156 HOLLAND: GEOLOGY OF THE NEIGHBOURHOOD OF SALEM. 



fissures through which one finds the aqua-marine in a matrix which 

 Leschenault believed to be an aluminous tufa 18 (VI, 344). 



About two lieues (5 miles) to the south-south-west of Salem, 

 in the mountain of Kantiamale (Kanjamalai), 19 there is a mine of 

 iron-sand which is collected in the ravines. It is very rich and the 

 iron obtained from it produces an excellent steel, from specimens of 

 which very good razor blades have been manufactured in England. 

 To convert the iron into steel the native workers place small pieces 

 of it, weighing about one pound, into a clay crucible ; for the cemen- 

 tation the metal is surrounded with three-sevenths of its weight of 

 the powdered, dry bark of the Cassia auriculata, to which are 

 added a few green leaves of the Asclepias gigantea, or of the Jatro- 

 phia curcas. The crucible is then tightly sealed with clay and 

 heated with wood charcoal to effect fusion 20 (VI, 344 ; IX, 255). 



After returning to Pondicherry, Leschenault started, in October 

 18 18, intending to visit the Western Ghats. On the way he visited the 

 localities where the Carnatic corundum had been obtained. The place 



18 As Heath in the following year (1819) worked, under lease from the East 

 India Company, the aqua-marine mine near Kangayam in the Coimbatore dis- 

 trict, there is not much doubt about the origin of these specimens (see note 

 No. 24). The handsome graphic granite occurring in, and abundantly around, the 

 aqua-marine pit may well have attracted Leschenault's attention ; he gives a 

 fuller account of the rocks after visiting the mine in the course of a subsequent 

 journey (see IX, 261, 262). 



19 There can hardly be a doubt, as Mallet has pointed out {Rec, Geol. Surv., 

 Ind., XXV, 124), that notwithstanding the bearing given (south-south-west 

 instead of west-south-west) Leschenault here refers to the well-known iron-ore 

 beds of Kanjamalai about 5 miles from Salem. 



20 The description of the native manufacture of steel by cementation in crucibles 

 shows that the process practised in the Salem district as long ago as 1818 was 

 essentially similar to that still carried on to a small extent in the adjoining 

 Trichinopoly district, though the industry appears to have disappeared from 

 Salem ; in the latter district, however, pariahs still make wrought-iron by a 

 direct method of smelting, and a kind of steel by decarburization of cast-iron shot 

 (Imperial Inst. Handbook, No. 8 (1892), pp. 15 — 22 and Rec, Geol. Surv v, Ind., 

 XXV, 145). 



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