Faraday to George Butler¹   5 March 1852²

Royal Institution | 4 March 1852

Sir

I have the honor to acknowledge the receipt of your letter³; and also, by Mr. Tozer⁴, of the substances referred to in it; I am happy that I could find time to make an examination; and beg you to offer the results to the Board of Ordnance. There were specimens of three substances[.] One of these was called friction composition: it proved to be a mixture of pulverized chlorate of potassia and sulphuret of antimony. The quantity was too small for me to determine the proportions;- but there can be no difficulty in preparing such a mixture, for the materials, & their effects when mixed, are well known here; and there was nothing particular in the proportion[.]

The cylindrical missile contained two mixtures, besides the ordinary powder about it; the central or axial portion, which was black, & the surrounding or chief part in bulk, which was brownish yellow. The central portion consisted of nitre, charcoal, and sulphur in proportions to form a gunpowder. I do not think it has ever been granulated; for the mixture appears to be but coarsely made. It may however have been meal powder or else a green mixture of the materials of powder. It has all the qualities of powder; & not having time, I did not ascertain its proportions.

The chief mass of the missile; i.e the yellow substance has only such hardness as to be cut or impressed by the finger nail. It breaks down under pressure, yet clings a little together. It softens & melts by heat and has probably been softened when put into its place, being adjusted there by pressure. It is granular in its structure; the sulphur & other materials used having evidently not been in a state of fine division or very perfect mixture; and if it has been softened by heat when put into its place, it has not been melted. It does not burn very vividly, that probably not being desired; but its habits in this respect will be better understood by trial & experiment. It contains the following substances:- Nitre - Sulphur - Resin, perhaps common resin - Wax - Metallic Antimony - No chlorate of potassia. The following are the results as to proportions which one portion gave me; but from the appearance I should conclude that the mixture is not accurately made, & that the proportions are likely to differ in different parts.

I have reserved as much of the composition as I could and return it herewith.

I am Sir | Your Very Obedient humble Servant | M. Faraday

Geo. Butler Esq | Secretary | &c &c &c &c

Endorsed: 5 March 1852 | Ordered to be transmitted, with the accompanying Packet, to the Director of the Royal Laboratory⁵. Acknowledge the receipt to Dr. Faraday, and express to him the thanks of the Board for his communication and for the trouble he has taken in this matter. | TH⁶

Wrote Dir Rl Laboratory and Professor Faraday | 5th⁷