The historical iron pillars at Mehrauli,
Delhi, and at Dhar, in Madhya Pradesh, have attracted the attention of scientists for over
a century and have been the subject matter of many publications (e.g.)1–4.
However, a third iron pillar located in Adi-Mookambika temple at Kodachadri village
in a remote forest area of the Western Ghats in Karnataka has not received much scientific
attention so far, partly because the concerned village is difficult to reach and partly
because the pillar itself is not as massive and imposing as the Delhi and Dhar monuments.
Even the Dhar pillar too has not been subjected to systematic scientific and
archaeo-historical studies like the Delhi pillar. In fact, two books have already appeared5,6
on this pillar, dated to mid-Gupta period (~ 375 A.D.) and located in the
vicinity of the still more famous Kutub Minar
Propelled by scientific curiosity as well as deep interest in
India’s glorious metallurgical heritage, the present author embarked on the
adventurous journey to Kodachadri twice during the last eighteen months and undertook some
preliminary studies on the material constituting this long-neglected pillar with
assistance
from fellow-metallurgists at the Karnataka Regional Engineering College, Surathkal; and
the Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam. Results of these studies,
as presented here, confirm the unanimous view of the local residents that this pillar is a
product of an earlier period in indigenous iron
making, and therefore deserves a detailed and serious study by scientists and
technologists devoted to India’s metallurgical heritage.
Popularly referred to as the Dwaja-Sthamba
(flag-staff) of the
temple, the Kodachadri iron mast or pillar has long been associated
in the minds of most scientists, particularly metallurgists, with the pilgrim centre of
Kollur, a town located in the plains, about 120 km north of the well-known port city
of Mangalore in South Canara District of Karnataka. This temple with claims to be the original
temple is associated with the killing of
the dumb (mooka) demon 
by the
lion-riding Mother Goddess in the adjoining forests, where the demon was
disturbing the penance of sages and holy men devoted to the Goddess. Today Kodachadri can
be reached from Kollur by jeep on a 40 km long winding and slippery mud road with
many hair-pin bends, often submerged in water during the rainy season lasting from April
to November. The iron flag-staff towers above the small temple (Figure 1 a)
and can be sighted a few kilometers away on the road, while approaching Kodachadri. If
local lore is to be believed, this flag-staff is actually the top portion of the Tri-
(trident) with which the Mother Goddess nailed down the wicked demon into the
bowels of the earth!
The
temple top has been recently renovated, somewhat on modern lines with brick, cement and
distemper (Figure 1 a, b), 
and a platform has been added ostensibly to
stabilize the pillar, but with possible un-thought-of and undesirable interactions in due
course between the cement of the platform and the iron of the pillar. Rising not less than
10 m above the ground level, with a rectangular cross-section of 8.5 cm ´
5.8 cm and characterized by rough, serrated and slightly reddish surface
(Figure 1 b) the pillar displays evidence on top for local melting, flow of
melt and solidification, caused by lightning during the monsoon period. Allowing for a
total height of 14 m, including the hidden portions in the platform and below the
earth, the weight of this flag-staff can be estimated as about 500 kg.
A very small piece weighing a few grams only was extracted from the
projecting rough surface of the pillar with the consent and cooperation of the temple
priest and was later subjected to a series of modern metallographic tests at the Materials
Characterization Laboratories of the Indira Gandhi Centre for Atomic Research, Kalpakkam.
To the author’s surprise, the X-ray examination could not reveal definite presence of
any element or compound besides pure iron (Figure 2 c), while the microscopic
study revealed only grains of iron (Figure 2 b) with very little pearlite
(eutectoid of iron and Fe3C, i.e. iron carbide generally referred to as
cementite). However, a few greyish and many rather large dark inclusions (Figure 2 a
and b) were noticed and could be subjected to microhardness testing and
electron microprobe analysis. While the small globular inclusions could be identified as
iron silicate containing some calcium (Ca) and phosphorus (P), the bigger irregular-shaped
ones consisted of only iron oxide (Fe2O3) with traces of other
elements like silicon (Si), calcium (Ca) and phosphorus (P). The VHN microhardness numbers
were around 140 for the iron grains, about 155 in the pearlite-cum-matrix areas, and
around 165 in the dark inclusions. From image analysis, the volume fraction of all the
inclusions was estimated as less than 2.0%. It was not possible to arrive at the exact
volume fraction of the greyish pearlitic area, but assuming it to be around 1.0%, the
carbon content of the pillar iron can be estimated as definitely less than 0.05%.
It is obvious from these preliminary investigations that the
Kodachadri iron pillar is not a product of modern iron making processes. The
composition of the material of the pillar, viz. less than 0.05% carbon in what looks like
almost pure iron, without the usual silicon, manganese and sulphur contents one associates
with modern iron and steel, and with inclusions of only iron oxide and silicate, strongly
suggests age-old indigenous methods for making the so-called Adi-vasi (tribal)
iron with pure iron ore and wood charcoal. The fact that this pillar has withstood the
onslaught of the sun, wind and rain in living memory,
and perhaps also of marine air with the Arabian
Sea only 40–50 km away, is proof of its high corrosion resistance, even though
its surface is not as smooth and clear as that of the Delhi pillar. Acting as a lightning
arrester during the rainy season, the top of the pillar seems to have melted frequently
and perhaps rapidly solidified through removal of heat by iron from the pillar
itself. A metallographic study of this part of the pillar is bound to yield some
interesting results.
The data reported here, although from a very small
piece of the pillar, point to the need for a more thorough and systematic scientific,
technological and archaeo-historical study of this iron mast, towering alone in its
majesty in a remote hilly and forest area of Karnataka.
ACKNOWLEDGEMENTS. I thank the authorities of the
Karnataka Regional Engineering College (KREC), Surathkal, and the Indira Gandhi Centre for
Atomic Research (IGCAR), Kalpakkam, for their interest, encouragement and assistance in
the work reported above. I
also thank Prof. N. Venkataraman, Dr K. L.
Bhat and Dr K. R. Udupa, Department of Metallurgical and Materials Engineering, KREC,
Surathkal, for accompanying and assisting me during the two visits to Kollur and
Kodachadri. My thanks are due to Dr Baldev Raj, Materials Group, and Dr V. S. Raghunathan,
Materials Characterization Group, IGCAR, Kalpakkam, for valuable assistance in arranging
for the metallographic studies reported in this paper. It is also a pleasure
to thank Dr E. S. Rajagopal and Dr A. K. Raychaudhuri, former and present Directors
respectively of NPL, New Delhi for their interest, encouragement and support at all times
during this study.