TARTAR. 



and put afide : a fecond portion of allies is then added, and 

 the efFervefcence and fcum are renewed and treated as before. 

 The whole of this operation is repeated fourteen or fifteen 

 times, after which the hquor b^xomes quite clear and colour- 

 lefs. TIic fire is then withdrawn, and the li([uor fullered to 

 remain perfeftly at rell for throe days. On the fourth, a 

 dirty white faline crull is removed from the fnrface, and two- 

 tliirds of the liquor laded out : the cryihds on the fides are 

 then colleAed by a ladle, and walhed in the remaining liquor ; 

 they are thus obtained perfectly clean, and require no fur- 

 ther preparation than drying on a wicker frame. Tlie 

 cryftals from the bottom are ftill fomewhat coloured, and 

 are either lold as an inferior fort, or are refined again with 

 fredi portions of the crude tartar. The liquor that remains 

 in the boiler, after the depofition of the cryitals, is a cold 

 faturated folutioii of tartai", and is employed in the firft lixi- 

 viation of the rough tartar." 



The method iifed near Montpellier has been found fo 

 convenient and eflfeftual, that it has continued without any 

 material alteratioa for a century. It is as follows : " The 

 apparatus required for this purpofe is, ift, a large copper 

 boiler; 2d, a ilone ciftern, larger than the boiler; 3d, a 

 number of glazed earthen pots (generally t wenty-feven ) , 

 which, together, hold fomewhat more than the boiler ; 

 4th, fome ftraiucrs of coarfe cloth llretched on wooden 

 frames ; 5th, four fmaller copper boilers, which, together, 

 hold as much as the larger boiler, and are ufed in the refining 

 part of the procefs ; and 6th, a mill to grind the tartar. 



" The large copper is firll filled with two-thirds of 

 mother-liquor, remaining from the previous operations, and 

 one-third of fpring-water ; a quantity of rough tartar is then 

 thrown in, and, when the liquor is faturated and boihng, it 

 is ftrained into the earthen pots. In about half an hour the 

 liquor in thefe pots, though ftill very hot, begins to depofit 

 cryftals on the furface and fides of the pot ; during which 

 time, more liquor and tartar are thrown into the large cop- 

 per, as at firft. 



" The liquor in the pots is then emptied into the ftone 

 ciftern, leaving the cryftallized crnft of tartar behind ; and 

 when the fecond boiling is faturated, the pots are again filled 

 as before, and the large copper again charged with the clear 

 liquor from the ciftern, and frelTi tartar. By thus five times 

 alternately preparing a hot faturated folution, and allowing 

 it partially to depofit its tartar in the pots, the latter become 

 lined to a confiderable thicknefs with a crnft of reddilh-white 

 tartar, much purer than at firft, and which obvioufly con- 

 fifts of an irregular cryftallized faline mals, and when walhed 

 with cold water, is fit for the fecond or proper refining pro- 

 cefs. For this purpofe the four fmall boilers are filled with 

 water, in which a imall quantity of clay is diffufed, which 

 renders it milky, rejetling the ftony and larger particles of 

 earth. The half-purified tartar is then added in fuch pro- 

 portion, that the water, when boiling, ftiall be fufficient to 

 diffolve all the foluble part, and the ebullition is continued 

 for a quarter of an hour ; the fire is then withdrawn, and the 

 liquor allowed to remain at reft till the next day. It is then 

 found covered on the furfaCe with a white hard faline cruft, 

 and a fimilar cruft, but more diftinCfly cryftallized, has con- 

 creted on the fides and bottom of the boiler. They are both 

 very pure tartar, the cruft on the furface, wliich is an amor- 

 phous mafs, is called cream of tartar ; and the other, cryjiah 

 of tartar ; but they are indifcriminately mixed. 



" The cruft is then broken down, and falls to the bottom ; 

 and the liquor, which is a clear pale red, is poured off gently 

 into the ftone ciftern, till it begins to run white, owing to 

 the clay at bottom, which latter portion pafles into a fepa- 

 rate veffel. The whole mafs of folid tartar left in the boiler 



is then walhed with cold watfr, till all the foulnefs (which 

 is merely fuperficial) is got out, and the water comes away 

 quite clear ; after which the purified tartar is taken out, and 

 dried on lloves or in the fun, and is jierfcctly pure and white. 

 The ordinary rough tartar yields about three-fifths of its 

 weight of the wliite pure fait. All the refiduary liquors 

 are employed in fubfequent operations, in the way already 

 mentioned." 



Schanb fays ( Annal. de Chim. xlix. 61.), that tartar may 

 be purified by fimply boiling it with powdered recent char- 

 coal, and thus very wiiite cryftals are obtained. 



Tartar, Burnt, a preparation ufed by glafs-manufac- 

 turers, and confifting of large lumps of red tartar, burnt or 

 calcined in earthen pans in an open fire, till they have done 

 fmoaking : it is of a blackifli purple colour. Neri's Art of 

 Glafs. 



Tartar, Cream of, Cremor Tartnri. See Cream 0/ 

 Tartar, Tartar, fupra. Super-tart rate of Potafh, under 

 Salts, and TaRtujtes. 



Cream of tartar has a fenfibly acid tafte ; it reddens the 

 blue colours of vegetables ; it may be faturated by uniting 

 with any of thofe fubftances, which are capable of forming 

 witli acids neutral falls ; and it may be afterwards feparated 

 from tliofe fubftances, and recover its former appearance. 



In the arts, and in the materia medica, this is a very 

 valuable fait. It is much ufed in dyeing, more efpecially 

 in giving the fcarlet and other modifications of the cochineal 

 colours. It is alfo often combined with alum, as a mordant 

 in fixing colours. (See Dyeing.) As an article of the 

 materia medica, cream of tartar, difliilved in water, forms 

 an agreeable and cheap acidulous drink ; and as a fweetcncr 

 of the blood, fome have taken it in whey or water-gruel, in 

 the fpring-time, to the quantity of half an ounce every morn- 

 ing, for three or four weeks. The folution in water, fwcet- 

 ened with fugar, is a pleafarrt beverage in febrile difeafes, 

 when its purgative quality is not likely to prove injurious. 

 See the next article. 



The difficult folubility of cream of tartar being an objec- 

 tion to its medical ufe, fome experiments were made by Dr. 

 Peter Jonas Berg, for rendering it more foluble by certain 

 additions, without altering its medicinal qualities. Borax 

 was found to anfwer bell for this purpofe. To four parts 

 of cream of tartar one of borax was added. Thefe were dif- 

 folved in a fufficient quantity of water, and the liquor 

 ftrained : about a fixtecnth part of impurities was left be- 

 hind. The pure folution evaporated yielded an acid, and 

 extremely foluble white fait. Lemery has alfo recommended 

 borax. It has, however, been obfervcd, that as borax con- 

 tains an excefs of alkali, the acid of the tartar would be neu- 

 trahzed, and a very different fait would be produced, w'c. the 

 tartrite of potajl} and foda ; which fee. Nova Adt. Phyf 

 Med. Acad. Cref. Lcop. Cai-ol. Nat. Curiof. tom. iv. 



Tartar, CryJlah of. See T Ant. \n, fupra, and Tar- 



TRITES. 



Thefe cryftals are fmall and irregular, but generally run 

 together into little niaffesof a wh.ite colour, femi-tranfparciit, 

 brittle, and eafily reduced into powder. Cryftals of tartar 

 are in common ufe as a laxative and mild cathartic ; they are 

 alfo efteemed for their cooling and diuretic qualities, and 

 have therefore been much emjiloyed in dropfies, .iiid in 

 other cafes requiring an antiphlogiftic treatment. Dr. 

 CuUen fays, that in large dofes they aft like a purgative, 

 in exciting the action of the abforbents in every part of the 

 fyftem, and m(,>re powerfully than the operation of any en- 

 tirely neutral falts. On this property is founded their utility 

 in the cafe of dropfy. They occafion a confiderable dif- 

 charge of ferous fluid into the bowels, which is thrown off 



in 



