The National tribune., 1881-10-01
FARM AND GARDEN.

USE OF COAL TAR ON THE FARM.-PrOfeSsOr
S. A. Knapp, of the Iowa Agricultural College,
thus recapitulates the uses of coal tar in farm
economy: "The attention of our readers has been
frequently called to the value of coal tar on the
farm, especially in the preservation of woods, and
we are more fOrcibly impressed with its value as
our experiments begin to assume the authority
OF demonstration. Much has been written of
It's adaptation to the needs of the farmer as a
cheap paint for Out-buildings: without detract-
ing from its value for such purposes, we are led
to believe that this is one of the minor consdera
tons III It's practical use, and that the great pur-
pose to which 1t Will be applied will be in the
preservation OF TIMBER and the conversion of
woods liable to decay from exposure to material
value for all purposes. That coal tar does almost
perfectly preserve our soft woods has been f1Ily
demonstrated so that it does not belong to the
speculative Last year, to test for Iowa the value
of our soft wood when properly treated, we boiled
posts of green Eastwood, water elm, cottonwood
white willow and oak, in coal tar, allowing them
to remain in the tank ten minutes each; then
they were drained and piled up exposed to the
sun one month, afterward they were set in the
ground as ordinary posts AT this date there is
no perceptible difference in their durability; all
are as sound as when set. What is most remark
able, the Eastwood holds nail apparently as well
as the oak In cutting cross section, the tar
seemed to penetrate quite distance, filling the
pores and hardening the wood from one-half to
three-quarters of an inch deep, was like cement
and impervious to water Much depends, doubt
less, upon the method of penetration. The wood
should be green to obtain the best results. Farm
ers are familiar with the decided improvement in
the character of the wood when cut green and
seasoned under shelter. Poplar, cotton wood, and
white willow thus prepared make excellent fuel
Beech and other woods for mechanical purposes
when the greatest sOlidity and tenacity of fiber
are required are dressed green and oiled then are
dried under cover. The charring of wood also
adds materially to its durability. Coal tar Sc
cures all these conditions. When the green post
or board is placed in boiling tar the sap is ex-
PEELED and is replaced by the tar to some extent
deeper portions are affected as by rapid seasoning
The vat for heating the tar may be made like an
ordinary sap pan, and of any length; put in a
barrel of tar and dip the whole post, or as much
as desired. The most particular part to be COW
cred is that Just above and below the surface
when set. Where great durability is desired, the
poSt SHoulu NC DoIieu lliliy IHuttS OI HlOre, ten
minutes will answer for boards 4 barrel of coal
tar, costing three dollars, will $50 posts if
boiled, or 200 if dipped onehalf length. The cost
of boiling lumber in tar is estimated at five dol
lars per thousand feet, and thus prepared, even
Eastwood is practically indestructible. Treated
with coal tar, the long, slim, white willow posts,
so abundant in the West, become as valuable as
cedar, and the ready solution of the question,
What shall we do for fence posts? AS paint,
one coat of hot tar is worth more than any known
preparation of oil for the preservation of wood"