WO – PA

XI.—Numerous experiments have been made with all kinds of wood, even with hard oak. In the preparation of oak railway ties it was discovered that pieces subjected to a temperature of 212° F. in a bath of heavy tar oil for 4 hours lost from 6 to 7 per cent of their weight, represented by water and albuminous substances, and that they absorbed in heavy oil and zinc chloride enough to represent an increase of from 2 to 3 per cent on their natural original weight. The oak wood in question had been cut for more than a year and was of a density of 1.04 to 1.07. This system offers the advantage of allowing the absorption of antiseptic liquids without any deformation of the constituent elements of the wood, the more as the operation is performed altogether in open vessels. Another advantage is the greater resistance of the wood to warping and bending, and to the extraction of metallic pieces, such as nails, cramp irons, etc. XII.—In the Kyanizing process seasoned timber is soaked in a solution of bichloride of mercury (corrosive sublimate) which coagulates the albumen. The solution is very poisonous and corrodes iron and steel, hence is unsuited for structural purposes in which metallic fastenings are used. The process is effective, but dangerous to the health of the workers employed. XIII.—The Wellhouse process also uses zinc chloride, but adds a small percentage of glue. After the timber has been treated under pressure the zinc chloride solution is drawn off and one of tannin is substituted. The tannin combines with the glue and forms an insoluble substance that effectually seals the pores. XIV.—The Allardyce process makes use of zinc chloride and dead oil of tar, the latter being applied last, and the manner of application being essentially the same for both as explained in the other processes. XV.—The timber is boiled in a solution of copper, iron, and aluminum sulphate, to which a small quantity of kainit is added. XVI.—In the creo-rosinate process the timber is first subjected to a steaming process at 200° F. to evaporate the moisture in the cells; the temperature is then gradually increased to 320° F. and a pressure of 80 pounds per square inch. The pressure is slowly reduced to 26 inches vacuum, and then a solution of dead oil of tar, melted rosin, and formaldehyde is injected. After this process the timber is placed in another cylinder where a solution of milk of lime is applied at a temperature of 150° F. and a pressure of 200 pounds per square inch. XVII.—The vulcanizing process of treating timber consists essentially in subjecting it to a baking process in hot air which is heated to a temperature of about 500° F. by passing over steam coils. The heat coagulates the albumen, expels the water from the cells, kills the organisms therein, and seals the cells by transforming the sap into a preservative compound. This method is used with success by the elevated railway systems of several cities. XVIII.—A durable coating for wood is obtained by extracting petroleum asphalt, with light petroleum, benzine, or gasoline. For this purpose the asphalt, coarsely powdered, is digested for 1 to 2 days with benzine in well-closed vessels, at a moderately warm spot. Petroleum asphalt results when the distillation of petroleum continued until a glossy, firm, pulverizable mass of conchoidal fracture and resembling colophony in consistency remains. The benzine dissolves from this asphalt only a yellowish-brown dyestuff, which deeply enters the wood and protects it from the action of the weather, worms, dry rot, etc. The paint is not opaque, hence the wood retains its natural fiber. It is very pleasant to look at, because the wood treated with it keeps its natural appearance. The wood can be washed off with soap, and is especially suited for country and summer houses. XIX.—A liquid to preserve wood from mold and dry rot which destroys the albuminous matter of the wood and the organisms which feed on it, so there are neither germs nor food for them if there were any, is sold under the name of carbolineum. The specific gravity of a carbolineum should exceed 1.105, and should give the wood a fine brown color. It should, too, be perfectly waterproof. The three following recipes can be absolutely relied on: a. Heat together and mix thoroughly 95 pounds of coal-tar oil and 5 pounds of asphalt from coal tar. b. Amalgamate together 30 pounds of heavy coal-tar oil, 60 pounds of crude wood-tar oil, and 25 pounds of heavy rosin oil. c. Mix thoroughly 3 pounds of asphalt, 25 pounds of heavy coal-tar oil, and 40 pounds of heavy rosin oil. XX.—Often the wooden portions of machines are so damaged by dampness prevailing in the shops that the follow-