-i 



i HEMI81 KY. 



[VEGETABLE COLOURS. 



Ut yellow colour U removed. Tlio residue of oli<l 

 matter is then to be iteeptxl in solution of carbonate of 

 4U, !MI cold ; and, aft. : , , ,.:t..M wnol U to be 



ni'iiktucvd M> M to abnorb the colour. It will appear of 

 iniullv rrd tint ; hut on tin- { a lu.lution of 



acid, or lemon juice, a nm^nifioent red colour U 

 afforded. By a repetition nf thin procraa the cotton may 

 be filled with colour, which can afterward* be ren 

 by the same means a those just employed. The colour 

 U tku* obtained inolated. A large quantity of the colour 

 U manufacture! n tin- banks of the Lea, near London ; 

 and alto near Paria. The winter month* are chosen for 

 the porpote, M the beat of summer spoils the tint 

 From the small quantity of colour produced from the 

 raw material, it U very elusive, and its use U elm-fly 

 confined to dyeing silks, and making " carmine saucers." 



Decoctions made by boiling the chips of Japan, Brazil, 

 and logwood, afford a red colour, with tin and alum as a 

 inordaunt ; and a black with salts of iron. These sub- 

 taiioes are chiefly used for dyeing wool and cotton 

 yarn. Each of them contains some t.innic acid, as do 

 Miinac, gall-nuts, oak-bark, walnut-peels, <tc. ; and such, 

 with iron, afford black dyes of various depths. 



Yellow colours are produced by the action of alumina, 

 as a mordauiit on infusions of turmeric, A-c. ; but these 

 colours are generally fugitive. Intermediate tints of 

 brown, maroon, <tc. , are produced by successively dyeing 

 the stuffs a yellow and Ted colour, until the desired tint 

 be arrived at. 



Blue vegetable colours are obtained from some lichens, 

 amongst which the rocella tinctnri<i is that most com- 

 monly used. All the lichens, however, afford colours of 

 some kind, and even those of a yellow and red tint. 

 Orchil, used in dyeing silk, is obtained from the rocella, 

 by means of ammonia, or more economically, urine, which 

 has so far undergone decomposition as to afford ammonia. 

 . th'-se plants, jieculiar colouring principles, such as 

 orciut, ibc , may be obtained, which are analogous to 

 garancine, alizarine, ivc. 



Indigo has, till the discovery of the production of 

 aniline from coal-tar,* been the chief source of the per- 

 manent tilue of the dyer. The colour from indiyo is not 

 U iii most other cases, by infusion or decoction 

 iti water, but l>y means of the strongest sulphuric acid. 

 The raw material, as imported, is in blue-coloured cakes; 



theae are powdered, and to them the strongest sulphuric 

 a i i is added. By this, the real principle of indigo U 

 disaolved out The principle of dyeing with this sub- 

 stance U that of first deoxidising it, which is done by 

 moans of the proto-sulphate of iron. This renders the 

 indigo in a state fitted for absorption by the fabric, 

 which, after being dipped into the solution, becomes of 

 a deep blue colour on exposure to the oxygen of the air, 

 and the colour then becomes permanent. In the process, 

 the alkaline earth, lime, is used with the proto-salt of iron. 

 And this introduces us to the production of aniline from 

 a vegetable, 01 we have shown its production already 

 from coal-tar. 



If inuigo be acted on by a hot solution of potass, and 

 then distilled, aniline is produced as a nearly colourless 

 liquor. It is highly volatile, soluble in water, and on 

 being oxidised by chromic acid, affords a rich purple tint. 

 It matters not what it is produced from, for it is equally 

 obtainable from indigo, nitro-benzole, and coal-tar. And 

 this is a matter of not only deep philosophical interest, 

 but, in the uses to which it is applied, has become a most 

 important article of commerce, t 



Into the varied treatment which this substance under- 

 goes, we of course cannot enter ; and we have made our 

 remarks more extended on it than we should have done, 

 solely because it affords an instance of a most remarkable 

 practical application of purely scientific research, and 

 which we are glad to say has been the means of enriching 

 those to whose perseverance we have been indebted for 

 it manufacture in quantities. 



Aniline forms numerous combinations with other 

 bodies ; its chemical formula has been stated as Cj 3 

 H; N, and thus it contains one equivalent of nitrogen. 

 Stating it in its relation to the phenyl series,! we may 

 use the formula Pyl H 2 N, or, C, H s + H., N. 



In this chapter we have selected some of the chief of 

 the many miscellaneous products of vegetable life, and 

 have endeavoured to arrange them in such connection 

 as would most conduce to their being understood by our 

 readers. With them we shall dismiss the subject of 

 vegetable chemistry, advising those who desire to pro- 

 secute the subject still further, to peruse the works of 

 Fownes, Graham, Miller, Odling, and others, to whom 

 we have ourselves been indebted for some of the facts 

 which have been adduced. 



CHAPTER XI. 

 ANIMAL SUBSTANCES. 



AI.BI MF.N FIBRINE CAKF.INB GELATINE PROTEINS KKEATINE BLOOD OIL AND FATS FIUNE AND TBEA 



hS, JST& MANUFACTURES FROM ANIMAL SOBSTANCtS MANURES, CANDLES, SOAP, TANNING, Eiv. 



TUB department of chemistry devoted to the considera- 

 tion of animal matter in general, has already been the 

 subject of an elaborate- paper in our previous pages ; we 

 shall, therefore, here couliue ourselves to a mere outline 



Of facts 



The elementary constituents of animal life are, like 

 tlione of vegetable existence, but comparatively few in 

 number. Carbon, h \\^>-ii, and nitrogen, are, 



if we may so call them, the essentials ; whilst sulphur, 

 phosphorus, lime, and metallic oxides, in exceedingly 



us, are the accidentals of animal matter. , 

 Aii i yet, -.M: In iiit a due proportion of each, the animal 

 would lie incoinplrtu ; for phosphorus is essential to 

 the brain, lime to the bones. And thus the. entirety is 

 made up of parts, having iU-tiiiite ratios, which cannot be 

 ifered with, lessened, or increased, without pro 

 during great change* in the being which may be their 

 inliiuct. 



cd not here enter into any description of the in- 

 dividual elements; that has already IK.-I-II done in our 

 . iou pages: we shall, therefore, call ntti n'l-ii to 

 a few siilmtunce* which either arc- part of, are secreted, 

 or excreUal, by the animal syxli >n. 

 See mult, p. 420. 



ALBUMEN. This substance is best typified in the 

 white of a hen's egg, which contains the yolk sus- 

 pended in nearly pure albumen. At a temperature of 

 100, it becomes solid, as is well known in the doin 

 operation of boiling eggs. It then ceases to be soluble 

 in water ; and if exposed to a high te it allonU 



ammonia, and impure charcoal. Albumen is ('muni in 

 the blood, and in many secretions of the animal. It 

 also exists in the juice, fruit, and seeds of plants. When 

 in solution, it is precipitated l>y metallic salts, those of 

 mercury being eligible, and by some acids, as the tan- 

 nic, etc. It* chemical composition, is stated by Mulder, 



>n . 



Hydrogen 

 Nitrogen 

 Oxy 



Phosphorus 

 Sulphur 



1000 



FIBRINK, so named from its fibrous appearance, is a 

 t Bee axlt, p. 420. ,Hlr, f. 420. 



