Prep. The pulped or bruised fruit is boiled along with 1⁄2 to 2⁄3 of its weight of loaf sugar, until the mixture jellies, when a little is placed on a cold plate; the semi-fluid mass is then passed through a coarse hair sieve whilst hot, to remove the stones and skins of the fruit, and as soon as it has cooled a little is poured into pots or glasses. It is usual to tie these over, when cold, with paper which has been dipped in brandy. The pots must then be placed aside in a dry and rather cold situation.
The following fruits are those from which jams are commonly prepared:—Apricots, cherries (various), cranberries, currants (black, red, and white), gooseberries (ripe and green), mulberries, Orleans plums, raspberries, and strawberries. Red currants are commonly added to the last, to remove insipidity.
JAPAN′. See Varnish, and below.
JAPAN′NING. The art of covering paper, wood, or metal, with a coating of hard, brilliant, and durable varnish. The varnishes or lacquers employed for this purpose in Japan, China, and the Indian Archipelago, are resinous juices derived from various trees belonging to the natural order Anacardiaceæ, especially Stagmaria verniciflua, Holigarna longifolia, Semecarpus Anacardium, and species of Rus (Sumach). For use, they are purified by a defecation and straining, and are afterwards mixed with a little oil, and with colouring
matter, as required. In this country varnishes of amber, asphaltum, or copal, or mixtures of them, pass under the names of ‘JAPAN’ and ‘JAPAN VARNISH,’
Proc. The surface is coloured or painted with devices, &c., as desired, next covered with a highly transparent varnish (amber or copal), then dried at a high temperature (135° to 165° Fahr.), and, lastly, polished. Wood and paper are first sized, polished, and varnished. For plain surfaces, asphaltum, varnish or japan is used. See Varnishing.
JAPON′IC ACID. C12H10O5. When catechu is exposed to the air in contact with caustic alkalies, black solutions (alkaline japonates) are formed; with carbonated alkalies, red solutions (alkaline rubates); the acid of the former may be separated. It is a black powder, insoluble in water, soluble in alkalies, and precipitated by acids. Buric acid forms red insoluble compounds with the earths and some other metallic oxides.
JARAVE. The Spanish name for SARSAPARILLA BEER. See Beers (in pharmacy).
JASPER. Syn. Iaspis, L. A mineral of the quartz family, occurring in rocky masses. It takes various shades of red, yellow, brown, and green, and is occasionally banded, spotted, or variegated. It was formerly used as an amulet against hæmorrhages and fluxes. It is now extensively worked up into rings, seals, snuff-boxes, vases, &c., for which it is well calculated from its extreme hardness and susceptibility of receiving a fine polish.
JATRO′PHIC ACID. Syn. Crotonic acid, Iatrophic a. A peculiar fatty acid discovered by Pelletier and Caventon, and originally regarded by them as the cathartic principle of croton oil and croton seeds, but since shown by Redwood and Pereira to be nearly inert.