30 BULLETIN 333, U. S. DEPARTMENT OF AGRICULTURE. 
the Southern States 1 (PL XIV, fig. 1). After many years' service 
there may be a deterioration in the treated wood. Other chemical pre- 
servatives are in use, but coal-tar creosote is usually the most effective 
preventive since it is also a fungicide and will not leach out in wet 
situations. For permanent timbers to be used in coal mines a pres- 
sure process with zinc chlorid has been found more suitable, accord- 
ing to tests conducted by the Forest Service. 
CABINET WOODS. 
Impregnation of cabinet woods, furniture, etc., with chlorinated 
naphthalene 2 is effective in rendering wood more resistant to termite 
attack; treated, perishable, northern cabinet hardwoods comparing 
favorably with untreated teak and mahogany after two and one- 
half years' test. 
wood-pulp pkodtjcts. 
Treatments have been tested for wood-pulp products, such as 
the various wood-fiber, " processed," or " composition " boards used 
for interior finish and as substitutes for lath, etc., when they are to 
be used in the Tropics and portions of the southern United States to 
prevent attack by white ants. It has been found that the practical 
method is to add various poisons during the manufacture of these 
boards. 
Experiments with such poisons and insecticides as white arsenic, 
bichlorid of mercury, zinc chlorid, copper sulphate, sodium fluorid, 
phenol, and dihydrogen potassium arsenate (KH 2 As0 4 ) have been 
conducted by manufacturers upon the recommendation of the Bureau 
of Entomology. It has been determined that where insoluble chem- 
icals were added in the process of manufacture of the board there 
was so low a retention that the cost rendered the treatment commer- 
cially impossible. Also in the manufacture of the board a large 
amount of water is employed which it is not practicable to save, and 
consequently a large amount of chemical, whether soluble or insoluble, 
is carried away. As yet the results of these tests do not warrant the 
drawing of definite conclusions. 
Dihydrogen potassium arsenate is a powerful insecticide, 3 is soluble 
in cold water, and should prove as effective as the insoluble white 
arsenic. Sodium fluorid has been been proved, by experiments of 
A. L. Quaintance, an effective insecticide and is also being tested as 
1 In the Tropics and along the Gulf coast of the Tnited States, where seasonal checking 
of timber is liable to occur after treatment and setting, a penetration sufficient to 
prevent white ants from infesting the timber through these checks should be secured. 
A more uniform penetration with a practical minimum to allow for checking, and 
a heavier impregnation (at least 15 pounds per cubic foot) are necessary. The depth 
of penetration can be determined roughly by the thickness of the sapwood. 
2 Process devised by the Western Electric Co., of New York. 
3 Information on this insecticide was obtained from the Branch of Southern Field Crop 
Insect Investigations from the experiments of B. R. Coad. 
