This machine enlarged at one bound the whole scale of working in iron, and permitted Maudsley's lathe to develop its entire range of capacity. The old 'tilt-hammer' was so constructed that the more voluminous the material submitted to it, the less was the power attainable; so that as soon as certain dimensions had been exceeded, the hammer became utterly useless.
a, a, a, tuyères; b, air-space; c, melted metal
A very important development of the manufacture of steel followed the introduction of the 'Bessemer process,' by means of which a low carbon or mild cast-steel can be produced at about one-tenth of the cost of crucible steel. It is used for rails, for the tires of the wheels of railway carriages, for ship-plates, boiler-plates, for shafting, and a multitude of constructional and other purposes to which only wrought iron was formerly applied, besides many for which no metal at all was used.
Sir Henry Bessemer says: 'It is this new material, so much stronger and tougher than common iron, that now builds our ships of war and our mercantile marine. Steel forms their boilers, their propeller shafts, their hulls, their masts and spars, their standing rigging, their cable chains and anchors, and also their guns and armour-plating. This new material has covered with a network of steel rails the surface of every country in Europe, and in America alone there are no less than 175,000 miles of Bessemer steel rails.' These steel rails last six times longer than if laid of iron.'
More than once it has happened that the youngest of thirteen children has turned out a genius. It was so in the case of Sir Richard Arkwright, and it turned out to be so in the case of Josiah Wedgwood, the youngest of the thirteen children of Thomas Wedgwood, a Burslem potter, and of Mary Stringer, a kind-hearted but delicate, sensitive woman, the daughter of a nonconformist clergyman. The town of Burslem, in Staffordshire, where Wedgwood saw the light in 1730, was then anything but an attractive place. Drinking and cock-fighting were the common recreations; roads had scarcely any existence; the thatched hovels had dunghills before the doors, while the hollows from which the potter's clay was excavated were filled with stagnant water, and the atmosphere of the whole place was coarse and unwholesome, and a most unlikely nursery of genius.
Wedgwood at Work
He was bound apprentice to his brother Thomas in 1744, when in his fourteenth year; but this weak knee, which hampered him so much, proved a blessing in disguise, for it sent him from the thrower's place to the moulder's board, where he improved the ware, his first effort being an ornamental teapot made of the ochreous clay of the district.
Armstrong, during the Crimean War, made an explosive apparatus for blowing up ships sunk at Sebastopol. This led him to turn his attention to improvements in ordnance. He invented a kind of breech-loading cannon, and soon had an order for several field-pieces after the same pattern. He began with guns throwing 6 lb. and 18 lb. shot and shells, and afterwards 32 lb. shells; and the results at the time were deemed almost incredible. He had both reduced the weight of the gun by one-half, reduced the charge of powder, and his gun sent the shell about three times farther. His success led to his offering to government all his past inventions, and any that he might in the future discover. A post was created for him, that of Chief Engineer of Rifled Ordnance for seven years provisionally.
The only reliable mode of proving the strength of Gunpowder is, to test it with service charges in the arms for which it is designed; for which purpose the balistic pendulums, are perfectly adapted
The three ingredients are now ground separately to a very fine powder. The mills which effect this, and incorporate, are so similar, that a description will be given under the head of “Incorporation.” Screening.After being ground in this way, the saltpetre is passed through a slope cylindrical reel, covered with copper sieving wire of 60 meshes to the inch, which, as it revolves, sifts it to the required fineness, being then received in a box or bin underneath. The charcoal and sulphur are likewise passed through similar reels of 32 and 60-mesh wire respectively, and that which remains without passing through, is ground again under the runners.
The only real use of these eprouvettes is to check and verify the uniformity of a current manufacture of powder, where a certain course of operations is intended to be regularly pursued, and where the strength, tested by means of any instrument, should therefore be uniform.