New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1881-07-20

poses of adjustment. One of these pairs of coils
has been fixed upon a handle like ordinary hand
telephone, while the adjustment is attained by
ing the secondary coil of the other or loose pair.
A battery of ten elements having great electro
motive force is used in operating this apparatus
The connections made upon the same general
principle described with the Hughes instrument, of
which this is modification, namely, the battery,
vibrator and two primary coils forming circuit
ana the two secondary coils and the telephone the
other.
All things being in readiness a correspondent of
IHE TRIBUNE was invited to place. the telephone
TO ms ear barely perceptible " hum was audible,
thc naiance not having been made per feet. Profess
SOP Bell who stood at distance of several feet
holding in his hand the fixed pair of coils took up
round bullet and held them the coil An i'll
creased sound was distinctly noticeable whenever
anGy w m tine dhftve % ea Of 9
bullet being within it, he passed it several times
near the end of the coils the lead approaching per-
haps to within one inch and Il half of the mstru-
nent, but always with the substance of his hand
inttgrvenpg, nt' Each passage was distinctly an n
and passing the coils over his cheek the result
was the same. Passing the instrument over
coins in his pockets and the buckles upon
his snSpenders made their presence distinctly
audible, and with some adjustments painfully
apparatus could he made to disclose the position of
iattenod bullet the fiat side being presented; is
hattcncd bullet presenting its edge to the insru-
ment, the distance is much less.
gulshcd electricians at distance, including Pro-
1essor hughes in London for suggestions in regard
to any of the several problems presented. and has
received several replies disclosing, in the wide
difference in the suggestions made, the fact
that the one problem of distance has never before
been made the subject of experiment in connection
with the lnductive balance. One electrician sug
gcSts hat the primary coil he of large wire and he
wound upon spool of considerable length hut small
diameter; the secondary coil being of smaller wire
wound on a Hat coil around the middle of the pri-
mary coil. Another suggests the same form, except
that the secondary coil be placed around the end of
its primary.
Drawings of several other forms have been sent
as suggest ions. dozen different coils dilering in
size OF wire, Shape-whcthcr flat or oblong--wit
the secondary bearing various relations in form,
position and size to its primary have been tried and
discarded.
The problems to be solved seem endless. To fix
the exact proportion of each element in the appara-
tus to the otherS-thc battery, the primary and
secondary coils the rapi,iiy of Vibrations the re-
Sistancc OF each part so that the greatest possible
aggregation of ininitesmal effects NAV h, OBJ
tanned, must engage the attention of the eminent
electricians engaged III the work for a considerable
time.
OF course the work of winding coils and construct
ing apparatus requires considerable skilled laHlr
and MIR. Watts, OF the firm of Davis & Watts of
Baltimore, telegraph instrument makers has III
response to Il call for assistance. volunteered his
services. and Is experimenting the mechanical part
OF the work.