Evening journal. [volume] (Wilmington, Del.) 1888-1932, 1890-01-21
LEcTuRE ON ELecTRIcITY.
The First of the Y. M. @. A. Winter
Evening Talks.


]. w Parker of Philadelphia, opened
the series of evening talks at the Young
Mems Christian Association, by lecture
on electricity and the Units of Meas
urement, last evening, The room was
packed aud many had to stand. Among
the audience were many ladies'.
Professor Isaac n. johnson of the
Board If Directors, introduced the
speaker Mr.. Parker spoke in an easy,
conversational tone and clearly explained,
as far as it was possible to explain, all
that is known about electricity he IL
Illustrated his lecture by running electric
motors and fans .and dynamo Motors
and dynamos are names for the same
machines when used in different ways.
The apparatus was made by the Q. and
@. Electric Motor Company, which is
represented by Mr.. Parker.
He first explained what is known of
electricity. It is not new force, the
ancients knew as much about 1t as we do
We have learned to excite 1t and make IL
apparent 1t is something that cannot
be analysed or weighed. The speaker
referred to the great stride the investi-
cations Of electricity had made through
the discoveries of BENJAMIN Franklin
He paid his respects to those persons who
advertise electric" belts, electric" bot
ties, and the like.
A blacksmith's fan revolving places the
air in motion, and that illustrates that
electricity is current The units of
measurement are as follows
| Volt unit of pressure.
Ohm unit of resistance.
Coulomb unit OF qusntity.
Ampere unit of size.
Farrad unit of capacity.
Watt unit Of horse power.
Pressure is called the electro motive
| force. The terms Volt, Ohm, etc, are
| taken from the names Of pro ninent men.
High tension and low tension are meas.
ured by volts When electricity meets
resistance caused by friction, tie resist
ance is measured by ohms. Everything
in nature will conduct electricity to a
greater or lesser degree.
The current Is harmless when under
300 volts. for all human beings can take
that much. Edison has discovered that
the amount varies in different persons
from 300 to 800 VOLTS. When the skin
is damp it offers less resistance. On arc
light circuits there are generally fifty to
sixty lamps, which require from 1900
to 1000 volts Of pressure. The Edison
current in this city is ON the three.wirs
system and is perfectly harmless
although it win burn. The SAME
quantity of electricity will be used in I
1900 volts pressure as is used in 20l
volts pressure. Ohm WAS the creates
electrician that ever lived. He discovered
the laws for measuring the forces
Seven hundred and forty six watts ar
equal to one horse power.
The speaker explained the system o
magnetism. Take horse shoe magne
highly charged, AID place on Its two
! poles piece of glass. on which are som
iron filings; thu iron filings will imme
diately form into line. This gave rise 4
the idea that electricity runs in lines
and they are called lines of force. tn
armature, which has copper rings aroun'
it, is placed at right angles to the lines 0
force, which flow from above to below
The armature divides the line
and when they are cut 100, 900, 600 time
in second, create one vol
Of pressure. The faster the armatur
4 revolves, the more pressure is created
The current goes through the brushe
into the copper wires wound around th
n magnet, and makes more force. II a.
lowed to continue above a certain poir
,e the wire would be burned. He illustrate
u how an electric current win build itse
up. by connecting q motor with the IN
candescent light wire. A "a candle
i power lamp was lighted slowly by Il
y building up Of the current.
There is nothing mysterious abol
e electricity but its nature. One featui
It of it is that it always goes back home.
The lecture was interesting to all, al
10 many stopped to ask questions when
4 was concluded. Mr. Parker viii continl
! the subject in two weeks.