The times. [volume] (Washington [D.C.]) 1897-1901, 1901-02-17

piications Of scientific discovery been Sc
numerous and SO far-reaching in their ef-
feet upon social conditions In brief re-
view OF The contributions of the nineteenth
century to the evolution OF the telegraph,
telephone, trolley car. electric lighting. and
other means OF utilizing electricity 1t Will
be possible 10 consider only n very few o.
the fundamental discoveries upon which
the enormous and rather complex super
structure CT today rests Happily these
are few In number, and their presentation
Is ali the more important because of the
TACT that In the popular mind they are not
accorded that Significance to which they
are entitled, II, indeed, they are remem-
bered at ALL
Inc first great step In advance of the
electricity of Franklin and his contem-
porar;es land his predecessors .,,r s.Ssea
years. was taken very near the end of the
last century. but 1t must be regarded as
the beginning of nineteenth century cleo
tricity. Two Italian philosophers. GaIvani
| and Volta, contributed to the invention of
| what Is known as the gaivanic or yoltaic
| battery, the output of which was not AT
first distinctly recognized as the electricity
of the older schools. BY this beautiful
discovery electricity was for the first time
| enslaved to man. who was now able to
| generate and control it at times and In
such quantities as he desired. Although
| the voltaic battery Is now nearly obsolete
as source of electricity, its invention
must always be regarded as one of the
| three epoch-making events in the history
| Of the science during the past 100 years.
For three-quarters of a century it was
| practically the only source of electricity,
| and during this time and by its use nearly
all of the most important discoveries were
made. Even in the first decade of the
| century many brilliant results were
reached. Among the most notable were
the researches of Sir Humphry Davy,
who, by the use of the most powerful bat
terry then constructed, resolved the hither-
to unyielding alkalies, discovering sodium
and potassium, and at the same time ex-
hibited in his lectures in the Royal In
stituton in London the first electric arc
light, the ancestor of the millions that
now turn night into day.
The cost of generating electricity by
means of a voltaic battery is relatively
very great. and this fact stood In the way
of the early development of its appIica-
lions, although their feasibility was per-
fectly well understood. Without any other
important invention or discovery than that
of the voltaic battery much would have
been possible, including both electric light
Ing and the electric telegraph. Indeed
electric telegraphy had long been n pos
sibility, even before the time of Galvani
and Volta. but It's actual construction and
use were almost necessarily postponed
until second capital discovery came TO
remove most of the difficulties
This was the discovery of a relation be-
tween electricity and magnetism, the ex-
istence of which had long been suspected
and earnestly sought A Danish profess
sor, Hans Christian Oersted, was fortu-
nate In hitting upon an experiment which
demonstrated this relation and opened up
an entirely new field OF investigation and |
invention. What Oersted found was that |
when conductor. as a copper wire, car |
rying an electric current was brought near |
freely suspended magnet, like n compass |
needle, the latter would take up definite
position with reference to the current
Thus an electric current moved q magnet, |
acted like magnet in producing mag |
netic field The subject was quickly /
taken up by almost every physicist in /
Europe and America. Arago found that
Iron filings would cling to wire through
which current was passing, and he was
able to magnetic steel needles by means
OF the current. Amperc. another French |
physicist. studied Oersted's wonderful dis
eovery both experimentally and mathe-
matically. and in an incredibly short time
SO developed Ii as to deserve the title of |
creator of the science of electro-dynamics
The first to make what Is known as an |
was an Englshman named |
Sturgeon, who used bar of soft iron
bent in horseshoe form Gas had long
been common In making permanent steel |
magnets, and after vanishing the iron
for insulation single coil of copper wire
was wrapped about 1t through which the
current from battery was passed. There
were thus two ways of producing visible
motion by means Of an electric current
that of Oersted's simple experiment in
which a suspended magnetic needle was
detected by current, and that made pos
sible by the production, at will, of an
The application of both
If these ideas to the construction of an
electric telegraph was quickly attempted |
and two different systems of telegraphy |
,rew out of them. One, depending on Ger
'ted's experiment, was developed In Eng
and first and afterward in Europe: the |
,ther, that involving the use OF signals | {
by an electric magnet, was de-
yeioped in America and was generally :
Known as the American method. 1t has
ong ago superseded the first method in I
Ictual practice. Its possibility depended |
IN perfeeting the electromagnetic and esi {
ecially on understanding of the prin- I
iples ON which that perfecting depended s
FOR the complete and satisfactory solu- 1
ion of this problem We are indebted to
he most famous student of electricity q
america has produced during the century, =
oseph Henry. In 1879. while a teacher in 4
he academy at Albany, N. Y. Henry ex- =
ibited an electromagnetic of enormously | I
reater power than any before made, in a
diving all of the essential features of the r
Magnet of today. The wire was insulated | h
y silk wrapping and many coils were .
laced upon the iron core. the intensity | r
magnetization being thus multiplied | 7
Ienry studied, also, the best form and ar 8
angement of the battery under varying | r
nnditions of the conductor. An electro n
Magnetic telegraph had been declared i'm +,
ossible In 1875, by Barlow, an English | r,
ian. who pointed out the apparently fatal
act that the resistance offered to the |
Irrent was proportional to the length of | :,
lie conducting wire ana that the strength O
the current would be thus SO much re- -
|