ch I moved up and down between the Light and it.
Others I found, which were, as to the bulk of the Ball, prety regularly
round, but the Surface of them, as it was not very smooth, but rough, and
more irregular, so was the reflection from it more faint and confused. Such
were the Surfaces of B. C. D. and E. Some of these I found cleft or
cracked, as C, others quite broken in two and hollow, as D. which seemed to
be half the hollow shell of a Granado, broken irregularly in pieces.
Several others I found of other shapes; but that which is represented by E,
I observed to be a very big Spark of fire, which went out upon one side of
the Flint that I struck fire withall, to which it stuck by the root F, at
the end of which small Stem was fastened-on a _Hemisphere_, or half a
hollow Ball, with the mouth of it open from the stemwards, so that it
looked much like a Funnel, or an old fashioned Bowl without a foot. This
night, making many tryals and observations of this Experiment, I met, among
a multitude of the Globular ones which I had observed, a couple of
Instances, which are very remarkable to the confirmation of my
_Hypothesis_.

And the First was of a pretty big Ball fastened on to the end of a small
sliver of Iron, which _Compositum_ seemed to be nothing else but a long
thin chip of Iron, one of whose ends was melted into a small round Globul;
the other end remaining unmelted and irregular, and perfectly Iron.

The Second Instance was not less remarkable then the First; for I found,
when a Spark went out, nothing but a very small thin long sliver of Iron or
Steel, unmelted at either end. So that it seems, that some of these Sparks
are the slivers or chips of the Iron _vitrified_, Others are only the
slivers melted into Balls without vitrification, And the third kind are
only small slivers of the Iron, made red-hot with the violence of the
stroke given on the Steel by the Flint.

He that shall diligently examine the _Phaenomena_ of this Experiment, will,
I doubt not, find cause to believe, that the reason I have heretofore given
of it, is the true and genuine cause of it, namely, That _the Spark,
appearing so bright in the falling, is nothing else but a small piece of
the Steel or Flint, but most commonly of the Steel, which by the violence
of the stroke is at the same time sever'd and heat red-hot, and that
sometimes to such a degree, as to make it melt together into a small
Globule of Steel; and sometimes also is that he