Part II.] Pearson: Antiseptic Treatment of Timber. 
87 
Past Records of Timber treated with Green Oil. 
There are no Indian records available as to the value ox this anti¬ 
septic when applied to Indian timbers, while the records available from 
Europe are also scanty. M. Henry, of the National Forest School of 
Nancy, quotes a case of spruce timber, painted over with Green oil and 
placed in the ground, having lasted 17 years. The surface exposed to 
the west was more corroded than that facing east, though the former was 
by no means destroyed. 
The Engineer, Mr. Dubois, is now experimenting with treated 
sleepers on the Toul line; the results, however, are not yet available. 
Summary. 
The necessity of considering Green oil as a possible antiseptic lies in 
the fact that it is cheap, as also that it contains heavy creosote oils, and 
should therefore be a good timber preservative. Definite proposals as to 
the lines on which further experiments with Green oil are made in 
Chapter IV. 
(9) MICROSOL. 
Microsol. 
Microsol* is an antiseptic solution, of pasty green appearance, soluble 
in water and according to an analysis made by Professor Arth of the In¬ 
stitute of Chemistry at Nancy, and quoted by M. Henry in his “ Preser¬ 
vation des Bois/ ; the solution contains the following ingredients :—Sul¬ 
phate of copper 70 per cent, in crystalline and powdered form, sulphate 
of soda, sulphate of lime, small traces of free silicate, and a copper-salt 
of sulpho-phenol, probably a product obtained from the dry distillation 
of wood. 
The treatment of timber with this antiseptic is by the Open Tank 
Method, by immersion or by applying the solution with a brush. The 
strength of the solution used, when mixed with water, varies from 2 per 
cent, to 4 per cent.; if timber is to be exposed to adverse climatic infl u- 
ences, a solution of at least 4 per cent, is necessary and the period of im¬ 
mersion must be at least 24 hours. 
* Microsol is procurable from A. Freitag & Co., Fabrique de Peinture, 156 Rue du 
Faubourg—Saint Denis, Paris, France, and from Rosenzweig and Baumann, Casscl, 
Germany. 
( 160 ) 
