16 BULLETIN 1231, IT. S. DEPARTMENT OF AGRICULTURE. 



Table G. — Results of tests of wood-pulp products, etc. — Continued. 



Treatment. 



Amount 



per 

 square 



foot. 



Amount per 



1,000 square 



feet. 



Cost ner 



1,000 

 square 

 feet. 



Condition of sample after attack of 

 white ants. 



Bichloride of mercury on sur- 

 face. 



Copper sulphate on surface. . . 



Ounces. 



! 0. 054 



.043 



.043 



.049 



! .040 



I . 045 



f . 051 



1 .045 



1 . 113 



I .082 



J 1.25 



\ 1.25 



f 1.51 



\ 1.93 



1.01 pounds.. 

 .S2 pound.. 

 .41 pound.. 

 .46 pound . . 

 .076 pound. 

 .0^4 pound. 



6.4 pounds. . 



5.2 pounds.. 

 14.1 pounds. 

 10.5'pounds. 

 12.1 gallons.. 



...do 



$1.77 



1.42 



.72 



.80 



.13 



.15 



.35 



.29 



.77 



.58 



5.06 



5.06 



Very slightly attacked. 



Unattacked. 



Very badly attacked; eaten through 

 the silicate layers on both sides. 

 Do. 



Unattacked. 



Badly attacked; eaten through to siii- 



Turpentine and varnish on 













Paraffin dipped at 132° F. . .. 



71.0 pounds. 

 62.5 pounds. 



2.49 

 2.28 









Very slightly att acked . 









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 zinc 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 Avoods, 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. 



ADDITIONAL COPIES 



OF THIS PUBLICATION MAY BE PROCURED FROM 



THE SUPERINTENDENT OF DOCUMENTS 



GOVERNMENT PRINTING OFFICE 



WASHINGTON, D. C. 



AT 



5 CENTS PER COPY 



V 



