Joshua Shaw, Artist And Inventor
The Early History Of The Copper Percussion Cap

Scientific American, 7 August 1869


Early life

Later life and the copper percussion cap

In 1814 he invented the copper percussion cap. He, however, kept the discovery secret until his arrival in America, when he sought to obtain a patent for it, but was refused on the ground of his being an alien, the law at that time denying a patent to aliens unless they had resided two years in the country. His claim to the origination of the invention was, however, recognized, although a patent was refused.

It was undoubtedly owing to this fact that Mr. Shaw became at a later period, an urgent advocate of reform in the patent laws of the United States, and their present liberal provisions are attributable doubtless, in considerable measure, to his exertions, the transactions of the Franklin Institute contain many papers upon the subject of patent law prepared by him.

During the delay the public got possession of the improvement, and Mr. Shaw failed to reap any adequate reward for his invention. In 1822 he obtained a patent for the percussion cap and lock for small arms, and in 1828, another for the percussion locks and wafer primers for cannon. The justice of his claims was afterward disputed, the inventions being attributed in part to Alexander John Forsyth, clerk of Belhlvie, Aberdeenshire, Scotland, to the celebrated Joseph Manton, London, and to John Day, of Barnstable, England, but the specification attached to their patents show that the copper cap as patented by Mr. Shaw, was a thing unknown to them. They had a knowledge of fulminates and methods of firing them, but there was only one thing in common with their methods and that of Mr. Shaw, the discharge of fulminates by percussion.

After a protracted investigation of his claims, the United States subsequently awarded Mr. Shaw $25,000, a very small portion of its real debt to the accomplished inventor. The award speaks volumes for the genuineness of Mr. Shaw's claims, but little for the generosity of the Government toward the gifted son of her adoption, who had bestowed upon the world, to use the language of the Committee of Patents, in their report on Mr. Shaw's claims bearing date Feb. 10, 1846, "is one of the most ingenious, and one of the most useful inventions in modern times." Of this award Mr. Shaw only received $17,000, the estimate of his claims being subsequently unjustly reduced to that amount.

Mr. Shaw received in 1817, or about that time, a premium from the Emperor of Russia for improvements in naval warfare.

In 1833 he visited England with a view to obtaining the adoption of improvements in cannon locks, which he had made, and the wafer primer for cannon which has been so largely used. Russia also adopted his improvements, agreeing to pay a stipulated sum for every piece of artillery upon which it was placed, but which we are informed neither Mr. Shaw, nor his family after his death, ever received.

Mr. Shaw died in Sept., 1860. He was a long member of the Franklin Institute, and contributed many valuable papers to its transactions, and enjoyed the friendship and confidence of many of the most distinguished men of his time. His genius as an artist has been universally acknowledged, but it is evident that his genius for work was the real basis of his success. As a controversialist he wielded a vigorous and fearless pen, and though one of the most genial and kind-hearted of men, was unsparing where he deemed censure deserved. He was the originator of several minor inventions beside the more important ones relating to discharge of artillery. Among these was the swivel diamond for glaziers.

His life was a constant warfare with obstacles and difficulties, but he retained his vigour to extreme old age, setting an example of perseverance and integrity well worthy of admiration and imitation.



A whole raft of people, including Colonel Peter Hawker, were claiming this around 1820 but the best documented evidence to date makes Joseph Egg the first. Vide De Witt Bailey, BLACK POWDER The Official Journal of the Muzzle Loaders Association of Great Britain, Volume 31 February 1984, pages 6-8.

Contrary to received opinion that the Board of Ordnance ignored all modern developments and did not even consider the cap until the 1830s, De Witt Bailey has details and correspondence concerning the trials of copper cap guns by the B of O during the middle of 1820. This was before the first recorded patent for such a thing by the Frenchman Francois Prelat on 28th July 1820.

We shall never know exactly who invented this system but it was such an obvious development from the patch lock that it must have occurred to a good many people almost simultaneously.

The above footnote was from correspondence with W.S.Curtis, February 2001.

For further discussion of the claims of Joshua Shaw, and other inventors, concerning the percussion cap see: 'Early Percussion Firearms' by Lewis Winant, Bonanza Books, 1956