, . THE LEMON TREE. 1241

Sl, lphuri n a ^ ovvs H to rest once before the chalk is added. After theui( C aci< ^ has been added, the filtered liquor is directed to be tested“ al m o st rate barytes, and if the precipitate thereby obtained be not®d(] e( i ft entirel y soluble in nitric acid,” more citrate of lime is to beftye en[ ? satur ate the great excess of sulphuric acid].—The Dublin Col-chalfi diluted sulphuric acid equal in weight to eight times the

Xfi . p °y e d).

tur ers 'l ,llce of lemons and limes is imported for citric acid manufac->h a ]^ r 111 Pipes and hogsheads. It is saturated with chalk or whitingVa *- ®y this means a citrate of lime is formed. This is pre-of j]j e ; •’ "drile the carbonic acid of the chalk escapes, and the mucilage' Ulce tor the most part remains in solution.

I ^ Re »ients. Products.

k = 50 5 J Carbonic acid. 22

Lfrtw ' 1 Lime .... ou

° n Juice} Water, mucilage, &c.

i l Citric acid. 58

X}

tl^.^pematant liquor is then drawn off, the citrate of lime passed»o , a s i ev e and frequently washed with warm water, until the muci-

_ 1 Carbonic acid gas 22

-Water, mucilage, &c.

-1 Citrate of lime .. 86

1 ana frequently wasnea wim waiui naici, uum wm xxxxx^x-Su *Phu •’ °^ l . er s °hible impurities are for the most part got rid of, andc j, ll . c ac i ( l diluted with water then added: sulphate of lime separates,llc ac ld remains in solution.

Ingredients.

1 Citrate of limp — e<? $ 1 Citric acid 58-* Sulphuric arid ~ r n 1 rjme ■ —. 28 =

Products

-1 Citric acid.58

=1 Sulphate of lime .. 68

Til

Pos t jg C ! ear solution is then evaporated (manufacturers use for this pur-ine Cr ( <;n toilers) and the concentrated solution set aside to crystallize,jl’or f,^ S t , a ^ s are afterwards purified by re-solution and re-crystallization.■*Vk es p! er details respecting the manufacture of this acid consultP 0u .’j ' le ™- Essays, \ ol. i. p. 539,2nd ed. 1823.)a ci ( p 5™ citric acid is sometimes adulterated with powdered tartaric^eid ; n le Iraud may be readily detected by dissolving the suspected°f car}, 1 Srna H quantity of water, and adding cautiously to it a solutiontar tari c ° nat , e Potash) taking care that the acid be in excess. If any' 3e Present, a white crystalline precipitate ( bitartrate ofe 8es f 0r 1S orine (l- The directions of the London and Edinburgh Col-. asc ertaining the purity of the acid are as follows:—

t' 5< t ls dissoi' S u bIo iii water ; what is precipitated from the solution by acetate of^ Solution r .• “'trie acid. No salt of potash, except the tartrate, is precipitatedij, 0 Cltnc acid. It is totally dissipated in the (ire ( Ph. Loud.)

h'e absen t ^ ie pl um beous precipitate in nitric acid is to show

• 4 s i Ce su lphuric acid or a sulphate.

Lor parts of water, is not precipitated by carbonate of potash: when"" &d.) a 1 le *1*1 of the red oxide of mercury, no ash is left, or a mere trace

Th

f' Ssi PatedT entS ° f citric acic * ^ viz - oxygen, hydrogen, and carbon) areea? ' r ed ox’T a le< ^ heat. But this dissipation is promoted by an agenta 1 v fixed Xlc . e of mercury) capable of supplying oxygen without leaving

°rf£ T SUl,lUm -.

°xicol. Gen.) ranks citric acid among the irritant poisons; but