282] FIR plaster-work nnd sand, that they be perfectly dry before the boards are laid, lest the latter become in- fected with the dry-rot. The mode of under-flooring may besuccess- fnlly applied to a wooden stair- case ; but no sand is then to be laid upon the plaster- work. The me- thod of extra-lathing may be prac- tised on ceiling-joists, sloping- roofs, and wooden partitions. The third method, namely, inter- gecuring, is similar to that of under- flooring ; but no sand is after- wards to be laid over it. Inter- securing is applicable to the same parts of a building as the method of extra-lathing ; but it is seldom necessary to be employed. Lord Mahon made several experiments, which shew the utility of this in- vention ; but we can only refer the inquisitive reader to tl e 68th vo- lume of the " Philosophical Trans- actions of the Royal Society/' for 3 7/S ; where he will find a satis- factory account of the manner of preparing the mortar, as well as the result of numerous trials made by the inventor. — See also Coun- try-houses and Fire-proof. The most expeditious way of extinguishing fire is a matter of equal importance, as the security ef buildings from that destructive agent. Hence various machines, and chem'cal preparations, have been invented by ingenious men, in order to promote so useful an object ; one of the earliest contri- vances was a barrel, filled with certain ingredients, hist proposed by M. Fuchs, a German physi- cian, in the year 17^4 ; and which effectually answered ^' purpose for v Inch it -was designed. — A si- milar inv< > introduced in- to this country by a Mr. Zachakv Gbbyl, whose machines were. . . ct wood, and contained only FIR. water ; they were exhibited befbrS several of the nobility, but did not meet with encouragement. In the year l/6l Dr. Godfrey produced certain vessels which in every re- spect succeeded. They are sup- posed to have been an improve- ment on Mr. Greyl"s, were con- structed with wood, and filled with a chemica] liquor, consisting of water, oil of vitriol, and sal-am- moniac. When thrown into rooms and other places that were pur- posely set on fire, they burst, and by their explosion completely ex- tinguished the flames : it is to be observed, that they were useless after the roof bad fallen in. These contrivances, however, are evident- ly more calculated for ships, than to be employed on land ; as they would be of great service for sup- press. ng tires in vessels at sea, and might be considered as necessary a part of their cargo as naval stores, or ammunition. In the 23d vol. of " Annals of Agriculture," Mr. William Knox, a merchant of Gothenburg, in Sweden, states that he has made a variety of experiments for extin- guishing lire by means of such sub- stances as are cheap and easily pro- cured. He divides them into simple and compound solutions. In the former class, he proposes to add to 75 gallons of water, () gallons of the strongest solution of wood-ashes ; or 6 gallons of the finest pulverized pot-ashes j or 8} gallons of com- mon salt, well dried, and finely beaten ; or 8 gallons of green vitriol or copperas., thoroughly dried nnd finely pulverized 5 or 1 1 £ gallons of the strongest herring- pickle ; or 9 gallons of alum re- duced lerj or 10 gallons of clay, perfectly dried, well beaten, and caret ally sii Among the compound solutions, Mr,
