Ancient metallurgy culminating in Indian ukku (wootz) steel and documented in Indus Script Corpora by Bhāratam Janam

Indus Script Corpora documented by Bhāratam Janam is an extraordinary catalogus catalogorum of metalwork in an extensive area spanning the Maritime Tin Route from Hanoi to Haifa. Indus Script hieroglyphs also signify metalwork on cylinder seals of Ancient Near East, in particular from Assur to Kultepe and on cire perdue artefacts of Dong Son Bronze Drums and Nahal Mishmar scepters and standards.

शैक्य-अयसम् Damasked steel; शकदेवाय चिक्षेप सर्वशैक्यायसीं गदाम् Mb.6.54.24; शैक्यायसानि वर्माणि कांस्यानि च समन्ततः 7.119.42 (com. शैक्यायसानि शोणितायोमयानि).(Samskritam.Apte) शैक्य [p= 1089,2] damasked (?) MBh.pointed (for शैख्य) MW. pointed (for शैख्य) MW.mfn. (cf. शैक्य) pointed , spiked MW.(Monier-Williams) 

बट्टलोहकम् baṭṭalōhakamबट्टलोहकम् Damasked steel. bhráṣṭra n. ʻ frying pan, gridiron ʼ MaitrS. [√bhrajj]Pk. bhaṭṭha -- m.n. ʻ gridiron ʼ; K. büṭhü f. ʻ level surface by kitchen fireplace on which vessels are put when taken off fire ʼ; S. baṭhu m. ʻ large pot in which grain is parched, large cooking fire ʼ, baṭhī f. ʻ distilling furnace ʼ; L. bhaṭṭh m. ʻ grain -- parcher's oven ʼ, bhaṭṭhī f. ʻ kiln, distillery ʼ, awāṇ. bhaṭh; P. bhaṭṭh m., °ṭhī f. ʻ furnace ʼ, bhaṭṭhā m. ʻ kiln ʼ; N. bhāṭi ʻ oven or vessel in which clothes are steamed for washing ʼ; A. bhaṭā ʻ brick -- or lime -- kiln ʼ; B. bhāṭi ʻ kiln ʼ; Or. bhāṭi ʻ brick -- kiln, distilling pot ʼ; Mth. bhaṭhī, bhaṭṭī ʻ brick -- kiln, furnace, still ʼ; Aw.lakh.bhāṭhā ʻ kiln ʼ; H. bhaṭṭhā m. ʻ kiln ʼ, bhaṭ f. ʻ kiln, oven, fireplace ʼ; M. bhaṭṭā m. ʻ pot of fire ʼ, bhaṭṭī f. ʻ forge ʼ. -- X bhástrā -- q.v.bhrāṣṭra -- ; *bhraṣṭrapūra -- , *bhraṣṭrāgāra -- .Addenda: bhráṣṭra -- : S.kcch. bhaṭṭhī keṇī ʻ distil (spirits) ʼ.(CDIAL 9656)

ఉక్కు (p. 0149) [ ukku ] ukku. [Tel.] n. Steel. Strength, courage, pride, vigour, potency. అయస్సారము, బలము, శౌర్యము. Steadiness. స్థైర్యము. తెలగ ఉక్కు. A very tough sort of steel. R. v. 197. ఉక్కు తీగె ukku-tīge. n. Steel wire. ఉక్కుతునక
 or ఉక్కుముక్క ukku-tunaka. n. A bit of steel, a brave, sharp or active man. ఉక్కుసున్నము ukku-sunnamu. n. Ashes of calcined iron, scoriæ calx.ఉక్కరి ukk-ari. (ఉక్కు+అరి) A man, a hero. శూరుడు, ధీరుడు. Ta. uruku (uruki-) to dissolve (intr.) with heat, melt, liquefy, be fused, become tender, melt (as the heart), be kind, glow with love, be emaciated; urukku (urukki-) to melt (tr.) with heat (as metals or congealed substances), dissolve, liquefy, fuse, soften (as feelings), reduce, emaciate (as the body), destroy; n. steel, anything melted, product of liquefaction; urukkam melting of heart, tenderness, compassion, love (as to a deity, friend, or child); urukkiṉam that which facilitates the fusion of metals (as borax). Ma. urukuka to melt, dissolve, be softened; urukkuka to melt (tr.); urukkam melting, anguish; urukku what is melted, fused metal, steel. Ko. uk steel.  

Ka. urku, ukku id. Koḍ. ur- (uri-) to melt (intr.); urïk- (urïki-) id. (tr.);ukkï steel. Te. ukku id.Go. (Mu.) urī-, (Ko.) uṛi- to be melted, dissolved; tr. (Mu.) urih/urh- (Voc. 262). 

Konḍa (BB) rūg- to melt, dissolve. Kui ūra (ūri-) to be dissolved; pl. action ūrka (ūrki-); rūga (rūgi-) to be dissolved. Kuwi (Ṭ.) rūy- to be dissolved; (S.) rūkhnai to smelt; (Isr.) uku, (S.) ukku steel.(DEDR 661)

Hieroglyph: Mora [the contracted, regular P. form of *Sk. mayūra, viâ *ma -- ūra>mora. See also Geiger, P.Gr. § 27 & Pischel, Prk. Gr. § 166. -- Vedic only mayūrī f. pea -- hen] a peacock J ii.275 (˚upasevin, see C. on this passage); vi.218, 497; PvA 142; DhA i.394. A peacock's tail (sometimes used as a fan) is denoted in var. terms in cpds., as mora -- kalāpa DhA i.387; -- piccha Vini.186; -- piñcha Vin ii.130; -- pīñja PvA 142, 176; VvA 147; -- sikali (?) KhA 49; -- hattha Vv 3344 (=mayūra -- piñjehi kataŋ makasa -- vījaniŋ); Pv iii.117. मोर [p= 835,3] m. a peacock (= मयूर) L. (Monier-Williams)

Rebus: Perhaps also as morakkha "a peacock's eye" at VbhA 63 (morakkhaka loha, a kind of copper, grouped with pisācaloha). It is more likely however that morakkha is distorted fr. *mauryaka, patronymic of mura, a local (tribal) designation (cp. murala), then by pop. etym. connected with mora peacock. With this cp. Sk. moraka "a kind of steel" BR. (Pali)मोरकम् mōrakamमोरकम् 1 A kind of steel.(Samskritam.Apte)

Hieroglyph: पोळ [ pōḷa ] m A bull dedicated to the gods, marked with a trident and discus, and set at large.  m (पोळ) A festive day for cattle,--the day of new moon of श्रावण or of भाद्रपद. Bullocks are exempted from labor; variously daubed and decorated; and paraded about in worship. 

Hieroglyph: पोळ [ pōḷa ] f A wall of loose stones. n C (Or पोळें) A honeycomb.पोळा [ pōḷā ] The cake-form portion of a honeycomb.पोळें [ pōḷēṃ ] n C A cake-form or flat honeycomb.

Rebus: पोळ [ pōḷa ] magnetite (iron ore) (Munda) पोलाद (p. 533) [ pōlāda ] n ( or P) Steel. पोलादी a Of steel. پولاد polād, s.m. (6th) The finest kind of steel. Sing. and Pl. See فولاد P فولاد folād or fūlād, s.m. (6th) Steel. Sing. and Pl.P فولادي folādī or fūlādī, adj. Made of steel, steel.(Pashto) pŏlād प्वलाद् or phōlād फोलाद् । मृदुलोहविशेषः m. steel (Gr.M.; Rām. 431, 635, phōlād).  pŏlödi प्वला&above;दि&below;, pōlödi फोला&above;दि&below;, or phōlödi फोला&above;दि&below; (= ) । लोहविशेषमयः adj. c.g. of steel, steel (Rām. 19, 974, 167, pōo).pŏlāduwu प्वलादुवु&below; । शस्त्रविशेषमयः adj. (f. pŏlādüvü प्वलाद&above;वू&below;), made of steel (H. v, 4).(Kashmiri)

tarḵẖaʿh aospīnaʿh, s.f. (3rd) Bar-iron (particularly the iron brought into Afg̠ẖānistān from Bombay, considered very inferior). Pl. يْ ey. خوږه اوسپینه ḵẖwaj̱ẕaʿh aospīnaʿh, The iron of Ḵẖurāsān, used in making steel and for all fine work.(Pashto) A. tikhā ʻ steel,M. tīkh ʻ pungent ʼ, tīkhẽ n. ʻ steel ʼ(CDIAL 5839) M. tikhār ʻ pungent ʼ, n. ʻ steel ʼ, tikhā̆rṇẽ ʻ to sharpen ʼ.(CDIAL 5840) एषणी 1 A goldsmith's balance. -2 A probe (of iron or steel).(Samskritam.Apte)

̃কার n. a blacksmith.  (Bengali)

The narrative of metalwork by Bhāratam Janam is embellished by an event enshrined in painting. The event occurred ca. 327 BCE when Purushottama presented an Indian steel ukku (wootz) sword to Alexander. The painting is in SAIL Institute, Ranchi.

Moola Mookambika, Kodachadri. Iron pillar.
Sankara Peetham, Kodachadri.
Rust Free Iron Pillar on top of Kodachadri Hill at Kollur, Shimoga Dt., Karnataka, India.

The iron pillar at Kodachadri in Karnataka

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 appeared^5,6 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 theTri-   (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.

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1. Hadfield, R., J. Iron Steel Inst., 1912, 85, 134–174.
2. Ghosh, M. K., NML Tech. J., 1963, 5, 31–45.
3. Prakash, B. and Tripathi, V., Metals Mat., 1986, 2, 568–579.
4. Balasubramanian, R., Curr. Sci., 1997, 73, 1057–1067.
5. Joshi, M. C. and Gupta, S. K., Kind Chandra and the Mehrauli Pillar, Kusumanjali Publication, Meerut, 1989.
6. Anantharaman, T. R., The Rustless Wonder – A Study of the Delhi Iron Pillar, Vigyan Prasar, New Delhi, 1997.

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.

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T. R. Anantharaman
 Metals and Alloys Group,

National Physical Laboratory,

Dr K. S. Krishnan Road,

New Delhi 110 012, India

http://www.iisc.ernet.in/currsci/jun10/articles13.htm

*The Kootub [Delhi], a photo by Robert and Harriet Tytler, 1858* (BL);
also: *The Kootub [Delhi]* [*Tytlers 1858b*]
http://www.columbia.edu/itc/mealac/pritchett/00routesdata/1200_1299/qutbminar/ironpillar/ironpillar.html
Iron pillar. Qutab complex.Delhi


A look at the inscription on the iron pillar
Source: Courtesy of Rob McNamee, Columbia College, Jan. 2005

One theory suggests the 7.2 meter tall  pillar (of which 1.12 meters is underground) was probably from a temple dedicated to Vishnu (the Hindu God of life & nourishment), and intended as a standard to support a figurine of hawk-faced, winged Garuda, Vishnu’s carrier, fitted in a deep socket embedded on top of the pillar.

The pillar is pinned to the ground by lead and iron projections from its buried portion.

Another theory is that the pillar itself portrayed Vishnu’s mace (“gada”) surrounded by his serrated disc (“chakra”).

Further evidence comes from the six-line three-stanza Sanskrit inscription in Brahmi script inscribed on the pillar. The inscription refers to its erection by Emperor Chandra, a devotee of Lord Vishnu, as a standard, or “Dhwaja Stambha”, in a temple called Vishnupada.

"He on whose arm fame was inscribed by the sword, when, in battle in the Vanga countries (Bengal), he kneaded (and turned) back with (his) breast the enemies who, uniting together, came against (him); He, by whom, having crossed in warfare the seven mouths of the (river) Sindhu, the Vahlikas were conquered; He, by the breezes of whose prowess the southern ocean is even still perfumed;

He, the remnant of whose energy – a burning splendor which utterly destroyed his enemies – leaves not the earth even now, just like (the residual heat of) a burned-out conflagration in a great forest; He, as if wearied, has abandoned this world, and resorted in bodily form to the other world – a place won by the merit of his deeds; (but although) he has departed, he remains on earth through (the memory of his) fame;

By the king, who attained sole sovereignty in the world, acquired by his very own arm and (possessed) for a long time; He who, having the name of Chandra, carried a beauty of countenance like the full moon, having in faith fixed his mind upon Vishnu, this lofty standard of the divine Vishnu was set up on the hill Vishnupada”

Uyudagiri Caves, Vidisha, Madhya Pradesh

Review: Delhi Iron Pillar: New Insights. Balasubramaniam, R. 2002. Delhi: Aryan Books International. Pp.168, figures 33. Price Rs.1800/- ($40/-).
by D.P. Agrawal

Several new insights on the Delhi iron pillar have been presented in the present monograph. The subject of iron extraction that was practiced in ancient India was briefly discussed and specific attention was focused on the composition and microstructure of iron of the Delhi pillar. The origin of high P content in the Delhi iron pillar, in particular, and in ancient Indian iron, in general, has also been addressed.
The identity of king Chandra of the Delhi iron pillar Sanskrit inscription has been critically addressed. The name Chandra firmly establishes that the king was Chandragupta II Vikramaditya. Numismatic evidence for the short name of Chandragupta II Vikramaditya being Chandra has been provided for the first time by comparing the archer gold coin types of all the Gupta monarchs. Arguments have been provided to show that the inscription was not posthumous in nature. The conquests of Chandra corroborate the conquests of Chandragupta II Vikramaditya. Numismatic and archaeological find spots have been analyzed to provide support to Chandragupta's conquests. The personal religion of Chandragupta II also lends strong support to his identification as Chandra. The identification of Chandra with Chandragupta II Vikramaditya poses the least contradictions. The locations of Vahlika and Vishnupadagiri have been critically analyzed. It is proposed, based on archaeological and historical evidence, that Udayagiri could be favorably considered as ancient Vishnupadagiri, where the iron pillar was originally erected. Careful archaeological excavations are necessary at Udayagiri to firmly confirm the original location of the iron pillar.
The various aspects related to the structural features of the pillar have been addressed. A detailed analysis of the dimensions of the pillar and its decorative bell capital has been presented. The presence of lead in various regions of the pillar has been addressed, along which the construction of the pillar has been explored in detail starting from the pillar bottom. The presence of lead in several regions of the pillar has been described and the possible implication for lead presence on the corrosion of the pillar has also been discussed. A brief discussion on the status of lead metallurgy in ancient India has been provided.
The various components that comprise the decorative bell capital have been addressed in detail and the joining methodology of the capital parts as well as the capital to the main body of the pillar has been established. Insights on the possible image of garuda, which was originally placed on the top of the capital, have been provided. The decorative capital of the Delhi iron pillar has been fabricated from individual pieces (that were produced by forge welding and not casting). The individual pieces that constitute the iron pillar's capital have been intelligently shrunk fit on a hollow cylinder in an artistic and aesthetic manner keeping sound engineering principles in mind. It is important to perform careful ultrasound measurements on all the various sections of the decorative capital in order to obtain further insights into the shrink fitting methodology.
The manufacturing methodology employed to construct the main body of the Delhi iron pillar has been elucidated. The vertical and horizontal methods of forging for manufacturing the main body of the pillar have been critically compared. Several aspects of the manufacturing methodology (hammering method, heating method, use of inserts, use of dies, possible handling method and surface finishing operation) have been discussed. Visual evidences suggest sideways addition of metal lumps with the aid of hand-held hammers with the pillar in the horizontal position. The addition of iron lumps on to the side of the pillar, with the pillar placed in the horizontal direction, appears the likely method of the manufacture of the pillar. The nature of the iron lumps that were forge welded on to the body has been discussed. The use of hand held hammers for the forging operation is also established. The ingenious method employed to handle such a large object has also been illustrated. The to-and-fro motion of the pillar during the forging operation must have been possible with the use of handling clamps on the pillar. The rotational motion of the pillar (and also handling) must have been aided by the use of rotating pegs inserted in the bottom and top cross sections of the pillar, and also on the sides of the pillar. The final surface finishing operations (hot hammering, chiselling and burnishing) produced the smooth surface and taper of the cylindrical pillar.
The current theories (environmental and material) for the corrosion resistance of the pillar have been critically reviewed. The apparent anomaly of a two-phase (iron and entrapped slag inclusions) heterogeneous structure of wrought iron of the Delhi pillar possessing superior corrosion resistance has been understood by mixed potential theory analysis. The nature of the protective passive layer on the corrosion resistant Delhi iron pillar has been addressed based on a detailed characterization of its rust. The rust is composed of iron hydrogen phosphate hydrate (FePO 4.H3PO 4.4H2O) in the crystalline form in addition to a-, y-, o-FeOOH and magnetite, all in amorphous form. The process of protective rust formation on DIP iron has been outlined based on the rust analysis. The passive film formation on the Delhi iron pillar has been contrasted with rusting of normal and weathering steels. The critical factor aiding the superior corrosion resistance of the Delhi iron pillar is the formation of crystalline iron hydrogen phosphate hydrate, as a thin layer next the metal-scale interface, which drastically lowers the rate of corrosion due to its low porosity content. The formation of protective crystalline phosphate is aided by alternate wetting and drying cycles, which is the important contribution of the atmosphere to the pillar's corrosion resistance. Therefore, the corrosion resistance of the Delhi iron pillar is due to both Delhi (the environment providing alternate wetting and drying conditions) and iron (with its high P content conferring protection by the formation of the crystalline iron hydrogen phosphate).
Suggestions have been provided at the end of each of the previous chapters on the studies that need to be conducted on the Delhi iron pillar. Scientists from the Indira Gandhi Centre for Atomic Research have conducted several scientific studies (in-situ metallography, radiography, sonography and surface potential measurements) on the Delhi iron pillar in 2001 (IGCAR 2001) and these studies should shed valuable insights. Most importantly, there is an urgent need to replace the lead sheet covering the surface of the pillar in the buried underground regions. When the pillar was re-erected by Beglar in the 19th century AD, the stone platform was constructed and a coating of lead was provided on the buried underground surface of the pillar. This uneven coating of lead (of about 3 mm in thickness) was found to be in an excellent state of preservation when the buried regions of the pillar was again excavated in 1961 on the eve of the centenary of the Archaeological Survey of India. However, the buried portion was found covered with rust layers ranging from a few mm to 15 mm. After removal of the rust scales (Pl. 36a), numerous cavities and corrosion pits were observed on the surface. The preliminary treatment of the pillar comprised of elimination of rust, earthy accretions and water- soluble salts resulting in the structure shown in Pl. 36b. The holes, cracks and cavities were consolidated and provided a rust preventive treatmen. The lead sheet coating was again provided to the surface for protecting the pillar from direct contact with mortar and the saline soil on the recommendation of the structural conservators and archaeological engineers. This new lead coating was provided much against the wishes of the Chief Chemist of ASI (Lal 1996). Therefore, the present corrosion rate of iron in the buried regions is much more than that of the exposed surface due to galvanic action with the lead layer, as lead is cathodic with respect to iron (Balasubramaniam 1999b). The iron in the buried underground region is currently subjected to intense galvanic corrosion. It has been suggested, first by Lal (1996), and recently by Anantharaman (1996) and Balasubramaniam (1997b), that the lead coating be removed and replaced with a zinc coating, because, unlike lead, zinc is anodic with respect to iron and therefore would sacrificially protect the iron underneath. However, this may not be appropriate because zinc corrodes rapidly in saline soils and the soil around the pillar, in its current location, is loaded with chlorides and sulphates (LaI1996). It is important to replace this lead coating (Pl. 38) with another suitable coating (epoxy-based coating, especially if the soil is saline, and maybe combined with cathodic protection) for proper preservation of this important cultural and scientific object (Pl. 39). The replacement of lead coating with a suitable coating must be addressed at the earliest by excavating the bottom regions of the pillar.
Although the Delhi iron pillar has been the focus of attention in the present monograph, it must be realized that there are several other large ancient iron objects in India. Some of these objects would be briefly reviewed here. The study of these objects has not been taken up on a large scale, with the reason probably being the lack of knowledge of these objects. It is anticipated that serious studies in the future will address these objects.

Image number: S0002164
The Lat Masjid (The Iron Pillar) - Dhar - Madhya Pradesh - Central India
Artist / photographer: Vernon & Co.Date: 1912
Country: India http://images.rgs.org/imageDetails.aspx?barcode=5620