Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.
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the measure of force, it was found from a series of daily obser- vations, extending over a period of five years, (1844-8,) that the quantity of electricity at the same place, undergoes a regu- lar increase and decrease in certain months of the year; that, contrary to general belief, the quantity of electricity is at its maximum in winter, and undergoes a decrease until it finds its minimum in June, and then again rises to its maximum in the succeeding January. The subjoined table represents the numerical results; and from this it will be seen that at the same level the quantity of electricity in the atmosphere is twelve limes as great in the cold month of January as in the hot month of June. Average of Five Years —1844 to 1849. Months. Quantity of Electricity. January, maximum, 605 February, " 378 March, " 200 April, " 141 May, " 84 June, minimum, 47 July, " 49 August, " 62 September, " 70 October, " 131 November, " 209 December, " 507 3. The Influence of the State of the Sky.— From the results under this head, it is made evident that the highest degree of electricity is not found in cloudy weather, but rather in the clear, serene sky; i. e., at a time when the atmosphere is free from clouds. Thus, for the whole year, the proportioned quantity maybe represented — cloudy 186, clear 273. In reference to the monthly variations, as influenced by the state of the sky, it was found that in January, the maximum month of the year, the proportionate quantities are, cloudy 268, clear 1133. Only