1. A daily average of 1 gallon per man is sufficient for drinking and cooking purposes. A horse, bullock, or mule drinks about 11 gallons at a time. standing up, an average allowance of 5 gallons should be given for a man, and 10 gallons for a horse or a camel. An elephant drinks 25 gallons, each mule or ox drinks 6 to 8 gallons, each sheep or pig 6 to 8 pints. These are minimum quantities.
One cubic foot of water = 6 gallons (a gallon = 10 lbs.).
2. The rough average yield of a stream may be measured is follows :- select some 12 or 15 yards of the stream where the channel is fairly uniform and there are no eddies. Take the breadth and average depth feet in three or four places. Drop in a chip of wood and find the time it takes to travel, say 30 feet. Thus obtain the surface velocity in feet per second. Four fifths of this will give the mean velocity, and this multiplied by the sectional area will give the yield per second in cubic feet of water.
PURITY OF WATER.
3. As the health of a force depends largely on the purity of the water provided, everything possible must be done to ensure an ample supply of pure drinking water, and to keep it pure when obtained. It is mainly through drinking impure or contaminated water that cholera, dysentery, and enteric fever are contracted and spread. The water supply will always be selected in conjunction with the sanitary or other medical officer, who will satisfy himself as to its fitness for use. No water should he used for drinking purposes that has not been sterilized by filtration, by heating, or by chemical means.
4. Men must be prevented from drinking water from unauthorized sources, and they must he trained to economize the contents of their water bottles, which, before marching, should be filled with weak tea or sterilized water. Bad water drunk on an empty stomach is more dangerous than that drunk with a meal. Thirst is best assuaged by first moistening the lips and mouth, and only drinking a small quantity at a time. Large draughts of water should never be taken, as thirst is only increased thereby, and, if taken when the body is over-heated, bad effects may follow.
5. Muddy water should be cleared of suspended matter before being boiled or filtered. The following methods may be used:-
(a) Alum (5 grains to the gallon, or 1 ounce, equal to a heaped up table-spoonful, to 100 gallons) is stirred into the water and allowed to stand. This hastens the deposit of the suspended matter.
(b) Tack a sheet on to a wooden frame so as to form a bag or basin put a couple of handfuls of wood ashes in the bottom and then pour on the water, placing a receptacle beneath to catch the water which percolates through.
(c) Take 2 casks and place one inside the other, the outer cask pierced with holes at the bottom and the inner near the top; the space between is filled with sand or gravel; when these are placed in a stream, the water rises through the filtering material between the barrels and flows into the inner one.
6. Filtration aims at purifying water by holding back suspended matter, including germs. The filter usually provided is the filter water tank; this will give about 200 gallons of filtered water in an hour. Another, the portable filter, capable of being carried on a pack saddle, will filter 60 gallons an hour. The filter candles should be boiled in water every fourth day.
7. There are two ways of killing germs in water, viz., by heat and by chemicals. Purification of water by heat can be scoured by either-
(1) Boiling in an open vessel, in which case it will be sufficient to bring the water to
the boiling point; or
(2) Heating in a special sterilizer, such as the "Griffith". The small type of these machines will sterilize 60 gallons an hour, the larger type, 350 gallons in an hour. The average consumption of fuel for each is a gallon of oil for each 400 gallons of water.
The chemical substance chiefly employed for sterilizing water is chloride of lime. This is employed as follows :- take a teaspoonful of bleaching powder (chloride of lime containing about one-third available chlorine) and remove the excess of powder by rolling a pencil along the top of the spoon. Dissolve the bleaching powder in a cupful of water, making sure that all lumps am thoroughly broken up, and then add three more cupfuls of water to the solution. Stir up the mixture, allow it to stand for a few seconds to let any particles settle (this stock solution, if kept tightly stoppered, may be used for 4 to 6 days) and add one spoonful of this milky solution to 2 gallons of the water to be purified. Stir thoroughly and allow to stand for 10 minutes. This will give one-half part of free chlorine to 1,000,000 parts of water; 1 lb. chloride is sufficient for 66,000 gallons.
Note.-Bleaching powder (chloride of lime) deteriorates rapidly when kept in cardboard packages or exposed to air.
8. Vessels or tanks in which drinking-water is stored, as well as being carefully covered, should be raised off the ground and provided with taps. Water-carts and barrels require frequent cleaning and periodical disinfection.
To clean water receptacles, dissolve 1 teaspoonful of permanganate of potash crystals in 3 gallons of water and rinse with this solution until a permanent pink colour remains.
9. Posts on the lines of communication should arrange to have enough sterilized water on hand to supply the wants of detachments passing through.
10. As a rule the military police, otherwise the first troops to arrive at a halting ground, will mount sentries on a1l water likely to he required for use., with such orders as will prevent any form of pollution. These sentries will not be withdrawn until permanent water guards are detailed.
11. The water supply should usually be marked with flags, as follows, by the advanced party of engineers:-
White for drinking-water.
Blue for watering places for animals.
Red for washing or bathing places.
12. If water is obtained from a stream, horses will he watered below the place where troops obtain their drinking-water, but above bathing and places. Patrolling by mounted men will often be necessary for some distance above the spot where the drinking water is drawn.
13. If running water is not available, the supply must be very strictly protected, a rough barbed wire fence, if procurable, being run round it to keep animals out. Animals should, in this case, be watered by bucket or nosebag; and washing should be allowed only at some distance from the water supply, empty biscuit tins or other receptacles being used to draw water for this purpose.
Similar precautions are often necessary with running water if other bodies of troops are halted lower down the stream.
14. If many animals have to be watered and the frontage is small, times should be laid down for each corps to water. Five minutes may be taken as the average time for watering an animal.
An officer will invariably accompany watering parties of more than 20 animals .
15. A field squadron carries 1 lift and force pump per troop and a field company 1 per section, with suction and delivery hose. A lift and force pump can supply600 gallons per hour at a combined lift and force of 60 feet, with 4 men at work, but twice that amount with 2 or 3 men if the height to which the water to be raised is small.
The following gear is carried for tapping water mains: field squadron: 2 sets, field company, 1 set.
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