Laboratories, their planning and fittings . s contains volatile and low melting-point constituents, which admit of itsapplication as a liquid, and also bodies which, on exposure, oxidise and per-haps polymerize, forming insoluble resinous solids. The wood drainsshould be put together with hot bitumen on their jointed surfaces, then begiven a good coat applied hot at the shop, and a further heavy coat melteddown with a blast lamp to form a complete, and finally, hard, almost glossy surface after fixing (including allarrangement of junctions andbranches) is finished. Lead Channels.—If lead isuse
Laboratories, their planning and fittings . s contains volatile and low melting-point constituents, which admit of itsapplication as a liquid, and also bodies which, on exposure, oxidise and per-haps polymerize, forming insoluble resinous solids. The wood drainsshould be put together with hot bitumen on their jointed surfaces, then begiven a good coat applied hot at the shop, and a further heavy coat melteddown with a blast lamp to form a complete, and finally, hard, almost glossy surface after fixing (including allarrangement of junctions andbranches) is finished. Lead Channels.—If lead isused for laboratory drainagechannels, it must, of course, besuitably supported by wood,and,provided solder is avoided ^ and dueallowance made for expansion, byusing drips where long lengths arerequired, it makes a very satisfac-tory material. The corrosion, ifcare be taken to avoid pouringstrong nitric acid on to it—andstrong acids should never beemptied into any drain—is quitetrifling. A detail showing suchThe best milled lead weighing. Fig. 90.—Settling Pots at Leipzig. use of lead has been given on page 336 or 7 lbs. to the sq. ft. should be employed. Settling Pots.—Opinions difi^er as to the use of settling pots or gulleytraps in laboratory drainage for the purpose of catching material which shouldnot find its way into the drains external to the building. Where there areno drains in the fittings, and all sinks contain grids which cannot be readilyremoved by the students, they are hardly necessary, except for the purposeof recovering mercury, for which provision may be made at the main channelexit or exits from the laboratory, but where a sudden drop is necessary, as ^ Burnt joints, made by fusing the edges of the lead itself together, should be used. LABORATORY SKRVICKS 149
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Keywords: ., bookcentury1900, bookdecade1920, bookpublisherlondo, bookyear1921
