The Helena independent. [volume] (Helena, Mont.) 1875-1943, 1891-09-29

change quality in different timbers? In
what relation does structure stand to
qualitys How far is weight o criterion
of strength? What difference is there
in wood Of different parts OF the tree!
How far do climatic and soil conditions
influence quality? The department pro-
poses to test the influence OF continued
service upon tho strength OF structural
material, under closely observed conai-
tions, and particularly to thus test
woods used in bridge construction. The
department thus states the manner in
which collections of test material will
made:
The trees of each species are taken from
a number Of localities Of different soil and
climatic conditions. Fiom each site five
trees Of each species are cut up into logs
and disks, each piece being carefully
marked, 30 as to indicate exactly its posi-
tion in the tree; four trees are chosen as
representative of the average growth, the
fifth or .check tree'' the best developed
specimen of the site.
Disks OF a few young trees, az we'll IA
~limbwood, are also collected for biological
study. The disk pieces are eight inches in
height and contain the heart and sapwood
of the tree from the north to the south side
of the periphery. From fifty to seventy
disk pieces and from ten to fifteen logs are
thus collected for each species and site.
A full account Of the conditions of soil.
climate. aspect. measurements, and deter
minable history of tree and forest growth
in general accompanies the collection from
each site.
The disks are sent, wrapped in heavy pa
per, to the botanical laboratory of the Uni
versity of Michigan, at Ann Arbor (Mr. F.
Roth in charged, to be studied as to their
physical properties, their microscopic and
microscopic structure, rate of growth, etc.
Here are determined, (a) the specific weight
by a hyerometric method; lbl the amount
of water and the rate of it's loss by drying
in relation to shrinkage; Coz the structural
differences of the different pieces, especially
as to the distribution of spring and sum-
norwood, strong and weak cells, open yes
sells, medullary rays, ETC.; (d) the rate of
growth and other biological facts which
may lead to the finding of relation between
physical appearance, conditions of growth
and mechanical properties.
The material thus studied is preserved
for further examinations and tests as may
appear desirable, the history Of each piece
being fully known and recorded.
The logs are shippedto the st. Louis test
laboratory in charge of Prof. j. B. Johnson.
They are stenciled off for saving and each
stick marked with dies, corresponding to
IN &tn raoor1 CO oa to ho ,orfaot1y,
as to number of tree, and thereby
its origin, and as to position in tree. After
saving to size, the test pieces are stacked
to await the testing. One-half of every log
will be tested green, the other half after
thorough seasoning. A determination is
made at the time of testing of the amount
of water present in the test piece, since this
appears greatly to influence results.
From each tree there are cut two or three
logs, from each log three or four sticks,
two of standard size, the other one or two
of larger size. Each standard stick is cut
in two, and one end reserved for testing
two years after seasoning. The standard
size for the sticks is 4x4 inches and sixty
inches long for CROSS breaking tests. There
will, however, be made a special series of
cross-breaking tests on a specially con-
structed beam testing machine, guaged to
the Watertown testing machine, in which
the full log length is utilized with a cross
section of six by twelve up to eight by six
teen inches, in order to establish the COM
p~arative value of beam tests to those on the
small test-pieces. 1t is expected that, in
the average, fifty tests will be made on
each tree, besides four or five beam tests, or
26O tests for each species and site. The
methods adopted for the tests will be de-
scribed more fully later.
All due caution will be exercised to per-
feet and insure the accuracy of methods
and besides the records, which are made di-
rectly in ink into permanent books, avoid
ing mistakes in copying, a series of photo.
graphs, exhibiting the character of the rup-
ture, will assist in the ultimate study of the
material, which is also preserved.
Chief Fernow believes that the results
of such tests, thoroughly and scientif-
cally made, will be the establishment of
a standard that will be adopted by the
world. The strength and value
Of a given piece of timber will then no
be a matter of opinion but an es-
tablished fact. He believes, too, that
the forest grower of the future, knowing
conditions which give certain quail
ties, will be able to produce timber ade-
luate to any commercial demands. The
work of extending the researches of the
department., to enable it to collect speci-
from every part Of the country, it
q expected will be furthered by con-
sress at the coming session, and cor
no more important work could be
undertaken by government.