the parts are put into and
detained in a bended posture, which by the agitation of Heat are shaken,
and loosened, and suffered to unbend themselves.
* * * * *
Observ. VIII. _Of the fiery Sparks struck from a Flint or Steel._
It is a very common Experiment, by striking with a Flint against a Steel,
to make certain fiery and shining Sparks to fly out from between those two
compressing Bodies. About eight years since, upon casually reading the
Explication of this odd _Phaenomenon_, by the most Ingenious _Des Cartes_,
I had a great desire to be satisfied, what that Substance was that gave
such a shining and bright Light: And to that end I spread a sheet of white
Paper, and on it, observing the place where several of these Sparks seemed
to vanish, I found certain very small, black, but glittering Spots of a
movable Substance, each of which examining with my _Microscope_, I found to
be a small round _Globule_; some of which, as they looked prety small, so
did they from their Surface yield a very bright and strong reflection on
that side which was next the Light; and each look'd almost like a prety
bright Iron-Ball, whose Surface was prety regular, such as is represented
by the Figure A. In this I could perceive the Image of the Window prety
well, or of a Stick, which I moved up and down between the Light and it.
Pages:
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148