STEAM

a ge THE, is of imumense | appea service in the forging of heavy guns, | tained armour plates, etc. The first that came} subje into extensive use was that patonted by | were + Nasmyth, in which the hammer head was|and t attached to the piston rod. Condio’s! vent a was intended to remove certain weak- — No es that became 7 sored in the earlier| his 6 forms, particularly sey breaking | autho of the piston or piston rod owing to the} STE fact that the jar of each stroke of the| provic hammer was transmitted to those parts. | subst: The anvil is placed between two u right | stand: wrought-iron standards which are joined steel, at the top. The piston-rod is fixed to this| bal an framework. The steam cylinder is|to th movable, and the bammer face is dove-| From tailed into its lower end. Steam is ad-|pan o mitted into the movable cylinder above | sabsts the piston, and its elastic force causes the| A eir cylinder to rise between the guide a to the | gradu: Foquired height. An exhaust valve is| occup then eee, te steam escapes, and the| true w cylinder the bammer attached de-| is ind - geends by its own weight. The air com-| longer | pre ed the lower end of the/ stant cylinder and the piston gives, by its ex-| The n Pausion, an additional impetus to the blow, | Londe sod in the more powerful hammers an/| river ‘ increased striking forve is obtained by |of ¢ admitting steam below the piston. The|‘* Mer Sttachment of certain mechanism enables enjoys the workman in charge to cause the| whic hammer to fall from any point in its ascent, | of cer Of to arrest the blow at any palns in its| depriy descent, thus providing for © striking | 1551, of blows of various degrees of force. These Steely ete, cape due ~ Mr. Wilson, —— cccupies an intermediate po-| of La Wrought iron and cast! 1863. it contains moro carbon than the| §7 r, but le than the latter, so that it| pain be prepared from either of those | amo nces, ~ an addition of carbon to | into rought iron, or a rms: the im- | in e7 ts from the cast iron. In the older} a fc s for the preparation of steel, which | His own «as the cementation proce , | the‘ nverting chest is filed with alternate | com of powdered charcoal and wrought-|_ §1 ars, and the whole is then kept at a} the pat for several days, the length of | cles, jepending on the services for which | to re eel is required. At the conclusion | of tt: operation the bars are brittle, and | of fc overed with blisters, from which | tant nstance the steel thus sly “panes Such 3 as biistered ateel, The Be emer ay sw is the one more gone rally em-| of 1 now. It is carried out in o largo| are | haped ve el called a “ converter.” | Nati his a quantity of molten cast iron} $1, and a powerful air blast is admitted | his below until the whole of the carbon | chir ther impurities have been burnt, a; S71 ion of affairs that is indicated by the| or s out of the flames at the surface of the | requ nma . The blast is then shut off, | the solten cast iron, Sante A sufficient | that n to convert the whole charge into | per « is added. The blast is again turned | long ‘a few moments to ensure that the/ ofa ials are thoroughly mixed. The con-| wate of the converter are then cast into/ an ©. These are afterwards heated to/ @ bo m= and beaten or rolled into bars, | tiller apacity of the converter varies from | forw 4 tons, and several charges may be} it sw with every day. Since the intro- | ship, m of this proce the iron and eteel | whe ry bas progre ed to auch an extent | ship: yecome, next to agriculture, the most | ased tant in the United Kingdom, em- Si 2, according to tlie census returns | exec il, upwards of 216,000 —— ey SELE, [s. 288]