Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.
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clouds; and very frequently have we witnessed the clouds of dust and trash violently raised, not hy the wind only, but by this force. And all this is reversed, as soon as the rain pours down, for it brings with it the superabundance of positive electricity from the clouds. At each clap of thunder, or rather at each flash of lightning, the needle of the galvanometer is agitated, and even driven back with force against its stops. At other times the magnetic state of the needle is found to be per- manently altered. Difference between Electricity and Magnetism. Dr. J. C. Atkinson, of England, thinks that magnetism and electricity are not identical, and differ in the effects which they produce upon the weather and climate. He says, — Magnetism of the earth is a state of continual and restless fluctuation, and that its changes from moment to moment are strictly simultaneous at every point where observations of this nature have been made. It is my impression that cold is an effect of magnetic influence, as solar heat in the atmosphere is an effect of electric action; and I conclude that the vital prin- ciple of temperature is the result of the combined agency of these two forces, variously modified, according to seasons and latitudes of the several places. The range of the barometer gradually increases towards the north pole. The rise of the barometer mercury may be observed in this country during the prevalence of northern winds, conveying as they do magnetic currents, till at last it reaches to two or three inches. On the contrary, between the tropics the variations of the barometer are exceedingly small, whilst winds from the southward, in tem- perate latitudes, if the electric current or wind is continued for any length of time, will cause a tendency in the mercury of the barometer to fall. The winds are more powerful in the production of weather than would appear at first sight; and although the moon was always supposed to exercise great control over the weather, yet it is strange that both Drs. Herschel and Clarke, great observers