Page:Popular Science Monthly Volume 72.djvu/51

 bountiful metals into our agreed standard of exchange, for, as a rule, such are thought, with and without reason, to be in no position to give adequate return for money advanced to perfect the methods which investors are assured will produce the desired results. Especially is this true of the possessor of so valuable a secret, who may alone soon place himself beyond financial concern through the agency the knowledge, which he seeks to share with a few preferred ones.

At the corresponding meeting of this section just ten years ago, my friend, the late Dr. H. Carrington Bolton, presented a paper on this subject, dealing specifically with the publications of S. H. Emmens, of New York.

It has long been known that golden-yellow specks would occasionally show themselves in silver solutions, but could not be obtained at will. Probably this phenomenon has often led to a supposition that silver might be transmuted into gold. Silver can be converted wholly into this form by the reduction of silver tartrate by ferrous tartrate. The solutions must be rather dilute and must be freshly prepared. A red powder is precipitated; this changes to black, and on the filter has a bronze color. After washing, it is removed in a pasty condition and allowed to dry spontaneously. This form of silver is very permanent when dry. It dries into lumps resembling polished gold. By brushing a thick paste of this substance over clean glass, beautiful gold-colored mirrors are obtained. The stronger acids, even when much diluted, instantly convert this allotropic form of silver into normal gray silver; this is also effected by means of pressure.

Using Lea's method, just described, as a starting point, Emmens thought to extend Andrew's doctrine of critical temperatures. By "the combined effect of impact and very low temperature," the former being produced by his force engine, a substance was obtained which was claimed to be common to both gold and silver, hence the name argentaurum. One ounce of silver was said to produce three quarters of an ounce of gold. It was stated that the chief source of expense incurred was in the time required for bringing about the desired molecular changes. A profit of at least $3 per ounce on all silver used was assured, however.

Sir William Crookes did not succeed, to his satisfaction, in repeating the work, although Dr. Emmens stated that during that year Dr. Cabel Whitehead, assayer to the mint in Washington, accepted six ingots of the alloy, approximately a thousand dollars in value.