CITRIC ACID.

303

we test the liquid till the decomposition be complete, and till the color verge rather towardthe green than the yellow. Eight parts of tartaric acid should be added to one of chro-mate to obtain a sure and rapid result. If nitrate of potash (saltpetre) is the adulteratingingredient, it may be detected by throwing it on burning coals, when deflagration will en-sue. The green color is a certain mark of the transformation of the chromic acid par-tially into the chrome oxvde; which is effected equally by the sulphurous acid and sulphu-red hydrogen. Here this metallic acid is disoxygenated by the tartaric, as has been longknown. The tests which I should prefer, are the nitrates of silver and baryta, havingpreviously added so much nitric acid to the solution of the suspected chromate, as to pre-vent the precipitation of the chromate of silver or baryta. The smallest adulteration bysulphates or muriates will thus be delected.

CINNABAR ; the native red sulphuret of mercury. It occurs sometimes crystallized|n rhomboids; has a specific gravity varying from 6*7 to 8'2; a flat conchoidal fracture;is fine grained; opaque; has an adamantine lustre, and a color passing from cochineal toruby red. The fibrous and earthy cinnabar lias a scarlet hue. It is met with disseminat-ed in smaller or larger lumps in veins, which are surrounded by a black clay, and is asso-ciated with native quicksilver, amalgam, with iron-ore, lead-glance, blende, copper-ore,|pld, &c. Its principal localities are Almaden in Spain , Idria in the Schiefergebirge ,Kremnitz and Schemnitz in Hungary ; in Saxony , Bavayia, Bohemia , Nassau , China , Ja-P ai b Mexico , Columbia, Peru . It consists of two primes of sulphur, = 32*240, com-bined with one of mercury, = 202,863 ; or in 100 parts of 12*7 sulphur -\- 87*3 mercury*^ the most prolific ore of this metal; and is easily smelted by exposing a mixture of it^ith iron or lime to a red heat in retorts. Eactitious cinnabar is called in commercev ermilion, which see, as also Mercury.

CINNAMON. ( Cannelle , Fr.; Zimmt , Germ.) Is the inner bark of the laurus china-^mum, a handsome-looking tree which grows naturally to the height of 18 or 20 feet, inSumatra , Ceylon, and other islands in the East Indian seas. It has been transplant-u to the Antilles , particularly Guadaloupe and Martinique , as well as Cayenne, but thereproduces a bark of very inferior value to the Oriental.

Cinnamon is gathered twice a year, but not till after the tree has attained to a certainand maturity. The young twigs yield a bark of better quality than the larger branch-'' s * The first and chief harvest takes place from April to August; the second, from No-ember to January. After having selected the proper trees, all the branches more thanree years old are cut off; the epidermis is first removed with a two-edged pruning knife,th e \ a ^ngitudinal incision is made through the whole extent of the bark, and lastly, withth G ^ Ua test P a *t °f knife, the true bark is carefully stripped off in one piece. Allstaf e ^ leces bark are collected, the smaller ones are laid within the larger, and in thisint e Jkey are exposed to the sun, whereby in the progress of drying, they become rolled2 q ta e shape of a quill. These convoluted pieces are formed into oblong bundles ofq 3 ? lbs. weight, which are placed in warehouses, sorted and covered with mats,bur ‘ Clnnamon should be as thin as paper, have its peculiar aromatic taste, withoutln S the tongue, and leave a sweetish flavor in the mouth The broken bits ofof c - 111011 ar e used in Ceylon for procuring the essential oil by distillation. 445,367 lbs.^ined^ 111 ? 11 Were knported into this kingdom in 1835, of which 16,604 only were re-CITRt ln ^ erna ^ consumption.

thi s a i ■ A*-®. (Jlcide citrique , Fr.; Citronensaure s Germ.) Scheele first procuredlar^ e 'Ai A l£ s pure state from lemon juice, by the following process. The juice put into aempi 0v U y ls t0 ke saturated with dry chalk in fine powder, noting carefully the quantitykquor ’ * The citrate of lime which precipitates, being freed from the supernatant foulPounds 1S f° We ^ was ked with repeated affusion and decantation of water. For every 10times its w ern Pl°y e d> nine and a half pounds of sulphuric acid, diluted with six®ixed °f water, are to he poured while warm upon the citrate of lime, and well

posed dn , ‘'be end °f twelve hours, or even sooner, the citrate will be all decom-The acid h' Clt ™ aca ^ ^ oat a b° ve > anl * sulphate of lime will be found at the bottom,drained an drawn off, the calcareous sulphate must be thrown on a canvass filter,. The citri •? washed with water to abstract the whole acid.

h aequi re 'Jl aei d l ^ us Stained may be evaporated in leaden pans, over a naked fire, tillSe l, evaporated^ eC *^ C gravity 1-13; after which it must be transferred into another ves-a Ppears fi rs t • ■ a steain or water hath till it assumes a sirupy aspect, when a pellicle

With great cir” ^ >atc * les . an( f then over the whole surface. This point must be watched“y c arbonizatio UmS T e if t *° n ’ *” or be passed, the whole acid runs a risk of being spoiled'rated acid out i ^ ae steam or hot water must he instantly withdrawn, and the coneen-and of f oar j a 0 a crystallizing vessel in a dry, but not very cold apartment. At thedissolved in a ’ ,, e cr y st allization will be complete. The crystals must he drained, re-canted, re-evnnnr^F°i ' 0n ,°' water, the solution set aside to settle its impurities, thene eessai 7 to 0 bt a i n a e Jij re - c ^tstallized. ^ ‘bird or fourth crystallization may be