mr. 
Mallet’s paper of 25th June, ’55, must have been written in September, 
’55, at the earliest, for at p. 232 reference is made to a proposal to shrink 
hoops upon 13-inch mortars at Woolwich—which proposal, he says, 
was made by Colonel Wilmot on the 25th of September, ’55.” Now, 
the numbering of the page to which he refers proves that it was a copy 
