Wood County reporter. [volume] (Grand Rapids [i.e. Wisconsin Rapids], Wis.) 1857-1923, 1895-10-31
ELECTRICAL NOTES.

The following comparison, due to
PalaZ, will be useful TO electrical en-
gineeTS in presenting the advantages
of electric lighting from the stand
point of GOODNESS. The figures quoted
are relative to a given quantity of
light: Are light, 4 incandescent hight,
a. kerosene, argand burner, 331; gas,
argbnd burner, $50; candle, 473; gas.
butterfly burner, 511. The heat Ques-
tifOn lis a very Important ONE, but lit
lis as nothing compared with the Ques-
tion of Initiated atmosphere. LIZ this
respect, of course, electricity COM
pares still more favorably with all
other sources of artificial light.
I'm a paper read before the Royal
Society ION the effect of pressue of
the surrounding gas ON the temporal
ture of the CRATER of an electric arc
light" Mr.. w. E. Wilson states that
of late yeals lit has often been as
stunned THAT the Temperatures of the
CRATER forming the positive pole of
the electric arc is THAT of boiling car
bon. The most modern determine
tiOmts give THAT point as about $500
degrees to $500 degrees G. In order
to investigate whether increased pres
sure i'm the gas surrounding an cleo
tlic arc would raise the temperature
of the CRATER, he used a strong cast
iron box. i'm the interior Of which an
electric arc light could be maintained.
in the box THE temperature of the
crater is considerably lowered instead
of being raised, and the experiments
seem to show that the temperature OF
! the crater, like that of a filament in
in incamdescent lamp, depends ON how
atmosphere and mot ON it's being the
temperature at which the vapor of
carbon has the same pressure afS the
surrounding atmosphere. That carbon
volatiIiZeS i'm some form at compare
lively low temperatures seems likely
from tihe way in which the carbon of
incamdescent lamp filamentS is trans
fe1ned to the glass The pressure of
the vapOr of carbon i'm the arc may
consequently be very small, and fur
'ther it wOuld seem that the suppose
tion of high pl'eslSUreS i'm the solar
photosphere lis not borne out by these
eXperilm entrs and THAT carbon may eX-
list There lin the solid form ait very
high temperatures, although the pres
suI'es are comparatively low In two
pole dynamoS THE proportions of ring
armatures vary from length equal
to One4half THE diameter Ito a length
equal ITO one and One-half diameters.
1T lis common to make the length equal
to the diameter For drum armatureS
the length sometimes equals ONE and
One-half diamefe11S and sometimes
, three diameterS. 1t lis common to find
the length equal to two dihmeters.
G11ta percha heated in hot water
at about 100 degrees F. becomes plas-
f1ic, amid will take a fine impression
with Slight pressure. When glItta
percta lis soaked for a few hours in
! benZole or naphtha, lit becomes
swollen, and if lit is then dipped in hot
water, lit becomes so Plastic THAT it
may be used with safety ON very
fragile and delicate objects, adapted
to electrotyping.
The cotton Thread used for the fila
ments of incandescent lamps is parcb-
j mentized before carboniZatiOm by
passing it SLOWLY Through a solution
Oh sulphu1fc acid two parts, waiter one
part, and finally washing 1T i'm waiter
IENtn every particle of the acid is re-
/ moved. The parchmentized thread,
after drying, lis reduced to a uniform
diameter by drawing it Through dies,
after the manner of wire drawing.
A thermOpile for experimental pur-
poses, may be made of pieces of Ger
man silver and copper Wire, twisted
and hard1SoIdered at the ends, per-
forming series of pairs, and arTaIIg-
ing the wires thus Joined i'm the form
of a many-p pointed star, 50 that the
German silver ana copper wires alter
nate the ends of the series being left
uncOnnected. The inner points of the
star are heated over kerosene lamp.
The wires may be No. Is and six
inches long.