At Mendip in Somersetshire, those who are employ’d in melting Lead-ore, if they work in the Smoke, are subject to killing Diseases. There is a Flight (or Steam) in the Smoke, which falling on the Grass, poisons the Cattle that eat it. Those who live very near where Lead-ore is wash’d, can’t keep either Dog or Cat, or any sort of Fowl, but they all die in a short time[[43]].
[43]. Lowthorp’s Abr. vol. ii. p. 576.
Such are the mephitical Exhalations in a little Cavern in Italy, call’d Bacca Venosa, the poisonous Mouth, not far from Naples, but more generally known by Grotto de Cani, the Dog’s Cave; because the Experiment of its poisonous Nature is frequently made upon Dogs; tho’ it be fatal as to any other Creatures that come within the Reach of its venemous Fumes. This wonderful Cave is (situated at the Bottom of a Hill) in Dimension, about eight Foot high, twelve long, and six broad.
From the Ground within it, arises a thin warm Fume (visible to the Eye) which is one continued Steam covering the whole Surface of the Bottom of the Cave; it does not disperse itself into the Air like Smoke, but quickly after its Rise, falls back again into the Earth. The Fumes rise about a Foot high and never higher, and hurt no Creature whose Head is above that height; but when a little Dog, or the Head of any other Creature is forcibly held in the Steam, it falls down dead, the Limbs convuls’d, and trembling; and if left there a little while, it dies, but if taken out soon, and laid in the open Air, comes to Life again, and sooner, if thrown into the adjacent Lake.
CHARLES the Great, King of France, and Emperor of the West (a Title of Honour other Gallick Monarchs have had in full view for some time) made the Experiment upon an Ass, whose Head was held in the Fume, and was soon destroy’d. Two Slaves put in with their Heads kept down to the Earth, were both soon kill’d. To this, I shall add some Experiments made by the ingenious Mr. Addison, who says——
—“A Dog that has his Nose held in the Vapour (within the Cave) loses all the Signs of Life in a very little time.” Then he observes, how long a Dog was expiring the first time, and after his Recovery, and found no sensible Difference. “A Viper put in, adds he, bore it nine Minutes the first time we put it in, and ten the second. When we brought it out after the first Trial, it took such a vast quantity of Air into its Lungs, that it swell’d almost twice as big as before, and it was perhaps, on this Stock of Air, that it lived a Minute longer.
“A Torch, Snuff and all, goes out in a moment, when dipt into the Vapours or Steams of that Cave——A Pistol can’t fire in it. I split a Reed, and laid in the Channel of it a Train of Gun-powder, so that one end of the Reed was above the Vapour, and the other at the bottom of it; and I found, tho’ the Steam was strong enough to hinder a Pistol from taking fire in it—that it could not intercept the Train of Fire, when it once begun flashing, nor prevent it from running to the very end—fire will live in it no longer than in Water, because it wraps itself in the same manner about the Flame, and by its Continuity hinders any quantity of Air, or Nitre from coming to its succour[[44]].”
[44]. His Works, vol. iii. p. 8, 97.
Nor are our Mines in Great-Britain altogether free from these fatal Damps, that have turn’d Coal-pits into Graves. In a Coal-pit belonging to Lord Sinclair in Scotland, seven or eight Men intending to work in a Place where they had been the Day before, but stepping a little further, they all fell down dead, as if they had been shot. The Wife of one of them, venturing to see her Husband, fell down dead as soon as she came near the Corps[[45]].
[45]. Lowthorp’s Abridgment, vol. ii. p. 373.