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ONE OF THE PROFESSORS IN THE UNIVERSITY OF PENNSYLVANIA; MEMBER OF THE AMERICAN PHI-
Tutte le invenzioni le più benemerite del genere umano, e che hanno svillupato l'ingegno e la
IN TWO VOLUME S.
STEREOTYPED BY L. JOHNSON.
I. AND J.
ALAP, OR JALOP (Ger. Jalapp; Fr. Jalap; It. Sciarappa; Sp. Jalapa), the root of a sort of convolvulus, so named from Xalapa, in Mexico, whence we chiefly import it. The root, when brought to this country, is in thin transverse slices, solid, hard, weighty, of a blackish colour on the outside, and internally of a dark grey, with black circular striæ. The hardest and darkest coloured is the best; that which is light, spongy, and pale coloured, should be rejected. The odour of jalap, especially when in powder, is very characteristic. Its taste is exceedingly nauseous, accompanied by a sweetish bitterness.—(Lewis's Mat. Med.; Brande's Pharmacy.) The entries of jalap for home consumption amounted, at an average of 1831 and 1832, to 47,816 lbs. a year.
JAMAICA PEPPER. See PIMENTO.
JAPANNED WARES (Ger. Japanische ware; Du. Japansch lakwerk; Fr. Marchandises de Japon), articles of every description, such as tea-trays, clock-dials, candlesticks, snuff-boxes, &c. covered with coats of japan, whether plain, or embellished with painting or gilding. Birmingham is the grand staple of this manufacture, which is there carried on to a great extent. Pontypool, in Monmouthshire, was formerly famous for japanning; but it is at present continued there on a very small scale only. It is prosecuted with spirit and success at Bilston and Wolverhampton.
JASPER (Ger. Jaspiss; Du. Jaspis; Fr. Jaspe; It. Diaspro; Sp. Jaspe; Rus. Jaschma). This stone is an ingredient in the composition of many mountains. It occurs usually in large amorphous masses, sometimes in round or angular pieces; its fracture is conchoidal; specific gravity from 2 to 2.7. Its colours are various; when heated it does not decrepitate: it is usually divided into four species, denominated Egyptian jasper, striped jasper, porcelain asper, and common jasper. It is sometimes employed by jewellers in the formation of seals. JERSEY. See GUERNSEY.
JET, OR PITCH COAL (Du. Git, Zwarte barnsteen; Fr. Jais, Jayet; Ger. Gagat; It. Gagata, Lusirino; Lat. Gagus, Gagates), of a black velvet colour, occurs massive, in plates; sometimes in the shape of branches of trees, but without a regular woody texture. Internal lustre shining, resinous, soft; rather brittle; easily frangible; specific gravity 1.3. It is used for fuel, and for making vessels and snuff-boxes. In Prussia it is called black amber, and is cut into rosaries and necklaces. It is distinguished by its brilliancy, and conchoidal fracture.-(Thomson's Chemistry.)
JETSAM. See FLOTSAM.
IMPORTATION AND EXPORTATION, the bringing of commodities from and sending them to other countries. A very large portion of the revenue of Great Britain being derived from customs duties, or from duties on commodities imported from abroad; and drawbacks being given on many, and bounties on a few articles exported; the business of importation and exportation is subjected to various regulations, which must be carefully observed by those who would avoid incurring penalties, and subjecting their property to confiscation. The regulations referred to, have been embodied in the act 3 & 4 Will. 4. c. 52., which is subjoined