At various times and in various places popular superstition has been excited by the occurrence of what have been called showers of blood. The destruction of cities and of kingdoms has been, according to historians, preceded by this awful omen. Yet this has been explained by a very natural and accountable phenomenon. In the year 1553, the hedges and trees, the stones of the pathway, and the clothes of many persons, were sprinkled copiously with drops of red fluid, which was supposed to be blood, till some observant person noticed the coincident appearance of unusual swarms of butterflies, and marked that the coloured drops proceeded from them. Again, at Aix la Chapelle in 1608, the same awful appearance occurred, especially on the walls of a particular churchyard. M. Peiresc, an able naturalist, residing at Aix, traced the phenomenon here to the same cause. Just before, he had found a large chrysalis, which he had enclosed in a box, in order to identify the species to which it belonged. A few days after, hearing a rustling, he opened the box, and discovered a beautiful butterfly evolved from the pupa, which had left upon the floor of its prison a large red stain. He saw that the character of this deposit agreed exactly with that of the ominous drops abroad, and remarking an unusual abundance of the same kind of butterfly, he conceived that he had revealed the cause of the terrific phenomenon. He was confirmed in this belief by the circumstance that the supposed blood-drops were not found in the streets of the town, nor upon the roofs of the houses, where they must have occurred had they fallen from the sky; and, moreover, that it was rare to see any on the exposed parts of stones, walls, &c.; but rather under the protection of angles, and in slight cavities--which agrees well with the habits of the insects in question. No doubt this was the true explanation of the phenomenon, but it does not say much for the powers of observation which could have attributed it to blood, for the colour is by no means that of blood, especially _dried_ blood, but much more crimson; and the earthy deposit, resembling chalk, which copiously remains after the fluid part has evaporated, would in a moment convince any one who was in the habit of comparing things which differ, that, whatever the substance was, blood it certainly was not.