Indian Forest Records. 
8 
[VOL. Ill 
of lime. Many other such solutions are in existence having as their 
base these Creosote oils. 
Chloride of Zinc. 
Chloride of Zinc obtained by dissolving metallic zinc in hydro¬ 
chloric acid is nearly as extensively used as Creosote, but it has certain 
disadvantages, amongst which may be mentioned its corrosive action on 
iron, it is also highly hygroscopic, that is to say, it readily absorbs 
moisture, which not only reduces its strength but is liable to 
render the treated timber damp. To overcome this drawback Creosote 
has been added to the salt, and the treatment given the name of 
“ Mixed impregnation”. It has many'good qualities, however, which 
have caused it to be so extensively used. Mr. Sherfesee, of the United 
States Forest Service, says that creosote and zinc-chloride are the onlv 
preservatives in common use in America. It is used to a fair extent on 
German Railways for impregnating sleepers and by the Telegraph 
Companies for treating their poles, but it is not so extensively employed 
as was formerly the case. Both Professor Henry, of the National 
Forest School at Nancy, and Hauptmann Basilius Malenkovic of 
Austria are not in favour of zinc-chloride alone, the latter officer saying 
that it cannot be compared with Creosote or fluoride solutions, though 
of value when mixed with other substances. 
Sulphate of Copper. 
Blue Vitriol or Sulphate of Copper used in Boucherie's and Margary’s 
processes has according to Sherfesee, fallen into almost total disuse in 
America. It has the disadvantage of losing its antiseptic properties and 
is liable to be dissolved in water and so get washed out of the timber. 
Warth, in drawing up his report in 1878, advocated copper sulphate as it 
had been employed by the Liibeck-Buchen, Ost-Preussen-Berlin-Stettin 
and other Railways. This salt, however, has not been recommended b}^ 
recent experts, and in India, where the treated timber is often subjected 
to much moisture, its use cannot be advocated. It is possible, however, 
that copper sulphate mixed with other substances may be of value as an 
antiseptic. For instance, a substance known as Microsol is on the 
market which is said to contain 7 0 per cent, of sulphate of copper, mixed 
with Phenol and sulphur compounds, and sulphate of lime. This patent 
solution is very strongly recommended by Professor Henry, an eminent 
expert on this subject. It is just possible that the gypsum forms a 
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