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At the same time he asserts, as a fact well ascertained by experiment, that "vegetables possess in themselves the power or resisting extreme cold for a certain length of time,.... and hence it is believed that there may exist in the organism of plants a force, independent of the conduction of caloric, which resists a degree of cold above the freezing-point."
All the peculiarities of electrolysis are capable of interpretation: the phenomena of the transport of ions, the fine experiments of M. Bouty, those of Professor Kohlrausch and of Professor Ostwald on various points in electrolytic conduction, all support the theory. The verifications of it can even be quantitative, and we can foresee numerical relations between conductivity and other phenomena.
The more blood passes through the skin, the greater will be the loss of heat by conduction, radiation, and evaporation. Hence, any action of the vaso-motor mechanism which causes dilatation of the cutaneous capillaries, leads to a larger flow of blood through the skin, and will tend to cool the body. Again, the special nerves of perspiration act directly as regulators of temperature.
It has been supposed that the copper covering of the roof, including the gilded dome, its rain-pipes and four excellent lightning-rods, have had the effect of neutralizing the air about it by constant conduction of mild currents. Yet the rod on the spire of Somerset Street Church, nearby and eastward of the State-House, but lower, has been seen to receive a disruptive discharge.
It was also shown that the voltaic arc is not a phenomenon of conduction, but is essentially a disruptive discharge, the intervals between the passage of two successive static sparks being the time required for the battery to collect sufficient power to leap over the interposed resistance. This was further confirmed by the introduction of a condenser, when the intervals were perceptibly larger.
But conduction and induction combined would not carry messages to a distance that would enable extensive communication. A new medium had yet to be found, and this was the work of Heinrich Hertz, a young German scientist. He was experimenting with two flat coils of wire, as had many others before him, but one of the coils had a small gap in it.
THE CAUSES OF DEFORMATION. As the earth's interior, or nucleus, is highly heated it must be constantly though slowly losing its heat by conduction through the crust and into space; and since the nucleus is cooling it must also be contracting.
By an extensive series of experiments with the above apparatus the author succeeded in proving that heat is evolved by the coils of the magneto-electrical machine, as well as by any other part of the circuit, in proportion to the resistance to conduction of the wire and the square of the current; the magneto having, under comparable circumstances, the same calorific power as the voltaic electricity.
In recent years other methods have been developed for generating electrical power in relatively small quantities for special applications. Semiconductors, which combine heat insulation with good electrical conduction, are used for thermoelectric generators to power isolated weather stations, artificial satellites, undersea cables and marker buoys.
All these somewhat obscure facts, and some others such as the different action of ultra-violet radiations on positively and negatively charged bodies are now, on the contrary, about to be co-ordinated, thanks to the modern ideas on the mechanism of conduction; while these ideas will also allow us to interpret the most striking dissymmetry of all, i.e. that revealed by electrolysis itself, a dissymmetry which certainly can not be denied, but to which sufficient attention has not been given.
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