. An encyclopædia of gardening; . hade ; but it loses at the sametime a portion of its hydrogen, and becomes insoluble in water; and thus it indicates its relation to ex-tract. Fourcroy reduced colors to the four following sorts ; extractive colors, oxygenated colors, carbo-nated colors, and hydrogenated colors ; the first being soluble in water, and requiring the aid of saline orvnotallic mordants to fix them upon cloth ; the second being insoluble in water, as altered by the absorp-tion of oxygen, and requiring no mordant to fix them upon cloth ; the third containing in their compo-sition a
. An encyclopædia of gardening; . hade ; but it loses at the sametime a portion of its hydrogen, and becomes insoluble in water; and thus it indicates its relation to ex-tract. Fourcroy reduced colors to the four following sorts ; extractive colors, oxygenated colors, carbo-nated colors, and hydrogenated colors ; the first being soluble in water, and requiring the aid of saline orvnotallic mordants to fix them upon cloth ; the second being insoluble in water, as altered by the absorp-tion of oxygen, and requiring no mordant to fix them upon cloth ; the third containing in their compo-sition a great proportion of carbon, but soIudIc in alkalies; and the fourth containing a great proportionof resin, but soluble in oils and alcohol. But the simplest mode of arrangement is that by which the dif-ferent species of coloring matter are cLxssfd according to their effect in the art of dyeing. The prinrijaland fundamental colors in this art arc the blue, the red, the yellow, and the brown. I. 3 150 SCIENCE OF GARDENING. Part 655. Tlie jflncst of all vegetable bbiee is that which Is known byOie name of indigo. It is the produce of the-lndigofera tinctoria,Lin., a shrub which is cultivated for the sake of the dye itattbrds, in Mexico and the East Indies. The plant reachesmaturity in about six months, when its leaves are gatheredand immersed in vessels filled with water till fermentationtakes place. The water then becomes opaque and green, ex-haling an odor like that of volatile alkali, and evolving bubblesof carbonic acid gas. AVhen the fermentation has been con-tinued long enough, the liquid is decanted and put into othervessels, where it is ajfitated! tUl blue flakes begin to is now poured m, and the flakes are precipitated in theform of a blue powdery sediment, which is obtained by de-cantation ; and which, after being made up into small lumpsand dried in the shade, is the indigo of the shops. It is insolu-ble in water, though slightly soluble in alcohol. B
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Keywords: ., bookcentury1800, bookdecade18, booksubjectgardening, bookyear1826
