PRESIDENTIAL ADDRESS. 25 
long waits, and that will be especially the case when Perth 
is connected up, as it must eventually be, by the Transcon- 
tinental Railway. Partial unification or rather complete 
unification of the main route necessitating a separate main 
line for part of the distance or the introduction of a third 
rail will then be imperative. 
Preservation of Timber.—The preservation of timber is a 
subject of the highest importance to railway engineers— 
so much timber is used not only for sleepers but also for 
bridge and other construction work. Timber can be treated 
by giving it a coat of some preservative liquid such as paint, 
tar, or other substance, but the surface treatment falls far 
behind any method of impregnation, of which creosote, 
chloride of zinc or mercury (corrosive sublimate) are the 
best known. The most recent method introduced into this 
country is ‘‘ Powellising,’’ and consists of treatment with 
molasses, by which the timber becomes thoroughly per- 
meated. It is stated to be completely successful. Dry 
rot does not under the most adverse circumstances attack 
the timber thus treated, and white ants and other insect 
pests can be completely warded off by the addition of arsenic 
to the solution. Sucha method should prove invaluable for 
sleepers, as not only does it render well known and approved 
timbers more durable, but it should enable classes of timber 
to be used which on account of liability to dry rot and 
attacks of insects are otherwise absolutely useless. I 
understand that the charge for treatment is somewhat 
high, in the case of sleepers about 1/- each. If this could 
be reduced to 6d. or even 3d., which may be eventually 
possible as the process must be a cheap one, the field of 
operations may become very wide. 
Ferroconcrete Sleepers:—Within the last few years the 
price of timber sleepers has risen in this country, partly 
owing no doubt to rise in wages, but partly also to the 
