New-York tribune., 1881-09-12
THE ELECTRIC EXHIBITION
OPENING THE DISPLAY IN PARIS

DYNAMOS-THE SIEMENS MOTOR AND TRAMWAY
A GREAT EXHIBIT FROM BELGIUM-DEPART-
MENTs OF THE BRUSH, EDISON AND OTHER
AMERICAN AND ENGLISH CoMPANIEs-woRK OF
TlF AMERICAN CoMNussIoNERs-THE EXHIBI-
TloN OPEN AT NIGHT, AT LAST.
IRON SPECIAL CORRESPONDENT OF TIRE TRrBUNE[
PARIs, Aug 26.-" First catch your hare" said
Mrs Glass; and her little culinary hint is good
enough for II whole moral apOthegrn In order to
write TO you about the Electric Exhibition, it is
rather de'lrabe to have an Exhibition to write
ABOUT. The present one, which by programme
should have been opened on August |, is still in n
very rudimentary condition; there has been no Off
clal and general lighting up-and OF Exhi-
nltion--in the evening; many show tables still
nearly or quite empty and many important
chines-n especial Mr.. Edison's monster engine-not
even set up. Dire has been the co olsequent confu-
sion, Inconvenience and discomfort Many impor
taht ofic ais scientists, and in
eral have found their plans brought to nOught by
the delay. have gone off on collateral eXcur-
sions to occupy the interval, gone home in the
hope to return month or two later. and somc-like
your correspondent-have fingered about in Paris
occupying their time best they might, waiting
from day to day for the first glimpse of adequate
material for study, observation or comment.
STILL where there is already on view such an m-
mense and varied mass of interesting matter
enough to furnish whole volumes of scientific re-
port and many PAGES OF even the most superficial
description, it would be unwise grumDlc and still
more SO to delay any longer. So with Mt further
preface shall beg to take you-in imagination--hy
the hand and plunge at once into the wilderness Of
wonders already heaped up in the paals de PIudus-
tie If we get IA hasty glance at even tithe
still smaller fraction of the whole shall be
lucky.
The great building with the exception of one
large room containing permanent exhibition of
colonial products is entirely given up to electricity
In a general way the main ground floor is occu-
pied by heavy machinery and the more serious
economic commercial devices of manufactures teeg-
raphy and the like, while in the gallery, occupy
ing the north side and ends, are exhibited the
lighter and more whimsical application of the sci
ence Still. there is much momentous material above
stairs, and much of curious electric toy-si oppIug
below. Come in with me-in fancy-through the
great east door at the end of the building where
practically only allowed to 20 out. As we
walked up from the Place de la Concorde YOU
noticed jus under one of the great equestrian stat
ues on the Place-the Chevaux de Marly-a little
wooden chalet meant for the starting point Of the
Siemens Electric Railway. Coastng round
the south side of the whom de / Horloge in the
Champs ElySees, we followed the little tramway up
to the east door, noticing that the slender rails
laid even with the macadam, and that the line is
fringed with row of light posts supporting a
double treble hnc OF wires with stout metal con-
meeting strips The Of this conductor-ln Inc
which Is not essential in the Semens system we
shall see presently. AS We enter the east door we
come right upon the Siemcns tramway wagon
standing quiet on its track ready for start some
time next week. Workmen inside have taken up
the floor to tinker the machinery, and will peep
in. And first. a brief word of explanation, which
shall not be very scientific in Difference to my own
weakness, and-possbly--your own.
The central principle of dynamo-electricity on
which large share of this great show is founded
is briefly, that core of soft iron surrounded by
spool of copper other wire. becomes "A magnet
when a current of electricity of auy kind is sent
through this wire, and loses its magnetism when
the current ceases Further, it, near the end of this
magnetHed core, we present au0thei with its
COLA bobbin. or arnatnre, as they call t-corr
number two likewise becomes magnetic. by lnduc-
ton, so called, and, equally by induction sets up
rather complicated series of currents in it's wire
spool winch run one way as it approaches the pole
of the fixed magnet and just the other ms il rccedcs
These movable bobbins grouped in various
arrangement 5, but III general way so as 20 form
flat wheel, a cylinder. round central axis at the
end OF which a neat device, apparently mysterious
but really pretty simple, called a conmutator. en-
ables the electrician to take off, on metallic brushes
the rapidly succeeding back and forth shocks or
currents, and turn them in direction. As tie
bobbin wheel in the different forms of dynamo
generator, makes from eight ten up to twenty or
more revolutions, and thus brings from one 10 two
hundred bobbins in contact with the fields, in q
second, it is easy to that the resulting current
though i'll theory interrupted is to all unaidcd phvs
zeal sense practically continuous much as the
musical tone of piano string with it's thirty forty
or fifty distinct vibrations in second. This result
ing current, therefore, sent through almost any
desired circuit of wire, is the real agent in the
n1a oil rio ltnl,ti,,,
plicatiOns. As TO the fixed or so-called ield-mau-
nets, that fine humor which enables them TO so
tickle the irritable fancy OF the elsc-quiet bobbins
w..s III the first instance attained by making them
OF hard steel, and giving them permanent magnetic
character. Just such to be seen here in the
Meriteus notwithstanding for all the world with
their ranks OF great horseshoes standing out on
every side like sort of new-fangled tiller-wbeel-
and adopted by the State for its lighthouse system
Instead of these, however it was generally preferred
to make the fields of soft iron (which retains little or
no magnetism when not under current), wrap them
in wire coils, and send through these coils as said
above, an electric current obtained from any ordI-
nary galvanc battery. But soon wonder came to
light 1t was found that III manufacturing the soft
iron cores it impossbe-even were il desired
TO get the metal soft not TO retain some orpi
nal, native magne ism of it own. Consequently no
battery is needed, and the present almost universal
form OF the dynaino-machine, generator is
simply this: First, a movable wheel or cylinder
set in with coils or bobbns, as above which wheel
Is kept In revolution by plain gearing from an or
ulnary steam or gas-motor engine. On either side
or all around-tbis wheel or armature ore nlacad
other masses of soft iron wrapped in other coils
hXed III position and constituting the fields The
rdH0hde OF the process is then briefly as follows:
Ihe gearing is slipped into place, the steam turned