by pressing the button
or turning the switch, thus making a complete and uninterrupted path in
which the current may travel and do its work. Until the time of Edison's
investigations of 1875, now under consideration, electricity had never
been known to manifest itself except through a closed circuit. But, as
the reader will see from the following excerpts, Edison discovered a
hitherto unknown phenomenon--namely, that under certain conditions the
rule would be reversed and electricity would pass through space and
through matter entirely unconnected with its point of origin. In other
words, he had found the forerunner of wireless telegraphy. Had he then
realized the full import of his discovery, all he needed was to increase
the strength of the waves and to provide a very sensitive detector, like
the coherer, in order to have anticipated the principal developments
that came many years afterward. With these explanatory observations, we
will now turn to the excerpts referred to, which are as follows:

"November 22, 1875. New Force.--In experimenting with a vibrator magnet
consisting of a bar of Stubb's steel fastened at one end and made to
vibrate by means of a magnet, we noticed a spark coming from the cores
of the magnet. This we have noticed often in relays, in stock-printers,
when there were a little iron filings between the armature and core,
and more often in our new electric pen, and we have always come to the
conclusion that it was caused by strong induction. But when we noticed
it on this vibrator it seemed so strong that it struck us forcibly there
might be something more than induction. We now found that if we touched
any metallic part of the vibrator or magnet we got the spark. The larger
the body of iron touched to the vibrator the larger the spark. We now
connected a wire to X, the end of the vibrating rod, and we found we
could get a spark from it by touching a piece of iron to it, and one of
the most curious phenomena is that if you turn the wire around on itself
and let the point of the wire touch any other portion of itself you
get a spark. By connecting X to the gas-pipe we drew sparks from the
gas-pipes in any part of the room by drawing an iron wire over the brass
jet of the cock. This is simply wonderful, and a good proof that the
cause of the spark is a TRUE UNKNOWN FORCE."

"November 23, 1815. New Force.--The following very curious result was
obtained with it. The vibrator shown in Fig. 1 and batter