Burlington weekly free press. [volume] (Burlington, Vt.) 1866-1928, 1910-09-22
CORRECT WEIGHTS AND MEASURES

To the Editor Of the Free Press:
Under the above heading chapter Is
due on the correct measurement of s,u
logs and round timber. Perhaps tho Are,
intimation that eXactness in this field was
possible was given IA bulletin t02 OF the
Vermont Experiment station copy Of
which anyone can have for the asking
A more extended and better discussion Is
given In the Forestry Quarterly. Vol III.
No. a. November, 1905. propose to set
forth here briefly just how the Champlaln
log rule is constructed. and Shall en-
deavor to make It clear to every reader
A board foot contains IA cubic inches
Now Il foot log Is IS inches long, so
that every square Inch in the small end Of
tie log represents one board foot in that
log Therefore the number of square
inches in the small end NJ the log is the
same as the number of board feet in the
whole log, Now, If the diameter he called
u, measured in inches. the cnd Of the log
contains in square inches as the school
boys know, 1854 times the square of the
diameter, or q. 1904 d. II this 10 reckoned
out for the different diameter- VOW will
have what is called the constructive rule,
which makes no allowance for waste In
the form of sawdust. slab or edging. 1t
is used by few firms who shave the logs
into vene ering, or work them into wood
pulp. etc. where there Is practically no
waste. For example. log y feet long
and y inches in diameter would yield 1i3
board feet solid. But a quarter inch saw
and inch boards causes n loss of one-Afth
in sawdust, leaving 90 feet and n small
fraction.
And now comes the allowance for slabs
and edgtng, or surface waste. The as
sumption will generally be easily admit
ted that the slabs and edging encroach to
he same average depth below the bark
surface of the log all around whether
the log is small or great. This makes
the surface waste proportional to the
amount of surface, or what Is the same
thing. proportional to the diameter. This
means that the allowance for surface
waste is number Of board feet found
by multiplying the inches Of the diameter
by certain factor. which factor Is the
same for all logs small and greet The
only difference OF opinion possible re-
lates TO what this factor should he. One
way Is to assume several different val
ues for this factor and then see what
quantities result. II We chose >. we mus,
subtract In our Pinch log 2xI2:24 feet
for surface waste. n we take / IA we
subtract in our 12-inch log 2xl2 equals "a
feet for surface. waste. n we take | IA we
subtract 10 feet. IL we take | we suhtTac;
- feet ard have left in the first case c.
feet Of trimmed boards. in the second case
shall have % minus 10 equals -, In
the last case which is the Chanplain
log rule we shall have 90 lninue 70
equals Il. Several mill men of long
experience assure me- that with good logs
IS feet can be realized and few feet
more. and from my mill tests the figures
- seem entirely justified This fixes the
factor one and since this factor must
hc the same for all diameters the for
nula will be
0G2S3 DID
where the factor G. SoSS allows for the saw
dust by taking onc-hfth out of g. 1854, and
the minus II il the allowance for slabs and
cdsing in first-class timber What abou,
small margin Of safety for the buyer?
This is secured by the rule OF neglecttng
al fractions OF an inch in taking diam
ctcrs, calling diameter of twelve and
three-fourths twelve inches. etc. This is
more convenient than reckoning as u
inches diameter between II l-2 and
70 l-2. You jump whole inch even In
that case. and since scaling sticks seldom
have any half inch marks on d man has
70 guess a the half inch. hut this way
he marks are plain and besides the rule
expects you to call 12 inches a diameter
which is anywhere from - to l3 inches
Instead of from II - to L. IL This way
" taking diameters leaves the buyer of a
,2-inch log several feet OF margin, theoret-