82 
Indian Forest Records. 
[Vol. Vi 
through the good offices of Messrs. The Assam OiUCo., a small experi¬ 
mental plant was erected at their works in Assam, while quite recently,. 
Government have ordered an up-to-date experimental plant from Home, 
to be erected at the Forest Research Institute, Dehra Dun. In spite of 
the want of proper equipment to carry out experiments of this class, 
some very valuable preliminary information has been collected as to the 
possibility oi treating Indian timbers under pressure, the results of which 
are given below. 
CO Treatment of Assam species of Timber under pressure at 
Digboi, Assam. 
In 1914, while on tour in Assam, Mr. Hart, the Inspector-General 
of Forests, arranged with the Honourable Mr. A. B. Hawkins, Manager 
of Messrs. The Assam Oil Co., to erect a small pressure plant at their 
works. The necessary sleepers having been prepared and seasoned by 
Mr. Cooper, the Divisional Forest Officer, Lakhimpur, the writer pro¬ 
ceeded to Assam in February 1915, to carry out the experiments. Of 
these sleepers, Dipterocarpus pilosus (Hollong) were cut between January 
and May 1913 and converted in June and July 1914, placed under cover 
in August of the same year and treated in February 1915. The timber 
was therefore felled two years before treatment. Moisture tests taken 
showed the air-dry wood to contain 27'45 percent, of moisture at the 
time of treatment, while absolutely green wood of the same species was 
found to contain 45'37 per cent, of moisture. The Terminalia myrio- 
carpa or ‘ Hollock 5 timber, was cut in June and July of 1914, the sleepers 
being prepared in July and August of the same year and treated in 
February 1915. The sleepers, therefore, had 8 months within which to 
season. Moisture tests showed these sleepers to contain 29'27 per cent, 
of moisture against 44*43 per cent, in absolutely green timber. 
The primary object of the experiment was to ascertain whether 
Dipterocarpus pilosus (Hollong) and Terminalia myriocarpa (Hollock), 
timber could be treated under pressure, though other species were also 
included ; and, if so, the best method of carrying out the work, i.e., the 
necessary period of treatment, the pressure required to make the timber 
take up the required quantity of oil, the initial vacuum if any required, 
the degree of seasoning necessary to allow of proper treatment and the 
final durability of the timber. 
The plant consisted of an iron cylinder, 8 feet long and 2 feet 2 inches 
diameter, fitted with a removable end, the cylinder being capable of taking 
a charge of 7 metre-gauge sleepers and to withstand a pressure of over 
200 lbs. per square inch. To the cylinder was connected pressure and- 
C 212 ] 
