It does not seem impossible that some of the extraordinary effects of lightning, either in striking repeatedly certain objects, or in seldom or never touching others, may be explained on meteorological grounds. The height, as well as thickness, of the clouds charged with the electric fire, must naturally greatly influence the direction of the latter, and though both elements vary enormously, in different countries and at different seasons, it is likely enough that the variation is comparatively trifling under given conditions, as, for example, in a district where there are prevailing winds, and where the configuration of the earth powerfully acts upon the drift and movement of the aerial masses, and the atmospheric conditions in general. As to the height of the clouds charged with lightning, there appears scarcely any limit, as it has been found that they at times rise above the summit of the most elevated mountain ridges on the face of the globe. The great naturalist and traveller, Alexander von Humboldt, measured the height of a storm cloud, discharging lightning, near the mountain of Toluca, in Mexico, and found that it was no less than 4,620 metres, or 15,153 English feet, above the level of the sea. The height of another, ascertained by Professor de Saussure, of Geneva, when ascending Mont Blanc, was 4,810 metres, or 15,776 English feet, or almost exactly three miles. Probably, these are exceptional cases, as even in mountainous districts the heavy moist and electricity-laden clouds seldom rise to such extraordinary heights; still, even such as they are they do not represent the extreme limit of elevation. A member of the French Academy of Sciences, M. De Lisle, records having measured, by trigonometrical observations, the vertical height of clouds in a thunderstorm, with strong flashes of lightning, which broke over Paris, and found it to be 8,080 metres, or 26,502 English feet. Consequently, this cloud-mass, charged with electricity, stood far above the summit of the highest mountain peak in the world.