Page:Popular Science Monthly Volume 3.djvu/804

780 1,200 feet, before he can reach his cottage, where he naturally looks for his food and sleep. This climbing of the ladders is performed hastily, almost as a gymnastic feat, and throws a heavy strain (amounting to from one-eighth to one-quarter of the whole day's work) upon the muscles of the tired miner, during the half-hour or hour that concludes his daily toil. A flesh-fed man (as a red Indian) would run up the ladders like a cat, using the stores of force already in reserve in his blood; but the Cornish miner, who is fed chiefly upon dough and fat, finds himself greatly distressed by the climbing of the ladders—more so, indeed, than by the slower labor of quarrying in the mine. His heart, over-stimulated by the rapid exertion of muscular work, beats more and more quickly in its efforts to oxidate the blood in the lungs, and so supply the force required. Local congestion of the lung itself frequently follows, and lays the foundation for the affection so graphically though sadly described by the miner at forty years of age, who tells you that his other works are very good, but that he is 'beginning to leak in the valves' Were I a Cornish miner, and able to afford the luxury, I should train myself for the 'ladder-feat' by dining on half a pound of rare beefsteak and a glass of ale from one to two hours before commencing the ascent."

Poisonous Volcanic Gases.—During a volcanic eruption on the little island of San Jorge, one of the Azores, in the year 1808, vaporous clouds were seen to roll down the sides of the mountain, and to move along the valley. Wherever they passed, plants and animals wilted and perished instantaneously. From this asphyxiating action, as also from their downward movement on the mountain-side and toward the sea, we may conclude that they consisted chiefly of some dense, deleterious gas, most probably carbonic acid. Their opacity is to be attributed to the presence of watery vapor, and their reddish color to the presence of fine volcanic dust. Finally, their injurious action on plants was doubtless owing to the presence of chlorhydric and sulphurous acid. Similar phenomena have been observed on occasion of other volcanic outbreaks, but nowhere so marked as in the case of San Jorge. In 1866, for instance, the volcano of Santorin emitted smoke charged with acid, which produced on plants effects similar to those observed at San Jorge in 1808.

A writer in the Revue Scientifique is of the opinion that the facts above stated give the solution of some of the problems raised by the exhumations at Pompeii. The strange posture of skeletons found in the streets of that town is very difficult to account for, if we insist on finding analogies with phenomena observed in modern eruptions of Vesuvius. A shower of ashes, however heavy, however charged with humidity, could never have thrown down and choked a strong man like the one who met his death while making his escape, in company with his two daughters, along one of the public roads. They must have inhaled a poisonous gas of some kind, which caused them to perish in fearful agony. This gas would not lie in a layer of equal thickness: in some places it might have a greater depth than in others. Hence, while some of the inhabitants would perish, the remainder would escape.

It is very probable that the eruption in the year 79 was accompanied with local emissions of carbonic acid, springing from points remote from the crater. In all volcanic regions, says the author, there are localities where, even when the volcano is inactive, carbonic acid exists in the atmosphere, in quantities sufficient to produce asphyxia: and the neighborhood of Vesuvius is particularly noted for the number of such localities. During an eruption, the amount of the gas given out is usually increased, and wells, ditches, quarries, etc., are filled with carbonic acid. It is sometimes dangerous to enter cavities in the rocks on the coast when a fresh breeze does not keep them free of the poisonous gas. In 1861 Ste.-Claire Deville came near meeting his death by entering one of these cavities for a few moments. The following week he and the author barely escaped being asphyxiated in the bed of a great quarry, which they had previously visited many a time with impunity.

A Relic of Ancient Etrurian Art.—An antiquarian discovery of very considerable