From trough to trough we go, breathing steam, and stepping into puddles, or reeking rivulets rippling over the stones of the pavement; but we are tempted on, like children, by the charm of the brilliant colors that flash upon the sight whichever way we turn. What a lilac this is! Is it possible that such a hue can stand? It could not stand even the drying, but for the alkali into which it is dipped. It is dyed in orchil first, and then made bluer, and somewhat more secure, by being soused in a well-soaped alkaline mixture. That is a good red brown. It is from Brazil wood, with alum for its mordant. This is a brilliant blue; indigo, of course? Yes, sulphate of indigo, with tartaric acid. Here are two yellows: how is that? One is much better than the other; moreover, it makes a better green; moreover, it wears immeasurably better. But what is it? The inferior one is the old-fashioned turmeric, with tartaric acid. And the improved yellow? Oh! we perceive. It is a secret of the establishment, and we are not to ask questions about it. But among all these men employed here, are there none accessible to a bribe from a rival in the art? There is no saying; for the men cannot be tempted. They do not know, any more than ourselves, what this mysterious yellow is. But why does it not supersede the old-fashioned turmeric? It will, no doubt; and it is gaining rapidly upon it; but it takes time to establish improvements. The improvement in greens, however, is fast recommending the new yellow. This deep amber is a fine color. We find it is called California, which has a modern sound in it. This Napoleon blue (not Louis Napoleon's) is a rich color. It gives a good deal of trouble. There is actually a precipitation of metal, of tin, upon every fibre, to make it receive the dye; and then it has to be washed; and then dipped again, before it can take a darker shade; and afterwards washed again, over and over, till it is dark enough; when it is finally soused in water which has fuller's earth in it, to make it soft enough for working and wear. What is doing with that dirty-white bundle? It is silk of a thoroughly bad color. Whether it is the fault of the worm, or of the worm's food, or what, there is no saying--that is the manufacturer's affair. He sent it here. It is now to be sulphured, and dipped in a very faint shade of indigo, curdled over with soap. This will improve it, but not make it equal to a purer white silk. Next, the wet hanks have to be squeezed in the Archimedean press, and then hung up in that large, hot drying-room.