306 
The N.Z. Journal of Science and Technology. 
[Sept. 
Table XII.—Strength of Timber before and after Impregnation. 
Control. 
Test. 
Loss 
Salt. 
Weight, in 
Pounds. 
N 
(Calculated). 
Weight, in 
Pounds. 
N 
(Calculated). 
per 
Cent. 
Zinc chloride .. 
Sodium fluoride 
Aluminium sulphate 
f 400 
400 
350 
■{ 385 
! 390 
370 
t 420 
f 400 
| 380 
i 384 
395 
I 385 
t 374 
359 
| 400 
. 386 
[_ 397 
f 405 
| 380 
375 
370 
J 400 
^ 400 
395 
359 
374 
385 
Aluminium and zinc 
948 
948 
835 
918 
931 
859 
990 
955 
910 
918 
933 
918 
900 
857 
955 
919 
950 
959 
910 
905 
859 
955 
955 
944 
857 
900 
918 
r 
360 
365 
310 
342 
349 
330 
373 
375 
365 
360 
345 
370 
350 
339 
357 
325 
355 
360 
300 
340 
335 
335 
355 
360 
345 
330 
350 
340 
320 
350 
355 
345 
325 
328 
330 
350 
324 
847 "j 
857 
729 
805 
820 | 
777 
880 J 
895 ) 
811 
859 
824 
883 > 
835 r 
809 
853 
847 
776 
859 1 
716 
811 
799 
799 
847 
859 
824 
787 
835 
811 
763 
835 
847 
824 i 
776 f 
783 
787 
835 
772 
11 
10 
10 
14 
Creosote. —Tests with creosote gave results so close to the control strength 
as to show no effect on the wood. Lignolite and Anti-damp, which were 
tested as samples of proprietary preservatives containing low-boiling hydro¬ 
carbons, showed an increase in elasticity, and slight rise in the breaking- 
strength. 
LEACHING OF ZINC CHLORIDE. 
Since railway-sleepers in New Zealand are exposed to considerable moisture 
in some districts, experiments were carried out with a view to determining 
the rate at which the salt leached from the native beech. Pieces of Tagus 
Menziesii, green and seasoned, were treated by the full-cell method and 
then placed in water, the amount of the latter being maintained at a constant 
level throughout the tests. The wood remained submerged for one day, 
and then was removed for six days, the object of the treatment being to 
obtain alternate wetting and drying, as would be experienced in practice. 
