[/13] 
away with fmall Sinus's. And I doubt not, but upon di- 
ligent inquiry, a great Catalogue of fuch might be had, 
difcovered in the Memorieof Man ; Befides many there 
are, which are known to open to the day, and to difcover 
themfelves without digging, as Pools Hole, Oakie FIole, 
^c. Again, the great and fmall Streams, which do arife 
from under the Mountains do evidence the hollownefs, 
and Sinoufnefs of them. Add to thefe that many 
Sinus s are made in that inftant , and are continued by 
the explofion and rending of the firft matter fired ; 
which may, and do, very probably, clofe again, when 
the force of that explofion is over ; but are fufEcientiy 
open to continue the Earthquake/ 
That thefe fubterraneous cavities are at certain times 
and in certain feafons full of infiamable Vapours; the 
Damps in our Mines fufEcientiy witnefs; which fired, 
do every thing as in an Eardi-quake, fave in a leffer 
degree.*^ 
Now, that the Pyrites alone ( which is our prefent 
Task^ of all the known Minerals, yeildsthis infiamable 
vapour, I think it highly probable, for thefe Reafons. 
1. Becaufe no Mineral or Ore whatfoever is Sulphu- 
reous, but as it is wholly, or in part a Pyrites : And al- 
tho this does contradid the general opinion of the Chy- 
mifts j yet they muft excufe me, if I diffent from them in 
this particular ; for wherever any of them, fhall find me 
Brimftone Naturally contain d in an Ore; there, lam 
very forward tobeleive, I fliall find them Iron alfo by 
the load-ftone, fo that betwixt u?, we fliall have difcover- 
ed the Pyrites difguifed in that Ore or Mineral. 1 have 
carefully made the experiment in very many of the Fof- 
fils of England, and do find them all to contain Iron^ 
wherever Brimftone, as 1 have elfewhere declared. 
2. Becaufe there is but one Species of Brimftone, that I 
b Vid. Phil. Tranf. 
know 
