Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 1, 1802).djvu/188

164&#93; i6 4 ] B A poured on it to dissolve the lime, ashes, &:c. while the mass is stir- red with an iron rake, to effect a- more minute intermixture. A coal lire is now lighted under the pans, and kept briskly burning forty-eight hours, without inter- mission ; at the same time, the pans' are continually supplied with sea-water, in order to impregnate these materials with a - greater de- gree of the saline quality, till they acquire a proper consistence for calcination in a melting furnace, known by the name of calcar. This apparatus is constructed in the usual manner, except that there is a wall above the grate-room, to separate the fire from the materials laid upon the bottom. An intense degree of heat is used in this cal- car, by means of which the saline mass boiled in the pan is com- pletely dissolved, and afterwards kept in a state of fusion for one hour, during which time, the vo- latile part is expelled, and a fixed alkaline salt remains: this, being cooled in iron pans, produces our British barilla, resembling that im- ported from Spain. Mr. King also declares, in the preamble to his patent, that this new chemical compound is calculated to serve as a substitute for manufacturing crown and broad window-glass, and also bottles, as well as for making soap and alum to much greater advantage, than any other material hitherto used in the pro- duction of those commodities; EARING of Trees, in horticul- ture, is the removing of the earth from the roots of those which are planted in a dry soil. This opera- tion should be carefully performed in autumn, without injuring the roots, around the trunk, so that rhe winter rains and snow-waters BAR may penetrate deeper in the ground, which, towards spring, should be * covered up again with manure ; because, at that season, the fre- quent night-frosts might otherwise prove destructive to the tree. BARK, in the dissection of plants, is the exterior coat of trees, corresponding to the skin of ani- mals. As these are furnished with a cellular membrane covering all the fleshy parts, and usually re- plete with white granulated fat, which can be liquified only by heat j so are plants surrounded with a bark abounding with oily juices, by means of which, Nature has rendered them inaccessible to cold ; because the spiculse of the ice are prevented from fixing and freezing the fluids, which circulate through the vessels. Hence it is, that evergreens continue their ver- dure at all seasons of the year, be- cause their bark contains an unu- sual proportion of oil, more than is dissipated by the heat of the sun. The bark of p'ants is liable to peculiar diseases, as well as to be preyed upon by insects, which fre- quently prove destructive to the tree. One of its most common enemies is the lark worm, which infests and perforates its substance ; and unless the parts affected be cautiously removed by the knife, and the superficial wounds plaster- ed over with a mixture of wax and turpentine, the stem will in pro- cess of time become cankered, stunted in its growth, and ulti- mately fail a sacrifice to the dis- ease. M. Buffon has ascertained, by repeated experiments, that trees stripped of their bark the whole length of the stems, do not live longer than three or four years. It