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History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c11.s1: Indus Civilization

History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c11.s1

Language
English

Contents

Indus Civilization

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The Indus civilization or Harappan culture (named after the first discovered site, Harappa) is well known for its uniformity and standardization in weights, measures, ceramics, architecture, extended over more than a million square kilometers, an area larger than that of Pakistan today. It spread in the west to Sutkagendor (Makran), in the east to Alamgirpur (Uttar Pradesh), to Rupar in the north and to Bhagwatrav in the south (Gujarat). Whether this uniformity indicates an empire or a trading zone can only be guessed.

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Bead factories have been discovered at the Harappan sites of Chanhudaro (Mackay, 1943) and Lothal (Rao, 1973). Beads were made of agate, carnelian, faience, shell, terracotta, gold, silver, and steatite; beads with inlay work and etchings were probably exported.

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A highly standardised system of weights and measures was evolved by the Harappans. Two systems of measurement were used : cubits and a long foot. A cubit was about 52 cm (52.5-52.8cm) and the long foot was 33.5cm. Graduated scales with decimal graduations (upto 1.7mm) have been reported. The cubical, stone weights followed a binary system (1, 2, 1/3 × 8, 4, 8, 16, 32 upto 12800) in the lower denominations, and the traditional Indian ratio of 1:16 (1 rupee is equal to 16 annas) may derive from this. The unit weighs 13.625 gm. Higher weights follow a decimal system with fractional weights in thirds. The accuracy of these weights throughout the Harappan territory is quite remarkable.

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According to the texts, Meluhha (identified with the Harappan zone) exported a variety of timbers, copper, gold dust, lapis lazuli, carnelian and other stones, ivory figurines of birds and monkeys, etc. Most of these items were available from India, except perhaps lapis lazuli. Baluchistan, Afghanistan, Oman and Rajasthan all have copper mines. Sixteen copper furnaces from Harappa, the copper workshops in Lothal, and the large quantities of copper-oxide ore from a brick-lined pit at Mohenjodaro all suggest that copper metallurgy was a developed craft in the Indus civilization. Placer gold is found in the streams of Punjab and Kashmir and may have been the source of the gold dust.

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Wheeler’s (1968) time bracket of approximately 2500-1500 B.C. for the Harappan culture was based upon the discovery of Harappan objects in Western Asian archaeological contexts and the Mesopotamian artifacts in Harappan sites. Fairservis (1967) found it hard to accept a millennium-long monotony for the Harappan culture and preferred a range of about 2000-1500 B.C. Allchin and Allchin (1968) proposed that the period around 2150-1750 B.C. would better support the evidence. We, however, have suggested periods of 2300-2000 B.C. for the nuclear regions and 2200-1700 B.C. for the peripheral zone of the Harappan culture (Agrawal and Kusumgar, 1974).

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There is, however, more definite evidence for contacts between Mesopotamia and the Indus during the Sargon of Agade (around 2350 B.C.) and Isin-Larsa periods (about 1900-2000 B.C.). Disk-shaped beads of gold and silver with axial tubes have been reported from Akkadian and Troy II levels.

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Analyzing the data on contacts between Mesopotamia and the Indus, Buchanan concluded: "The Mesopotamian evidence, therefore, does not require a date of for the mature Indus civilization much, if at all, before the 23rd century B.C. It would be surprising if it lasted more than 300 years. We think that this is a fairly balanced conclusion from the archaeological evidence" (1967 : 107).

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A fairly large number of radiocarbon dates is now available for Harappan sites (Agrawal and Kusumgar 1974), and there are also 14C dated sites like Balakot, Damb Sadaat, and Kot Diji with both pre-Harappan and Harappan deposits. Harappa itself has few 14C dates nor do we have any dates for the lower levels of Mohenjodaro. Radiocarbon dates in the main Indus region show a spread of about 4250-3950 B.P., which agrees well with the archaeological evidence from Mesopotamia.

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In the peripheral zone, Kalibangan in Rajasthan has been exhaustively dated. Considering only those samples that were protected from more recent contamination by a good soil cover, we find that TF-607 and TF-608 date the beginning of the Harappan culture at that site around 4150 B.P. and that TF-143, TF-149 and TF-946 date the upper levels to around 3700 B.P. Lothal provides a quite consistent set of dates giving a minimum spread of 4050- 3650 B.P. (obtained by adding one standard deviation on either side). In view of the thinness of the occupational deposit at Lothal, compared to the other Harappan sites, we prefer the minimum time spread of around 4050-3750 B.P. This bracket is further confirmed by the radiocarbon dates from Surkotada, also in Gujarat, where a bracket of 4150-3750 B.P. covers the total Harappan occupation and is in conformity with the dates from Rojdi. Thus, a comprehensive bracket of 4250-3650 covers both the nuclear (main Indus) and the peripheral Harappan timespreads. (Fig. 1).

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RADIOCARBON DATES IN YEARS B.C. (BASED ON HALF - LIFE 5730 YRS)

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*Fig. 1 Chronological time spreads of different stone and metal using cultures in India*

Metal Technology of the Harappans

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Before we discuss copper artifacts and their technology, it will be useful to mention the types of ores and their main locations in India. The main Indian copper minerals are (a) chalcopyrite (CuS.Fe₂S₃), (b) chalcocite (Cu₂S), (c) malachite (CuCO₃). Cu(OH)₂, and (d) azurite (2 CuCO₃.Cu(OH)₂). The major copper mines are located in the 80 km long Khetri belt in Rajasthan and the Singhbhum copper belt in Bihar, which is 130km in length. Other important deposits occur in the districts of Guntur, Arcot, and Kumaon (Brown and Dey 1955; Agrawal 1971). Sources in Baluchistan, such as Shah Maksud and Kalih Zeri, have also been mentioned as probable mines for Harappan copper (Sana Ullah 1931).

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Pre-Harappan (or Early Harappan) contexts are generally poor in copper; from the pre-Harappan levels of Kalibangan, for example, we have three artifacts, including a *parasu* (hatchet). Only from Nal, in Quetta, is there a richer repertoire composed of knives, bangles, and axes.

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The Harappans were far richer in copper and also in copper tool types, although they continued to use chert blades. They had flat celts, knives, arrowheads, spearheads, chisels, razors, fishhooks, saws, drills, etc. (*Fig. 2*), in addition to vessels and metal figurines. It may be noted here that tubular drills, true saws, and needles with eyes at the pointed ends are contributions of the Harappans to the world of instruments. The Harappans were the only people in India who used metal lavishly for vessels, including a variety of vases.

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Most of them seem to have been made in two parts, the bottom and the top, and then joined together. For vessel fabrication they used sinking, raising and lapping, and for joining metal they used *running* on and riveting techniques (soldering was used only for noble metals). Metallographic examination shows that they resorted to open and closed casting, slow cooling of casting, annealing and cold work (Agrawal 1971; Agrawal et al. 1978b).

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Small animal and female figurines (for example, see *Fig.3*) were cast by the *cire perdue* (lost wax) process (*Fig. 4*), although none of the Harappan moulds is as ornate as the Chinese, nor as intricate as the Mesopotamian examples. A number of axes from Chanhudaro and Mohenjodaro show puckered surfaces, indicating that they did not always use *green poling* in open moulds; the use of green branches for poling in molten copper releases hydrocarbons which reduce the oxides, thus avoiding blowholes.

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Pure copper is not a hard metal, but it can be made harder through beating (cold work). Too much cold work, however, makes the edge brittle and it then requires heating (annealing) to make it ductile again. Alloying copper with arsenic or tin increases its hardness considerably, and today we know that copper should be alloyed with up to 4-5% arsenic and 8-12% tin for maximal ductility and hardness. We have now more than 200 analyses of Harappan artifacts (Agrawal et al., 1978b), which indicates that only 23% were alloyed with tin, 12% with arsenic, 8% with lead, besides a smaller percentage with an admixture of these elements. It should be noted that the Harappans used both Sn and As alloying and the Chalcolithic cultures exclusively tin alloying (*Fig.5*). In an effort to locate copper artifacts, we find a hatchet at Khurdi (*Fig.6*) similar to one found at Kalibangan. As regards Fig. 2 Main Harappan metal artifact repertoire

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Fig. 3 Bronze image of a dancing girl from Mohenjodaro indicates the use of cire perdue technique

Cire Perdue Casting

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1 2 3 4

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Fig. 4 Cire Perdue casting method explained: Stage 1. The terracotta core with pins., Stage 2. Wax model of the cat enclosing the terracotta core.; Stage 3. Terracotta covering over the wax model; the arrows indicate inlet and outlet for the molten metal. Stage 4. The molten metal washes out the wax model and replaces it with the metal. The casting is allowed to cool and the clay covering is broken to uncover the bronze figure

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HARAPPA CULTURE CHALCOLITHIC CULTURE COPPER HOARD CULTURE

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Fig. 5. Histograms of alloying patterns of protohistoric cultures. Note that only the Harappans use both tin and arsenic alloying. The Chalcolithic cultures use only tin and the Copper Hoard culture only arsenic alloying. This pattern shows that these three technologies were distinctive copper sources used by the Harappans, a large number of ancient copper workings have been radiocarbon dated (Agrawal et al, 1976), but none of the dates so far is older then 3150 B.P. With further work, older working are expected to be found. We have also tried to use comparisons of trace-impurity patterns between ores and artifacts. In both the Khetri (Rajasthan) ores and Harappan artifacts, gold is absent, but a number of other trace elements (silver, iron, arsenic, antimony, lead, bismuth, tin, nickel, zinc, manganese, cobalt, aluminium, copper molybdenum, titanium, magnesium, and vanadium) are present, suggesting the use of the Khetri ores by the Harappans. This method is not foolproof, and it is therefore hoped that results can be reconfirmed by the use of lead isotope ratio comparison between ores and artifacts and also by the techniques used by Chernykh and Tarakhova (personal comm.). Circumstantially, Khetri mines of Rajasthan are likely to have been exploited by the Harappans, because they are found in roughly the same areas.

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