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DYEING AND CALICO PRINTING.

Manilla Indigo is found in light, brick-shaped, or irregular masses; colourlight blue ; fine-grained and homogeneous ; it effervesces with acids, in conse-quence of containing carbonate of lime. This indigo is rarely used for dyeing?being too poor, but it is largely employed for making washing-blues. It also isimported in wooden boxes, generally weighing from 50 to 60 kilos.

Madras Indigo : fine blue or bluish-violet, less rich than, but equally light(specifically) as, Bengal indigo, and characterised by the feature that the cakeshave retained the impression of the folds and texture of the cloth on whichit was placed while soft. The low Madras qualities have an unpleasantgreenish hue, and contain sometimes 50 per cent of mineral matter. Theboxes in which it is sent to Europe weigh on an average from 80 to 90 kilos.

Guatemala Indigo occurs in small irregularly-sized lumps, packed in serons—bags or bales made of cow-hides, weighing about half as much as theBengal boxes. The Guatemala indigo is, as regards quality and variety, notunlike the Bengal, but the ware is never so well sorted, and therefore generallyless valuable : the light blue kind is more rare amongst this indigo, and whenit occurs it is poorer in colouring matter than the same variety of Bengalindigo. The reddish-coloured Guatemala is not well suited for dyeing, sinceit is very poor in blue, and contains too great an excess of brown extractivematter. Notwithstanding these defects the indigo in question often containsexcellent qualities. The distinguishing marks or brands are— Indigo Guatemalaflor , Sobre saliente, and Corte.

Caraccas Indigo resembles greatly the last-named kind, but is generally lessesteemed : it is packed in surons.

Mexican Indigo stands between the two last-named, but does not of lateyears come into the market any large quantity.

From a paper published* by M. R. E. Meyer on a sample of indigomanufactured in Cochin China, we learn the following particulars, first, asregards that sample, and secondly, about some other varieties of indigo:—The Cochin China growth consists of small, flattened, irregular lumps,weighing from 3 to 6 grms. each. Judging by the impression left on the sur-face, the paste has been pressed between linen while yet wet: the colour is apure bright blue, without any violet hue. It adheres to the tongue, exhibits acoppery gloss, is very homogeneous, and its fraCture does not show any foreignsubstance. The author estimated the indigotin in this ware, and found itsaverage quantity to be 51-85 per cent, while the estimation of this colouringmatter in the following sorts of indigo gave the following quantities :—Bengal,ordinary deep blue, heavy substance, not adhering to the tongue, 55 : Bengal,deep reddish-blue, 63-5 ; Bengal, fine violet-blue, light (specifically), 68-25;Bengal, superior quality, 69-5; Guatemala, very common brownish-blue, 55-25 ;Guatemala, bright blue, common sort, 57-75. The author was unable to obtaineither any of the Java or of the best Guatemala kinds. The quantity of ashpresent in the Cochin China indigo amounts to 22-36 per cent, consistingchiefly of phosphate of lime, accompanied by small quantities of carbonate oflime, iron, alumina, magnesia, soda, but not even a trace of potassa; traces,however, of copper and lead were found, due to the vessels employed in themanufacture. The ash in Bengal indigo only amounts to 6*63, and in twovarieties of Guatemala to 11-34 and 7-28 per cent.

* “ Bulletin de la Societc Industrielle de Mulhouse," May, 1870, p. 253.