In 1847 a powerful cylinder, of Burnett’s construction, hermetically closed, was laid down adjoining the sawmills in Woolwich dockyard. It was found to admit the largest description of timber for the purpose of having the moisture extracted, and the pores filled with chloride of zinc. Three specimens of wood--English oak, English elm, and Dantzic fir--remained uninjured in the fungus pit at Woolwich for five years; while similar, but unprepared, specimens were all found more or less decayed. The cost of preparing timber by this process is 12_s._ per load, besides 2_s._ for landing and loading: 1 lb. of the material costing 1_s._, which is sufficient for 9 or 10 gallons of water. Sir W. Burnett and Co.’s works for hydraulic apparatus and tanks are at Nelson Wharf, Millwall, Poplar; their office is at 90, Cannon Street, London. Their terms are-- “For timber, round or square, including planks, deals, hop-poles, paving-blocks, &c., against rot, 12_s._ per load of 50 cubic feet. “For park palings, cabinet work, wine and other laths, as per agreement. “For railway sleepers, 9 feet long, 10 inches by 5 inches, landing and reshipping included, 7_d._ each. “For timber to be rendered uninflammable, 25_s._ per load.” Sir W. Burnett’s firm now sell their patent concentrated solution at 5_s._ per gallon: each gallon must be diluted with 40 gallons of water, according to the instructions in the licence, for which no charge is made. The reader will probably have observed that this process is _considered_ to render timber uninflammable; then let us see what will be the cost of obtaining a fire-proof house. The principal building material which causes the destruction of our houses by fire is wood--_combustible wood_. If, therefore, (as nearly all our houses are “brick and timber” erections,) we render this wood uninflammable, what will the cost be? The following is an _approximate_ estimate of the extra expense, including sundries, &c.:-- Timber and Deals. Cost of House. Additional expense. Loads. £ £ 25 1000 34 15 600 21 10 400 14 8 250 12 When will the Building Act compel us to use this table _in daily practice?_ Although among the many attempts to preserve wood those in England have proved the most successful, it should be mentioned that France, Germany, and America have given much attention to the subject.