NEW MODE OF MAKING WOODEN BUILDINGS FIRE-PROOF.

Hawke's Bay Times, Volume XIII, Issue 568, 13 April 1868, Page 4

NEW MODE OF MAKING WOODEN BUILDINGS FIRE-PROOF.

(Prom the Colonist.) Aj? firtjclfi on the subject of rendering Umber incombustible, appears in a Erench paper, and is of so much importance to people residing ia wooden buildings, that we direct special attention to the subject. A series of expe-

riments were some time since made by a French chemist, with the view of discovering a cheap and simple method of treating wood so that it should net be liable to take fire, and indeed, could resist for a considerable time at least, the action of ordinary flames. These experiments, conducted in Paris by M. Schatteman, have been successful not only as regards the rendering of wood incombustible, at least exteriorly, but also with respect to that most important point in the practical use of the process, moderation in price. M. Schatteman’s method consists in coating the wood with chloride of lime. This will, it is acknowledged protect only the surface; but that protection is very great, inasmuch as it is asserted, it will prevent the spread of flames. The particulars of the process and the means for testing its efficiency, are thus set forth:—

Chloride of lime, or more properly chloride of calcium is obtained on a large scale by decomposing bones with hydro-chloric acid, which dissolves the calcareous part without attacking the gelatine they contain. This neutral and liquid chloride marks 14 degrees by Baume’s areometer and contains 15 per cent, anhydrous chloride. To this liquid an equal weight of slaked lime should be added, and it may be applied to the woodwork to be preserved. The operation should be repeated twice with a common whitewashing'brush. The cost is at the rate of about 5 francs per 100 square metres ; the liquid costing 1 franc, and the rest being the man’s wages. Where chloride of lime cannot bo bad it may be made by treating chalk with hydro-chloric acid. To test the incombustibily of wood prepared in this way, take a few bricks and enclose a square with them; fill up the space with a kilogramme of straw, place three wooden laths across, coated as above, then put another row of bricks upon the first, and place three uncoated laths across. Having well secured them, set fire to the straw, when the uncoated laths will catch fire and be completely consumed in five or six minutes, while the lower ones, protected by their coating will only glimmer and burn and be carbonised where the flames touch them : but will everywhere be safe from combustion. Fir should be selected for the experiment.”

A metre is about 39 English inches, so that 100 square metres is about 110 square yards, which extent can be cooated for 5 francs or 4s 2d in English money. A kilogramme is a French weight of 2|ib3 English, which is the amount of straw required for the testing experiment.

Of course, the cost would be at least double here. In the first place, it would be an expensive and slow proceeding for each consumer to manufacture his own chloride of lime, while to purchase it ready made necessitates a large outlay, as it is imported from England, and is subject to an import duty of 2s 6d per square foot. Still, if the experiment set forth above were tested and found correct, and should a consequent large demand for chloride of lime set in, no doubt means of manufacturing it here in large quantities could be adopted by which duty could be avoided, and the article greatly cheapened by being produced on the spot.