Or, if you wish to make the experiment on a smaller scale, pour about an ounce of the above liquid into a wine-glass, into which insert a piece of soft amalgam of silver, the size of a pea, and the effect required will immediately be produced. The silver, separating in the form of prismatic needles, will arrange itself so as to assume an arborescent appearance.
The Lead Tree.
The precipitation of a solution of acetate of lead by means of a piece of zinc, so as to form what is commonly called the lead tree, is perfectly analogous to this theory, but is too well known to require illustration.
The Tree of Mars.
Dissolve iron filings in aqua fortis moderately concentrated, till the acid is saturated; then pour gradually into the solution a solution of fixed alkali, commonly called oil of tartar. A strong effervescence will take place, and the iron, instead of falling to the bottom of the vessel, will afterwards rise, so as to cover its sides, forming a multitude of ramifications heaped one upon the other, which will sometimes pass over the edge of the vessel, and extend themselves on the outside, with all the appearance of a plant. If any of the liquor is spilt, it must be carefully collected, and be again put into the vessel, where it will form new ramifications, which will contribute to increase the mass of the vegetation.
To form a Metallic Tree, in the Shape of a Fir.
In a small globular bottle with a tall neck, dissolve one ounce of fine silver in three ounces of nitric acid; put the bottle into a sand bath, and let it remain over a slow fire till the liquid be half reduced; then add three ounces of good white-wine vinegar, a little warmed; shake the mixture, and place the bottle in any place where it is not likely to be disturbed: in about a month’s time a beautiful metallic fir will appear, ramifying to the very surface of the liquid.
To make a Gold or Silver Tree, to serve as a Chimney Ornament.
Make an amalgam of a small portion of fine gold, and ten times the quantity of purified cinnabar.
Grind and wash the amalgam in water, till no black colour appears: when perfectly clean, dry the amalgam, and insert it into a glass retort; place it in a sand bath over a slow fire, which must be preserved ignited for a day or two; gradually increase the heat, to expel the mercury from the gold, whose metallic vegetation will be perfectly in proportion to the mercury which escapes. When the fire is extinguished you will find the mercury expelled into the receiver, and the gold remaining in the retort will be soft and malleable, possessing the purest appearance; the mass will have sprouted branches, in perfect imitation of small shrubs and trees of different forms and height, which may be separated from the heap, serving as their base, when taken from the retort. These will allow even of being made red hot without injury to their appearance, or fear of decomposition, and may be used as ornaments for any length of time.