In the issue of the London _Electrician_ of June 8, 1894, under the
heading, “Hertzian Waves at the Royal Institution,” the following
remark occurs: “It is wholly probable, as Dr. Lodge suggests, that
Hertzian waves may often have manifested themselves in physical
laboratories to the annoyance of the workers, &c.”
I may mention in this connection that in 1877, if I remember the year
correctly, while working a Ruhmkorff induction coil, one terminal of
which was grounded and the other terminal of which was attached to an
insulated metallic body, Prof. Houston and I noticed that when the
sparks were passing between the terminals of the coil, it was possible
not only to obtain minute sparks from all metallic bodies in the
immediate neighbourhood, that is, in the same room, but that delicate
sparks could be taken by holding in the hand a small piece of metal
near metallic objects in many other rooms and on different floors in
the building, although the pieces were not connected to ground. These
could only have been Hertzian effects, but there was no recognition of
their true character at the time, though the effects were seen to be
connected with the very quick charging and discharging of the insulated
body. An account of these experiments was, I think, published in the
_Journal_ of the Franklin Institute at the time. I desire also to
mention, as coming under my notice within the past year, a curious and
rather amusing illustration of the principle upon which the beautiful
instrument for detecting the presence of electric oscillations, devised
by Dr. Lodge and called by him the “coherer,” is based.
It was reported to me when in Philadelphia that a certain
electro-plater had found that he could not pursue his silver plating
operations during thunderstorms, and that if he left his plating over
night and a thunderstorm came up the work was invariably ruined. I was
disposed to be thoroughly sceptical, and expressed my disbelief in
any such effect. Being urged, however, I went to the silver-plater’s
shop, which was a small one, and questioned the silver-plater himself
concerning the circumstance which had been reported. While it was
evident that he was not a man who had informed himself electrically,
I could not doubt that, after conversing with him, he had indeed been
stating what was perfectly true, namely, that when his operations of
plating were going on and a thunderstorm arose, his batteries, which
were Smee cells, acted as though they were short-circuited, and the
deposit of metal was made at too rapid a rate. The secret came out on
an inspection of his connections. The connections of his batteries
to his baths were made through a number of bad contacts which could
not fail to be of high resistance under ordinary conditions. I could
readily see that virtually he was working through a considerable
resistance and that he had an excess of battery power for the work.
Under these circumstances a flash of lightning would cause coherence
of his badly contacting surfaces, and would improve the conductivity
so as to cause an excessive flow of current, give a too rapid deposit,
and--as he put it--“make the batteries boil.”
The incident suggests the use of Dr. Lodge’s ingenious instrument in
the study of the waves which are propagated during thunderstorms, of
which waves we have practically little or no information.