In the neighbourhood of Prome a considerable quantity of varnish is extracted from the tree; but very little is obtained at Martaban, owing, as I am told, to the poverty of the soil, and partly also to the circumstance of there being none of the people in that part whose business it is to perform the process. This latter is very simple: short joints of a thin sort of bamboo, sharpened at one end like a writing-pen, and shut up at the other, are in serted in a slanting direction into wounds, made through the bark of a trunk and principal boughs, and left there for twenty-four and forty-eight hours, after which they are removed, and their contents, which rarely exceed a quarter of an ounce, emptied into a basket made of bamboo or rattan previously varnished over. As many as a hundred bamboo's are sometimes seen sticking into a single trunk during the collecting season, which lasts as long as the tree is destitute of leaves, namely, from January until April; and they are renewed as long as the juice will flow. A good tree is reckoned to pro duce from one and a half to two, three, and even four viss annually, a viss being equal to about 31 lbs. avoirdupois. In its pure state it is sold at Prome at the rate of one tical, or 2s. 6d. the viss. At Martaban, where every thing was dear when I was there, the drug was retailed at two Madras ru pees per viss; it was of an inferior quality, and mixed with sesamum oil; an adulteration which is often practised.
The extensive use to which this varnish is ap plied, indicates that it must he a very cheap com modity. Almost every article of household furni ture destined to contain either solid or liquid food is lacquered by means of it. At a village close to Pagam on the Irawaddi, called Gnaunee, where this sort of manufacture is carried on very exten sively and to great perfection, I endeavoured to obtain some information relating to the precise mode of lacquering; but I could learn nothing fur ther than this,—that the article to be varnished must first be prepared with a coating of pounded calcined bones; after which the varnish is laid on thinly, either in its pure state or variously coloured by means of red or other pigments. I was told that the most essential as well as difficult part of the operation consists in the process of drying, which must be effected in a very slow and gradual man ner; for which purpose the articles are placed in damp and cool subterraneous vaults, where they are kept for several months until the varnish has become perfectly dry. Another object for which
the drug is extensively employed, is as a size or glue in the process of gilding; nothing more being required than to besmear the surface thinly with the varnish, and then immediately to apply the gold leaf. If it is considered how very extensively that art is practised by the Burma nation, it being among their most frequent acts of devotion and piety to contribute to the gilding of their numerous reli gious edifices and idols, it will be evident that a great quantity of the drug must be consumed for that purpose alone. Finally, the beautiful Pali writing of the religious order of the Bnrmas on ivory, palm-leaves, or metal, is entirely done with this varnish, in its native and pure state." A full account of Varnishes will be found in our article JAPANNING, written for this work by Mr John Farey, Vol. XI. p. 53, 54. See CAOUTCHOUC, Vol. V. p. 29!, and CHEMISTRY, Vol. V. p. 766.
On Japanning and Varnishing.—It has been a great desideratum among artists to render shellac colourless, as, with the exception of its dark brown hue, it possesses all the properties essential to a good spirit varnish, in a higher degree than either of the other resins. A premium of a gold medal, or thirty guineas, " for a varnish made from shell, or seed lac, equally hard, and as fit for use in the arts, as that at present prepared from the above substances, but deprived of its colouring matter," has long been, and is still offered, by the Society, in London, for the encouragement of Arts, Manu factures, and Commerce. These ends are perfectly attained by the process given by Dr. Hare, which leaves nothing to desire, excepting on the score of economy. Were the oxymuriate of potash to be manufactured in the large way, the two processes, that of making the salt, and of bleaching the resin, might be very advantageously combined.
Method of bleaching shell, or seed lac. By R.