LOAM (Terre-limoneuse, Fr.; Lehm, Germ.); a native clay mixed with quartz sand and iron ochre, and occasionally with some carbonate of lime.
LODE, is the name given by the Cornish miners to a [vein], whether it be filled with metallic or earthy matter.
LOGWOOD (Bois de Campèche, Bois bleu, Fr.; Blauholz, Germ.); is the wood of the Hæmatoxylon Campechianum, a native tree of central America, grown in Jamaica since 1715. It was first introduced into England in the reign of Elizabeth, but as it afforded to the unskilful dyers of her time a fugitive colour, it was not only prohibited from being used, under severe penalties, but was ordered to be burned wherever found, by a law passed in the 23d year of her reign. The same prejudice existed, and the same law was enacted against indigo. At length, after a century of absurd prohibition, these two most valuable tinctorial matters, by which all our hats, and the greater part of our woollen cloths, are dyed, were allowed to be used.
Old wood, with black bark and with little of the white alburnum, is preferred. Logwood is denser than water, very hard, of a fine compact grain, and almost indestructible by the atmospheric elements; it has a sweet and astringent taste, and a peculiar not inoffensive smell.
For its chemical composition, see [Hematin].
When chipped logwood is for some time exposed to the air, it loses a portion of its dyeing power. Its decoction absorbs the oxygen of the atmosphere, and then acquires the property of precipitating with gelatine, which it had not before. The dry extract of logwood, made from an old decoction, affords only a fugitive colour.
For its applications in dyeing, see [Black Dye]; [Brown Dye]; [Calico Printing]; [Dyeing]; [Hat Dyeing], &c.
The imports of logwood for home use, were, in 1836, 12,880 tons, 13 cwts.; in 1837, 14,677 tons, 13 cwts. And the amount of duty received was, in 1836, 2,480l.; in 1837, 2,552l.
LOOM (Metier a tisser, Fr.; Weberstuhl, Germ.); is the ancient and well-known machine for weaving cloth by the decussation of a series of parallel threads, which run lengthwise, called the warp or chain, with other threads thrown transversely with the shuttle, called the woof or weft. See [Jacquard Loom] and [Weaving].
LUBRICATION. The following simple and efficacious plan of lubricating the joints and bearings of machinery by capillary attraction, has been kindly communicated to me, by its ingenious inventor, Edward Woolsey, Esq.:—