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aqueous exhalation, and spontaneous decomposition. But bere we are to consider the manner in which thefe evils are to be remedied, rather than the mystery of their formation.
To obviate the fire-damp, miners are in the habit of crawling on their hands and feet, and with a taper affixed to a long stick for setting fire to the inflammable air*, which sometimes goes off with a terrible and sometimes fatal explofion.
With respect to the choke-damp, no means has yet been devised but ventilation, it being supposed to be stagnated air.
With respect to the mode of ventilation, and the correction of this species of air, we will offer but a few words.
* Some years back a scheme was projected at WHITEHAVEN to light up that town by means of the inflammable air in the pits, which was to be conveyed by pipes throughout every Atreet. As chemistry advances, may not the water of the Thames be decomposed in certain appropriated places, and the inflammable air conveyed throughout $. Strand and City, and this part of the town be splendidly illuminated each night at a very moderate expence ?-Since the discovery of the nature of combustion, and the constituent principles of water, it is hoped that the candid reader will not consider this hypothesis as a mere rhapsody. Were a person to survey London now illuminated as it is by Argent' s lamps, and the product of the Greenland fisheries, and compare it with what it was five hundred years back, and he will perhaps feel inclined to extend his views on the prospect of future improvements !
A shaft*, as it is called, should be carried down somewhat flanting, and the funnel conveyed to the bottom of the pit, whereby the heavier and purer air from above would defcend; while a perpendicular shaft, or chimney, with its mouth arising from the top, would carry up the lighter and corrupted air together with the inflammable.
* Vide Vol. I. page 67. It is curious to observe the knowledge which cur ancestors had of the nature of air. Ray, in a work, entitled The Wisdom of Gui manifestid in the Works of Creation, written in the last century, says, page 73, in speaking of air-fhafts, “ Indeed, 'were there no damps in minés, “ yet the nitrous part" (the NITROGEN or oxygen as it is now called) “ of “ the air being spent and consumed by the breathing of the miners, the re"mining part" (the AZOTIC) “ would be unfit for respiration, unless new " and freth air were to succeed.”-In anotler place he says, page 72, “The 66 air is the fewel of the VITAL FLAME, without which it would speedily “ languish and go out.”--Again he says, p. 73, “ Fishes, and other water « animals, cannot support life without it, for if you pät your hand or any
cover over a vessel containing fith, so as wholly to exclude the air, they will “ be suddenly suffocated.”-Again, page 74, “ Neither is it less necessary to “ infeets, for if you put oil upon them, so as to obstruct those orifices that 6 draw in air, if you obstruct only fome, the parts that are fupplied with air 66 from them are fhortly deprived of 11 JTION, while the rest of the parts 6 that are untouched retain it.”--Again, page 75, he says, “ I am persuad“ ed, with my learned friend Dr. Hulse, that the chief use of the circulation “ of the blood, through the cotyledons of a calf in the womb (which I have « often dissected), and by analogy through the placenta uterina, seems to be
THE IMPREGNATION OF THE BLOOD WITH AIR” (he has above explained the species of air) “ for the feeding the vital flame : for if it were only for nutrition, what need of two such great arteries to convey the
Should fixed air, notwithstanding this, ftagnate in some parts of the pit, an engine, such as they water gardens with, should be used to absorb the fixed air, or else water should be kept continually boiling; for as the steam condenses, it would become impregnated with the fixed air. This ought constantly to be observed, where charcoal fires are employed. A tea-kettle boiling by the side would obviate the chief, if not the whole, of the evil.
In the Hift. de L'Academie des Sciences, Anno 1710, we are told of a baker of Chartres, going along with his son, a robust young man, into a cellar 36 stairs deep, who followed him with a candle, the candle went out on the middle of the stairs. Having lighted it afresh, he was no sooner got into the cellar, than he cried out for help, and they heard no more of the son or father, His brother, an able youth, ran immediately after him, cried out he was dying, and was heard no more. He was followed by his wife, and the by a maid, and still it
6 blood thither? Secondly, I have observed the umbilical vessels to terminate
in a multitude of PAPILLÆ. Now these PAPILLÆ do resemble the “ RADII of a fish'S GILLS, and most probably have the same use, viz. To " SECRETE AIR, and convey it to the fætus, so that the fætus in the womb « doth resemble à fith in its mode of living, or else why should there be such
an instant necessity of respiration so soon as the fætus is fallen off from the 66 womb :"
was the same. Such an accident struck the whole neighbourhood with a panic, and no one was forward to venture any farther, till a fellow, more hardy and zealous than the rest, perfuaded that the five people were not dead, would go down to give them help. .He cried too, and was heard no more. Upon this a fixth man, taking with him a hook, drew the last of them forth without going to the bottom, who, fetching a deep figh, died. Next day the baker's friend, undertaking to get up all the carcases with the hook, was let down with ropes. He called out, and in the haste the rope breaking, he fell into the cellar, and was dead. The magistrates, taking cognizance of the case, the physicians were consulted, who advised a good deal of water to be thrown down. This being performed, a dog and a lighted candle were let down without injury to either, and the dead bodies in this cellar were taken out.'
There is a small grotto at the foot of a little hill, about 8 feet high, 12 long, and 6 broad; froin the ground there arises a thin subtle fume visible enough to a difcerning eye, which does not spring up in little parcely here and there, but is one continued streain, covering the whole surface of the bottom of the cave; and has
* Called Grotto del Cani.
this remarkable difference from common vapours, that it does not, like smoke, disperse itself into the air, but quickly after its rise falls back again, and returns to the earth; the colour of the sides of the grotto being the measure of its ascent, for so far it is of a darkish green, and higher only common earth, and therefore we find no inconvenience by standing in it; and so no animal, if its head be kept above this mark, is in the least injured. But when a dog or any other creature is forcibly held below it, or by reason of its finallness cannot hold its head above it, it presently, like one funned, loses all motion, falls down as dead, or in a swoon, the limbs are convulsed and trembling, till at last no more signs of life appear than a weak and almost insensible beating of the heart and arteries, which, if the animal be left there a little longer, quickly ceases too, and then the case is irrecoverable ; but if snatched out, and laid in the open air, it soon comes to life again, and sooner yet if thrown into the adjacent lake.
The Russians and Germans are frequently exposed, during their cold season, from the noxious air of their stoves, and want of due ventilations.
As foon as a person with them is discovered to be deprived of sense and motion, he is stripped naked, and VOL. III.