Mediaeval Sinhalese Art c22.23

c22.23

The steel is thus very free from sulphur and phosphorus and very rich in carbon. It is *Steel* stated to resemble somewhat the older forms of Sheffield tool steel, which, however, seldom contained more than 1·5 per cent of carbon. The high percentage of carbon is characteristic and interesting, for it has been pointed out by Ritter Cecil von Schwarz* that "it is well known by every manufacturer of crucible cast steel how difficult it is sometimes to get the exact degree of hardness to suit certain purposes, especially with reference to steel for cutting blades, &c. With the ordinary process endeavours are made to reach the required degree of hardness by selecting such raw materials as on an average have the required contents of carbon in order to correspond with the required hardness as far as possible. The natives [of India] reached this degree by introducing into their cast steel an excess of carbon, by taking this excess gradually away afterwards, by means of the slow tempering process, having it thus completely in their power to attain the exact degree by interrupting this decarbonising process exactly at the proper time in order to cast steel of a quality exactly suitable for the purpose."