Part I.] Pearson: Antiseptic treatment of Sleepers. US 
cell creosoting method of preserving timber, which has not only stood 
the test of time but is one universally accepted all over the world where 
treated timber is used for Railway purposes, and is therefore one which 
we may look to as likely to give us satisfactory results. 
No definite idea can as yet be formed as to the relative merits of 
treating in Open Tanks or Pressure Cylinders, as the period during which 
the experiments have been in progress is insufficient. On the other 
hand it can be stated definitely that the Open Tank treatment in any 
case is only of value if either the number of sleepers to be dealt with is 
small, or if the idea of treating sleepers is a temporary one or in default 
of a pressure cylinder. If the work is to be of a permanent nature and 
more than 25,000 to 50,000 sleepers are to be treated annually not 
only are better results obtained but it is more economical to put in a 
pressure plant. 
(2) Results according to species treated. 
(i) Treated ‘ Chir ’ sleepers. 
Finns longijolia. Some years ago about 1,000 untreated ' Chir ’ 
sleepers were laid in the line as an experiment and they had all to be 
removed in 29 months, or roughly after 2| years. The PoweUized ‘ Chir ’ 
have lasted 9 years in very wet localities, and are stiU doing fairly well 
in the moderately moist and well in the dry localities. It can therefore 
now be stated definitely that PoweUized ‘ Chir ’ sleepers will last four 
times as long as untreated ‘ Chir ’ sleepers, if not longer. The ‘ Chir ’ 
treated with a mixture of Earth Oil and Creosote have not been more 
than six to seven years under observation, but they too, from their 
present condition, have every indication of doing as well as the PoweUized 
sleepers. The experiments are not yet complete as by far the greater 
number of the sleepers treated by different processes are stiU in the line, 
on the other hand we can fix the life of well treated ‘ Chir ’ sleepers 
fairly accurately. In dry localities they wUl probably last 12 to 13 years, 
in moderately dry 10 to 11 years and in wet localities 9 to 10 years. The 
above periods of duration are based on sleepers being laid in main lines, 
subjected to heavy traffic, and as the sleepers under experiment were 
neither selected before treatment nor laid to the best advantage, the 
above estimates may be taken as conservative. There can be no doubt 
whatsoever that when dealing with treated ‘ Cinr ’ sleepers the best 
results can be obtained by laying them sap down and heart up and that 
the life of the sleepers can be considerably increased by using bearing 
plates. It is hardly necessary to state that the sleepers should be passed, 
and if possible bored and adzed, before treatment. 
[ 25 ] 
