The Washington times., 1904-12-04

work, contrary TO the experience OF Lord
hayieigh. an alternating current arc
was Inferior 70 the direct current arc
the latter being very much OF the kind
10 be seen on the streets nightly in hum
drees Of thousands Of lamps whose arc
Is apparently a shining white bow Of light
between the two carbon sticks inside
the z,obe.
Up 10 the present time. an arc light
direct current dynamo OF special wind
ing has. therefore, been used by Mr..
Bradley. giving current at the high
pressure or 1900 volts. which is faf
above anything ever used before ia thiA
country. although some direct current
pOwer-transmissiOn had been done In
Switzerland with machines of 25O0d
volts, the strain on the insulation of
the machines being very severe.
Drives Air Through Flames.
supply Of current. being now obtained
from dynamo machinery the power. "a
operate which comes from Niagara. Mr..
Bradley leads IL into the nitrIfying
chamber, where the ares are 10 accom-
plish In an instant results ON which Il
Is The custom of nature TO expend fonk
centuries This chamber Is a big box
OF metal six feet high and three feet In
diameter. Inside Is a revolving cylinder
or hollow shaft. The box has openings
10 admit the air and circulate II. and
around its wall are rows OF fixed elec-
trical contacts for arcing points ar
ranged In six rows of twenty-tbree
each.
The positive pole OF the dynamo "a
gnnnarfan in 1.sf
these by wires. so as 10 include an in
d"etance coil in each circuit. whose OBJ
Ject II is 10 prevent the arcs from
short circuiting' and burning out the
dynamo. The negative pole or side OF
the dynamo circuit IS connected with
the revolving member inside the cham
bef the cylinder having contact proiec-
uons. or wire fingers. corresponding 70
the contacts on the shell Of the box so
that, IS IL spins around. the currents
from the i0O00-voIt dynamo arcs cross
as shown In the afr between the sta
uonary contact points and the revolvins
ones.
The arcs are :hus rapidly and inces-
sanity made broken. and remada
within the chamber. A motor at the
ton or the apparatus drives the cylinder
al speed of from 800 to so revolutions
per minute. while air is forced into the
chamber at a rate OF five cubic feet
per arc contact per hour The air
leaves the chamber after this treat
ment laden with 25k per cent OF oxides OF
nitrogen. The wires on the hedgehog
barrel In the chamber are tipped with
platinum. 10 minimize wearing down in
the intense flame or the are. They are
so set. each a little In advance OF the
other. as 10 form spirals from top to
bottom Of the shaft. enabling the arcs
TO work on the chambered sir without
cessation.
Like Teeth of Music Box.
The electric arcing that goes on in
the nitTify.ng chamber is not unlike tho
effect that would be produced II tho
wire teeth OF a music box drum were
touched by the finger. setting up vibra-
ton and causing a squirt OF white fame
every time a tooth is touched. The
arcs which thus wind spiral-wlse around
the shaft are themselves six or eight
inches long-thin. white. resistlcss darts
OF all consuming flame. This Is very
long arc. those in lamps being usually
but half an inch. In front OF each line
Of arcing points Is an air pocket, at the
bottom of the chamber, TO catch the de
composed air. Thence pipes lead away
which entrain the air and its gases
TO an absorption tower. where. the pro-
cess IS completed
The absorption or water sprinkling
tower used is OF the ordinary kind COM
mon 10 chemical processes, and the re-
suit or this treatment Is nitric and
nitrous acids. If the gases are brought
into contact with caustic potash. we get
saltpeter. II the base is caustic soda,
We get nitrate OF soda. Prof. Chandler.
the distinguished chemist OF Columbia
College, New York IN a careful inVesti-
cation Of the process. found that with
the current at Niagara costing so per
is, one and one-third
horsepower per year-the expense for
the energy required would be a little
less than l.6 cents per pound OF 20 per
cent nitric acid. which is the customary
commercial strength OF acid selling at
cents per pound.
The tremendous effects or 80 cheap a
fertilizer on agriculture can be readily
understood As an illustration. II is
only necessary TO follow the work OF
Sir John Lawes and Sir Henry Gilbert.
with the aid Of nitrate of soda. which