indian heritage in metals alloys

8/14/2019 Indian Heritage in Metals Alloys

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Indian Institute of Scientific Heritage www.iish.org

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INDIAN INSTITUTE OF SCIENTIFIC HERITAGETriva nd rum 695 018, Ind ia

( 0471-2490149)

www.iishglobal.org

INDIAN HERITAGE

IN

METALS AND ALLOYS
http://www.iishglobal.org/http://www.iishglobal.org/


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INDIAN HERITAGE IN METALS AND ALLOYS

It is of great importance to discuss the subject of ancient Indian metallurgical science.

Important and relevant evidences are available on this subject from the Sanskrit based

scientific literature and also from the archeological research works. As mentioned in the

introduction of this thesis, every artifacts obtained during the archeological excavation,

has been evaluated for their periods through the modern carbon dating techniques.

Similarly the period of active exploitation of the mines for the minerals and ores was also

evaluated through the same technique. Using that data, the date of the mines and metal

samples was mentioned in the discussion part of the thesis.

A variety of Sanskrit literature both spiritual and scientific are available for screening the

ancient metallurgical knowledge. The information on the literature can be proved correct

by the evidences available from thousands of ancient metallic samples of many millennia

old collected from various sites.

Vedas give preliminary information on the names of certain metals. Susrutha

samhitha, the celebrated Ayurvedic book also contain large amount of data on the

metals which are used for the surgical instruments. They also contain information

regarding carburisation type of techniques adopted for the metals used for thesurgical instruments. Kautilya s Arthasasthra gives great details on a variety of ores

for each of the metals known during his period (300 BC). A Buddhist monk

Nagarjuna has written Rasaratnakara in 200 AD. It appears from the available

literature source that another Buddhist monk with the same name , Nagarjuna has

rewritten the book in the 6th century AD. This book contains variety of information

on the metals and alloys, including their production and purification. Rasahrudaya

and Rasarnava of Govindabhatta, Rasarnavakalpa and Rasendra choodamani of

Somadeva,,etc belong to the period 9th to 11th century AD. In fact the study of

metals , their alloys and compounds was a part of the rasachikilsa. Hence all thechemical books deal with the subjects of metals and alloys. Bruhath samhitha of

Varhamihira is a general book which also describe the metal processing. Even

though there exist a few books specifically discussing the metal science like

Lohathanthra, they are not available at present in print. However some books and

connected research papers appearing on Bharadhavaja s Vymanika thanthra and


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other instruments give details of a number of artificial metals known as kruthaka

loha. Thus in this thesis work, I have gone through these Sanskrit based literature,

including the most authoritative Rasaratna samucchaya for collecting data on the

metal science.

The literature based knowledge appears to begin from the Vedas. In Rig Veda

(1.122.14) a golden ear ring is mentioned as hiranyakarnam manigreevam. A golden

necklace is again mentioned in the stanza 1.33.8 as hirnyayena manina

srumbamaana. This gives the knowledge of the metal gold as an ornaments. In

Sukla yajurveda the following lines give us the knowledge on the metals like gold,

iron, lead, tin, silver and carbon steel respectively in the following lines (18.13)

Interestingly each of these metal has different physical and chemical characteristics

and need different types of extraction and purification process. The names of these

metals give enough proof that their production technology was known.

Archeological evidences (given in the later part) support with the period, the above

statement on the knowledge of these metals. The ores and metals mentioned in the

Vedic texts are also obtained during the excavation from Lothal, Mohan jodaro,

Kalibangan, Bhagavanpura, etc. An interesting quotation from Atharva Veda gives a

comparison of the colour of the Universal person with that of various metals

(11.8.7-8)

His flesh has the colour of iron, blood has the colour of copper, bones

have the colour of tin ( or tin oxide - thrapu bhasma) and his odour is

that of pushakara (lead)

This comparison indirectly gives the knowledge of the metals and some

of their physico chemical characteristics like colour and odour,

During a period almost near to that of Vedas. Chandogya Upanishad

is one of the earliest Upanishads chronologically coming at par with

the Vedas.


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An interesting philosophical approach of the metallurgical knowledge

is given in Chandogya Upanishad (6.1.6) through one sentence and it

conveys a lot about the metals and their processing.

By knowing the nail cutter, all that is related with iron metal can be

known...... i.e. Iron is the essence of the tool.

This statement gives us a direct information that when a metal is

discussed by its name it is understood that the metal production

technology, including the knowledge of ores, metallurgical extraction,

purification, temperature connected with all these processing and also

the unit operations required to convert the ore into pure metal , was

well known

Ancient Indian mines and minerals

Even though proofs have been submitted by Mukherjee 76 on a series

of mines utilised for the production of various types of metals during

Vedic period, it appears that the earliest description of the mines is

given in the Arthasastra written by Koutilya. He has clearly given the

duties and privileges of the Director of mines.

The Director of mines is responsible for the handling and proper

utilisation of the ores, minerals, chemicals, etc. He should have the

knowledge of these materials and their availability. He is responsible

for the examination and utilisation of three types of ores classified

under bhoomi - prasthara - rasa dhatus. He should know the quality

of the ores by means of colour, smell , taste and using the acidic -

alkaline textural flavours.

Koutilya focussed mainly the gold, silver lead, tin , coper and zinc

ores and metals in his explanations (Arthasasthra 2.6.4) . He has

given the correct picture of the utilisation of the resources from the

mines as the treasury has its source of income from the mines, from

the treasury, the army comes into being, with the treasury and the


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army, land is obtained. With the treasury is its ornaments, the mines.

( Arthasasthra 2.12.37).

In Arthasasthra the melting process (dravana or vipalana) ,

solidification process (mruthi)etc., are explained very systematically. Proper heating is required for making the metal alloys says

Arthasasthra

As a scientific proof on the metal processing, the carbon dating

technique has shown that extraction and purification of the metals

like silver, tin, copper, lead, iron and zinc, were undertaken during

Koutilyas period (300 BC) and far before that.

Also the best evidences are available for the Sanskrit explanation given

by Koutilya on the mines, which can be substantiated by the above

techniques. Based on the study reports it could be proved that the

Rajpura, Dariba, Udaipur mines in Rajasthan were very active from

1300 BC . The Hatti mines in Karnataka was active from 1000 BC,

Ramapura and Agucha mines were exploited for the metals from 700

BC and Zawarmala, Ambamata mines of Rajasthan were actively

utilised for the metals from 500 BC. One of the most important

observation is that the Kormaranahalli and Tadanhalli mines in

Karnataka were yielding iron ores from 1300 BC. The description ofiron in Vedas was also due to the fact that mines from Atranjikhera,

Pandu - Rajar - Dhibi in Bengal ; Alamghir in Rajasthan and

Varanasi in Uttarpradesh were all subjected to a very high level of

iron ore production during this period i.e. Also before and during

1200 BC, which is crucial period as far as iron production is

concerned.

It is important to search the Sanskrit based information mentionedabout the physico chemical characteristics of the ores and minerals of

the metals. In Arthasasthra ( 2.12.30) the ores are thus described:


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The colour of different ores can be yellow, mixed yellowish red, when

disintegrated it can have bluish colour, and the colour of green gram,

black gram, curd, turmeric, terminelia seeds, liver of animal, spleen,

sand, jasmine bud, seed of neem, etc. Some of the ores when heated

remain the same and some ejects out smoke and surf.

These descriptions of the ores are perfectly in agreement with the

characteristics of the ores of copper, gold, silver, lead and tin .

A series of outstanding descriptions are also given on a variety of

minerals and ores of specific metals. The scientific content of these

descriptions can be obviously available when those facts are compared

with the actual modern knowledge on the subject. The description ofthe silver ores is given in Artha sasthra:

Native silver ores are of eighteen types. They are classified on the basis

of their colour:. the ores having the colour of conch shell, camphor,

pearl, jewel, lotus flower, etc., some times the silver ore get mixed with

lead and some are white outside and black inside. When heated some

of the ores produce smoke. In these ores, the density is directly

proportional to the metal content in it.

The copper ores are thus described in the part of Artha sasthra :

The copper ores may have different colours and appearance as:

heavy, tawny, green (Chalcopyrite ore) ; dark blue (malachite ore);

yellowish tint (azurite ore and pale red (native ore of copper)

This explanation in Arthasasthra agree literally all the qualifications ofvarious types of copper ores given in the parenthesis.

Lead ores are described thus in the book:


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It is greyish black like kaka mechaka (galena ore of lead), yellow like

pigeon bile (gossam ore). (Here too the characteristics agree fully with

the descriptions given.)

The tin ores are described in these words by Koutilya:

The tin ores are grey saline or like brown burnt earth (cassiterite ore

of tin)

Iron ores are thus described and their modern equivalents are also

given:

Iron ores are greasy stone, pale red and having the colour of limonite

or of the Sindudrava flower ( haematite ore of iron). The iron orewhich has the colour of crow egg or birch leaf is vaikruthaka dhatu (

magnetite ore).

After describing the physico chemical type of characteristics, Koutilya

has further mentioned the duties of the Lohadhyaksha. The

Lohadhyaksha should establish factories for the production of metals

like copper, lead, tin, copper and alloys like vaikruntaka, arakuta,

brass , bronze and bell metal . All the business related with the

metals should be undertaken by him. Says Artha sasthra:

The subject of metallurgical science inevitably deals with the subject of

furnaces, kilns and crucibles used for the production and purification

of the metals and alloys. Thus mentioned in Rasaratna samucchaya

on the kilns used for the production and purification of the metals:

The equipment used for removing the impurities is known as the

Musha/ kiln.

Different types clay is used for the preparation of the kilns. This

gives a good information on the ancient Indian background knowledge

on the ceramics science.

Yellowish white and heavy sand or reddish white sand that can

withstand high temperature for a long time, is the best for the

manufacture of the kilns .


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Different types of kilns / mushas used for processing a variety of ores

and metals are thus described in Rasaratna samucchaya:

Vajra-yoga-vajradravaini-gara-vara-varna-roopya-vida-vruntaka-

gostani-malla-pakva-gola-maha-manduka-musala are the names ofthe common mushas used.

Detailed descriptions are given in the Rasaratna samucchaya on the

preparation method and clay composition for the production of the

above type of kilns. Different furnaces mentioned are named here

based on their sizes, shapes and the purpose they serve.

The temperature for the extraction and purification of a metal is

attained according to the nature of the metals and ores. The process

by which metals are extracted is sometimes called Kupeepaka vidya.Different types of putas are used for getting specific temperature. All

these putas when subjected to the modern tests, are found to provide

the temperature between 750 - 900 C. The duration of

maintaining the temperature and the dimensions of these putas are

given below

Name of the putas dimensions Duration

of heat

Mahagajaputa furnace 36" width x depth 150 min

Gajaputa 22 " " 100 min

Varahaputa 16" " " 50 min

Kukkutaputa 9" " " 5 min

Kapota puta On the surface of the earth lowtemperature


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The above time duration was experimentally proved using the modern

instruments after making the putas by following the details given in

the above mentioned book on the dimensions 77

The above types of putas were made using cubical arrangement ofcow dung cakes. For example in mahagajauta, 2000 cow dung cakes

were used and in other putas 1000, 800, 40 and 8 cakes ,

respectively were used.

From this it is clear that there existed a standard set up for the

furnaces. Metallurgical process were not adopted as a crude heating

procedure. Every puta has a definite specification to follow.

Qualification of pure metals are described in Rasarnava ( 52 -55). The

purity of the metal flowing out of the furnace can be judged usingthese physical parameters.

Pure metal is the one which when melted in crucibles, does not give

sparks, bubbles, spurts, lines or scum on the surface. The molten

metal which does not produce any sound and is tranquil like gem

flows out from the furnace.

The above explanation given agree well with the qualifications on the

purity of the samples obtained during archeological studies. Thepurity of the metal was assayed using modern instruments and found

to have the following composition

Name of metal and alloys Place from where obtained

% Purity

Copper Nalanda 97.9

Copper Mohenjodaro97.1

Copper Atanjikhere 97.3

Copper Harappa 98.8


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Copper (ii) Harappa 99.0

Silver Mohan jodaro

94.5

Lead Mohan jodaro

99.7

Bronze Takshasila 85.0 % Cu + 9.8 %

Sn

Brass Takshasila 55.4% Cu + 34.3%

Zn

These metal and alloy samples were produced during a period

ranging between 3000 BC - 200 BC

Thus archeological evidences submit absolute proofs for the

metallurgical capabilities explained in the Sanskrit literature.

Corrosion of metals: Degradation of metals by way of the reaction with

oxygen, moisture, acidic and alkaline materials present in the

atmospheric air is a natural phenomena. This is termed as corrosionin modern science. The concept connected with the corrosion and the

degradation of metals is clearly mentioned in Rasarnava (7. 89, 90)

Gold, silver, copper, iron, lead and tin are the six types of metals

which undergo self degradation at a slower rate in the reverse order of

this arrangement. ( the statement means in the reverse order of the

arrangement the metals are more and more stable)

I.e. Gold is the least (slowest) corroding and the tin is the fastest

corroding metal and the rate of corrosion increases in the ordersteadily.

Yajnavalkhya smruthi refers to the cleaning of the metals in the

Acharadhyaya 78


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Tin, lead and copper may be cleaned with alkali and acids. Iron ,

bronze and copper alloys are cleaned with ash and water.

The rationale being this is that the use of acids and alkalies rapidly

decompose and dissolve the corroded impurities accumulated on thesurface of the metals and cleanse the surface.

Alloy making: The ancient Indian authoritative knowledge on the

production of the alloys has been well appreciated from time

immemorial. A number of examples are available from different parts

of India for demonstrating the authority on the metallic alloy

production. Arthasasthra says that the coins are manufactured

using different metals, by alloying. The Director of coinsLakshanadhyaksha has the responsibility of making coins with

different denomination as given below:

The Director of coins should know how to make four types of coins: i.e.

Coins of one pana, half a pana, one fourth of a pana and one eighth of

a pana using copper, silver , lead, iron and if required other metals.

This descriptions gives the scientific way of alloying the metals known

during the period of Koutilya. The following statement if furtherexplained with the help of commentaries:

The above statement means; padajeevana type of coins contains 4

parts of silver and 11 parts of copper and 1 part of any other metals

like iron, tin, lead, or antimony. This coin is known as Mashakam.

Half of this composition known as ardha mashakam, one fourth of

this, gives a coin known as kakani, one eight of one pana is ardha

kakani.

This gives an upto date type of knowledge of alloy making process for

the production of coins, which is one of the sophisticated techniques

adopted for getting uniform size, shape, weight and quality for coins


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Bronze: Bronze was one of the most commonly used alloy in ancient

India. Archeological information available on the bronze is plenty.

Bronze and brass are the two alloys obtained from almost all theexcavated sites, in India. This shows that, the processes of

preparation of bronze was familiar through out this continent.

Temples in south India have many bronze and brass statues , idols,

big vessels and other items.

Panini s Ashtadhyayee ( 8.2.3.1) gives the information on brass and

bronze vessels.

Brass and bronze vessels can be used for storing ghee, milk, etc.

Panini was a contemporary scholar of the ruler Pushyamitra Sunga

(187 BC). Rasaratna samucchaya (5.205) gives the composition of one

type of bronze as:

Eight part by weight of copper and two parts by weight of tin give the

bronze.

Archeological studies support this description , as many bronze

samples contained 10 -20 % tin alloyed with copper.

Brass: The Indian technology of brass production is as old as that of

bronze. The metal, zinc was called suvarnakara because it converts

copper into gold like alloy. Two methods were followed in India for the

production of brass. First method, by directly alloying the copper and

zinc and the second is by alloying copper with zinc minerals, like

calamine. Rasaratnakara (3) gives this explanation:

What wonder is that calamine ( zinc ore) roasted thrice with copper

convert the latter into gold ( gold coloured alloy - brass)

The procedure explained here is the direct alloying of copper with zinc

ore. Zinc metal from the calamine ore alloys with copper to give

brass. Modern metallurgical studies have shown that the maximum

content of zinc which can alloy to form the brass, from zinc ore is 29%.


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Majority of the brass samples obtained during archeological

excavation contained less that 28% zinc. This proves the common

procedure adopted in ancient India was as given in the above Sanskrit

lines, alloying by hating copper with calamine (zinc) ore.

Rasarnva (7.34 -38) gives thus on the brass alloy formation:

Zinc, a metal like tin converts copper into gold.

This line is partly repetition of that from Rasaratnakara . Hence the

word gold is to be interpreted as gold like

Panini in Ashtadhyayi (5.1.30) has mentioned the word Suvarnakara

for tin/zinc while discussing the coins made of copper by alloying with

tin / zinc.

Brass samples obtained from Lothal contained 6.04% zinc and 70 %

copper. This belongs to the period of 2200 BC. Earliest brass sample

obtained, containing more than 28% zinc, was from Takshasila (4th

century BC). Obviously, here the zinc metal was alloyed directly with

copper, since the zinc content in the alloy was above 29%. Rasaratna

samucchaya ( 5.191 -193) gives the description of brass as follows

Brass is of two kinds which are known as reetika and kakatundi.

The former when heated and plunged into sour rice gruel turns into

copper colour and the latter turns black by the above treatment. Theformer is heavy, soft, yellow, resistant to hammering, brilliant and

smooth.

This explanation stands scientific as far as the qualifications of

alpha and beta types of brass are concerned. The brass which

contains less than 28% zinc has all the above said property and it is

known as alpha brass, where as the second one is beta brass that

contains above 28% zinc in it.

Bell metal: The qualification required for the bell metal alloy is

different from those of other types of alloys. It should give a perfect,

melodious and attractive sound. The bell metal alloy is mentioned in


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Arthasasthra. Method for separating copper from bell metal is

described in Rasaratna samucchaya (8.37)

Molten bell metal is heated with a little tala or orpiment, blown with a

bent tube and freed from Ranga of tin and what we get is the copperseparated from bell metal . (Ghoshakrushtam thaamram means the

copper extracted from bell metal). This copper may contain traces of

other metal components also, hence may have special grade and

quality.

Panchaloha: Panchaloha is the most common alloy used in making

idols in temples for the last few thousand years. Sanskrit and

regional language literature give detailed description on the

panchaloha vigrahas. Charka samhitha gives this explanation (1.70)

In pancha loha , gold and separately copper, silver, tin, lead and iron

are alloyed.

In Rasaratna samucchaya (5.212) panchaloha alloy is separately

described as follows:

An alloy of five metals of tin, copper , brass , iron and lead is called

panchaloha.

Metal seal:

Bruhath samhitha of Varahamihira (57 -1.7) gives the explanation of

a metal seal known as Vajrasanghatha.

An alloy of eight parts lead, two parts bell metal and one part brass

has been described by Maya as the vajra sanghatha metal seal.

Pure metals:

Copper: Yajurveda mentions about copper, in the name thamra.Copper metallurgy has got a long tradition in India. Mehargarh

excavation has shown that the copper samples obtained from there

belonged to 8000 BC. One of the many samples obtained from this site

recorded the production period which can be around 7786 +/- 120


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BC. More than 2500 copper samples could be excavated from different

archeological sites.

As far as the Sanskrit literature is concerned, it appears that

Arthasasthra comes first in the description of copper, other than

Vedas. The earlier mentioned are the descriptions of copper ore and

various alloys made of copper. The purity of copper metal obtained

from Harappa was 99% and that obtained from Mohen jodaro was 97

%. Ancient copper technology should have been good to get this level

of purity for the copper metal.

Iron: There are evidences available from Mesopotamia, Egypt and

Afghanistan on the efforts taken in the production of iron during 3000

- 2000 BC. Similar trials were also conducted in Cyprus during 1600

BC 80 . Historical data proves that upto 1600 BC, none including

Greeks and the Mediterranean people could produce iron. After

putting all the evidences together, it can be concluded that till 1200

BC, iron production was not conducted succesfully anywhere in the

world, other than in India. Yajurveda mentions about iron as

syamam and also loham. In Susrutha samhitha and Charka

samhitha, the use of iron based drugs for treating the anemia as anasavam is mentioned. This asavam is known as Loha asavam:

For years together, the iron nails are treated/stored in ghee and that

ghee is used for the preparation of iron asavam.

Archeological evidences show that iron was commonly produced in five

regions in North India during or prior to 1200 BC. An iron sample

obtained from Ahar was dated during 1300 BC. Rasaratna

samucchaya gives defintion and explanation for the three types of iron

( Rasaratna samucchaya 69)

Three important classes of iron are Munda loha ( cast iron),

Teekshana loha (carbon steel) and Kanta loha (soft iron).


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Further classification can be seen in the explanation of each of the

above type of iron

The Munda loha is of three kinds; mrudu, kunda and kadra.

Theekshna loha is of six types. Khara, sara, hrunnala, trivrutta, vajra

and kala

Kanta loha is of five classes which are bhramaka, chumpaka,

karshaka, dravaka and romaka.

It is an interesting information to note that the above classes and

subclasses are well defined in modern science, with physico chemical

characteristics of the product.

In Rasaratna samucchaya, the qualities of roasted iron (which is ironoxide) and the rust of iron ( it is also the iron oxide) are compared

(148)

The qualities of the air roasted iron and the rust of iron are the same.

Therefore the latter was also acceptable for medicinal purposes.

Carburisation is a process of hardening the iron which is achieved by

inducing more carbon in the metal by heating. This method is of

special use in hardening and sharpening the iron tools like swords.

Bruhath samhitha (50.26) explains the method of carburisation of iron.

The iron weapons treated with a day old solution made of the burnt

powder of bananas, mixed with butter milk and then sharpened

properly, will not break in stones, nor become blunt on other

instruments.

Carburised iron weapons were spotted in many places by the

archeological study groups. The process of carburisation has been

discussed in detail by Bhatia 80 b . The quality of Indian steel hasbeen referred to by Ktesias who was in the court of Persia in the 5th

century BC. Swords made in India were purchased by Persian kings.

Alexander the Great was said to have received 30 pounds of Indian

steel in 326 BC, from King Porus for making Damascus swords.


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The above information are important historical evidences on the

capability of iron metallurgy in India and also the quality of the metal

produced here. They also support the scientific explanation given in

the Sanskrit literature.

Silver: Silver metallurgy was known to Indians at least from the period

of Mohanjo daro civilisation. A variety of silver articles was obtained

from there. Arthasasthra describes silver as follows (2.13.31)

Silver has the colour of jasmine bud. It contains a lot of lead, it may

have the colour of sky, it is white, soft and also precious. When mixed

with 4 parts of lead, the alloy will have the colour of fresh curd.

Artha sastra describes the purification method of silver as a

continuation of the above lines:

The impure silver is mixed with bone powder, 4 parts lead, 4 parts

sand, 4 times cow dung, 3 parts kopal together 17 parts. This

mixture is taken in a kiln, mixed with salt and sand and melted. The

pure silver gets separated in the pure form. If mixed with some gold, it

adds to the lustre of silver.

The above two explanations fully agree with the scientific

observations on silver metallurgy and charecteristics. In fact this is

the actual process adopted for the removal of impurities such as lead,

iron,etc from the silver during its extraction process.

Qualifications of silver are further explained in Artha sasthra (

2:14:33)

If silver is mixed with lead, it gives an alloy with a bad smell. The

alloy will be rough, less coloured and less shining in appearance.


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This silver has to be purified with the bone powder in a furnace ( if lead

is to be removed)

This concept explained is practised in the modern cupellation process

also, for the purification of silver. Instead of the calcium andphosphorous present in the bones, calcium phosphate lining is

directly given in the crucibles, known as cupels , in the modern

process. Detailed description of other silver alloys is given in Artha

sasthra ( 1.13.31)

An alloy of 3 parts of copper and 28 parts of silver has the colour

swetha lohita. The alloy with 3 parts of gold and 28 parts of silver

has a colour peetha raga.; two parts of silver and one part of gold givean alloy with green gram colour . Two parts of silver, one part of gold

and 1/6 iron give black coloured alloy which when mixed with

mercury gives silver with a colour of golden bird s feather.

These descriptions give us full information on the technology adopted

for making different types of silver alloys and also their physical

characteristics. The description continues and some more varieties of

silver alloys are mentioned:

The alloy of two parts of silver and one part of copper is known

triputakam; one part of iron and one part of silver is known as

vellakam; one part each of iron, silver and gold is known as

vellakapasaritham. One part each of copper and gold is known as

hemapasaritham.

Almost all these types of alloys could be located from various

archeological centres during excavation studies. One sample of the

silver alloy obtained from Mohan jodaro had a silver content 94.5%.

Rasarnava (12.42.2) gives the colour of silver- gold alloy

Twenty five percent gold with silver will have the colour of pure gold.


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Rasarnava (12.49.2) says that for sales purposes the above alloy can

be further mixed with silver..

Thus the literature descriptions and the practical observations on silver

are scientifically agree to the highest level of accuracy.

Mercury: Mercury is a liquid metal which is described in all the

Rasachikitsa books written in Sanskrit. Charaka samhitha and

Susrutha samhitha give detailed description on mercury and many of

its physico chemical characteristics including some of the compounds

like oxide, sulphide, sulphate, etc.

Rasaratnakara (37) gives this explanation on the distillation process of

mercury extraction

The mercury ore (known as darada ) when distilled in a distillation set

up gives drops ( of mercury ) with the help of water (when condensed

the vapour with water)

This is also the modern procedure adopted for the separation of

mercury from its ores like calamine. In Rasaratna samucchaya (8.64)

the following description is given

When the refined ore of mercury is heated in a distillation set up, the

vapours move up, down and sides. When condensed with water, it

gives drops of mercury which can be collected . This mercury when

reacted with tin, a solid amalgam is formed.

Rasaratna samucchaya ( 3.141,144) describes the mercury distillation

process

When the mercury ore is distilled and the vapours are condensed, it

gives the mercury known as suta. ( this explanation is also

application for zinc)


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Lead: Rasaratna samucchaya (5.171) gives this definition for the metal

lead:

Readily fusible, very heavy, having a black and white appearance on

fracture having off foetida odour and black on the outside surface is

the lead.

This gives an absolute characteristics of the metal lead. The purity of

lead obtained from ancient sites of Mohan jodaro was 99.7%. This is a

proof on the quality of the lead production technology existed here .

As mentioned earlier, the lead was used for making the metal seal

known as vajra sanghath an alloy containing lead as an important

component. (Bruhath samhitha 57.1.7). Rasaratna samucchaya givesone of the applications of lead ore as a hair dye (3.146)

Hingularda or cinnabar was known to occur in two varieties; inferior

and superior grades, The ore coming from Gurjar province near the

Abida mountains, coloured yellow with lamella, can be used for

preparing hair tonics or dyes.

Zinc: Zinc is an ash coloured low melting metal. It has been described

in this thesis under the alloy brass. The detailed description of the

production of zinc metal is given in Rasaratna samucchaya.

Brinjal shaped crucible is attached with a 12 angula long tube over it

like an inverted flower of dhatura. A hole of 8 angula diameter is made

in the tube. This crucible is used for the

zinc distillation (Rasaratna samucchaya 10.22,23)

A series of brinjal shaped crucibles, set up in series as rows, werefound during the excavation of zinc producing sites in Rajasthan.

Dozens of crucibles thus arranged in 6 x 6 sets, used during 1500

BC or before, could be located from these sites.


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In Rasaratnakara (31,32) the flow of zinc metal from the distillation set

up is thus described:

There is no doubt that this process yields an essence of metal (zinc) of

the appearance of tin, from the crucible known as mooka musha.

Crude tin resembles the zinc metal. Biswas 82 has given a detailed

description on the metallurgical process of ancient Indian technology

on zinc production. He has concluded here that the brass containing

36% zinc, was produced in India directly by alloying zinc and copper.

The brass samples containing 46% zinc is brittle and those

containing 36 - 46% zinc were of medium texture. This type of

products were also obtained during the excavation. Some of the brasssamples of the Vedic period belonged to alpha and beta types.

A zinc sheet was excavated from Agora, a town in Athens, Greece. It

has been proved that this sheet was produced in Takshasila in the

3rd century BC.

A number of historical and archeological evidences support that the

zinc production in India started many millennia ago. This technology

was smuggled to the West , first in 1597 AD, by a metal smithLibavius 83 . In 1616 AD, the name Zinc was given to this metal by

Parcelius. ( till then this metal was known in West as Malabar lead).

Later on, William Champion, a metal smith from Warmeley, UK. who

collected the details of the metallurgical process from Rajasthan,

applied for the patent in UK. It is said that a person by name Dr.Lane

visited Rajasthan for collecting the details of the zinc extraction

process84 and the technology was spread from there. Thus Indian

technology on the production of zinc metal got directly and indirectly

transferred to the West, during the 16th and 17th century AD


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Tin: The metal tin has been discussed in detail in almost all the

Sanskrit Rasathanthra books. Rasaratna samucchaya ( 5. 153, 154)

describes, in detail the qualifications of alpha and beta type of tin.

There are two types of tin known as khuraka and misraka. Khurakamis the superior quality tin and the misraka is the subordinate one.

Khurakam type of tin is white , soft, flexible, tooth coloured, dense,

without making the metallic sound which is beta tin and the mixed

black and white coloured one is the misraka, the alpha tin.

Rasopanishad gives a detailed description on production, purification

and alloy making with tin metal. The full chapter description on tin

can be seen in Vangasthambhana sodhana adhyaya of the

Rasopanishad. Rasarnava (7.112) gives the process for the purification

of tin metal

By putting powdered bones of buffalo in the crude molten tin metal

and sprinkling its urine, the tin can be produced and purified from its

ores.

The bone powder acts as the source of calcium for the tin purification

by acting as the flux in the removal of the impurities. The phosphorus

present in the bone reacts with atmospheric oxygen to form

phosphorous oxide and in presence of water, the phosphoric acid is

formed, which purifies the tin.

The modern technology for the production of tin came to be known in

Europe only in the 16th century AD through a metallurgist Agricola 85

where as in India the metallurgy of tin has a history of thousands of

years. The metal is also mentioned in Yajurveda as thrapu.

Vijay Deshpande 86 has conducted detailed studies on the ancientIndian technologies on tin. Particularly the details given in the

Rasopanishad and proved that all the descriptions are scientifically

true. He prepared a variety of tin alloys by following the descriptions


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given in Rasopanishads. One alloy of tin giving a marvellous

appearance is described in Rasaratna samucchaya (20 -2)

Tin with mica and equal quantity of gold are placed in a closed

crucible along with a plant product known as vimala and roasted. It isaccomplished in a koorpathootha to get an alloy of metal resembling

emerald in colour and lustre.

Dr. Pandy has proved the quality of the alloy by producing the same.

Many similar explanations are available in the Sanskrit literature on

tin based alloys . A variety of tin alloys were also excavated from the

archeological sites. A few examples are given with bronze alloys.

Gold: Gold is a metal well known to Indians for many millennia. It is

mentioned as a synonym for the wealth and property in Vedas. Gold

purification has been explained in Arthassthra (2.13.31)

Different types of gold having various colours mixed with lead and

converted into metal sheets, mixed with cow dung cakes, sand of

Sourashtra and salt. This is then heated strongly to get the best

coloured gold, in bluish white, greenish, dove coloured, etc

Many alloys of gold for coin making are described earlier in this

chapter. One such alloy referred to is given in Bharadhvaja s

Amsubhodini 87 .that alloy is prepared as follows:

Eight part of potassium iodide, 16 parts of copper of chuleethamra

grade (one out of 16 grades available) , 8 parts of gold namely

hiranyaka grade, ( one out of 12 grades of gold known). 6 parts of

arsenic sulphide, 5 parts of mercury, 6 parts of quarts are heated in a

crucible of tortoise shape and melted at 432 temperature and then

poured the molten alloy into the mould.


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This alloy was prepared by prof. Dongre 87 and proved the

descriptions are well in agreement with the facts mentioned.

Thus Sanskrit literature carry a lot of information on the subject of

metals and alloys. Many of these alloys and some of these methods

might not even have come to the notice of the modern scientists.

Hence it is worth while to peruse into the subject by which one can

fetch better or more useful information on metals and their alloys


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CONCLUSION

There were hundreds of books written in Sanskrit discussing the subjects of

mathematics, astronomy and metallurgy, which are the original contributionsof ancient Indian scientists

Hundreds of commentaries were written in Sanskrit and in other languages

which also contained original contributions other than detailed explanations of

the methods, process and data of the original book.

Many books, data and technology were transported/smuggled/taken/donated

to foreign countries during or before or after the renaissance period, in the

West.

Many of these books were translated in foreign languages by scholars. Original

books and their translated versions have also spread to different countries.

During the renaissance period many European scholars studied these books

and brought into light the original scientific content in them. Some of these

knowledge have been utilised by the Europeans and others. Some of them

were claimed by the foreigners .

In these books information on almost all the aspects of the modern

mathematics are given. These contributions start from the number system to

the most complex geometrical parameters and theorems.

Many of these discoveries are original contribution of Indians which are at

present known in the names of the Europeans or Western scholars. Many

more theorems are still unknown to the world of mathematics even now.

The Indian concept of astronomy and geography is perfect modern knowledge,

which are at par with the latest observations.


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Many details available in the modern astronomical books are also available in

the ancient Indian astronomical books, some which may need more refinement.

Some of the latest views on modern astronomy perfectly agree with the

knowledge that is thousands of years old, which originated in India.

Much of this knowledge has been obtained as a result of the original

experiments and studies conducted by ancient Indian scientists.

A variety of instruments have been explained for the determination of the

astronomical data. They were all arrived at based on the scientific

observations. In many cases only the conclusions are given in the Sanskrit

books.

Detailed observations and scientific data are presented against the

superstitions mentioned as the stories in the Puranic texts.

As far as the metallurgical part of the thesis is concerned , data available

shows that mines, minerals, metals, ores, etc, are described in detail , in

Sanskrit literature. These descriptions are substantiated by the archeological

observations.

The solid proof of the metallurgical capability available are from the

archeological sources of these metals and alloys from various sites spread over

this nation

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