by William Hubbard
[From a typescript contempory with the ms.]
Dr. S. D. Cushman was inventor of several electric devices, the fire alarm
system, etc. He was a telegraph operator for the government in the
Civil War. He had a factory in Racine, Wis. for the manufacture of
cable lightning rods.
While constructing a telegraph line from Racine, they were troubled a great
deal with lightning, as a good deal of the route was through a low, swampy
district and the dampness made the poles a partial escape for the lightning
and consequently caused the shattering of the poles - lightning arresters
were not as well known in those days as now - consequently a device was
made which was practically a trap to catch lightning which was constructed
as follows;
Two copper discs were placed in close proximity to each other so that lightning
could jump across and escape to the ground. A is an electric magnet,
B a permanent magnet a trifle longer than the electric magnet; C is a wood
block insulating permanent magnet from the electro magnet.
If the lightning did jump across the space on its way to the ground, it
would momentarily charge the electro magnet and attract the metal disc
down - and in contact with the permanent magnet - and the permanent
magnet would hold it down, they would know then that the lightning had
passed over the grounded line and had been arrested as designed.
There were several of these boxes connected on the line at different points
preferably low, swampy places having the most dampness.
While adjusting one of these boxes a sound was heard as coming from the
box. The sound resembled the croaking of a frog and on going over
to another distant box, they discovered that there were frogs, all about
that box. In experimenting and hallowing on the box disc they discovered
that they would be heard at the other box or boxes on the line, and from
that, the boxes were used as "talking boxes", not only on that telegraph
line, but between the shops and other places. In trying to have them
adopted in connection with fire alarm boxes, the voice was not loud enough
and were not adopted. Cushman did not apply for a patent on them.
All evidence and testimonials of the above are on record in the United
States District Court in Chicago.
William Hubbard
[Typist unknown]