The southern sentinel. (Winnfield, La.) 1883-1910, 1885-10-09
IlMRsR AND TOOLS.
The Varying Eject on Machinery Of DIFF
fer~nt Kinds Of Wood.


It is fact well known to millmen
that it is not always the harder woods,
in the ordinary acceptation Of the term,
that are the most wearing to the saws.
Many practical persons marvel at this.
and wonder to themselves why piece
Of timber showing small crushing, ten
sion. and other strengths, requires moro
| power TO work into lumber, and at the
same time wears out the saws and cut
ting tools faster than other varieties Of
timber. the strength of which, in most
respects, is greater.
According TO the Lumber Trade Jour
nal, log of black walnut and one of
!, burr oak of the same size worked into
/ he same sized stuff will show widely
| different results on both saws and ma
| chinetg. IL We attempt to rive or split
these Logo. the walnut will work much
easier thar the oak. and so far as the
various strc;, Tbs are concerned the oak
| Is superior BY far, but when worked or
cut into by tools of any description the
walnut presents much greater resistance
| than the oak. and the same il true as re-
gar.x many other varieties of hard and
/ soft timber.
II we take longitudinal section OF
these comparatively soft timbcrs sshici
are so hard on cutting edges, we VII
find the minute pores or intersticcs fillcsi
with minute glistening particles or
CRYSTALS; and subjected to ehcininal
analysis we will find them composed OF
silica, ono OF the very hardest minerals
known. while with tho hard, easy work
ing Woods they will be found nearly or
quite absent BY both the microscope
and analysis. These little particles, SO
! finely divided as to be insusceptiblc Of
ordinary touch. are really better grit
than ordinary sand. and are the means
of cutting off the fine edge of cutting
toas. as saw teeth, plane irons, and
the like
Two plane irons. made of q fine quality
, of steel, rs near alike rs it was possible
TO make BY an accurate, skilled me-
| ehanic, were each hardened in our
laboratory by means of mercury. then
finely sharpened, that the edges Of each
presented precisely the same appear
ance beneath the magnifier.
| These were each inserted in an or,li-
nary plane. aad one placed on oak. the
ether on piece of walnut, both pieces
Of wood having been previously dressed.
At the rate Of one hundred pounds
pressure. each iron was crowded for
! ward four inches. On the oak stick.
the pressure from the rear indicated
609.5 pounds. while with the walnut
the Indicator showed pressure of over
one Thousand pounds, Tho irons were
both now withdrawn. and first placed
beneath the microscopes; the one used
on the oak presented general upset
appearance. the edge Of the iron show
ing a slight tendency to turn down
ward. there being sufficient heat gem
Grated by the friction TO partially draw
she. temper along the minute edge.
which. howeves. would not cxtcnd back
soflicicnt to materially affect the wear
ing and cutting properties of the iron
If Ia constant use.
The iron used on the piece Of walnut
/ shoHed. a ratche4. .potched appear-
/ ance al along the minute edge, aud by
TIC aid OF the most accurate means q
measurements al band. these notchcs
were all found to be Of the same depth.
but different distances apart. proving
conclusively that tho particles Of grit
| or crystals which caused them, were
Harder than the best mercury steel, aid
we're an Of the same siso,
and evenly dhtribused, a. far a.
regards depth Of deposit In the
| grain OF the wood. The small spaces Of
the iron edge between theso nosches o.
scratches were found nearly Is the en-
tire edge appeared originally. showing
| again that The cellular tissue Of walnut
outside its mineral deposits, was really
softer than that of oak; hence, were Il
not for these deposits the timber would
cut much easicr. OF eonrse. 4 tho iron
had been drawn back. and again showed
through, the notches would have been
more apparent aud general. increasing
each time. and the distance showed
until the entire cutting edge had been
Of itself cut off,
Consulting the laws governing plant
or vegetable growth. We are told that
all food before becoming At for asslm-
lation mast be- reduced TO Ia gnseous
state. II this be 20, tie question arises:
How or by what methods OF plant
growth and assimilation is it possible
for silica to appear in It's original crYs-
4alline state among The tissucs Of the
!. growing or matUrcd tree, white il IS
| universally known that this variety al
wood grows only where this miucral .
abundant Ia some al tts modified formse
1T h not, however. Of great interest TO
manufacturers inst how Il gets there.
hnt that Il is present h shown concltl-
siveiy. TO get I'D Of it. oven were Is
possible. would destroy thu beauty and
general eharHctcrsts Of walnut. and
/ n opcrcaraa lie anffx,s. - tx<,la ~.s,A.9