Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 4, 1802).djvu/283

253&#93; TUR feftion of many other branches in mechanics. The machine ought to be fixed in a light place, at a suf- ficient height to allow the turner to inspett his work, without endan- gering his eyes by the sudden se- paration of chips. Previously to fixing the wood, bone, ivory, or metal, on the lathe, it ought to be rounded with a small hatchet, with a file, or with a plane ; and the centres of the surfaces at each end should be ascertained ; for this purpose, it will be advisa- ble to lay the piece of wood upon a board ; and, after opening a pair of compasses nearly to half the thickness of the piece, one of the legs must be attached to the board, and the point of the other brought into conta6t with one of the ends of the piece to be turned. Four equi- distant arches must then be de- scribed at the circumference of such end, which should intersctSt each other within ; and, if these be ac- curately made, the point of inter- se.aion will be the centre. The middle of the opposite extremity ought now to be determined in a similar manner; a small hole be made in both ; the points of the puppets inserted ; and the piece firmly fixed, so that it may be ea- sily revolved. Next, tljc cord ought to be passed twice round the piece, aird adjusted to the strap conne6ted with the wheel : when the rest is placed as closely to the work as possible, the turner moves the wheel, by means of ihc foot-hoard ; then presses a gouge, or other chis- sel, against the wood, in an hori- zontal diredion j and thus, by the steady, well-regulated application of liis tools, gives it the requisite form. After having completely turned the work, it requires to be TUR bsi polished either with the skin of the Shark, the Rough Horse-tail, or other substance adapted to the na- ture of the material, thus mami- fa£tured. TURNSOL, or Turnksoi., a valuable dyeing drug, which is pre- pared chiefly in the village of Grand-GaLargues, near Montpel- lier, from tiie Crototi t'lnciorium, L. in French called Muarellt : this plant produces a round stalk with many leaves, and seldom exceeds nine inches in height. — It is there- fore erroneous, when our volumi- nous contemporaries uniformly as- sert, on the authority of M. Nis- soLE, that TuT-WAoZ is obtained from the tops of the Hdiotropiutn. tri^ coccutn, L and, though it may be true, that such drug is occasionally n)anufa6tured from the latter ve- getable, yet the genuine article is doubtless the result of the follow- ing process. Toward the latter end of July, or early in August, the flowering tops of the Maurelle, or Litmus- Croton, are expeditiously colle^d, and bruised ; when the dark-greeii sap is expressed into stone vessels, with the addition of urine. Linen or woollen rags are next dipped into this liquor, and immediately dried in the sun ; after which they are suspended for seven or eight hours, over casks containing stale urine, quick-lime, and alum, till they ac- quire a blue or dark-violet colour j and, if necessary, again immersed in the juice, dried, and treated as before. Thus prepared, they are packed, and sold by the French under the name of Tournesols en drapeau. These blue shreds are chiefly employed for tinging wines, cheese, linen, and paper. When infused with distilled water, they afford an excellent test; for, on pouring