_Electrical Experiments on Amber._
_Saturday, July 3, 1762._
To try, at the request of a friend, whether amber finely powdered
might be melted and run together again by means of the electric
fluid, I took a piece of small glass tube, about two inches and a
half long, the bore about one-twelfth of an inch diameter, the glass
itself about the same thickness; I introduced into this tube some
powder of amber, and with two pieces of wire nearly fitting the
bore, one inserted at one end, the other at the other, I rammed the
powder hard between them in the middle of the tube, where it stuck
fast, and was in length about half an inch. Then leaving the wires in
the tube, I made them part of the electric circuit, and discharged
through them three rows of my case of bottles. The event was, that
the glass was broke into very small pieces and those dispersed with
violence in all directions. As I did not expect this, I had not, as
in other experiments, laid thick paper over the glass to save my
eyes, so several of the pieces struck my face smartly, and one of
them cut my lip a little so as to make it bleed. I could find no
part of the amber; but the table where the tube lay was stained very
black in spots, such as might be made by a thick smoke forced on it
by a blast, and the air was filled with a strong smell, somewhat
like that from burnt gunpowder. Whence I imagined, that the amber
was burnt, and had exploded as gunpowder would have done in the same
circumstances.
That I might better see the effect on the amber, I made the next
experiment in a tube formed of a card rolled up and bound strongly
with packthread. Its bore was about one-eighth of an inch diameter.
I rammed powder of amber into this as I had done in the other, and
as the quantity of amber was greater, I increased the quantity of
electric fluid, by discharging through it at once five rows of my
bottles. On opening the tube, I found that some of the powder had
exploded, an impression was made on the tube, though it was not hurt,
and most of the powder remaining was turned black, which I suppose
might be by the smoke forced through it from the burned part: some of
it was hard; but as it powdered again when pressed by the fingers, I
suppose that hardness not to arise from melting any parts in it, but
merely from my ramming the powder when I charged the tube.