It is a striking instance of the triumph of mind, that by the introduction of lightning conductors into different civilized states, the power of this most energetic agent of nature is controled, and comparative security provided for life and property, otherwise in imminent jeopardy, when a severe thunder-storm occurs. Experience has taught the prime importance of furnishing exposed or elevated structures with a conducting apparatus, and has sufficiently shown that the immunity from danger enjoyed by many an unprotected building has been merely accidental; for when the teeming thunder-cloud has been wafted within reach of the edifice hitherto unscathed, the delusion has vanished that man may carelessly and with impunity thrust up his handiwork into the region of storms, as if daring the fury of the tempest, and inviting down its vengeance. The fine tower of St. Mark’s, at Venice, rising to the height of 360 feet, terminates in a pyramid which was severely injured in 1388. In 1417 the pyramid was again struck, and set on fire, having been constructed of wood. The same event happened in 1489, when it was entirely consumed. After being rebuilt of stone, the fell lightning renewed its destructive stroke in 1548, 1565, 1653 and 1745; and on the last occasion the whole tower was rent in thirty-seven places, and almost destroyed. It was again ravaged in 1761 and 1762, but in 1766 a lightning rod was put up, which has since protected it from damage. At Glogau, in Silesia, an interesting example of the value of conductors occurred in the year 1782. On the 8th of May, about eight o’clock in the evening, a thunder-storm from the west approached the powder magazine established in the Galgnuburg. An intensely vivid flash of lightning took place, accompanied instantly with such a tremendous peal of thunder, that the sentinel on duty was stupefied, and remained for awhile senseless, but no disaster occurred. Some laborers at a short distance from the magazine saw the lightning issue from the cloud and strike the point of the conductor, which conveyed it in safety by the combustible material. A different result took place with reference to a large quantity of unprotected ammunition, belonging to the republic of Venice, deposited in the vaults of the church of St. Nazaire, at Brescia. The church was struck with lightning in the month of August, 1767, and the electric fluid, descending to the vaults, exploded upward of 207,600 lbs. of powder, reducing nearly one-sixth of the fine city to ruins, and destroying about 3000 of the inhabitants. The Indians, whenever the sky wears a lowering aspect, so as to threaten a severe thunder-storm, are said to leave their pursuits and take refuge under the nearest beech-tree, considering it a complete protection, as it is affirmed that no instance has occurred of the beech having been struck by atmospheric electricity, when other trees of the American forests have been shivered into splinters in its neighborhood.