Iron in Ancient India c7.s5.8

c7.s5.8

Surprise has not unreasonably been expressed at the fact that the iron pillar at Delhi and other ancient specimens of iron have not rusted in a marked degree. General Cunningham offered a curious explanation of this fact by supposing that the oil of the bodies of the pilgrims who visit the Delhi pillar and embrace it as a mark of merit keeps it immune from rusting, but the learned General does not seem to have explained how the capital of the pillar, which is too high for human embrace, could be preserved in the way it has been preserved. The Delhi pillar is the best preserved of all the pillars. Mr. Graves points out that some of the Konarak beams were so heavily rusted that flakes half a foot square and half an inch thick could be scaled off. Most of them, however, were only superficially rusted and the rusting is mainly due to the beams remaining underground for two or more centuries. The iron clamps found at Bodh-Gaya are also very heavily rusted. The specimens of Singalese iron examined by Sir Robert Hadfield were well preserved, though belonging to the fifth century A.D. Dr. A. S. Cushman¹ is disposed to be philosophically inclined when he says, and says perhaps rightly, that "chemical and physical examinations of such ancient specimens might point the way to practical improvement in our own age, for one criticism that was often passed on modern steels was that their tendency to corrode and disintegrate stood in direct ratio to the rapidity with which they were manufactured ....... It seems to be a law of Nature that her materials should respond to the manipulations of the hands of man, and acquire properties that machinery cannot give." Be that as it may, two explanations are possible of this remarkable power of ancient specimens of iron of resisting corrosion—either there was something in the composition of the iron or that the beams were painted, or both. To the author it appears that both the factors have operated in enabling the Indian iron pillars and beams to withstand the corroding influence of wind and rain. In the first place the one point remarkable regarding the composition of the Delhi iron, Singhalese iron and other specimens of ancient iron is that all these specimens of iron are *free* from manganese and sulphur and contain a *tolerably high percentage of phosphorus*. The author agrees with Dr. Cushman when he suggests that probably "low manganese with low sulphur and high phosphorus would lead to high corrosion resistance" in iron.