New-York tribune., 1874-11-23
APPLIED SCIENCE.

TEMPERATURES IN PNEUMATIC STEEL "ANi'"
According to Kraus. the flame enters the Sl Slen'ena
Martin furnace at temperature OF about ''o'
toyer 400 Fah.l, and the furnace itsei Acquires
temperature of 1,S00oC (S,s430 FahJ iheso nHui0o
may be taken as the maximum. In the Desse"'oi
Convertor . higher temperature is possible-say
,oooC "A sOoo Fab V since the carbonic oxide formed
by the combustion Of the carbon or the cast lIo Is
not so readily dissociated az high temperatures :s
earbonic acid and scic 5pS cG acid The small neck Of
the converter aids the accumulation Oh ncao w
efecting an increase OF pressure WHICH III Turn ~
tards dissertation.
prpt,crNG RICH IRON OREs.-Dupuy's Direct Pro
cess il described as new method of IRON
ore from its oxyd to cakes of compact
metal at one heat. These are then Withdrawn, ana
at the same heat forged for wrought iron, While Tor
steel purposes they are thrown without forging into
the molten bath of the Siemens furnace, or cut up
and melted in pots. The ore is used as ORDINARILY
prepared for the common forge fire. 1t is mingled
with the proportion of pulverized charcoal found
requisite for complete reduction, which is but few
bushels to the ton of iron. 1t is then placed in thin
sheetiron cansters of any convenient portable sze
holding each say from 100 to 20O pounds. Many of
these TO the extent Of several TONS subjected to
The proper degree of heat in peculiar but inexpcn
siye furnace where in short time the operation IS
completed. After reduction. which is the nrse
stage the iron is left in porous, cellular condition.
by the exit of its oxygen. The increasing heat then
gradually softens ii to the pasty state. when by It's
own weight it settles and consolidates, thereby
not only closing its cells spaces from the inroad
of furnace cases. but pressing out much OF Its lmpu
ities, which have become liquifed, aud flow away
from the metal In few hours, by properly proper
tionipp the carbon it is well known that rich ore
may be reduced either to the malleable state 1or
forO Or fO pleasure,
covered clay crucible and nearly all the netai may
be saved. This process simply substitutes sheet
BILE protects the metal equally well In Its transition
state and has the advantage of beng HOMOGENEOUS
with the mass, and finally is worked up with IL. AS
the iron comes from the fire surrounded with It's in
easement it is found to have lost by deoXydlzauon
more than third of its original weight, while II
is only about One-Qnarter Of Its original BULK: IN
this condensed solidifed condition it is well fitted
for economical transportation TO distant points,
there to be forged for iron or melted for steel he
small cost for plant warrants the production OF this
metalw herever the crude materials may be most
cheaply collected but where the erection and opera
tion of extensive machinery for after working Is
NECESSARY NAV it be inconvenient and inadmssible.
The asserted superior quality OF this charcoal MALE
able iron over northern blooms for forging or Tor
steel, added 10 Its more ecOnOmlcal consumption Oh
fuel, ore and labor, would seem to commend IL.
EFFECT OF CARBoNIC ACID AND OF OXYGEN ON
TIE GROWTH OF PLANTs.-The effect of carbonic
acid upon the termination Of seeds and upon the
development of chlorophyll in young plants has
been made the subject of investigation by Boehm.
Seeds OF sunhOwer garden-cress. flax, poppy, oat
barley, rye. knot-grass, and maize were allowed
TO germnate and grow in TASKS containing mixtures
of atmospheric air and carbonic acid the amount
the latter varying from to so per cent in the diff
ferent TASKS. The latter were exposed to difiused
daylight at a temperature of 80 to go Ceptigrade
The injurious effects of carbonc acid on germna-
hon, observed by Saussure, were here confirmed.
As regards the effect upon the development otchlo-
~rophyl in the young plants, the author concludes
as follows:
the experiments described suffice, believe, to show
the remarkably injurious effect OF carbomc acld gas on
only per cent Of carbonc acid in the air becomes no.
teeeoe especially by s eect on tno ScR CLRaGh h a o,
amount OF oxygen equal to that in the ar contains one
half carbOnc acid, not only was there no GROWTH but
The plants after short time persisted.
This effect of carbonc acid upon the plantlet
while living at the expense of the reserve nutri-
ent in the seed the author regards very remark
nble in view of the fact that green leaves in such
medium decompOse the carbOnic acid with consider
able energy. He remarks:
Since the green plants in virtue Of their capacity
their substance from inorganic material they create for
themselves at the same time the condition OF growth at
the expense OF material already asslmuatcu
These observations have in the opinion of the
author, an important bearing upon the theory that
before and during the period of carboniferous de-
posts on the surface of the earth, the atmosphere
contained very much more caIbOnic acid than at
present. He says:
In view of the fact that plants vsiby sieken in an
atmosphere which contains but small percentage OF
rarbonic acd. must conclude that in atmosphere
not much richer I'm carbonic acid than that exist
Ing part, at least OF the present vegetation OF the
earth would perish But from this, one of two things
must follow. Either the composition OF the terrestrial
atmosphere must always have remained the same, as
must necessarily be inferred from its bOundessness
as seems 10 more probable plants must have ex-
listed in former geologic periods caOable OF enduring
larger amounts Of carbonic acid in the atmosphere.
Boehm has also studied the effects of pure oxygen
upon the termination of seeds. Seeds moistened
and placed in pure oxygen, at ordinary atmospheric
pressure failed 10 pass beyond the first stages of
Termination. When, however, the oxygen was di-
iuted with four-ifths of its volume of hydrogen,
and likewise when its tension decreased by the
pheric pressure the seeds terminated well as IN
ordinary air These observations quite in accord
with others lately made by Bert upon the influence
of variations in atmospheric pressure upon the vital
phenomena of plants. The experiments of Bert
showed that the termination of seeds in ordinary
air was hindered when the pressure was increased
Go five atmospheres, and that it failed entirely III an
atmosphere of pure oxygen at ordinary pressure;
and finally that in ordinary air, at low pressure
Ia nineteenth to seventh of one atmOSmphere1, the
termination was likewise hindeTed. Too large
quantity or too high tension. Of oxygen in the at
mosphere seems to be unfayor to gerniuatiOn of
seeds.
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