A Wlrelesa Trolley.
V"K!I?V ininniVfinrnt In electrical
4 I systems carries with It tho prom
" 4 I Iso nf :i now revolution in a busi
ness that Is a succession of revo
lutions. Tho latest revolution
promised is an invention of I W. Pullou
of Camden, N. J., by which, it is claimed,
tho ovcrlu'inl wire nnil the third rail wilt
be dispensed with, and electric cars driven
by an Invisible system. At intervals of
Sixteen feet or more extending midway be
tween the tracks Is a series of little metal
buttons, and that is all. The buttons rise
Only an inch above the sorfaee of the street
r road. One must look elosely to see them.
The system itself, however, is extremely
implc. These Inconspicuous little buttons
lire perfectly dead, electrically, until the
car loaches them. A powerful magnet
carried beneath the car serves, however,
to clc.se the circuit beneath the metal but
tons, whereupon the buttons become, sud
denly alive, giving what energy Is needed
to the car. The current thus picked up re
turns by the regular trolley rails, which
thus complete the circuit. The instant the
car lias passed and the magnet has ceased
to lnllueiice the metal button itrniature bo
low the points of contact, the little metal
button is left dead once more.
The metal buttons are in reality the top
Of air-tight boxes sunk flush with the level
of the street. The box itself is about ten
inches square and two inches deep. Their
mechanism Is extremely Himple, and there
fore unlikely to get out of order. Those
boxes placed at Intervals of sixteen feet
are In turn connected by on underground
conduit, which brings them all into tho
BJiuic circuit. This wire. It will be seen, is
completely hurled underground beneath the
pavement of the stret, so that its danger is
absolutely nil.
Kxhaustive tests have been made by the
Wireless Railway company to prove the
absolute seicntitie safety of the wireless
tyslcm.
It Is the Important economy in Installing
uch a system, however, that will prob
ably make the strongest appeal to the
railroad management of the thousands of
miles of trolley Maes throughout the coun
try. The argument for the new system
over all existing systems sounds very con
vincing. The wireless system requires little
or no digging. It is possible If desired to
run the conduit connecting the contact
points along the surface of Ihe ground
enclosed In a wooden covering. The cost
of the new system is also somewhat lees
than the objectionable overhead or even the
third rail system.
riie First Klcrtrl' iaa.
The Klectrlcal World nnd K.nglneer, In an
article by Hrottur Potamlan, professor of
physics in Manhattan college, puya flttinjj
honor to the memory of the medieval stu
dent whose researches in magnetism ap
pear to entitle him to be called "The First
Klectrlelan," and hence the lieglnner of
the great industry by which tltut journal
lives.
Ills name was Pierre de Msricourt. enm
tnonly called, from having made a Journey
to the Holy Land, Petms Poregrluus, or
l'eter the lllgrlm. Itefi.re his time the
lodestone, or natural magnet, was well
known, but was regarded chiefly as a curi
osity, though It had begun to be used by
seamen, in a rude form of the mariner's
compass, as a means of nailing which way
was north when the stars were hidden.
In the year 12ti8 this Peter the Pilgrim
was employed as a military engineer In the
nrmy of diaries of Anjou. at the siege of
J.ucera, in southern Italy. Probably bis
military duties did not keep him busy, for
lie found time to consider what he hail
learned about tho lodestone und to endeavor
to apply l(s force In the construction of a
anotnr.
He thought he had succeeded In Inventing
machine that would go on forever, and
his delight was so great that he sit down
and wrote a long letter to a friend at heme
In Pieardy, one Sigerus do Koucaiicourt. I'l .
which he described not only his peipeunl
motion machine, hut told the results of all
his experiments with the magnet. Kroin
this letter lirother Potamlan finds that:
1. Piter the Pilgrim was the first to ns
sign a definite character to the poles of a
lodestone, nnd to give directions for deter
mining which is north and which Is south.
2. He proved that unlike poles attract
each other, and like poles repel, and that
n pole may neutralize a weaker like one
nnd even change its polarity.
3. He was the first to pivot a m:ign "tlzod
needle and surround It with a gt ailia 'el
circle, and to determine with this device
the position of an object by Its magnetic
bi-nrtng ns done today In compass survey
ing. 4. He established by experiment that
every fragment of a lodestone. however
small, Is a complete magnet, thus antici
pating a standard modern laboratory illus
tration of the molecular theory.
5. His magnetic motor, while, of course,
its motion failed to be perpetual, eti'i usly
anticipated the modern electric motor In
Its plan of construction and in Its roll inee
on constant changes of polarity In tho field
to pull the armature around and keep It
revolving.
frrlng by Kleetrlelty.
"Various methods have been proposed
from time to time for transmitting sight
electrically." says Klectro, "but they seem
to lack certain necessary features. A
system has Is-en devised by M. A. Nlsco,
however, which seems to Mm to be
practical. A sensitive screen Is prepared
by coating a metallic net with some In
sulating gum. Into the meshes of this
net copper wires are inserted before the
insulation hardens. After drying the
surface Is dressed off with a tile and Is
then coated with selenium, thiis forming
a sensitive connection between the wires
iiinl the net. The screen prepared In this
way is treated to crystalline th selenium,
so as to bring it into the proper sensi
tive condition. The copper wires which
terminate in the screen are then led Into
an ebonite cylinder, and pass out through
holes corresponding in jsisition to their
termination in the sensitive screen. These
holes are arranged in spirals in such a
way that a metallic blade which revolves
around tie cylinder successively makes
contact with every terminal. The blade is
revolved nlsiut the cylinder at a speed of
fimt revolutions per minute, so that every
contact is repeated ten times a second.
From the blade nnd from the wire net of
the sensitive screen wires are led through a
battery and to a telephone receiver. If a
picture be thrown upon the sonsith-e screen
and the blade be revolved about the cylin
der a varying current will bo sent through
the telephone, the intensity of which will
vary with each contact, according to tho
Intensity of the light falling upon the cor
responding siH-tion of the screen. This
telephone by means of a sensitive carbon
microphone repents through the transmis
fciim line the current variations produced by
the apparatus Just described. At the receiving-
station a second telephone repeats
the variations in current through a second
nifcrophone In a local circuit arranged to
produce a spark. The Intensity of the
spark at any instant corresponds to the
intensity of Illumination of a particular
part of tho selenium screen. This spark
Bap is placed within a cylinder having
spiral slots, and the slotted cylinder 0 -Volvos
in synchronism with the contact
blade nt the transmitting station. This
arrangement throws the light of each spark
on such a part of a receiving screen as to
produce an illuminated imago similar to
that thrown on the sensitive receiving
screen. The method can only produce va
riation in illumination, t requires two
wires, one for synchronizing the moving
parts and one for transmitting the varying
current."
lutprsslluniil Klrrtriral foiiares.
"According to the present Indications,"
says the Klectrlcal W orld and Kngitiei r.
"the International Klectrlcal t'ongr, s. to
bo In Fission at St. Louis September 12 to
17, 1!M, will be one of the most succe-rful
that has yet been held, both with 10 pat
to the numl-er of aillnslons and to the
value of the transactions. I'p to date
jilxxit a.r.'J) circular letters of Invltaiions to
Join the congress have hei n Issued to pi r
sons ot associations In North America.
From these S7." postcard aeceiitancoM of
membership liaxo I oen received. About X)
similar circular letters of Invitation hive
been recently sent to other ci untiles. It Is
Intended to Issue in all about ,"..in imita
tion circular letteis In America and about
f.lM) In foreign countries. It is exp-eted
that many persons will Join the congri ss,
both In Amerlia and abroad, who do not
expect to attend the fcssb iis In St. 1 ills,
in order to secure a cooy of the transac
tions, which will form one and pirhip
two large octavo volumes. Koiently 2 0
special letters of Invitation have- bien Is
sued on behalf of the committee nf nrg.n
Izatlon to prominent electricians and elec
trical engineers, signed by the president
and general secretary of the committee, re
questing papers for the congress In tho
various sections. Of these Hi have re 'ii
sent to foreign authors, and 131 to Amer
ican authors. There has not been time to
receive replies from mere than a few for
eign authors, but twenty-one acceptanc'S
have, up to date, been received from abroad
and forty-Fix acceptances from North
America. Sixty-seven papers are thus al
ready promised for the congress, nrd the
number Is steadily increasing. A consid
erable number of Invitations to contribute
paper have yet to be Issued. It Is hoped
that tho congress will convene with a full
program in inch fed inn nnd that nt I -ast
half of the papers may be from fo o'gn
countries. According to tlie plans 1 f tho
committee, papers for the congress pro
grnrr. are specially Invited, but prtpcra vol
untarily 0IT1 red will be submitted to the
officers of the sections to which the papers
belong, and may be Inolud d In the program
by invitation at their reipnst. If the sub
jects are desirable, and If the schedu'e 11I
loted to each section will permit. It hclnir
the desire of the section officers to secure
and off.-r the best possible program and
presentation."
irlriirami by Ire Kenee.
Two Ingenious New Knglanders, young,
ambitious to become masters of the teleg
rapher's key, having no capital with which
to erect poles and stiinijr wire, concluded
to experiment with a barbed wire fence as
a means of transmitting messages. "About
I'm feet east of my father's house," sayB
one of them, "was a barbed wire fence
which we found on Investigation extended
to within only a few reds of my friend's
homo. The fence didn't follow a straight
line by any means there were several
short hreiiks In It. TTrre and there It sur
rounded a cow pasture or a hennery, or
described a semicircle back of a dwelling,
lint these Irregularities, wo thought, d'd
not matter. We were determined to utllixe
that fence.
AVe knew that pulnt ordinary nous?
paint was a good nonconductor of electric
ity. My friend's father had Just built and
painted a new barn, ami he had three or
four quarts of the paint left over. This
was more than enough for our needs.
"With a small brush we applied a daub
nt evfry point where the barbed wire
strand we decided to use was fastened."
We were careful to see that the oily sub
stances got In Iwtween the wire and the
post, or between the wire and tho trees.
as the rase might tie, Whom the first coat
had become thoroughly dry, we applied
another In order to make lite Instillation
as complete a possl'.ite.
"Then arose the ipiestlon of batteries.
Why, we asked ourselves, were glass cells
necessary? Would not any sort of siif
Insulallng receptacles of suitable slxo an
swer the purpose.' If so, there were
enough half-gallon paint pots at our dis
posal fo furnish a complete otitllt of
crowfoot butteries. Wo tried one. by way
of experiment, and found that It worked
admirably.
"How to v ecu re nine plate and coppers
for the batteries was next to be consid
ered. Wo already had four clues, but at
least three times that number would he
needed. I suggested that wo make some
ourselves, by collecting and melting a
quantity of old zinc sheeting which the
farmers In the neighborhood had used to
protect lb. -lr onhaiils from caterpillars.
"lty making an ini re-slili III .-anno
moulders' sand with one of our old zincs
we were able to t lit n out a dozen plates
without any trouble. The coppers se ond
band, to be sure, but none Ihe less serv
iceable we obtained from our good friiud,
the station agent, who never hesitated to
discard as useless to himself anything
likely to be of value to us. A few pounds
of blue vitriol would sutlloe to generate 'the
current, and for this we had to pay, ns I
remember It, about SI.
"Well, after giving those batteries from
twenty-four In thirty-six hours In which
to acquire their full strength, our Instruments-cheap
and clumsy as they were
rescinded perfectly. The only dllllculty we
experienced was In rainy weather, when
the water, trickling down tho fence posts,
robbed us of iluid' by partially grounding
the circuit. liven this annoyance might
have been overcome by using relays.
"Was the line of any real benefit to usT
Perhaps you can answer that for yourself
when 1 tell you that we used It for three
years and became expert telegraphers."
.
Huh Sliced Promised.
A "moiio-rail" line l.i to Is- laid between
Palis and Marseilles, and travel at the rate
of ISO miles an hour Is promised. Hurveys
have been going 011 for some lime 011 tho
outskirts of the capital, at the Mediterra
nean seaport, and s one localities between
them. I tut. one train oil the iitinent will
Is able to compete with It, and that Is the
lUrlin-l lainburg, which Is not yet finished,
and the speed of which is to be J miles an
hour. The Paris-Marseilles train will Imi
faster still. Hut. according to all tho infor
mation, passengers will not. nt the first, 1st
conveyed by the French inonn-rall. Tho
French mono-rail is to be restricted, at the
beginning at any rale, to parcels and gnoda
traffic. In this it Is expected to create an
astonishing revolution. In the first place,
the whole newspaper world of Paris la
deeply Interested III It. A Paris newspaper
posted early In the morning reaches Mar
seilles late at night rat her late, one. would
think, for the reading public. Hy tho
mono-rail it can bo delivered at about 10
o'clock in the morning.
He Caught It
A southern Missouri cxmange liila of a
traveling man who stopped one night 111
a hotel in a small oz.uk county town and
asked to be culled at 3M o'clock so that
ho might catch a train. In order to ac
cede to the giicat'a request the landlord
had to remain up all night, as he had no
cleric and 110 alarm clock. He found it
hard to keep awake, and when :i::ill o'clock
finally did conn he was in a surly frame
of mind. Knocking on the guest's door, ho
said: "Oil up. It's :! :m. " In a sleepy tone
of voice the guest replied: "Oh, I guess
I'll let that train go and sleep until 7
o'clock." "Well, I guess not." said tho
landlord. "I've stayed up all night to git
you up and you're goto' to git up." Tho
guest caught the early train.- Kansas City
Star.