Friday, August 19, 2011

Chennai Chunam

Recreations in Agriculture, Natural History, Arts and Miscellaneous literature, by James Anderson, LLD was published in April 1799.

James Anderson was a distinguished personality who was based in Chennai and whose botanical garden in the city was world-famous. The suffix to his name, apart from the LLD, reads

“FRS. and FSA.E . Honourary member of the Society of Arts, Agriculture, Sec. Bath; of the Philosophical Society, Manchester; of the Agricultural Society, Altringham ; of the Philosophical So-ciety, Newcastle; of the Society for promoting Natural History, London, of the Academy of Arts, Sciences, and Belles Lettres, Dijon; of the Royal Society of Agriculture, St. Petersburg; of the Royal Economical Society, Berlin; of the Philosophical Society, Philadelphia; correspondent member of the Royal Society of Agriculturet Paris; and Author of several performances.”

Here, he describes the virtues of ‘chunam’- or limestone used as cementing material in India, and recommends it for use in England as well.

No cement for building hath as yet been discovered in Europe that can be compared with the fine Chunam of India for closeness, toughness, durability, and beauty. It sets as quickly as stucco, and at the same time acquires a hardness greatly superior to our best lime mortar, and is alike proper for works under water, as for those that are exposed to the air; so that it supersedes the use alike of gypsum and of puzzuolana, or terras.

It can be made here at all times, only that, during the monsoon or rainy season, it does not dry so soon, and causes more trouble to the workmen; I do not see therefore why it might not be done in England; and if houses were built in England as in India, there never would be the smallest danger from fire; for whatever accident might happen to the furniture, scarce any of our houses here can be injured: the walls are all of brick and mortar, and when fine-chunamed are exceedingly beautiful; as any colour, or variety of colours, may be given to it.

The wood of the doors and windows are never so much connected with it as to cause any danger: our roofs are equally secure, and probably the strongest and most durable in the world, being with difficulty broke down; the whole forming a solid mass, and the mortar harder than the brick. If a room does not exceed twenty-five or thirty feel breadth, large solid beams of teak (tectonia grandis), of about sixteen or eighteen inches square, are laid across from wall to wall; and at the distance of twelve or fourteen feet asunder. Joists of about seven inches depth and four inches breadth are then laid across the beams about a foot asunder.

When these are all properly fitted, and the wall all around raised to a level with them, the bricklayers begin at one corner, and go on diagonally to the other with great quickness, placing the bricks On their edge and applying them close to one another, after having covered their surfaces well with mortar mixed with a considerable proportion of jaggary, or coarse sugar, and also the top, on which they lay it thick. The workmen sit upon moveable planks laid across the joists. The under surface has a curious appearance, from the bricks seeming to have no support.

It is astonishing how few bricks thus jammed fall down, although I have seen terraces made when rain was falling very heavy, and running through in all parts as through a sieve; and those are reckoned strongest that are built in the wet weather, as there is less danger of vacuities than in the dry season, from the quick drying of the chunam.

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