_ , 
PROTECTING WOODS AGAINST TERMITES. 11 
treated timber by the writer indicate that the “ open-tank ” method 
of impregnation with coal-tar creosote renders wood resistant to 
attack by wood-boring insects for at least 15 years. Treating of 
wood by this method can be done with homemade apparatus (PI. I, 
fig. 4), using unskilled labor. The timber should be well seasoned 
before impregnation, however, and the treating should be very care- 
fully done; a uniform penetration should be secured, sufficiently 
deep to allow for season checking; this is especially necessary if the 
treated timber is to be set in warm climates. 
Impregnation treatments by the more technical pressure pro- 
cesses are the most effective, as well as the most costly, but the results 
usually justify the extra cost. Inspections of treated timber by the 
writer indicate that impregnation by the full-cell pressure process 
will render wood resistant for at least 25 years: 
The results of the tests of the comparative effectiveness of the 
superficial methods of treating timber in protecting it against at- 
tack by termites are given in Figure 3 and Table 4, while the re- 
sults of the impregnation treatments are given in Table 5. 
TABLE 4.—Results of tests of the relative effectiveness in preventing attack by 
termites of miscellaneous superficial chemical preservative treatments for 
crude or finished forest products. 
Preservative. Method of application. | “Pecies of wood Effectiveness. 
treated. 
Liquid M, a volatile yellow fluid, 2 per | Both brushing, 2coats | Yellow pine....... Failure after 4 
cent solution. applied hot, and months. 
ipping. 
“Ebonizing,’ chromic acid and aniline | Brushing, applied hot.| Ash and yellow | Failure after 5 
oil. pine. months. 
Liquid S, a yellowish oily liquid with a | Both brushing, 2coats | Yellow pine....... Failure after 6 
strong varnish odor. (one week between months. 
coats), and dipping. 
Preservative T, a preservative paint... i otbs Wonushine and. |wAshs «. 2. te. sot Failur e after 1 
soaking. | ear. 
Oil S, a creosote oil made from coni- | Brushing.............. Chesinnie 2 Effective for less 
ferous wood. than 5 years.1 
Oil C, a very light gravity brown oil, |.._.. 7 i le LE La ba Ae Bo A Do. 
containing much tar, acids, and water. | | 
1 Period when first examination was made after setting. 
TABLE 5.—Results of tests of methods of impregnating woods with preservatives 
to prevent attack by termites, 1913 to 1922. 
Treatment. Results. 
Full-cell pressure process: ; 
Commercial wood creosote (No. 126), tested with yellow pine.......-...-..-.---- No failures. 
Commercial coal-tar creosote (No. 154), tested with yellow pine.-.........------- Do. 
Coal-tar creosote oil A, tested with yellow pine........------..------------------ Do. 
Coal-tar creasote oil B, tested with yellow pine:..........0.52.-...--.2---------+- Do. 7 ( 
Steaming for various periods under different pressures, tested with ash...........| Fail ree . after 6 
months. 
Empty-cell pressure process, using yellow pine for test: , 
Weatmmantiow dud CLOOSOLG: GINO. 126)5 225... Se tcccennccccce ns secancusccucuesce- 5 Lg out of 12 
in 1922. 
Grrarmprorucanl-tar Creosote (NOs 154) 2. os 4. go doe cen nc ese cee ccc ee eee ne No failures. 
Re UEMOCRMSSHANDIE A F405) pe eoe ede te FOR STF SS IES. OS! EO Do. 
Sine RraeNAGS AA OL Leb: Et ere Seven HE Sn yg foe EN oh cpm oe oS gaeeircuns ame oasal- Do. 
Open-tank process, using yellow pine for test: : \ Phd: 
Geermercia wood.creosote (NO. 126). s25.22 -de.ch el ccd emis onus owe} eee nae Hoe 1 failure in 1916; 9 
failures out of 12 
in 1922. 
Smaart Con tat CLEOSOLGUNOs184).o 0 eee ac cap 8 S- wale node cneeeececune- 2S No failures. 
EE Par Sat ent a See Steno: et eee eS A aL Oe Sie ot 2 Do. 
See TeE MIT OLOOL) (> tos5) wermew, oh Es kode oe ot ob yin ea one <= Do. 
Boiled in iron sulphate solution for 2 hours,then plunged in copper sulphate| Failure after 64 
solution and left for 2 hours. years. 
1 Period when first examined after placed in test. 
