Essay on the Architecture of the Hindus c4.s16.7

c4.s16.7

*Chunam* is prepared in the interior of India from a gravelly sort of limestone dug out of quarries, and along the coast from shells washed out of salt-water marshes. Of the two, the shell *chunam* is generally considered the strongest and most durable. The following is the mode of preparing stone *chunam*: The pebbles or gravel stones are first beat with wooden pestles, to separate the alluminous clay which adheres to them; after they are thus cleaned, they are sorted, as of a white or brown quality. In some places the stone is burnt by simply laying alternate layers of stone and charcoal on the ground, in the proportion of two parts of charcoal to one of stone, and thus allowed to burn out. The stone, after being burnt, is slacked by laying small quantities in heaps and throwing water on them; and as soon as the heat begins, the whole is mixed up together and stirred about till it is reduced to a dry powder. The lime is now considered fit for the use of the builder. Shell *chunam* is manufactured much in the same way, excepting that it is again cleansed by the manufacturer in a dry state, by strewing it down against the wind, after the manner that corn is winnowed to separate the chaff. The burning, also, is differently performed: the charcoal is mixed up with the shells, and burnt in large open kilns, with a grated bottom and longitudinal flue, communicating with four or more lateral openings. The stone *chunam* forms a coarse sandy powder, and the shell a very fine impalpable one. From these two substances all the mortar for building throughout India is prepared; they are mixed with clean sharp river sand in various proportions, according to the use for which they are intended. For brick work, from one part and a-half to three of sand is mixed, with one or two of the fine slacked lime; for the coarse undercoat plastering, from one to two of sand with two of lime; and for the last and fine upper coating, two to three of sand with one of lime. When the mortar is prepared for the brick work in rough plastering, it is simply beat up with pure water in long stone troughs, with wooden pestles about a yard and a-half long and shod with iron hoops. *Chunam* intended for fine plastering and ornamental works is ground by women, on an oblong granite stone and a cylindrical upper stone about four inches in diameter; the mixture is sometimes ground two, three, and four times, to bring it to the required fineness and purity.