Indian Science and Technology in the Eighteenth Century: Some Contemporary European Accounts c23.s5.t11: Conclusion

Indian Science and Technology in the Eighteenth Century: Some Contemporary European Accounts c23.s5.t11

Language: English

Conclusion

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It was my intention to have compared this little furnace with some of the minor furnaces of Europe—but as my knowledge of the latter must have been derived from books, I prefer giving facts derived from actual experiment, and leave the comparison to those who are better able to make it: the quantity of crude metal smelted in my four furnaces from the 30th April to the 6th June, was¹² 354½ maunds, and its cost was 304 Nagpur or 260 Calcutta Sicca Rupees—hence its cost per maund was 11¾ annas, or two pounds, six shillings per English ton—and the produce per week of four furnaces was 71 maunds or 2¼ English tons.

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These data show the cost of the iron both in its crude and malleable state and Captain, now Colonel Presgrave’s report gives the latter so fair a character that it may be useful to follow up that report by another obtained from the Calcutta Mint on some pieces of *Jowli* and *Ageriya* iron which were wrought up to the state of English bar iron—and submitted to trial—the substance of the report is as follows:

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A piece of the Jowli iron being broken showed about half the surface of a fine blue tough appearance, the other half had a very brittle appearance of a glassy white colour resembling what the smiths in England call cold-short; this piece 1 inch broad and ¾ inch thick was put into a clam and a lever applied to it; it twisted with a fair resistance, and bore one revolution in 6 inches without showing a fracture; it was then warmed and a hole punched through it, which it bore in a way that would have been expected in a piece of good English iron and better than the general run of English iron purchased in the bazar would have borne it. An eye being turned at each end, the space of 10 inches long was drawn down to one third of an inch square, and dead weight scale fashion without the use of the lever applied and in the length of six inches it elongated:

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| 1/10th of an inch with | 3378 | lbs | |
| 2/10th “ “ | 3624 | ” | |
| 3/10th “ “ | 4795 | ” | |
| 5/10th “ “ | 5127 | ” | |

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and drew itself to near a point and broke with 5246.

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A piece of the Ageriya iron, on being broke, showed a small portion of its fracture light blue tough vein, the remainder silvery white, showing very fine particles, and was what the smiths in England would say had an inferior appearance, it was 1 inch broad by inch thick, and was twisted cold one revolution in 6 inches without showing a fracture and appeared to be much stronger (to the twist in proportion) than the above piece from Jowli, though much softer; it was then heated, and punched which it bore in a manner sufficient to give it the character of very fair average iron; an eye being turned at each end, the space of ten inches long was drawn down to one third and dead weight scale fashion without the use of the lever, applied and in the length of six inches—it elongated 1/20 of an inch, with 4748 lbs, and made a square break with 5376 lbs.

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Though the Ageriya piece gave no notice of its approaching failure, whilst suspending a weight; yet when brought to the bend, it showed itself possessed of the power of elongating, and bore more bend without showing a fracture than the piece of Jowli and stood the bend better than the general run of English iron purchased in the bazar.

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The above statement was addressed to Captain Forbes, superintendent of the hon’ble Company’s steam engines and machinery, to whom I applied to obtain a trial and the experiments were all made by one of the most able and practical men of the Mint—named Thomas Pigg.

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Having now exhausted all my information which was obtained from actual experiment and impartial trial and proof I shall conclude with the following remarks—viz: that the Indian forge is able to make crude metal, for two pounds six shillings, and good malleable iron for five pounds ten shillings per English ton; it is moreover susceptible of improvement; it requires but little outlay; it is portable; and may be transported from place to place, the implements being the only things necessary to carry; it may be erected in places which combine the advantages of proximity of ore and fuel and where other furnaces requiring a large supply of water cannot be set up—and it may be erected for temporary purposes and abandoned when the object is fulfilled without material loss, the furnaces being the only part which would be lost and their cost is about 6 shillings each.

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The employment of so simple a forge in England would be absurd—but considering it an instrument adapted to the existing condition of the country where it is used—it assumes a different character—for such is the cheapness of labour and fuel that I question whether any other furnace would compete with it—and if by improvement it can be made capable of working on a larger scale; arsenal materials, materials for bridges and other heavy work—it certainly is an object worthy of attention, as a great saving of expense might be effected by its use.

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Note
1. Laterite is a term given by Dr Buchanan to a species of iron clay very prevalent in India.
2. *Note*: See the map which accompanies this paper. [Omitted here. —*Editor*].
3. *Note*: It may here be observed the nature of the clay is a material point with regard to this implement, and at Tendukaira it is well adapted, being near the great trap-range, and reposing on a mass of cretaceous limestone belonging to the trap family; in all probability therefore it contains a small portion of lime; a few small grains of wacke may also be observed in it and in addition to these *Kodo* straw being mixed with it the potash derived from these materials facilitates the fusion of its silex, whilst the lime renders it a fusible compound, the ingredients of which are well assorted, and seem to be well adapted for use. The native smelters once deserted these mines on account of some pique, but the quality of the clay brought them back again.
4. *Note*: The broad end 3½, the narrow end 2½, the mean of which is 3 parts. These dimensions do not greatly differ from those of the native smelters, on the contrary they are founded on the mean of all the measures I could procure—and the difference consists in their being regular and fixed while those of the natives are irregular and often governed by caprice.
5. *Note*: The vertical angle is obtained by means of the wedge the thickness of which is adapted to the angle of 12 degrees, and the horizontal angle is obtained by keeping the ends of the wind tubes a certain number of fingers breadth as under when embedded in the Akaira. These quantities never differ much.

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6. *Note:* The refinery is convertible into a blacksmith's forge by taking out the iron plate and building up a wall in the middle so as to destroy the reverberating effect.

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7. The furnaces all varied in their produce but the mean is 18½ Panchseri—a Panchseri is 5 sers—eight of which or 40 sers are equal to a maund.

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8. *Note:* I tried all the descriptions of ore and made experiments on roasting it—the result of which could only be ascertained by making the iron; the first six marks constituted the bulk of the quantity submitted for trial, and their iron result may be safely taken as a fair average; the other three are the result of my experiments on roasting the ore—previous to smelting.

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9. The common English bar iron yields about 70 per cent of such highly wrought bars.

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10. *Note:* The roasting of iron ore, previous to smelting is supposed to repay with advantage, the additional expense it occasions; and the reason of its ill success with me I can only explain as follows: The furnaces of Europe are I believe in general perpendicular that is—the ore and fuel fall perpendicularly and consequently their descent is more rapid; but in India the furnaces are oblique, and the descent of ore and fuel more gradual and hence sufficient time is gained for dissipating sulphur, or other volatile ingredients before it reaches the point of greatest heat; this appears to be the fact as the chimneys of these furnaces are always coated with sulphur; it would seem also that the metal acquires more carbon under the effect of both operations than the Indian refinery, constituted as it now is, can dispose of—and hence the hardness of the last three marks as observed by Captain Presgrave.

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11. *Statement of Expense*

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| 6 Men for each Smelting Furnace or 24 for 4 furnaces from 30th April to 6th June, or 1¼ month at 4 Rs. each per mensem | 120-0 |
| Charcoal for the Furnace for the same period | 134-0 |
| For digging ore | 14-2 |
| Carriage of ore | 15-5 |
| Carriage of charcoal | 14-9 |
| Head-Man | 6.0 |
| *Total Cost of Smelting* | *304-0* |