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DYEING AND CALICO PRINTING.

regard to Chemistry and Mechanical Science is too obvious for comment, butattention must be drawn to the important fadt that, notwithstanding theprogress made in those sciences with which the art has more or less incommon, our knowledge of the subjedt itself is but slight. We are entirelyignorant of the laws which govern the combination of dyes and pigmentswith fibrous tissue, and totally unable to point out the chemical differencebetween white and coloured fibre, or to explain the causes of the appearanceor disappearance of colour. There is not a single experiment on recordwhich will enable the'reader to judge whether colouring tissue by dyeing isa chemical phenomenon or not; neither does there exist a quantitativedetermination of the amount of alumina, iron, or tin, which may combinewith or be attached to cotton, wool, or silk. It is, moreover, still uncertainhow much colouring matter may combine with these metals, and whether anydefinite compounds exist; in fadt, there is no chemical theory of dyeingworthy of the name.

The history of dyeing is another question.

Its invention or discovery may be said to have been coeval with the firsttraces of civilisation ■, it is impossible to determine the time when the art ofimparting colours to fabrics was first pradtised, but there is reliable historicalevidence as to its antiquity. In those portions of Asia where at a remoteperiod there existed a high degree of civilisation, a somewhat advancedproficiency in the art appears to have been reached, especially in Phoenicia,whose capital city, Tyre, was the Manchester of antiquity, and about fourteen orfifteen centuries before the Christian era became celebrated for the productionand application of the famous Tyrian purple.

According to Pliny and Aristotle, this valuable and costly dye was obtainedfrom a kind of mollusc, a little reservoir in the throat of which on beingpierced yielded one single drop of liquid. This liquid, at first colourless,became gradually lemon-coloured, then sky blue, and in a few days purple.Bancroft (“ On Permanent Colours ”) says regarding it:—

“ To avoid the trouble of opening the small reservoir in each fish thesmallest species was generally bruised whole in a mortar, though the otherfluids of the fish must have necessarily debased the colour in some degree.The liquor when extracted was mixed with a considerable portion of salt topreserve it from putrefaction, and was then diluted with five or six times asmuch water, and kept moderately hot in leaden or tin vessels for the space often days, during which the liquor was often skimmed to separate all im-purities ; after which the wool, being first well washed, was immersed and kepttherein for five hours, then taken out, carded, and again immersed, and con-tinued in the liquor until all the colour was exhausted. To produce particularshades of colour, nitre, urine, and a marine plant called Fucus wereoccasionally added. Several of these varieties of colour have been par-ticularly mentioned by ancient writers. One of them, which was very dark,seems to have been a violet, inclining towards the reddish hue ; ‘ Nigrantisroses colore sublucens ’ (Pliny, lib. ix., sedt. 50). Another, and less esteemed,was probably a kind of crimson ; but the most esteemed, and that in whichthe Tyrians particularly excelled, resembled coagulated blood ; ‘laus ei sutnmain colors sanguinis concreti ’ (Pliny, sedt. 62). There was, moreover, afourth kind known in later times, an account of which may be found in