National Republican., 1885-05-23
pnoenrss sor ELEcrnIc SCIENCE

by &. y. INIntnor, Examiner Glass
Electricity, United States Patent
Once.
A worry close relation exists between
heat, light, and electricity, fact made
tho more apparent when We realize
that each may be produced from the
other. 1t has long been known to tho
scientific world that the heating effect Of
electricity upon conductor through
which II travels is dependent upon three
things, viz:
/. Tho resistance Of tho conductor.
9. Tho time during which tho electricity
passes through the conductor. 3, The
square Of tho strength of tho current.
Based upon these facts, we arc enabled
to estimate what amount Of energy Is re-
quired to give specified amount of light,
and hence how much coal must first be
converted into heat. heat into steam,
steam into powor through an engine, and
power into olectrity through a dynamo
machine, and electricity into light
through heated conductor, heated to in.
candesoenee in glow lamp by reason Of
the resistance which the hlament offors
to tho passage Of the current, or to n
fusion in an arc lamp for similar reason.
Understanding, then, the doctrine OF
tho correlation Of forces which is based
upon tho idea that power is mover ac-
tually lost, but is converted into an
other form, the intelligent mind readily
jumps nt the conclusion that IL light and
electricity arc deducible from heat.
naturally each must be dedueible directly
from tho other and such is the fact.
But the problem Of generating cleo
trioity directly from heat is not Of easy
solution, and to-day we are obliged to
utilize two intervening stops and cum
brous mechanism in the nature Of the
steam engine and the dynamo.
To the inventor who first hits upon
successful thermo-eleotrica generator,
adapted to domestic uses, generating cur
rent in sufficient quantity aud undcr
proper tension or pressure for lighting
and heating purposes, directly from the
combustion of wood OF coal will be yielded
an untold fortune and fame worthy Of
the greatest inventor.
As early as 1921 il was known in tho
scientific laboratory that If two metals Of
different nature wcro secured together
and heated at their junction by q spirit
lamp a current of electricity would pass
from one metal to the other and through
an external circuit, joining their free
ends in direction dependent upon the
individual poculiarities of the metals.
The metals giving the best results in this
direction are bismuth and antimony.
To Prof. Seebeck, of Berlin, belongs the
honor Of this great discovery. But little
progress has been made in the art beyond
the development made in laboratory OK
periments. Many curious and puzzling
phenomena have presented themselves to
electricians, perhaps the most curious of
which is that current Of electricity will
flow in one direction through thermal
battery of a given construction until its
parts are heated to o certain specified
temperature when it will suddenly re.
verse and run in the opposite direction
during an increase OF the temperature.
Any two metals properly Joined in
thermal relation have their reversing
point, which is called the point Of thermo-
electric inversion.
Tho first really practical thermal bat
terry capable Of generating sufficient cur
ront for domestic uses, as in tslegraphy,
was invented in 1867 by Moses q. Farmer,
a resident Of New York, an inventor now
well known in the electrical art.
His battery was composed Of German
silver and an alloy of copper, zinc, and
nickel, and had q fair electro IN otiye
force, but possessed a great defect, in
that it rapidly degenerated, owing to the
great increase in its internal resistance
on being heated, and also to the fact that j
the bars Of metal broke and disintegrated
readily on cooling.
All generators of electricity of what
ever nature designed for practical every
day use in the arts, shouldn't least possess
one important requisite. viz, constancy;
and to this end any variation in the in
ternal resistance is Objectionable.
In thermal batteries as now known this
great difficulty has not yet been fully
overcome. When the metals are sub
jectcd to intense heat rapid oxidation
takes place during the process of COM
bustion; the elements crack or fuse, or
are distorted in such manner as to ma
terially increase the internal resistance of
the battery, and hence Proportionately
nullify its action.
To overcome this difficulty many ideas
have been suggested, such as embedding
the metals in solid brick and thereby
subjecting them to heat by conduction
rather than by direct contact, thus avoid
ing oxidation.
Alloys of metals not easily oxidizable
have been used, but to no especial bene-
fetal purpose. IL will be understood
that an increased electromotiye force, or
capacity to generate electricity in guam
tity and under increased potential or
PRESSURE is attained with thermal batteries
by joining up several simple elements just
as galvanic batteries are usually Joined in
series or tandem, the inner functions of
the two metals being subj ected to intense
heat, while theit outer functions are sub
jected to intense cold, the joint action of
the heat and cold producing difference
Of electrical potential or pressure through
an exterior or working circuit propor-
tional to the difference in temperature
between the heated and cooled portions
and the number of such single elements
so Joined up. This difference of tempera-
ture or unequal distribution of heat in
the circuit then sets up flow of cleo
tricity from the heated to the cooled
junction or vice versa, and so on through
out the series just as we find currents of
air passing from points of cooler areas to
those of hotter areas on the surface of
the earth. To use better comparison,
Just as We find currents of air rushing
from areas of comparative meteor illogical
quiet to points where rapid evaporation
is taking place upon the earth's surface
There has been much careful research
into the question of the generation OF
electrical currents by the direct action of
heat upon metals and their alloys, but
with all that has been done in this direc-
tion as yet no successful apparatus exists
The whole number Of patents granted
by the United States patent office to date
amounts to fourteen only. OF this num-
ber the first was granted in 1867 and tho
last March 3, 1885. Tho first patent
taken out in England for this type of
generator was in 1913. The time is com
ing we doubt not when every person may
heat and light his house from a single
furnace, and at the same time be fur
nished with power enough to meet the
demands of light houseWork. such as
washing, ironing, running Of sewing ma
chimes, &c. This field is to-day the one
which furnishes greater possibilities than
any other in the electrical art, and in
ventors should turn their attention to it
rather than to waste valuable time, AS