New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1881-08-01


cunt and around the primary coil OF wire
Rer. second. A hand telephone only is placed
les being connected and the vibrator set in motion,
ae secondary coil is placed so as to cover the prim-
y aay and and the operator having the telephone at his
ear hears the pulsatons of tn primary current sent
through the vibrator with each motion of it's sprng,
an induced current being produced in the secondary
coII by It's contiguity with the primary.
+ Up to this point the ground traversed has been
familiar to all electricians for many years. Profes-
Saratoga paper, consisted in the fact that if the
secondary coil be gradually turned to one side
nductye effects p0i and tn the S resultant ltS' tone
from the vibrator diminish until q, point is
OF the secondary coil remains upon the primary coil,
wnen the effect of the induction had
beyond the point of silence the results be-
come Immediately apparent.
At the point of silence it was discovered that that
portion of the secondary which still covered an
equal portion of its primary, was very sensitive
to the presence of metallic substances not
the two coils formed a portion, disclosing
their proximity by making again audible the sounds
instrument were equal to those given by the Hughes
balance, but the latter furnishing amore convenient
form for general it first adopted the basis
of experiments.
FOLLOWING NEwL INES.
railing to attain the result deemed essential
for hnal success namely, the detection Of the
presence of leaden bullet at three inches distance
the professors ceased for time to experiment and
betook themselves to theorizing.
In the balance there were necessarily two primary
and two secondary coils, and of given electromo-
tive force only onc-half could be utilized for
induction. With the Bell instrument only
one coil in each circuit necessary. In all ex-
perlments with the vibrator difficulty had been ex-
perienced by the rapid oxdization of the platinum
points of contact, bright spark being produced
by the induction of the individual convOlutions
OF the primary coil upon each other. Moreover this
bp law pf iuHI f,ou
familiar to all electricians, had the effect at the be-
ginning of EACH pulsaton to reduce the strength of
the direct current and at the end of each pusation
to continue Its effect when 1t dc ,irablo that
there should be no current upon the wire at all.
To avoid these results and secure absolute clear
ness in the pulsations condenser" similar IN form
to that used for like purposes in connection with
of teiegraphy was addei to the primary circuit
and this proved to be the act which crowned the
efforts OF the eXperlmentors with success
SUCCESSFUL EXPERIMENTS.
A correspondent of The TRIBUNE who this even
ing witnessed experiments with the newly con-
structed instruments. audibly and Enthusiastically
detected the presence of leaden bullet
held at distance of three and one
half inches from the sensitive area of the secondary
coil, this being half inch beyond the distance
which Professor Bell set himself the task
to attain. Even greater though less pro-
nounced results have been attained: a bullet
disclosing its presence in one experiment at a
distance of five inches In this experiment n curl
GUS fact noticed. At a distance of three
and a half inches less, the fundamental
musical tone of the vibrator was conveyed
through the telephone to the ear of the
operator But when five inches distance was
reached the resultant tones were two octavcs or
more higher than those of the vibrations. Thus in
some mysterious manner, the laws of harmony are
found to be related to those of electricity, and may
in the future play not,nnmportant part rs AN aux
lllary to the work of practical siirQerV
An old soldier who was shot in the breast i'm the
war OF the Rebellion, and who still carries the bull
let in his person, was made the subject of expert
ments this afternoon, and the presence of
the metal below the shouderbade was made
distinctly audible. week ago an experiment was
made in the Presidents case, the instrument used
being the Hughes balance with detective range
of two inches. The back was explored for some
time without any results but when the detector
was placed over the point of the abdomen where a
dlscolored protuberancc made its appearance i'm
mediately after the wound occurred, indistinct
audible effects noticed. This was con-
firmatory, in so far it went, of the
theory of the attendant physicians in regard
to the place where the bullet is imbedded
but it was not sufficiently definite to warrant feel
irg of certainty. DR.. Agnew was present when the
experiment was made, but DR.. Hamilton was not
When the latter arrived last night he was desrous
OF witnessing repetition of the experiment. and
Professor Bell and his associate to the White
House for the purpose When, however, they made
known the greatly enhanced result of later expert
ments it decided to postpone further tests pon
the President until tomorrow morning when it il
expected that the position of the bullet will be
made definitely known. The experiment is to
take place at half past s. There will be no greater
cause for excitement fatigue to the patient than
would be given by placing an ordinary teIephone
near his person. since all the sounds except those
produced by the te ephOne in the ear of the operator
will be contained in distant rooms.
OFFICIAL pIrT 7 C,rTNc