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He called the separate atoms or groups of atoms into which bodies undergoing electrolysis are separated, the radicals, or ions, and named the electro-positive ions, which appear at the cathode, the kathions, and the electro-negative radicals which appear at the anode, the anions.
The southern range of tables is numbered from 14 to 23; and the northern range from 38 to 47. In the next case are the Oxides of Copper; bismuth; red oxide of zinc; cobalt ochres; oxide of uranium; and pitch ore. In the nineteenth case are the Oxides of Lead; and in the twentieth are the first of the oxides of electro-negative substances.
It was thus that man in this state of consciousness was compelled to picture the foundation of the physical universe as being made up of gravity and electricity, as we meet them in the modern picture of the atom, with its heavy electro-positive nucleus and the virtually weightless electro-negative electrons moving round it.
Pure gold is generally found in separate crystals or grains, but the metal is mostly found combined with other substances. It is alloyed, for manufacturing purposes, with copper and silver. Half of the third case, and cases 4, 5, and 6 in this room, are covered with various electro-negative metals and metalloids, classed according to the system laid down by Berzelius.
Hence the compound radical which united successively with these two elements must itself be at one time electro-positive, at another electro-negative a seeming inconsistency which threw the entire Berzelian theory into disfavor.
This theory of binary composition of all chemical compounds, through the union of electro-positive and electro-negative atoms or molecules, was extended by Berzelius, and made the basis of his famous system of theoretical chemistry. This theory held that all inorganic compounds, however complex their composition, are essentially composed of such binary combinations.
Electro-positive particles unite with electro-negative particles to form chemical compounds, in virtue of the familiar principle that opposite electricities attract one another. When compounds are decomposed by the battery, this mutual attraction is overcome by the stronger attraction of the poles of the battery itself.
This interchange of atoms goes on until the two atoms of hydrogen which are freed last abide on the surface of the copper. The "contact electricity" of the zinc and copper probably begins the process, and the chemical action keeps it up. Oxygen, being an "electro-negative" element in chemistry, is attracted to the zinc, and hydrogen, being "electro-positive," is attracted to the copper.
This "secondary" or reacting current is evidently due to the polarisation of the foils that is to say, the electro- positive and electro-negative gases collected on them. Professor Groves constructed a gas battery on this principle, the plates being of platinum and the two gases surrounding them oxygen and hydrogen, but the most useful development of it is the accumulator or storage battery.
Such a substitution would be quite consistent with the dualistic theory, were it not for the very essential fact that hydrogen is a powerfully electro-positive element, while chlorine is as strongly electro-negative.
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