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962 cannot be rendered safe by suitable treatment. The aim of purifica- tion is to obtain an effluent which is not only safe, but is palatable, of good appearance and attractive.

Water for horses is not usually purified. Almost any clear river or pond may be used in the crude state, and the instinct of the animals often leads them to refuse a contaminated water, even if it looks pure. In many cases in Flanders in the World War water from ponds and marshes, though foul and repulsive, was made quite potable by simple treatment. The military value of this fact is evident. Broadly speaking the purifying processes are those which remove suspended matter, and those which render innocuous bac- teria which would be harmful.

English waterworks practice in civil life relies almost entirely on the action of the gelatinous film forming on the surface of a sand filter, for removing bacteria, but the processes of sedimentation, filtration and oxidation, which purify water in natural streams and lakes, can be imitated by artificial means working more rapidly than the ordinary sand filter process. Sedimentation can be accelerated by the addition to the water of an alum solution. Filtration can be effected by passing the water under some pressure through a po- rous medium; oxidation of bacteria by agents such as chlorine in measured quantities. In the field the steps taken are to precipitate the suspended matter by alum solution and then to treat the clear water by chlorination. The former process, though helpful in the latter treatment, is not in itself sufficient to produce a potable water. Chlorination is generally effected by introducing into the water a solution of calcium hypochlorite (bleaching powder) by means of the Horrocks apparatus. This is designed so that a test may be readily applied by men of intelligence to ascertain the condi- tion of the water as regards free chlorine, and to calculate from this the amount of bleaching powder which must be introduced in order to destroy bacteria.

The apparatus for chlorination consists of a box containing six cups to be filled with the water, two tin spoons each holding 2 grammes of bleaching powder, a special cup for the chloride of lime solution, glass bottles containing a test solution of zinc iodide and starch (which has a certain colouring effect on water containing free chlorine), pipettes, stirring rods, etc. The method of using is to put varying quantities of the test solution in each of the six cups of water and observe after half an hour. From the coloration of the water, bleaching powder in proportionate quantities is added for every 100 gal. of water in the chlorinating tank.

Poisons can be removed from water by various chemical processes, though it may be easier and cheaper, and certainly safer, to trans- port other water by road or rail rather than trust to remedial measures. A contaminated well can be rendered usable in a few days by cleaning out and continuous pumping, and in the case of organic pollution by the addition of large quantities of bleaching powder, followed by pumping out after a period of rest.

VI. Plant and Machinery. The British service water cart (Mark VII.) holds 118 gal. and consists of a galvanized iron cylin- der, together with filtering apparatus, two pumps, a box for small stores, a sterilizing kettle, the whole being mounted on a wooden frame with cranked axle and wheels for horse draught. The two filters are placed on the frame in front of the cylindrical tank and can be used either separately or together. Each consists of a steel cylinder in which is contained a cloth-covered steel reel and a chamber for the clarifying powder.

Tank lorries are ordinarily improvised from ordinary motor lorries by mounting two 3OO-gal. tanks anchored to a wooden frame bolted to the chassis, with a 2-in. pipe connecting the tanks and a 2-in. draw-off. These tanks should have internal baffle plates to reduce the swaying action of the water in travelling. Another method is to sling canvas tanks from framing on the lorry.

The Norton tube well, a perforated tube with hard driving head, and driven by blows from a " monkey," is useful in obtaining supplies near the surface in certain soils. Used with a lift and force pump they are suitable for small installations, but they only yield 200 gal. per hour. They were very useful in the cavalry operations in the Sinai peninsula, where water was, by their use, frequently obtained in the dry beds of wadis.

The lift and force pump, which is an article of store, can lift water through a suction hose from 2028 ft. and force it to a height of 60 ft. above its former level. It consists of a horizontal barrel 4$ in. bore with a double piston working with a 4-in. stroke and oper- ated by a crank pivoted above the barrel and worked by manual power. The suction hose comprises four 12-ft. lengths of prepared hose, internally wired, and at the end there is a strainer, a perfo- rated steel drum. The delivery hose consists of one 3O-ft. length of 2-in. canvas hose. This pump is very handy and easily worked by unskilled labour.

Other pumps for manual power are the semi-rotary for small deliveries up to 30 gal. a minute (an ordinary piston and plunger pump) and the chain helice pump, which is an endless chain, or spiral- ly wound band, with a weight at the end suspended and worked by a vertical wheel at the top of the well. The surface tension of small quantities of water adhering to the links of the chain, or the spiral band, is not broken in the rapid movement of the rising chain until it is discharged at the summit of the circuit. It is a very simple form of pump, but only suitable for small discharges.

Of the many patterns of power pumps there are comparatively few that meet the needs of an army in the field, in respect of being easily transported, reasonably free from chance of breakdown, and economy of fuel. It is important that the types used in the field should be few and that parts should be standardized so as to facilitate repairs. There should always be a number of spare parts accom- panying each machine, and there should be other spares kept for general use at store depots. All suction and delivery connexions especially should be standardized. As a motive power, high-speed internal combustion engines are generally of most use, if properly connected with the pump and operated by competent personnel. Slow and medium-speed oil engines may be found very useful.

A pumping set will generally consist of (i.) prime mover, direct gear, or belt coupled to (ii.) pump with valves, strainer, suction piping and foot valves (iii.) starting gear for engine or motor, set of spanners, etc. Different classes of pumps will be required for delivery to tanks near the supply, hasty installations on pipe lines, deliberate installations for rest camps, etc., and pumping from deep wells. The variety of pumps suitable for each class is considerable. Men- tion, however, may suitably be made of the air lift pump, which, on account of its having no working parts below ground, and for several other reasons, is the most useful form of pump for military work. Such a pump can be mounted on a lorry and can go round a scries of wells, pumping from each the day's supply into an extemporized reservoir and then going on to the next. It is a device for raising water by compressed air introduced in a vertical tube connected with the rising main, either concentrically with that pipe, or in a separate tube parallel to it. The utility and efficiency of this device has been amply tested in war, and much attention and valuable experience has been devoted to the theory and practice of its use.

As regards pipe-laying, cast iron pipes, though ordinarily used in civil water supplies, with their lead joints are unsuitable for military work because of the relatively heavy weight as compared with steel tubes of the same diameter; also they are brittle and unsuited for rough handling, and the jointing takes more time than the screwing! up of steel tubes. The latter should, therefore, be invariably used in the field. As a rule they are not made of larger diameters than 6 in., but larger pipes can be obtained, and many miles of lo-in. and 12-in. pipes were put down in the Sinai peninsula in 1916. For most pur- poses wrought iron screwed and socketed piping is suitable; the British standard threads for the pipe ends should be insisted on, and the whole should be capable of standing a test of 300 Ib. per sq. in. (ogo-ft. head). If in mountainous country (as with the British in Italy, where heads of 2,000 and 4,000 ft. had to be negotiated), the pipes must be of the hydraulic type, with special joints.

Many special fittings are required with a pipe system, elbows, tees, crosses, etc., and many devices for control and delivery, such as valves, taps and stop cocks. The main point to remember is that 1 there is no economy in having inferior and cheap fittings, for the \vaste ; of water which follows their use costs far more than the extra cost of water and more reliable articles. (G. K. S. M.)

WATSON, JOHN CHRISTIAN (1867- ), Australian politician, was born at Valparaiso, Chile, April 9 1867, when his parents were on their way as emigrants to Australasia. He was educated at the public school of Oomaru, N.Z., and as a boyi began work as a compositor. He also made an early entrance into politics, attaching himself to the Labour party, which came into prominence during the great strike of Australian dock and trans- port workers. He was president of the Sydney Trades and, Labour Council in 1890. From 1894-1901 he was a member of| the N.S.W. Legislature, where he opposed plural voting andi inclined towards protection as a means for keeping up the white j man's wages. Consequently after federation, as a member of| the Commonwealth Parliament he gave his support to Sir Edmund Barton and Mr. Deakin and exacted in return legisla- tion in labour interests. For a short time in 1904, on the resigna- tion of Deakin, he formed a Labour Ministry, but resigned after a few months, though he continued to lead the Labour party until a tariff, of which he could approve, had been passed by Mr. Deakin in 1908. He then retired from public life.

WATSON, SIR WILLIAM (1858- ), English poet (see 28.414), was knighted in 1917. His later poems include The Heralds of the Dawn (1912); The Muse in Exile (1913); Retro- gression (1916); The Man Who Saw (1917) acd The Superhuman Antagonists (1919).

WATTERSON, HENRY (1840-1921), American journalist (see 28.418), was among the first to urge, in 1911, the nomination of Governor Woodrow Wilson as Democratic candidate for president. In Aug. 1918 he retired from active editorship of the Louisville (Ky.) Courier- Journal, remaining " editor emeritus." On March 2 1919 a special edition of this paper was published, containing tributes from his admirers throughout the world.