110 
POSTS. POLES. RAILWAY SLEEPERS. 
other hand, should never be allowed to stand until they become su ject o eai 
decay. All other things being equal, stout posts or poles will last longei an 
slender ones. To immerse Eucalyptus fence posts in a bath of creosote wou e 
possible; but it would be wasteful of preservative and far too costly foi genera 
practice. To immerse long, heavy poles in a bath of creosote is obviously 
impracticable. With Eucalyptus posts and poles, therefore, preservative tieatment 
must be applied to the vulnerable parts, and must aim chiefly at protection of the 
surface. Sap wood, unless it can be converted into a protective jacket by thorough 
saturation with creosote, should be stripped off, and the preservative applied direct 
to the mature wood. The neck of a pole, having been prepared by clean stripping, 
and being quite dry, should receive two dressings of creosote before insertion in 
the ground. After insertion in the ground and partial ramming, the soil as it is 
further filled in and rammed round the neck may be saturated with tar and 
creosote. Or, a narrow cylinder may be left round the neck and filled in with tar 
and cement or with tar and ground carbonate of lime. In either case the work 
must be finished just above the surface of the ground with a waterproof collar of 
bitumen or cement. The treatment of fence posts should be similar to that of wire 
poles, but for obvious reasons it must be less costly. 
Where timbers are subjected to extremely trying conditions throughout their 
length, as is the case with railway sleepers, it becomes desirable to impregnate 
their tissues in every part with a preservative agent. Two principal methods are 
in use in Europe and America for achieving this object. The more costly but more 
effective method first extracts all moisture from the wood by suction in a vacuum 
and then forces the preservative into the tissues by powerful pressure. In the other 
method the wood is simply placed in a bath of creosote heated up to, but not 
beyond, 200° Fall., for a sufficient time to ensure saturation, and then taken out and 
drained on a stage. For a full account of all preservatives in use and all methods 
for their application, readers are referred to.books that will be found in any well 
stocked engineering library and to bulletins that will from time to time be issued 
by the State Forest Service. 
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