Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.

quantity and intensity; by the Barometer and other instruments, for ascertaining the atmospheric density, humidity, ozone, &c.; or by the Thermometer, for its heat and cold. Such like meteorological observations made with much care, and that by all these present helps for testing and comparing the normal and abnormal electricities, and other states of the atmosphere, together with another class of observations for de- termining the magnetic variation in the earth, — simultaneously made on the land and on the sea, on different continents, in the extreme north and extreme south, as well as at the equator, — are to any philo- sophic, or logical mind, full of significance, as relating to health and disease, life and death, in the great human family. We will only remark very briefly, that with regard to the real electric state of the atmosphere, and of the terrestrial globe, philosophers have long differed. But of late, Arago and De la Rive have concluded and do now assume, that our globe possesses, at least on its solid surface, an excess of accumulated negative electricity, and that this is the same with bodies on its surface'; that the atmosphere itself, on the whole, is positively electrized, and arises from the same source as the negative of the globe. They noticed that when the most highly charged storm clouds approach mountains, the clouds go towards them with a rush, and with that quickness in proportion as the summit of the mountains have the more marked negative tension. They are then observed to linger, and adhere as it were to the mountain, as if indifferent or slow conductors, yielding successively either electricity. This, we notice, is observed only in respect to static electricity. If, now, we consult the galvanometer, we find phe- nomena for study in dynamic electricity. For when the cloud approaches the mountain, and as it commences to pass, the in- strument gives indications of ascending currents, because the electricity of the ground is found to be attracted towards the