1794 Pa. Laws 764, An Act Providing For The Inspection Of Gunpowder chap. 337
Whereas gun-powder imported from abroad, and manufactured within this state, have frequently been found to vary much in its strength, and sometimes of inferior qualities, and its defects not discovered until brought into actual use: And whereas the modes heretofore used to prove the force thereof have been found uncertain and variable; and whereas Joseph Leacock, of the city of Philadelphia, hath invented an engine, called a pendulum powder proof, with a graduated arch and catch-pall, by which it is conceived that the force of gunpowder may be proved by experiment, and the article reduced to certain and uniform standards of strength, whereby the manufacture may be advanced towards ultimate perfection, and the purchaser and consumer protected against fraud and imposition. § 1. . . That from and after the first day of October next, all gun-powder manufactured within this state, with intent to sell the same within the city or county of Philadelphia, shall be put in good and tight kegs or casks of twenty-five, fifty, or one hundred pounds neat weight, each made of well seasoned timber, bound together with at least twelve hoops, and having a hole bored in each head, of the diameter of one fourth part of an inch, well stopped with corks, and having the tare weight to each cask marked thereon, and that all such gun powder, and all other gun-powder, wheresoever manufactured, imported into the port of Philadelphia, or brought into the city or county of Philadelphia for sale, shall be deposited forthwith on such importation or bringing by land or by water, in the public magazine in the said city, and delivered to the care of the keeper of the same, who shall give his receipt for the same, deliverable to the order of him or them who shall so deposit the same. § 2. And be it further enacted by the authority aforesaid, That David Rittenhouse, Francis Gurney and Thomas Procter be, and they are hereby, appointed Commissioners, to procure at least two pendulum powder proofs, upon the construction invented by the said Joseph Leacock, as nearly uniform in the length of the radius and weight of the pendulum, and in length of caliber and weight of the pistol, as they can procure the same, and therewith make experiments of the respective strenght or force of of the several species of gun-power imported from abroad, and manufactured within this state, sufficient in number to assertain the quality and force of three different degrees of strength in explosion, and marking the number of degrees on the graduated arch of the said engine, to which equal quantities be weight of the said three species of gun-powder, rammed with equal force into the pistol, shall elevate the said pendulum; and the powder which shall be barely capable of raising the said pendulum to the lowest rate of elevation, shall be standard for the state of Pennsylvania for gun powder of the first or lowest proof; and the powder which shall be capable of raising the said pendulum to the highest rate of elevation, shall be the standard of gun-powder for the State of Pennsylvania for the third or highest proof; and the middle or second proof standard of gun-powder shall be ascertained by the number of degrees of the said graduated arch, to which the same quantity of weight in equal moieties of the first and third proof powder shall be capable of raising the said pendulum; and the said standard being fixed and ascertained, the said Commissioners shall make report thereof in writing, by indentures under their hands and seals, on part thereof, together with one of the said pendulum powder proofs, and as accurate a draft and description thereof as can be made shall be returned to the Governor, to be filed and remain in the office of the Secretary of the Commonwealth, on other part shall be returned to the master of the Rolls, to be recorded in his office, and filed among the laws of the state and the other part together with the other pendulum powder proofs, shall be delivered to the first inspector of gun powder to be appointed in pursuance of this act, and by him, and his successors in office, to his and their succesors, as often as another officer shall be appointed.