16 BULLETIN 1231, U. S. DEPARTMENT OF AGRICULTURE. 
TABLE 6.—Results of tests of wood-pulp products, ete——Continued. 
| | 
| Amount | Cost per 
| Amount per | Ie 
per : 1,000 Condition of sample after attack of 
Treatment. | square ag orcas | square white ants. 
| foot. z feet. 
| Ounces 
f 0.054 | 1.01 pounds-. a 77 
| .043 | .82 pound.. 1.42 | Very slightly attacked. 
Bichloride of mercury on sur- .043 | .41 pound... te 
face. 049 | .46 pound.. -80 | Unattacked. 
-040 | .076 pound. .13'| Very badly attacked; eaten through 
.045 | .084 pound. =e the silicate layers on both sides. 
.051 | 6.4 pounds... LoD Do.. 
.045 | 5.2 pounds. - -29 
Copper sulphate on surface. . . 113 | 14.1 pounds. .77 | Unattacked. 
082 | 10.5 pou - 58 ey | ‘ * 
F 1.25 | 12.1 gallons... 5. 06 adly attacked; eaten through to sili- 
PING 2 shh es setoet Ge = Se x rs F oe. 
Turpen H 1025 aldo 2k 5.06 | cateinsmall places on both sides. 
Turpentine and varnish on | { 12 SL axe ree een eres ioe 
surface. | ASS. Alo. Aes See CN ee 
Paratim. Gippediatw3a2> Be ac ase) 71.0 pounds. 2.49) | , 
Paratin dippediatio0> Bh 45 eee. 62.5 pounds. 2.28 | Veryslightly attacked. 
Results not given in some cases. 
: SUMMARY. 
The most effective preservative in protecting timber to be set in 
the ground from attack by termites is coal-tar creosote. The length 
of service required must determine whether the method is to be a 
superficial treatment or a more costly but permanent impregnation. 
Impregnation by the “* open-tank ” method with coal-tar creosote 
renders wood resistant to attack by termites for at least 15 years. 
Impregnation by the full-cell process with coal-tar creosote renders 
wood resistant for at least 25 years. This method is recommended 
for wood to be exported for use in tropical countries. 
Brushing several coats of coal-tar creosote on timber will add from 
2 to 5 years to its life; pigments may be added to the oil to give the 
wood a painted appearance. 
For interior woodwork, furniture, cabinet woods, etc., impregna- 
tion with zine chlorid, bichlorid of mercury, sodium fluorid, or 
chlorinated naphthalene is effective; the woods can be painted after 
such treatments. 
Another protective method is to treat the hidden, cheaper cores of 
furniture, cabinet woods, etc., with preservatives during manufac- 
ture and then overlay them with veneers of termite-resistant woods. 
Effective poisons to be added to wood-pulp products during manu- 
facture are crude carbolic acid and coal-tar creosote. 
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