But what then would be the electric spark which is visible, and must therefore be really material?
MRS. B.
What we call the electric spark, may, Sir H. Davy says, be merely the heat and light, or fire produced by the chemical combinations with which these phenomena are always connected. We will not, however, enter more fully on this important subject at present, but reserve the principal facts which relate to it to a future conversation.
Before we part, however, I must recommend you to fix in your memory the names of the simple bodies, against our next interview.
[*] It has been questioned by some eminent chemists, whether these two last agents should not be classed among the inflammable bodies, as they are capable of combining with oxygen, as well as with inflammable bodies. But they seem to be more distinctly characterised by their property of supporting combustion than by any other quality.
[*] Of all these earths, three or four only have as yet been distinctly decomposed.
[*] These first four metals have commonly been distinguished by the appellation of perfect or noble metals, on account of their possessing the characteristic properties of ductility, malleability, inalterability, and great specific gravity, in an eminent degree.
[†] Mercury, in its liquid state, cannot, of course, be called a malleable metal. But when frozen, it possesses a considerable degree of malleability.
[*] These last four or five metallic bodies are placed under this class for the sake of arrangement, though some of their properties have not been yet fully investigated.
[*] These crystals are more easily obtained from a mixture of sulphuric with a little nitric acid.