digested out of that red rib-marrow, and which, if given to the child, greatly increases the proportion of red corpuscles in the blood and stimulates all the constructive processes of the body. This will sell for a much larger sum a pound than veal.

And so there are various other substances taken from the sweetbreads proper, the neck-and-throat sweetbreads, the thyroid gland, the parotids, and the suprarenal capsules which can be used in medicine and can be sold at a large profit to people brought up to believe that "eating the part strengthens the part."

Glycerin a By-Product.

And when all has been extracted that you would think could be extracted, all the bits and scraps and scrapings and what not are put into a tank and cooked and cooked until all is dissolved that can be dissolved. The residual fat is skimmed off, and the last bit of glue, and the insoluble matter at the bottom of the tank, go for fertilizer, and then, in the packing-houses that don't know their business, the tank water is let run away. But there is much valuable nitrogenous matter in those waters which the first-rate packers utilize. And there is glycerin there.

In the old days the candle-makers who used palm-oil had their own troubles with glycerin. If a candle was blown out, the smoldering wick used to leave an offensive odor. It was the glycerin that caused this. Naturally, the only thing to do was to take it out of the candle, and the next thing was to get rid of it down the gulley into the creek. People complained, as people will; but what else was an honest chandler to do? Latterly they have been figuring on the matter, and some of them have come to the conclusion that they used to let as much as two thousand dollars' worth of glycerin get away from them every week.

In the last five years the soap-makers have learned that they can realize more money out of the glycerin than they can out of the soap they make. Some of this glycerin is refined, but the great part of the crude goes to the manufacturers of dynamite, which is nitroglycerin mixed with infusorial earth, so as to weaken it.

There is just as much acid after the glycerin is turned into nitroglycerin as there was before. After it is washed out the nitro is left apparently unchanged. It is not broken up, but it is on the edge of it. Give it a knock and it all flies to pieces at once so suddenly that it will loosen more dirt in a second than a hundred pick-and-shovel men could scoop out in a week.

Wealth in Refuse Heaps.

Back of the tin shop there used to be a heap of shining clippings. The heap of clippings isn't there now. If there are any bits of tin too small to make the backs of buttons, they are pressed together to make window-sash weights.

Nor is that pile of sawdust back of the sawmill any more. The butchers want it for their floors, but that isn't the most economical use for it. There are acetic acid, wood alcohol, naphtha, wood-tar (and all that that implies) to be had from the distillation of sawdust—to say nothing of sugar from birch sawdust. The reason there isn't more money in the sawdust than in sashes, doors, and blinds which the factory turns out is because we have more faith in cog-wheels than we have in test tubes.

In machinery, big or little, Americans stand at the head of the class; in industrial chemistry they are at the foot of the class.

We pay the Germans about ten times what we ought to for phenacetin, because we can't get it into our heads that there is any money in applied organic chemistry. Coal-tar was once a nuisance, but the Germans make indigo so much better and cheaper from it now that they have put the indigo-plant out of business.

The red trousers of the French soldiers are dyed with German alizarin, also a coal-tar product, because it doesn't pay to raise madder any longer. In coal-tar are all sorts of valuable drugs, dyes, and perfumes. But we don't know it—industrially.

Stay! I do my country an injustice. We can make moth-balls and carbolic acid. But that is as much as ever we can do. And this is why we do not utilize the saw-dust and make a better business out of it than the sawmill can.

And garbage! I wonder how much orange-peel and lemon-peel is thrown away in New York City every day, and how much the neroli or essential oil that could be got from it would be worth. I wonder if the stalks and fag-ends of vegetables could not be distilled and something made from them. But the limit of our wisdom in regard to garbage is: burn it and get power from it. Somebody is going to get rich from this garbage problem one of these days. But it will be the test-tube and not the cogwheel that will make the money. It will be the industrial chemist, not the mechanic.

Fortunes Lurk in Old Wool.

See what a difference such knowledge has made in the wool industry. Sheep's wool is dirty and greasy when it comes to the mills. Wash it with strong alkali in running water. That is what has always been done. But a man in Massachusetts thought it would be a good idea to dissolve the grease with some such solvent as naphtha. He saved the naphtha to use over again; he recovered the grease, which is the most softening and penetrating of all fats and is most valuable for ointments, and he recovered carbonate of potash. Sheep wearing heavy wool in the hot weather perspire freely, and this perspiration contains carbonate of potash.

After the wool is once woven into cloth, we may dismiss from our minds all thought of effecting any more economies. When the suit of clothes is worn to rags, the rags are still as good as new, for the wool is picked out into strands of fiber again and woven anew. It isn't ground into shoddy as it was in the days of the Civil War.

The wool is picked apart as long as it has any staple to it at all, and forms part of the most expensive and enduring of fabrics. It may be mixed with cotton, but when it comes to be a rag again, the cotton is burned out either with acid or with heat, the dust is taken out, and once more behold absolutely pure wool, much safer to wear than the new wool of the tropics and semi-tropics. When there is not enough wool to hold together it goes into our clothing. With wood ashes and scrap iron it ceases to be a fabric and becomes a dye, Prussian blue.

The cotton rag has no such long life. All it is good for is paper stock. The paper business is essentially a wealth from waste industry. For a long time, linen rags, cotton rags, and old rope were the only materials of which paper was made. Cheap books and magazines and newspapers had to wait until it was discovered that the resins and gums in which the fibers of wood are imbedded could be dissolved away, leaving the pulp of the wood in just the same condition that the pulp of rags was.

Where Old Magazines Go.

If the resins are not thoroughly dissolved away the paper turns brown in the course of time. Naturally enough, the wood-pulp makers let the solution of resins run off and become a nuisance, but they, too, are learning that there are glucoses and pyroligneous acids and all manner of riches to be obtained from the solution of the vegetable matter, to say nothing of the possibilities of a sort of gum or glue which is softened both by heat and by moisture.

And just a word about an economy found necessary by the magazines and newspapers which take back the copies the newsdealer does not sell. These "returns" were hard to get rid of. Paper is mean stuff to burn in quantities. So far as the texture of the wood-pulp paper is concerned, it might be used to print on again, but how are you going to remove the ink? Let the ink stay on and use the pulp over again for pasteboard boxes. And that's what becomes of the newspapers and magazines that nobody buys.

If you will look over journals devoted to concrete and its wonders, you will see a good