If you put mercury into a solution of nitrate of silver, and leave them for a few days to combine, the result will be a precipitation of silver in a lovely arborescent form, the arbor Dianae, beautiful beyond description. Such are my favourite ash trees when the summer sunshine sparkles on them. It is their bare, silvered trunks that give the special charm to these hanging woods.

Thus began a business which now yields the owners of the beds one hundred million dollars yearly. It was soon found out that the nitrate in its raw state contained properties that were injurious to plants and that these should be first eliminated. Forthwith reduction works were established to extract the deleterious substances.

The don said I'd kill it all, but I knowed better, for I had seen the wild stuff growing like fun all round the edges of sich places. But it don't seem to hitch on in the spots themselves. S'pect it's too stout there." Jack at once recalled the accounts he had heard of the nitrate beds on the Peruvian hills, though he did not dream then of the importance of this discovery to him.

This is also apparent from the astonishingly minute quantity of certain substances which suffices to produce sensible inflection and aggregation such, for instance, as the 1/20000000 or even the 1/30000000 of a grain of phosphate or nitrate of ammonia!

Five minutes later the foremost team was leaving the nitrate bed, starting on its long journey at the slow pace of oxen, while the other soon followed. Vague reports had reached Jack before he had left on his trip, of the uprising of the people, and of the guerrilla warfare being carried on by the straggling armies of the North and South.

Their return was marked by a fortunate incident; the engineer discovered a substance which replaced tinder. It is known that a spongy, velvety flesh is procured from a certain mushroom of the genus polyporous. Properly prepared, it is extremely inflammable, especially when it has been previously saturated with gunpowder, or boiled in a solution of nitrate or chlorate of potash.

Normally this organic nitrogen is transformed in the soil, first into ammonia nitrogen, next into nitrite nitrogen, and lastly into nitrate nitrogen, these three transformations being effected by biochemical action produced by different kinds of living microscopic organisms called bacteria.

Having previously carefully fitted a watchglass to a wide-mouthed bottle, nearly fill the bottle with the contents of the stomach, blood, secretions, etc. Place a few drops of a solution of nitrate of silver on the concave surface of the watchglass, and cover the mouth of the bottle with it. The vapour of hydrocyanic acid, if present, will form a white precipitate which may be tested.

Conscience and nitrate of silver are telltales that never forget any tampering with them, and the broader the light the darker their record. Now to our work. Here is a square of crown glass three-fourths as large as a page of the "Atlantic Monthly," if you happen to know that periodical. Let us brush it carefully, that its surface may be free from dust.

I asked Dinky-Dunk about the nugget, and he says it's genuine gold, without a doubt. He also says there's one chance in a hundred of Whinnie actually having a claim up in the gold country, but doubts if the poor old fellow will ever get up to it again. It's about on the same footing, apparently, as Uncle Carlton's Chilean nitrate mines.