From Thomas Cooper
Carlisle May 22. 1813
I received yesterday, the specimen of composition of the Congreve Rocket.1 I have not yet accurately analysed it, because it appeared to me from its obvious properties, that I could make a composition sufficiently similar. I have not returned it to you, because I take for granted you have reserved some of it: if not, as I have used very little of the lump you sent me, it can be returned.
The specimens I send by this day’s mail, are similar to the original lump
In colour: mine are not so brown, not having been made in an iron vessel, to which the brown tinge of your piece, is evidently owing.
In taste previous to combustion.
In taste of the residuum after combustion.
In odour; & in combustibility.
For the purpose of trying this, let the specimens be fired by pressing upon similar pieces of each, a red hot wire for a few seconds.
If when tried, any difference should be found requiring alteration, I think I shall be able to make it; but I fancy they are so nearly alike, as to be ⟨r⟩easonably deemed substances sufficiently similar.
Improvements might be made, but at an expence that wd. not compensate the superiority, as at present I think.
The composition of the larger lump, is saltpetre 4 parts by weight: sulpher ⟨o⟩ne part; Rosin one part; Gunpowder ¼ of a part. The smaller, Salpetre 3½ parts.
The manipulation requires several precautions, as I found by experience, all of which if you deem it worth while, I will detail.
I advised Mr. Madison, not to attend my lectures this session, as he came at the ⟨m⟩iddle of the course, and I think he may employ his time beneficially, if he chuses to be studious, at the Classics and history. I remain with much esteem Your friend
RC (DNA: RG 45, Misc. Letters Received).
1. On 5 June 1813 the Daily National Intelligencer reported that “a piece of the composition of a Congreve Rocket picked up at Havre-de-Grace, having been transmitted to the President of the U. States, he sent some of it a few days ago to Thomas Cooper,” who had “so far ascertained the constituent parts, and their proportion, of this combustible substance, as to make a composition in color, consistence, taste, odour, and combustibility so nearly alike to the Congreve Rocket, as to remove all doubt of their similarity, and equal competence for any destructive purpose.” The Congreve rocket, consisting of an iron cylinder packed with and propelled by explosives, was developed by William Congreve for the British military beginning in 1804. The British used the weapon repeatedly during the War of 1812, most notably at the battles of Bladensburg, Fort McHenry, and New Orleans. Despite Cooper’s efforts and those of others, American forces made only minimal use of rockets during the war (Frank H. Winter, The First Golden Age of Rocketry: Congreve and Hale Rockets of the Nineteenth Century [Washington, D.C., 1990], 13–17, 24–28, 66–72, 141–45).