“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 its 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 exactly in the proportion of those quantities; 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 weight, but would be to the full as serviceable on ship-board, as the present pieces, which are so much overloaded with metal.
“The author’s scheme then for augmenting the force of the present sea-batteries, is no more than this plain principle, that all ship-guns should be cast upon the model of the thirty-two pounders, measuring by the diameter of the respective bullet; so that for each pound of bullet, there should be allowed one hundred and two thirds of metal only.
“The advantages of this scheme will appear, by the following comparison of the weight of the present pieces with their weight proposed by this new fabric.
| Pieces. | Weight now in hundreds. | Ditto by new fabric. |
|---|---|---|
| 24 | 48 to 46 | 40 |
| 18 | 41 to 39 | 30 |
| 12 | 34 to 31 | 20 |
| 9 | 29 to 26 | 15 |
| 6 | 24 to 18 | 10 |
“Hence then it appears, that the twenty-four-pounders will be eased of six or eight hundred of useless metal; and instead of an inferior caliber now used, much larger ones of the same weight may be borne, especially when it is remembered, that this computation exceeds even the present proportion of the thirty-two-pounders; so that from the above projected eighteen pounders, for instance, two or three hundred weight may be safely taken.”
The changes then proposed by the author are these:
| Pounders. | Hundreds. | Pounders. | Hundreds. | ||||
|---|---|---|---|---|---|---|---|
| For | 6 | of | 24 and 18 | new | 12 | of | 20 |
| 9 | 29 and 26 | 18 | of | 28 | |||
| 12 | 34 and 31 | 18 | of | 28 | |||
| 18 | 41 and 39 | 24 | of | 40 | |||