. Preventive medicine and hygiene. ugs near the bottom whichhold charcoal and sponge. Alum is used as the coagulant. The Darnall filter used in our army is also based upon the principleof mechanical filtration. It consists primarily of a reservoir and asiphon, the immersed end of which is armed with a wire cage over which SANITATION OF BAKEACKS AND CAMPS 1283 Canton flannel is wrapped as a filtering material. This siphon is cleansedwith boiling water and primed with a small pump. The water to befiltered is first treated with the coagulant—alum and sodium carbonatein the ratio of one pound per
. Preventive medicine and hygiene. ugs near the bottom whichhold charcoal and sponge. Alum is used as the coagulant. The Darnall filter used in our army is also based upon the principleof mechanical filtration. It consists primarily of a reservoir and asiphon, the immersed end of which is armed with a wire cage over which SANITATION OF BAKEACKS AND CAMPS 1283 Canton flannel is wrapped as a filtering material. This siphon is cleansedwith boiling water and primed with a small pump. The water to befiltered is first treated with the coagulant—alum and sodium carbonatein the ratio of one pound per five hundred gallons. The bacterial effi-ciency is about ninety to ninety-five per cent. The Darnall filter canfilter two hundred gallons every four hours; it weighs fifty-two should not be depended upon to do more than clarify the water, whichmay then be purified with chlorinated lime. The Darnall filter has been extensively used throughout the UnitedStates Army. It is the most easily managed and transported of any of. U^^ Darnall Siphon Filter—- a ? ? ! 1 1 Siphon With cloth 2 Without cloth Fig. 199.—1. The filter cage with the cloth covering. 2. The filter cage without thecloth covering. All the parts of the apparatus rest in the largest can, and thisis transported in the crate. (Wilsons Field Sanitation, George Banta Pub. Co.) the modern field appliances for clarifying turbid water, for which it isespecially applicable. Fig. 199 shows the construction and operation ofthis filter. Chemical Disinfection.—The best chemical with which to purifywater is bleaching powder—chlorinated lime (page 900). A very muddywater may first be filtered. The manner of chlorinating water in ourarmy is by the use of the Lyster bag. This consists of a waterproofcanvas bag holding forty gallons, with five faucets near the bottom, sothat the entrained sediment will not be drawn off. A glass ampule holdingone gram of chlorinated lime is broken into a little water and this pouredin
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Keywords: ., bookauthorwh, bookcentury1900, bookdecade1910, booksubjecthygiene
