C 3 
Experiment XXII. 
If a Lump of the, Mineral Matter be reduced to a 
fine Powder, and attentively viewed through a Mi- 
Crofcdpcj it app^rs very like th« Sand of Ifchta^ and 
is very proper for Writing-Sand; Whence I con- 
je£hire, that that Sand is nothing elfe, but the [fame] 
Matter for a long time comminuted by the Aftion 
of the ;Sea. 
Experiment XXIII. 
In fome of the Stones there appear fome few Veins 
of '©DW,"tn others of Silver, but infenfible ; and in 
others, which arc very heavy, there is fome Anti- 
mony. . . 
E.xperiment XXIV. 
A great Difpute arofe in the Academy on the Rife of 
the Damps j for what Reafon thefe fhould be 
fcen only in the old Stratu of the minieral Subftanccs, 
. and not in the new, where by the Adion of the Fire 
they ought to ilTue : Which Thanomenon, if I am 
not miftaken, may be accounted for in this manner : 
As the cooling of the burning Matter began at the 
Surface, we may think, that the more fubtle hetero- 
geneous Particles, upon the doling of the Pores at the 
Surface, remained in Quantities buried in the lower 
Parts of the Matter 5 which, in Procefs of Time, be- 
coming acutangular and of deleterious Figures, yet 
cannot offend while imprifoned: But in new Erup- 
tions, wherein the Shocks given to the Matter pro- 
duce many FilTures, the Damps, meeting with lefs 
Refiftance there, ilTue forth ; As when the Aii* is a 
long 
