Thonurs Gill. NICHOLAS MILL.
Damascus Steel.
The steel of which the beautiful sword blades of Damascus are manufactured, has hitherto baffled all attempts at imitation. • It is generally supposed to be made of slips or thin rods or wires of iron and steel, bound together by iron wire, and then incited together by heat. The most skilful workmen of other countries have attempted to imitate this process, but in vain ; so that there is reason to think that the secret of the manufacture has not vet transpired. The colour of the Damascus blades is a dull bluish grey, and scarcely exceeds in hardness common steel from the forge. It is difficult to bend: and when bent does not resume its shape ; the principal character, however, is its water. or a peculiar wavy appearance running from hilt to the point in narrow lines, the thickness of a harp sicord wire, which never cross each other. These waving lines arise from a slight difference in the degree of polish occasioned by the unequal action of acid upon the steel ; any weak acid would produce this ef fect, but at Damascus sulphate of alumine is acid. This appearance of waving lines has been imitated by a false damasking or etching, but the genuine Damascus blade is distinguished from the false one by the obliteration of the lines in grinding, which takes place in the latter. In the real Damascus blades, grinding nearly removes the water ; but it immediately reappears by rubbing the blade with lemon juice.
On Indian Steel or Trootz.
This valuable material has lately been introduced with great success into cutlery. Sir Joseph Banks was the first person who drew the attention of the public to Wootz, having received it from Dr. Scott of Bombay, and submitted some of it to the trials of skilful workmen so early as 1795. It is imported in the state of round flat cakes, about five inches in diameter, and an inch thick, each weighing more than two pounds. The following is the method of making it in India. Pieces of forged iron and wood are en closed in a crucible, and heated together in a furnace. The fire is urged by three or more pair of bellows pe culiar to the country. In this way the wood is charred, and the iron is melted and converted into steel. It crystallizes in the crucible in the state above men tioned. According to Mr. Stodart it ought to undergo a second fusion, which should be conducted with the greatest care, and when this is well done, it is so much improved as to be fit for every purpose of fine cutlery, and infinitely superior to the best cast steel of England. In forging, it requires the utmost at
tention. Dr. Scott informed Sir Joseph Banks, that it " cannot bear anything beyond a slight red heat;" for when this happens, part of the mass seems to run, and the whole is lost as if it consisted of metals of different degrees of fusibility. Mr. Stodart also found that it was useless when overheated, that in hardening it should be quenched at a cherry-red colour, and while tempering, it should be heated from thirty to forty degrees higher than the best English cast steel.
According to Dr. Pearson's * analysis, it seems to differ from steel only in containing a little. oxide of iron. He and Mr. Moore obtained the following mea sures of its specific gravity.
Wootr has been more recently (1819) examined by Mr. The piece which he used was cut from the middle of the cake given by Sir Joseph Banks to Mr. Stodart, when heated cherry-red. In 460 grains he found besides the carbon and iron, 0.3 of a grain of silex, and 0.6 of a grain of alumine. The best. English cast steel, submitted to the same 'experiments, yielded no earths. Mr. Faraday at tempted in vain to imitate wootz, although he ob tained specimens of iron giving abundance of silex and alumine by analysis.
On a future occasion, however, he was more suc cessful by employing the following method. Pure steel in small pieces, and in some cases good iron when mixed with charcoal powder were heated in tensely for a long time. In this way were formed carburets highly crystalline, and of a dark metallic grey colour, like the black ore of tellurium. 'When broken the facets of several buttons of 500 grains were about the eighth of an inch wide. This carburet consisted of This metal when reduced to powder in a mortar was mixed with pure alumine, and the whole sub jected to an intense and long heat. An alumine alloy was thus obtained of a white colour, a close granular texture, and very brittle. It contained 6.4 of alumine. With 67 parts of this alloy 500 grains of good steel were fused, and formed a perfectly malleable button which forged well, and gave the beautiful damask pe culiar to wootz, by the application of dilute sulphuric acid.