The Saint Paul globe., 1898-01-10
APPROPRIATIONS ARE NEEDED
BILLS BEFORE CONGRESS WHICH
1T IS HOPED WILL
PASS.
SOME RESULTS OF RESEARCHES.
Important Discoveries Made With
the Small Means Already at
Command.
Special to the Globe.

timber tests by the forestry division Of
the department of agriculture. Senator
McBride's bill appropriates $4,000, and
Representative HurIey's $100, 900. These
measures have the hearty support of
the leading architects and engineers of
the whole country. 1t is most inpor-
tant that one or the other should be
passed by the present congress, pre-
ferably the one carrying 1000, for
this is not too large a sum in view Of
the immense advantage to be gained
from the work in all branches of the
building industry.
TO the chief of the forestry division,
DR.. Bernhardt E. Fernow, belongs the
credit of organizing this systematic
study Of structural woods. AS far back
as 1910 something Of the same sort was
attempted by q French scientist, but
the extent Of the undertaking present
ly overwhelmed him and he stopped
work. Later, and about the time that
DR.. Fernow took it up, some Prussian
experts attacked the same subject. But
they soon paid their American con-
temporary the high compliment Of con-
Tossing that his methods were far su-
periOr to theirs, so that the United
States government has the honor of
standing today first in this field of re-
search. In view Of our supremacy, it
is pitiful to see how little encourage
ment the work has received from con-
gress. In the old times it was Gus
tomary to appropriate $4,000 as a lump
sum to enable the secretary of agricuI-
ture to continue his Investigations in
the domain Of forestry. but without
specifying the particular uses to which
the money should be applied. Six or
seven years ago Senator Allison became
interested, and succeeded in adding
$4,000 to the old appropriation, but
with a like indefiniteness of direction.
The difficulty with this sort of appro-
priation has always been that it might
be used for any purpose which could
be construed as falling within the
sweeping terms of the law. One sec
retary, being interested in timber tests,
could use the whole sum for that work;
another having different ends in view,
could divert the whole or any part of
the appropriation to his own favorite
objects, leaving timber tests quite out
in the cold.
Moreover, in the case of any such
lump appropriation, whatever balance
remained at the end of a fiscal year
is covered back into the treasury in
stead Of being applied to the continu-
ance of work of some particular sort
which may require persistent pushing.
The advantage of a specific appropria-
tion, thereform, would be that as much
or as little might be used within any
given time as circumstances seemed
to require, and the balance could be
husbanded to await later developments.
For some time now nothing to speak
of has been spent on timber tests, be-
cause an impression seems to have pre-
vailed that the occasional tests made
of a few sticks or beams by engineers
engaged in some special work covered
all the necessary ground. This no
tion loses sight of the fact that en-
pirical tests to meet some specific de-
mand do not supply the data needed
for broad scientific generalization; and
the fact remains that nowhere in the
world outside of the forestry division Of
the United States government have
any such systematic general inVestiga-
tions been conducted as those of which
DR.. Fernow has had charge. During
the last summer, as there was no gov
ernment money at his disposal for con-
tinuing his old laboratory work, he
took six months Of the time of a 81, 400 |
clerk, and 5000 for the rent Of a ma
chine from the Southern Railway COM |
pany, and through these agencies |
reached a discovery which is destined !
to revolutioniZe all known methods of |
timber testing, ahd to place the de- |
signing Of wooden beams for construc-
ton upon a safe basis.
To understand what has been accom- |
plished 1t should be promised that tim |
ber-testing has always been too eXpen- |
sive for its own good. The variability |
of wood in comparison with iron, for |
tice of guessing rather than of scien- |
tific determination, when there were
any data whatever on which to base a |
guess. AS most of these data have |
been gathered from European sources, |
they relate chiefly to European woods. !
Engineers, taking these data, have en- !
ployed what they term a "factor of !
safety" in deciding how far they will |
be guided by facts already ascertained. |
1t might more properly be called a fac |
tor of ignorance, because it represents |
the measure Of what they do not know. |
And 1t is pretty large measure, most |
wasteful in it's application. For exam
pie, supposing that the data at hand |
show that a certain species Of wood |
will bear a strain of 5000 pounds to the
square inch, one engineer would divide /
by his factor of safety, say ten, and
subject his timber to only 500 pounds |
strain; another. using five as his fac
tor, would subject his timber to 1000 |
pounds strain. Or, in building a barn.
the same engineer might use five for
his factor on the ground of the COM
paratively little risk to life, who would
use the factor ten if he were putting
the seme timber into a theater or a
church. Here is direct waste of nine
tenths or fCur-ffths, as the case may
be; and, when this waste can be elm
mated, the result is bound to be a saw
i.1Cr ~
and architectural work every year in
this country alone.
The Investigations Of the forestr,
division have shown that in coniferous
woods a difference of 10 per cent be-
tween species is actually no differ
ence; that is 10 per cent is the maxi
mum range of equality, and the diff
fererces within that range are liable
to result from variability of material
errors of the machine, or errors of
construction. With broad-leaf woods,
familiarly known as hardwood, the
maximum range of equality is IS per
cent. But the greater discovery Of
all, made this summer, is that only
one kind of test-that Of compression
is necessary. The tension test, for
which large beams and very expen-
siVe machinery and labor were neces-
sary, is no longer required. as the
mathematical relation between the two
tests has been ascertained with much
accuracy on the results of a compress
sion test made with a little block in |
ordinary laboratory may be figured !