New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1877-03-31

A very Convenient phrase indeed, is that which
calls the passage of electricity current Bear
ing i'll mind that it Is rather simlle than n 1act
it will serve to pcturSto the MIND what happens
when the telephone is in operation. Suppose that
the current of electricity is represented by steady
stream issuing from n pipe and running along
smoothly. At the point 5 the current strikes
stone and is tlerceforth thrown into waves. After
this the current flows oyera dam, T. If the dam Is
easily shaken, the waves will communicate to IT VI
brations and those vibrations will exactly CORE
spond TO the waves. Applying this conception TO
the telephone, the approach of the metal 6 occa-
sions waves in the electric current, and these are
communicated by the current to the vibrating lid d.
I'm an exceedingly instructive lecture Il few nights
ago on the Grtmme electric light, AT Cooper lns;i-
tutc d. G.. F. Barker made clear FaTadays view
of this subject. Here rays Of force extending
| in certain wcil-asccrtaned curves around and 20
| some distance from the poles OF magnet What
ever contracts expands that field OF force, creates
current Of electricity, where current already
exists Strengthens or weakens it. And this again.
is The effect of the approach Of iron to the poles or
its removal from them, Dr. Barker proved to his
audience by the oscillation OF gayanonetcr. the
image of which was magnihcd and thrown on a
screen by electric light But what actually takes
place In the iron of the magnet around which the
NJ Joule of England has the credit of discovering
MANY years ago, that the iron through which
an electric current flows is elongated during the
massage Of the current. series of exact expert
nents by Prof. A. NJ. Mayer, about five years ago,
| developed a large amount of curious data on this
| subject. Among other things proved was the fact
that a length, ming occurs in an iron rod around
which current is passing and that the increase in
the volume of the rod thus caused is exactly equaed
byare1ucton in vOlume-a shrnkage in the diameter
of the rod. Another point ascertaned was that the
change in the Dimensions of metal iS practically III
| Simultaneous the whole change of length produced
by given strength of electricity is equally great
whether the current is turned on very slowly or all
at once Just in the operation OF the telephone,
the changes in the strength of the current must be
wholly and instantly transmitted, no matter what
| NAV be their number and variety. Furthermore
| and this is a very suggestive experimental the
metal OH the membrane is suffered to rest against
| the magnetic poles any sounds sent will still be
| heard though family. They are reproduced by the
| molecular movements of the iron itself.
WHAT THE sPIRITUAIIsT MEDIUMS MISSED.
In point of fact the aforementioned cOntrivanee is
to some extent reproduction of the earliest tee-
phone invented by German-Philip Reiss-abOut
Is wears ago. In that telephone the vibrations Of q
stretched membrane in the sending instrument were
| caused to make and break an electric circuit The
receiving instrument was singe-cOil magnet in
| closing an iron bar and was mounted on sounding
box. Music could be transmitted by this telephone,
| and further contrvances developed the sounds re-
ceiyed so that they could be heard in large hall.
But only the sound of the notes. e. the pitch of the
| music-was transmitted. The notes were all equal
| in strength and quality. much greater success in
| sending music by electricity has been latterly
| achieved by the telephone of Mr.. Elisha Gray OF
| Chicago. The public has more or less COMPOUNDED
the performances of this instrument with those OF
| the one invented by Prof. Bell. Mr.. Gray's tele-
pbone was shown at the Centennial Exhibition, and
called forth much interest among the men OF science
who examined it, Its leading feature is the use OF
| tuninC-forks tuning-fork may be so introduced
| into a telegraphc circuit TO make and break The
| circuit Such fork vibrating certain fixed mum
! her of times per second, according to its specia
| mitch or musical note, will break and restore thu
| electric current an equal number of times pei
second. -Four years ago Mr.. Gray made curious
discovery as to some means by which this interlnt
tent current can be made audible. III the believer
in mesmerism and psychic force had known O.
| it in time, they might have made muci
| capital for their theories out OF that dis
| coyery and the mystery that enshrouded TIT
I performance. Mr.. Gray had violin with a sllyel
Mate set in the front of it, II the end OF wire ovc
which was sent an intermittent current such as ha
been described was held in the hand, and the finger
Of the same hand were lightly rubbed over the silve
Mate the note OF the tuningfork at the other end OF
tbe line was reproduced, and could be distinctly