Part IV.] R. S. Pearson: Antiseptic Treatment of Timber, 13 
The most noticeable point in the above table is the relatively few 
treated specimens remaining after 5 to 6 years, which is attributed not 
so much to the want of toxic properties in the salts, as to the fact that the 
salts have been washed and leached out of the timber by excessive mois¬ 
ture. Taking, as an example, the Atlas experiment, four out of twelve 
specimens remain after 5 years and 10 months, of which the timber 
of two of them is so durable that it is doubtful whether it requires 
treatment. Be Hit has given equally poor results, while Hylinit is little 
better than either Be'llit or Atlas. 
Of these salts, Sodium Fluoride and Chloride of Zinc have given the 
best results which, however, compare unfavourably with the results 
obtained with the oil solutions. The superiority of Coal tar creosotes 
over salt solutions, in damp climates, is further emphasized by the fact that 
the timber was treated by applying the oil with a brush or by a short 
immersion period, as against a long period of immersion often covering 
several days, in the case of the salt solutions. 
(:) Fifth group of Laboratory Experiments. 
Experiments carried out with Anticide, McDaugall’s insecticide, Mort-ant 
and Burnettizine. 
Th : s group of experiments is virtually a continuation of group IV, 
it having been separated from that series only in order to fac l.tate 
description, and on account of the experiments having been started at a 
later date than those described above. All four antiseptics dealt with 
are patents. 
The method of treating the timber, in the case of Anticide , was to 
allow it to rema’n in the cold solution for 61 hours. The specimens 
treated w'th Mort-ant were given a 15 minutes immersion, those treated 
with McDougalVs insecticide a 21 hours immers : on in a 4 per cent, solution, 
while the solution of Barnettizine was made up to 40 per cent, strength, 
heated to 170°F. and the specimens allowed to remain submerged for 64 
hours. 
The reason for subjecting the timber to different periods of immersion 
was due to the recommendat ons of the patentees of the various suos- 
tances, and to the per od of immers on having to be regulated in 
direct proport on to the cost of the solution. Generally speaking, salt 
solutions are cheap as compared with coal-tar products, hence the long 
periods of immers on permissible in the case of experiment coming under 
groups IV and V. 
[ 14-3 ] 
