Woodbridge also invented the _wire-wound cannon_, and a machine for winding the wire upon the gun, thus giving the breach part, especially, immense strength. In England, among the first notable and greater inventors in ordnance during the latter half of the century, a period which embraces the reduction to practice of the most wonderful and successful inventions in weapons of war which the world had up to that time seen, are Lancaster, who invented the elliptical bore; Sir William Armstrong, who, commencing in 1885, constructed a gun built of wrought-iron bars twisted into coils and applied over a steel core and bound by one or more wrought-iron rings, all applied at white heat and shrunk on by contraction due to cooling, by which method smooth-bore, muzzle-loading cannon of immense calibre, one weighing one hundred tons, were made. They were followed by Armstrong, inventor of breech-loaders; Blakely, inventor of cannon made of steel tubes and an outer jacket of cast iron; and Sir Joseph Whitworth, inventor of most powerful steel cannon and compressed steel projectiles. In Germany, Friedrich Krupp at Essen, Prussia, invented and introduced such improvements in breech-loading cannon as revolutionised the manufacture of that species of ordnance, and established the foundation of the greatest ordnance works in the world. The first of his great breech-loading steel guns was exhibited at the Paris Exhibition in 1867. A Krupp gun finished at Essen in the 70’s was then the largest steel gun the world had ever seen. It weighed seventy-two tons, and was thirty-two feet long. The charge consisted of 385 pounds of powder, the shell weighed 1,660 pounds, having a bursting charge of powder of 22 pounds, and a velocity of 1,640 feet per second. It was estimated that if the gun were fired at an angle of 43° the shell would be carried a distance of fifteen miles. It was in the Krupp guns, and also in the Armstrong breech-loaders, that a simple feature was for the first time introduced which proved of immense importance in giving great additional expansive force to the explosion of the powder. This was an increase in the size of the powder chamber so as to allow a vacant space in it unfilled with powder. In the United States, Rodman, commencing in 1847, and Dahlgren in 1850, and Parrott in 1860, invented and introduced some noticeable improvements in cast-iron, smooth-bore, and rifled cannon. In France General Paixhans and Colonel Treuille de Beaulieu improved the shells and ordnance. The latest improvements in cannon indicate that the old smooth-bore muzzle-loader guns are to be entirely superseded by breech-loaders, just as in small arms the muzzle-loading musket has given way to the breech-loading rifle.