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MARINE REVIEW Published every Thursday at 418-19 Perry- Payne Bldg., by the Marine Review Pub. Oo. Wo, SN. CLEVELAND, O., NOV. 30, 1899. Subscription $2.00 a year. Foreign $3.50 a year. No. 22 FIRE-PROOF WOOD FOR SHIPS. AN INDUSTRY OF RECENT DEVELOPMENT BUT OF GREAT IMPORTANOE FROM A NAVAL STANDPOINT --DESORIPTION OF ONE OF THE PLANTS AND PROOESS OF MANUFAOTURE. All the navies of the world, and the United States navy in particular, profiting first by the lesson of the Chinese-Japanese war and later by our war with Spain, have realized the absolute necessity for discontinuing the use of all combustible material in the construction and equipment of war vessels. The one special lesson of these wars to the naval architect has INTERIOR OF DIGESTER, SHOWING TRACKS, ETO. been the danger of destruction of the vessels by conflagration in action, and the most important step towards overcoming this danger has been the adoption of fire-proof wood wherever it is possible to use it. But the use of fire-proof wood is not alone confined to vessels of war. Under- writers are urging its adoption in large buildings, where structures ab- solutely fire-proof are desired, and with reduced costs, which will come later on, the use of this chemically-prepared material will undoubtedly extend to merchant ships which, with steel decks, steel deck houses, steel "masts, etc., are gradually reducing to a minimum the materials that are "liable to destruction by fire. ; 5 : Methods adopted for fire-proofing wood are very interesting, but be- fore entering into a detailed account of the process, it may be well to refer to the evidence of necessity for such material furnished by the bat- tles of Manila and Santiago. Official reports on the battle of Santiago state that the In- "fanta Maria Teresa, Almirante Oquendo and ~ Vizcaya were destroyed by conflagration, caused by explosion of shell in the interior, which set fire to the woodwork. The strong- est evidence as to the importance of this question, and likewise illustrative of the in- tensity of the fire, and the rapidity with which it spreads, is given by the fact that on these vessels men were driven from loaded guns, not by projectiles, but by conflagration. That conflagration is more destructive than gun fire was likewise emphasized iby examination of the Spanish vessels after the battle of Ma- nila. But long before the Spanish war, and especially following the battle of the Yalu, the dangers of combustible material were realized in our own navy. The constant en- deavor has been to reduce woodwork every- where: to a minimum, steel or some other non-combustible material being substituted wherever practicable, and where wood 1s used at all it is required to be subjected to approved fire-proofing processes. ven desks, chairs, tables, etc., now used on naval vessels are made of fire-proof wood. : Fire-proofing wood is in a measure like embalming; for the veins of the human be- ing and of the wood are first relieved of their Original sap and juices, and a preservative fluid injected. Fire-proofed wood, therefore, is not only proof against time, but it resists decay with great success, since the properties which permit fermentation, which induces dry rot, have been removed. Further, the wood is so thoroughly filled that when paint or oil is applied but comparatively little is needed. Tests have shown that fire-proofed wood is stronger in many instances, and in a few instances a trifle less strong, than it was originally. DESORIPTION OF THE NEWARK WORKS. One of the plants in this country engaged in this line of work is at Newark, N. J., and is operated by the American Wood Fire-Proofing Co., which has principal offices in New York. At the Newark works is a large yard in which is laid a network of narrow gauge tracks, con- necting with a spur of the Central Railroad of New Jersey, by means of which it may receive lumber to be treated, and materials for' preparing the bath to which the wood is subjected The treated material may then be shipped 'by train or by boat, as the property has a frontage of 250 feet on the Passaic, where a large dock is now being built, which will take up most of the front. The plant consists essentially of three large di- gesters, which are built up of 34-inch flanged steel, and guaranteed to a pressure of 400 pounds to the square inch. Two of these are 6 feet 8 inches in internal diameter, and 106 feet in length, and the third is of the same diameter and 32 feet in length. One end is permanently closed by a hemispherical head; the other end is provided with a massive cast steel hinged cover, 6 tons in weight, which is hung on a vertical hinge and may be swung to one side during the charging and emptying of the digester. It is provided with 36 heavy radial bolts, which engage the same number of sockets formed on the face of a cast steel flange on the digester. The locking bolts are of a rectangular cross-section and are cam-shaped at their outer ends, while at the center they abut against the inner side of a large plate washer. This washer is carried upon a massive screwbolt, which projects from the center of the cover, and is driven home against the cover by means of a massive threaded nut and hand- wheel. As the nut is screwed home, it presses the plate washer down upon the inner ends of the radial 'bolts, driving them into their several sockets and causing them to act with a cam-like effect to press the hinged cover to a snug bearing upon the face of the digester. A track formed of lengths of Z-iron runs the full length of the digester. A short piece of movable track is provided, by means of which these rails may be connected with the system of tracks which extends throughout the yard. The wood which is to be treated is loaded upon small trucks until it conforms approximately to the curve and diameter of the cylinders, care being taken to observe a somewhat uniform spacing, in order to allow a free circulation for the chemical solution with which the wood is to 'be treated. The timber is then secured to the trucks by iron bands and the trucks are wheeled into the cylinders and clamped down securely to the track. The end doors are then packed with a rubber gasket, swung to, and securely clamped. Steam is now admitted at a pressure of 10 pounds and the whole charge is submitted to a steam jbath, which penetrates the wood, softening and loosening the dried juices which have remained in its fiber. The length of time depends both upon the variety of the wood and its thickness, and it may be anywhere from one to fiity hours. After the steaming process is complete, a powerful vacuum pump is applied for a period of from three to fifteen hours, the vacuum as recorded bv the gage being from 2714 to 28 inches. The immediate effect of the vacuum is to draw out of the cellular structure of the wood all of the saps, juices, etc., arfd leave it in a condition which might be described as that of an extremely finely divided honeycomb. When the vacuum treatment is complete, an alkaline solution is allowed to flow into the cylinders, great care being taken to prevent the entrance of any ~ DIGESTER OPEN, SHOWING METHOD OF STACKING WOOD.