96 
Iron and sulphur would remain mixed together for ages without in¬ 
flaming, if they were kept perfectly free from water, being incapable of 
taking fire, whilst they continued in that state* 
But though it is certain, from the experiments above, that mixtures of 
iron and sulphur, when moistened with a proper quantity of water, will spon¬ 
taneously take fire; yet the origin of subterraneous fires cannot, with any 
great degree of probability, be referred to the same principle, unless it can 
be shewn, that nature has combined together in large quantities iron and 
sulphur, and distributed the composition through various internal parts of 
the earth. 
Now that this is really the case, we can have no doubt. There is per¬ 
haps no mineral more commonly met with, than that which is composed of 
sulphur and iron. It has been found not only upon the surface of the earth, 
but at the greatest depths below it, to which mines have been hitherto 
driven; not only in England or Italy, Europe or Asia, but in all parts of the 
world. 
In England it goes by the name of copperas-stone, from its yellow co¬ 
lour; but its scientific appellation is pyrites, from fire, a denomination 
expressive enough of the property this mineral has of spontaneously taking 
fire, v r hen laid in heaps, and subjected to moisture. 
For although Lemery was the first person who, by artificial mixtures of 
water, sulphur, and iron, produced heat, yet that natural mixtures of these 
substances would spontaneously take fire, was known long before he made 
his experiments. 
Thus, to omit what is said by Pliny and the ancients, we are told upon 
good authority,* that in the year 1604, one Wilson, at Ealing, in Yorkshire, 
had piled up in a barn many cart-loads of the pyrites, or brass-lumps, as 
they were called by the colliers, for making of vitriol, or some secret pur¬ 
poses of his own, when the roof happening to be bad, the pyrites were wet¬ 
ted by the rains, and in this state began to smoke, and presently took fire, 
and burnt like red-hot coals. 
The same accident was observed, above an hundred years ago, at Puddle 
\Yhaif m London, where heaps of coal which contained much of this pyrites 
took fire. 
* Vide Power on the Microscope, who was contemporary with, and wrote a few years after, 
Hooke. 
