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cause of the Earth s heat, who was the first to attribute it to the conflict of 
its elements, and we shall soon have again occasion to notice his clear expo¬ 
sition of this sentiment, when we come to investigate the origin of hot- 
springs. 
Lemery, who published a Practical Course of Chemistry the year after 
Mayow,* endeavours to account for subterraneous fires, from the following 
practical observations. 
He mixed twenty-five pounds of powered dulphur, with an equal weight 
of iron-filings , and having kneaded the mixture together, by means of a little 
water , into the consistence of a paste, he put it into an iron pot, covered it 
with a cloth, and buried the whole a foot under ground. 
In about eight or nine hours time, the earth swelled, grew warm, and 
cracked ; hot sulphureous vapours were perceived, a flame which dilated the 
cracks was observed; the superincumbent earth was covered with a yellow 
and black powder; in short, a subterraneous fire, producing a volcano in mi¬ 
niature, was spontaneously lighted up from the reciprocal actions of sulphur, 
iron, and water. 
The theory of this experiment is as follows. The water coming into 
contact with the iron, is decomposed. The oxygen of the water unites with 
the iron , and hydrogen gad (inflammable air) is given out, which dissolves a 
portion of dulphur, and becomes in consequence sulphurated hydrogen gad. 
This may be known by the fetid odour exhaled, as likewise by the flame 
emitted, which is more lively than that of sulphur, and less so than inflamed 
hydrogen air. 
Mons. Beaume, who observed this phenomenon, arising from an hundred 
pounds of iron-filings, and as much sulphur in powder, relates, that the 
flame produced rose to above a foot in height.-p 
That part of this experiment which relates to the production of flame, by 
the fermentation of iron-filings and sulphur when made into a paste, has 
been frequently repeated since the time of Lemery. 
* Mayow published in 1674. Vide note * page 62. 
f How this air next comes to be inflamed, is probably as follows. The oxygen of the water 
over and above what saturates the iron, goes to form with the sulphur, sulphuric, or vitriolic acid, 
and we know that this acid mixed with water, raises it to a high temperature, and, under the present 
circumstances, sufficient to inflame the sulphurated hydrogen gas. 
