Today in 1878, US Patent 209163 A was issued, an invention of William H. Ewing, for his “Improvement in Barrels or Kegs.” There’s no Abstract, although in the description it includes these claims:

My invention relates to certain improvements in barrels and other like packages, the heads of the same being of wood, arranged and secured in a novel manner, while the sides, or that part usually made of wooden staves, are made of sheet metal, which is manipulated in the following way: A sheet or plate of metal of suitable thickness and size is passed through a train of rolls or under a hammer in such way as to draw out or lengthen the middle of the plate in one direction. The object of this is to secure the requisite bulge or swell to the barrel or keg, both for convenience in handling and to give additional strength. The sides of the plate which correspond to the ends of the barrel or keg: are stamped or out in any convenient way, so as to form a series of three or more clips, a, thereon. These clips are used for securing the heads, and also chine-hoops, as presently described.