PROTECTING WOODS AGAINST TERMITES. 15 
Certain of the woods named would make very suitable veneers to 
overlay and conceal chemically treated interior and hidden parts 
of furniture, which could be made of any of the cheaper woods of 
the United States. Impregnating with zinc chlorid or steeping with 
bichlorid of mercury would be a suitable treatment of the cores 
or interiors, after which the resistant woods could be glued upon 
them. The extremely poisonous character of mercuric chlorid ren- 
ders its use dangerous. It is slowly volatile and there ts a possibility 
that it will be gwen off continuously in small quantities from the 
treated wood. This matter should be carefully considered in case 
mercuric chlorid treatment is used for furniture and other house- 
hold articles made from Kyanized wood. Coatings with heavy white 
lead paint might prove a safeguard. 
POISONS FOR WOOD-PULP PRODUCTS. 
In the tests of insecticides for wood-pulp products, white arsenic, 
sodium arsenate, bichlorid of mercury, zinc chlorid, phenol (carbolic 
acid), copper sulphate, antimony, sodium fiuorid, and creosotes were 
tested. The wood-pulp products in the test were various processed 
boards used in interior finish and as substitutes for lath, tiling, etc. 
Where the board was made of four plies of fiber laminated with 
silicate of soda, some samples were treated on each ply before lami- 
nation, while others were treated only on the surface. These tests 
were made in the Tropics in cooperation with American manufac- 
turers. For the money invested, crude carbolic acid and creosotes 
gave the best results, though the odor is a disadvantage. A summary 
of the results is given in Table 6. 
Canvas finished by the cupra-ammonium process is not attacked by 
termites. This process consists in subjecting the fabric to the action 
of a solution of copper hydroxid in ammonia, whereby a compound 
of copper and cellulose is formed on the surface in addition to some 
change in the physical character of the fabric due to partial solution 
and reprecipitation of the cellulose. The treatment is readily re- 
moved by acids and other solvents for copper oxid and fades grad- 
ually on exposure to the weather. It has never been determined in 
the Bureau of Chemistry whether this fading is due to actual loss 
of copper or whether it is due to chemical change. 
TABLE 6.— Results of tests of wood-pulp products treated with poison to prevent 
attack by termites. 
Amount Cost per | 
Amount per 1,000 | Condition of sample after attack of 
7 per 
Treatment. square ga ae square white ants. 
foot : feet. 
| aii See Bt 
Ounces. Pa 
NepiicEeAled sas Stk eat tet Wola NOne:— = -- —.2foc oe. 3 | Badly attacked; eaten through to sili- 
| cate. 
age ie : 111 pounds... {Badly attacked but not eaten through 
Zine chlorid in plies.......... veeeeeeee- {91 pounds. . \ $1.01 { to silicate. : 
7: . 7 pounds....| - .31 | Veryslightly attacked. 
Zine chlorid on surface. .-....)...-.----. {3 pounds... .14 | Slightly attacked. 
| 10 gallons 3.50 Unattacked. 
Srde Garbolic acid)... 2.5. .)2 25.2. 6 gallons 2.10 | 
| 1 gallon..... 35 | 
aS: Do. 
amends 2 ea te Ou Sides... |...) 5 .|oec oc coos ccleecee-n--- | Slightly attacked. 
