CANNON (continued)

" Now what dimensions and weight of metal are more than sufficient for these purposes, we may learn from the present practice of the navy, in the fabric of the thirty-two pounders, the heaviest guns in common use; these are made to weigh (if the author's information be right) from fifty-two to fifty-three hundred weight; that is somewhat less than an hundred and two-thirds for each pound of bullet.

" From this then the author concludes, that any smaller piece, made upon the model of these thirty-two pounders, and having their weight proportioned in the same manner to the weight of their bullet, will fully answer all the purposes recited above, and will be of unexceptionable service.

"And he founds his opinions on these two principles: first, that the strength of iron, or of any other metal, is in proportion to it's substance; so that, for instance, where it has one-half the substance, it has one-half the strength; and this supposition, he presumes, will be scarcely contested. Secondly, that the force of different quantities of powder fired in spaces which they respectively fill, is not exactIy in the proportion of those quantitles; but the lesser quantity has in proportion the least force: that is, for instance, the force of one pound of powder, in like circumstances, is less than one-half the force of two pounds. And this principle the author has deduced from many repeated and diversified trials of his own; and he believes it will be found agreeable to all the observations which have been made, or shall be made, on this subject.

"From these two considerations he hopes, it will be granted him, that, if two pieces, a large one and a small one, are made with all their dimensions in proportion to the diameter of their respective bullets, and consequently their weights in the same proportion with the weights of their bullets, then the larger piece, with the same proportion of powder, will be more strained, will heat more, and recoil more than the smaller.

"Hence then, as we are assured, that the present thirty-two pounders are of a sufficient strength and weight for all marine purposes, we have the greatest reason to suppose, that, if all the pieces of an inferior caliber were formed upon the same model, measuring by the diameter of the bullet, these smaller pieces would not be defective, either in strength or weigh; but would be to the full as serviceable on ship-board, as the prefent pieces, which are so much overloaded with metal.

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