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Creosote has the advantage that being more or less oily, it does not 
wash out of the wood readily, so that it is adapted to ties in wet places. 
Zinc chloride, while classed as a soluble salt, has given good satisfaction 
and is applied with pressure in the same manner as creosote, the process 
being known as “Burnettizing.” We were shown a red oak tie at the 
Mt. Vernon plant which had been treated with zinc chloride in 1899 and 
the wood was still sound and heavy, the main failure being where it had 
been cut by the tie plates. This showed a durability of 22 years, whereas 
red oak untreated is rated at about eight or nine years only. This would 
seem to belie the statement that zinc chloride is unsatisfactory because of 
its solubility in water. There has been complaint that it interferes with 
the automatic signals by its effect on the electric current. 
Results of treatment and effect on different species —Mr. J. H. Water- 
man, Superintendent of the Galesburg plant, rates the value of the dif- 
ferent processes in the following order: first, straight creosote ; second, the 
Card process; and third, Burnettizing (zinc chloride). According to his 
experience the average life of an untreated tie is not over four years, but 
over twelve years’ life are got out of some of their treated ties, with the 
possible exception of chestnut. He believes that much depends on the 
thoroughness of the treatment and the time of the year when the timber 
is cut. Thorough air-seasoning is recommended for every stick of timber 
treated. 
His observations upon the ordinarily less durable species are of value 
in this discussion. He states that cottonwood if properly treated with creo- 
sote will give as long life as any tie he handles. Beech, birch, and maple 
will only give about four years’ service without treatment, but make good 
ties when properly treated. As to hard maple, his road has in Nebraska 
a number of these treated ties in the track and he believes that they will 
get twenty years of life out of 90 per cent of them because they were cut 
in the winter months; and the same can be said of birch, soft maple, and 
beech if properly handled. The latter is a species which has been brought 
into the market within the last few years, altogether because of the use 
of preservatives. Mr. Waterman further believes that durability of ties 
will be doubled by the use of heavy rails and tie plates, since the failure 
of many softwood ties is due to cutting rather than to decay. 
Ordinary pressure process—Leaving out the Rueping process, the 
ordinary pressure process with zinc chloride or creosote is to put the trams 
carrying ties or other material into the retort and draw an initial vacuum 
of about 25 inches for one hour, more or less according to the specifica- 
tions of different railroads. The creosote is then introduced under suf- 
ficient pressure to drive the preservative into the pores of the wood, the 
length of time for absorption depending upon the species of wood and, 
