854 REPORT—1899, 
The following Papers were read :— 
1, The Dover Harbour Works. By J.C. Coonz, MInst.C.E., and 
W. Martuews, M.Inst.C.#. See Reports, p. 479, 
[Ordered to be printed in extenso.] 
2. On Non-Flammable Wood and its Use on Warships. 
By HK. Marswauy Fox. 
The one serious defect of wood as a material of construction is the danger from 
fire that always attends its use. Efforts to eliminate this danger have repeatedly 
been made. Faraday demonstrated that many chemicals possessed the property, 
when impregnated into the pores of the wood, of reducing the inflammability of 
the same. 
Among the fire-proofing chemicals used from time to time have been: tung- 
state of soda, boracic acid, sulphate of ammonia, sulphate of magnesia, chloride of 
zine. 
Fire as an element of naval warfare is traceable as far back as 190 B.c., when, 
according to Livy, the Rhodians made use of fireships, or vessels filled with com- 
bustibles, set adrift among the hostile fleet. Repeatedly since that early date 
fireships have played a not unimportant part in naval warfare. 
With the advent of ironclads the utility of fireships passed away, but the 
naval battles of the Chinese and Japanese War in 1894 showed conclusively that 
in a new form fire was still a serious factor in naval engagements, three Chinese 
warships being burned to the water’s edge owing to their woodwork being set 
ablaze trom the shot and shell of the attacking fleet. It was this object lesson 
that induced the naval authorities of the United States in 1895 to look about for 
a remedy to prevent the wood of their warships from burning. Experiments with 
wood impregnated with fire-proofing chemicals were made by the Government 
of that country, with the result that two cruisers and two battleships then 
under construction were fitted out with non-flammable wood. After some sixteen 
months of service trial, a re-examination of the subject was officially ordered, 
owing to reports that the treated wood corroded metals, absorbed moisture, and 
failed to properly retain paint. The examination resulted in the continuance of 
its use and extension to other American warships. 
In 1897, H.M. Admiralty commenced the investigation of non-flammable 
wood, and after various tests specified it for the new royal yacht, the new battle- 
ships, cruisers, and torpedo-hoat destroyers now being constructed. 
The process by which wood is rendered non-inflammable consists in placing it 
in cylinders of steel, closing the same tightly, and submitting to alternate appli- 
cations of heat and steam, after which the air is exhausted and the fire-prooting 
solution—one of the ingredients of which is phosphate of ammonia—admitted. 
Pressure pumps are then applied, forcing the liquid into the pores of the wood. 
The degrees of steaming, vacuum, and pressure vary according to the character 
of the wood, All kinds of wood are not amenable to the process—some because 
of the large quantity of resin or oil they contain, and irregular fibres resist thorough 
impregnation. Teak, Austrian oak, Norway spruce, and American pitch-pine, 
are particularly resistent, while yellow deal, white pine, mahogany, ash, elm, 
birch, cherry, and English oak lend themselves readily to the treatment. In 
the softer woods timber from three to four inches in thickness has been im- 
pregnated successfully, but in the harder woods rarely more than two inches 
can be impregnated throughout. For all practical purposes, it has been found 
that impregnation for one inch all round renders the wood non-flammable 
throughout. The amount of solution taken up by the softer woods is greater 
than that absorbed by the harder woods. White pine takes more than twice 
its original weight, while mahogany, oak, and teak only take up about 75 per 
cent. of original weight. After the wood has become thoroughly impregnated 
the next step is to evaporate the aqueous portion of the solution from the 
