can our thirst for knowledge find an object capable of satisfying it. But, more important still, is the cultivation of our moral and religious feelings,-those affections and habits which bind us to each other, and to our common Father and Redeemer. These, above all, prepare us for the joys of heaven. The pure, and holy, and pious alone shall see God. Those who have cultivated Christian charity on earth, are alone fitted to be denizens of that happy land whose Eternal King is love, and the duties and enjoyments of which consist in loving and being beloved.

NINTH WEEK-MONDAY.

CLOTHING. THE ART OF DYEING ITS MODERN HISTORY.

WHATEVER knowledge of dyeing the ancients possessed, appears to have been nearly lost about the fifth century, a period when almost all the arts were in a state of decay, and but few traces of civilization remained in the Western Empire. A faint knowledge of the arts was, indeed, retained in Italy, and afterwards kept alive by occasional intercourse with the East, in consequence of the Crusades, as well as by the introduction of various articles of luxury and refinement, by the commercial enterprise of the Venetians. This importation continually afforded new materials for industry, and new objects for imitation, and gradually led to the revival of the arts in Italy. The knowledge of the arts of dyeing, practised by the Greeks and Romans, was, in some measure, restored by the acquisition of chemical sciences, which early began to shed a feeble light, in modern Europe, over the objects of human industry.

From Italy, the knowledge of dyeing gradually spread itself through the other states of Europe. In the fifteenth and sixteenth centuries, some works were published, detailing the processes then in use, which seem not only to prove, that greater attention had then begun

to be paid to the art, but to have afforded the first great stimulus to its improvement. Indigo had long been known as a dye; it is mentioned by Pliny, under the name of indicum,* and seems to have been early imported from Syria and Egypt in considerable quantities. This drug came, however, to be much better known after the Dutch had established their trade with the East Indies, from whence they imported it.

I have already had occasion to remark, that accident has frequently contributed more to the improvement of the arts, than the most refined speculation; and this was strikingly exemplified in the discovery of the modern scarlet dye, as well as in that of the ancient purple. The kermes were early used for dyeing, and the term scarlet was applied to the color produced by these insects; but that color was very different from the brilliant scarlet now in use, which is derived from cochineal, an article which was unknown in Europe till the discovery of America; and which, even after its importation, produced for a considerable time not a scarlet, but a crimson hue. About the year 1630, it was accidentally discovered, that the nitrate of tin possessed the property of exalting, in a very remarkable degree, the color of this drug, and converting it from a dull crimson to an intense and brilliant scarlet. It is said, that a German chemist, of the name of Kuffler, having accidentally dropped a solution of tin, by aquafortis, into a decoction of cochineal, was the first who observed the singular effect, and who took advantage of it, by employing it in his dyehouse. The secret became soon afterwards known in Paris; and, having been, in the year 1643, conveyed to

* [Indicum simply means Indian, or from India, and being applied to the foreign drug to denote whence it came, was at length used as the name of the article itself, forming by a slight change the word indigo. The proper Indian name for the article is Anil. It is procured from several, but especially from two or three plants, belonging to the order of vetches.-AM. ED.]

† [Both of the dyeing substances mentioned above, are parasitic insects, of the genus Coccus, the one inhabiting a species of oak, in warm climates of the Old world, and the other dwelling on certain species of cactus, in the tropical regions of the New. This genus of insects, in some of its species, goes by the common name of the scale insect.-AM. ED.]

England by a Fleming, gave rise to a dye-house at Bow, near London; whence the new color was for some time called the Bow dye.

In 1662, the Royal Society of London directed its attention to the subject of dyeing; but the chemical art was then too little understood, to permit of much success in their labors; and the art made little progress in England, till a much more recent period. In France, the case was different. The legislature of that country not only appointed proper persons to superintend, officially, the practice of dyeing in all its departments; but held out suitable rewards for the encouragement of such individuals as should contribute, by their discoveries, to the progress of the art. The beneficial effects of this liberal policy, were quickly felt in the numerous improvements in dyeing, which were suggested, from time to time, by the eminent men who filled the official situations. The investigations of Hellot, of Macquer, and of Berthollet, who, each in his turn, held the office of superintendent of the practice of dyeing in that country, gave a new character to the art, and raised it from an obscure, empirical employment, to the rank of a branch of chemical science. The latter, in particular, distinguished himself by conjoining extensive observation with enlightened theory; and published a treatise, which may be considered as a standard work on the subject, since it contains not only a detailed account of the practical operations of the art, but a correct theoretical view of the principles on which it is founded.

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The two eminent Englishmen who have conferred the most important benefits on the practice of dyeing, are Dr. Henry of Manchester, and Dr. Bancroft. The latter, in particular, has thrown new light on this art, by his two volumes, entitled, Experimental Researches concerning the Philosophy of Permanent Colors,' the second of which was published in 1813. In this work, he has corrected various mistakes of his predecessors, and has advanced the scientific and practical principles of the art still nearer perfection, by applying to it more extensively the growing resources of chemistry.

NINTH WEEK-TUESDAY.

CLOTHING.-THE ART OF DYEING-ITS CHEMICAL PRINCIPLES.

BEFORE leaving the subject of dyeing, it seems desirable that something should be said respecting the principle on which the art depends, so far as it has hitherto been discovered by chemical analysis.

Dyeing is effected by the principle of chemical affinity. There must be such an affinity between the stuff to be dyed and the coloring matter, otherwise the process will not be effectual. Now, this may be either direct or indirect; or, as Dr. Bancroft expresses it, the coloring matters may be either substantive or adjective; "the first including those matters which, when put into a state of solution, may be fixed with all the permanency of which they are susceptible, and made fully to exhibit their colors in or upon the dyed substance, without the interposition of any earthy or metallic basis; and the second, comprehending all those matters, which are incapable of being so fixed, and made to display their proper colors, without the mediation of some such basis." Both of these kinds of dyes are to be found in various productions of the animal, vegetable, and mineral kingdoms; but the adjective are much the most numerous. These having no affinity, or but a very slight affinity to the cloth itself, are yet powerfully and permanently attracted to another substance, which, in its turn, is attracted to the cloth. This intermediate agent is called a mordant, and the effect was long known, before the chemical principle on which it depends was at all suspected. It was not till the last half-century, that the true theory was understood. Before that period, the most absurd and unphilosophical opinions were entertained concerning it. Dr. Bancroft suggested the right principle in regard to ink and the black dye, which he attributed to the chemical affinity between iron and the coloring principle of galls; but Mr. Keir was probably the first, who proposed

a true explanation of the cause of the adhesion of the coloring matter to stuffs. Berthollet, however, ascribes the theory of mordants to Bergman. This eminent chemist observed, that, when wool or silk was immersed in a solution of indigo in sulphuric acid, the former attracted the coloring particles more forcibly than the latter; and that both, having a stronger affinity for the indigo than the solvent, were by this means able to deprive the bath of its color, and attach it to their own fibres. Upon the same principle, he explained why the colors communicated to the wool were more durable, as well as more intense, than those communicated by the same process to silk.

On this principle, depends "the truly wonderful" art of calico-printing, which consists in communicating different colors to particular spots or figures on the surface of cotton or linen cloth, by placing it in a bath of compound dye, the rest of the texture retaining its original whiteness. This art was known in India, as already mentioned, at a very early period. To the uninitiated among the ancients, it must have appeared like magic; and, although the science of chemistry has laid open to the moderns so many mysteries and secrets of Nature, yet, even now, it is a matter of curiosity and admiration to behold a colorless texture, after being immersed for a short time, drawn forth, exhibiting figures of vivid and various hues, durably marked on its surface. This art is of comparatively recent date in England; but no branch of industry has risen to perfection with greater celerity. At present, the elegance of the patterns, the beauty and permanency of the colors, and the expedition with which the different operations are carried on, are highly admirable.

If we inquire into the cause of colors, we shall find that this depends not so much upon the chemical constitution of a body, as on a certain arrangement or disposition of the particles of the surface. Many bodies display different colors, according to the particular angle under which they are viewed, while others assume a change of color, simply by the change of their mechanical condition.