12 BULLETIN 1231, U. S. DEPARTMENT OF AGRICULTURE. 
TasBLe 5.—Results of tests of methods of impregnating woods, etc.—Continued. 
Treatment. Results. 
Open-tank process, using yellow pine for test—Continued. 
Boiled 13 hours in a stock solution of poisoned kerosene emulsion (1 gallon water, 
2 gallons kerosene oil, } pound naphtha soap, + pound sodium arsenate)— 
os Adipsved to ‘cool in mixture.) 3 7. oh Te. ae aan oe oe ee ee Failure after 6 
years. 
‘\Copled and dipped in carbolimeunas. 21555. 2201. shod eh: cece ae: Peek Do. 
Boiled 1 hour in 2 gallons of creosote emulsion poisoned with 3 pound sodium 
arsenate— 
ra dowed £0 colin the miixtnre sor 3 Oe A eee ee Do. 
Hettin*kerosene'oil for 1 hour aftertreatment. - 222. 2-20 sre oes ee eee Do. 
_Left in coal-tar creosote for 1 hour after treatment..........-.-...-.-.-------- Do. 
Boiled 1 hour in 1 gallon kerosene oil, 1 gallon coal-tar creosote, 4 pepe naphtha | Not attacked by 
soap, 3 pound sodium arsenate, 1 gallon water; allowed to stand 1 hour in car- | termites after 6 
bolineum. years’ test. 
Boiled 4 hour in a 5 per cent solution of sodium arsenate and left soaking for 2 Do. 
days, then boiled for 1 hour in sodium arsenate and soaked for 1 hour in car- 
_ bolineum. 
Boiling: ; 
Paraffin wax, tested with both coniferous and hardwood species. ....-..--------- Failu Xs e after 6 
months. 
Saccharine solution and arsenic, tested with maple and ash..........-...---..--- Failure after 14 
years. 
Chlorinated naphthalene, tested with both coniferous and hardwood species...-- Ne attacked after 
years. 
Impregnation and baking: | : 
Formaldehyde and carbolic acid combination, tested with pine..........-...---- | Failure after 8 
years. 
Encysting: | . ‘ 
Naphthalene, paraffin, and silica, tested with ash...-.............-..-.----------| Failure after 7 
years (sweat 
badly). 
OTHER TREATMENTS. 
? 
There are also simpler though less effective methods other than 
treatment with chemicals to prolong the life of timber, such as set- 
ting in stone, charring, steaming (PI. I, fig. 2), ete. By burning (i.e., 
for poles, posts, etc.) in an open fire till the outer layers are charred, 
wood is rendered more resistant to insect attack. Charred wood will 
not be damaged by termites till one year after being set in the ground, 
and not seriously damaged till after at least two years of service. 
However, charring should not be depended upon to preserve wood, 
although it is quite possible that it renders the wood more resistant 
to insect attack. A more effective method is to dip the butts of fence 
posts for a few minutes in crude oil and then char them. 
TREATMENTS FOR WOOD PRODUCTS NOT TO BE SET IN CONTACT 
WITH THE GROUND OR IN WET SITUATIONS. 
Finishing products—such as cabinet woods, furniture, and the in- 
terior woodwork in buildings—as well as unfinished products stored 
to season before finishing, require treatment different from that given 
to crude products to be set in the ground. While the preservatives 
with which such woods are to be treated should generally be anti- 
septic, they should never be insoluble in water, except in the case of 
flooring or other woods near or in contact with the ground. ‘These 
preservatives in most cases should not “sweat out” or stain the wood. 
Impregnation with 2 to 5 per cent solutions of zinc chlorid by the 
Bethel full-cell process or “ Burnettizing ” is in most common prac- 
tice; only the woods which treat with the greatest difficulty require 
6 per cent solutions, 
