Soda was acted upon in the same manner as potash, and exhibited the same results; but its decomposition required a stronger action of the battery, or it was necessary that the soda should be in smaller pieces than the potash.
The metallic globules produced from the potash remained fluids in the open air, at the time of their production; but those from soda, though fluid at the time of their formation, upon cooling, became solid, having much the lustre of silver. The alkalies could be made to produce metallic results in vacuo.
Since Mr. Davy’s first experiments on this subject, several others have been made, much in the same manner, upon the earths. Messrs. Pontin and Berzelius, two Swedish chemists, have succeeded in obtaining metallic amalgams from lime, magnesia, strontites and barytes; but they could produce no such effect on alumine and silex. Mr. Davy however effected this, by a battery of 36000 square inches.—He also improved upon their other discoveries. He, by distillation, drove off the mercury from the amalgamated metals which they obtained from the earths, and procured a pure metal.
Ammonia was also found to contain a metal. This discovery inclines one to believe, that the air we breathe contains metal in a gaseous state, as azote, which is a component part of ammonia, forms a large portion of our atmosphere.
When compounds, soluble in water, were put into water contained in agate cups, and subjected to the action of Galvanism, their decomposition was rapid.—A solution of the sulphate of potash, being put into two cups and Galvanised by fifty pair of plates, for four hours, the acid was found by itself in the cup connected with the positive end of the battery, and the alkaline basis in the cup communicating with the negative end. Similar phenomena took place in solutions of sulphate of soda, nitrate of potash, nitrate of barytes, phosphate of soda, sulphate, succinates, oxalate and benzoate of ammonia; also with alum. When muriatic salts were used, they afforded oxymuriatic acid. When metallic solutions were employed, metallic crystals and an oxyd were deposited on the negative wire, and a great excess of acid was found in the positive cup.—Strong solutions afforded signs of decomposition quicker than weaker ones.
We could enumerate a variety of similar experiments, but the limits of our work forbid it.
CHAP. VIII.
Experiments which may be performed without the assistance of the Battery.
To shew the Galvanic light.
Place a piece of zinc upon your tongue, and a piece of silver between your cheek and upper jaw; then move your tongue so as to bring the two metals in contact with each other, and you will perceive a very curious sensation upon your tongue, accompanied by a cool sub-acid taste,[[21]] and at the same time you will see a flash of light, whether your eyes be open or closed. The sub-acid taste resembles, in a degree, that produced by electricity.[[22]]