Potable water

“ That in time of flood a large proportion, both of the suspended and dissolved filth, is conveyed down to the intakes, and in ordinary weather considerable portion of soluble organic matter makes its way to the pumping works, and is still present in the water distributed to the consumers. ”

“ HOW TO MAKE A FILTER. For drinking, and for all ordinary purposes, it is of the greatest importance that water should be as pure as possible. When water which is nearly soft, and wholly free from organic impurities, cannot be obtained from wells or springs, filtered rain water should be employed. ”

“ WaterWater helps to regulate the concentration of the minerals in the body and carries food to the tissues by holding the food materials in solution in the body fluids. It also is invaluable in helping to carry off the body’s wastes and assists in regulating the body temperature. Four to eight glasses of pure water every day make for health. ”

“ The filtration of water may now be considered. The water of our wells is presented by nature ready filtered to the hand of man, and often exhibits an admirable degree of transparency and purity. It acquires this state by percolating through the mineral strata of the earth, which deprives it of the organic matter it derives from the soil and subsoil, but, at the same time, it dissolves a portion of the saline and earthy media through which it passes, and hence acquires that peculiar ‘hardness’ which is constantly found in spring water. ”

“ But it is plain that no river sinks from sight unless it finds porous or honeycombed rocks that let it through. The water seeks the nearest and easiest route to the sea. Its weight presses toward the lowest level, always. The more water absorbs of acid, the more powerfully does it attack and carry away the substance of lime rocks through which it passes. ”

“ Such a salt-water saucer of fresh water is maintained full to overflowing by the rainfall, and owing to the frictional resistance of the sand and to capillary action and the fact that a given column of fresh water is balanced by a shorter column of sea water, the fresh water never sinks to the mean sea-level unless artificially abstracted. ”

“ For the most widespread use, the most desirable water is a cold water as free from mineral content as possible, and especially one lacking an excess of lime and magnesia which make it hard; also lacking an excess of acid constituents like sulphur dioxide, carbon dioxide, or chlorine, which give the water a taste, or which make impossible its use in boilers. ”

“ In a very small pond or tank the quantity of this kind of work is soon appreciable, and if we reflect on the amazing amount of water all over the globe, including seas and oceans, which swarm with infusoria, the total effect produced in a single year must seem considerable, even when compared with that portion of the earth's crust that is subject to alteration from all other causes put together. ”

“ Put any measured quantity of the water into a platina, or silver evaporating basin, the weight of which is known, and evaporate the water upon a steam bath, at a temperature of about 180°, nearly to dryness; and, lastly, remove the basin to a sand bath, and let the mass be evaporated to perfect dryness. The weight of the platina basin being already known, we have only to weigh it carefully. When the solid saline contents of the water is attached to it, the increase of weight gives the quantity of solid matter contained in a given quantity of the water. ”

“ Aqua Pluvialis, when collected in the open fields, is certainly the purest natural water, and consequently of the least specific gravity; the bodies which it holds in solution are, carbonic acid, a minute portion of carbonate of lime, with traces of muriate of lime. Dew is said to be water saturated with air. Rain water ought, however, to be boiled and strained whenever it is collected near large towns; Hippocrates gives this advice, and M. Margraaf of Berlin has shewn the wisdom of the precaution by a satisfactory series of experiments. ”

“ River-water is in general purer than spring-water; as the neutral salts washed down from the earth decompose each other, except perhaps the marine salt; and the earths, with which spring-water frequently abounds, is precipitated; yet it is not improbable, that the calcareous earth dissolved in the water of many springs may contribute to our nourishment, as the water from springs, which contain earth, is said to conduce to enrich those lands, which are flooded with it, more than river water. ”

“ The water begins to get salt when the evaporation from the lake exceeds the inflow. The inflowing waters bring in a small amount of saline and alkaline matter, which becomes more and more concentrated as the evaporation increases. ”

“ Hence we see the Benefit of frequently replenishing the Water with fresh Air, which we find is necessary not only to preserve the Life of [Pg 72] Land Animals, but also of Fish; as also the Use of their Gills, to spread in thin Sheets fresh Supplies of Water, that they may the better come at the Air in the Water; for which Purpose both Sides of their Gills are furrowed with many fine Furrows, not only thereby to enlarge their Surfaces, but also more minutely to divide the Water, whereby to come at the Air in it. ”

“ The common methods of rendering water clear by filtration, or soft, by exposing it to the sun and air, &c. are so generally known, that it is unnecessary to spend time in explaining them. We shall only, in general, advise all to avoid waters which stagnate long in small lakes, ponds, or the like, as such waters often become putrid, by the corruption of animal and vegetable bodies with which they abound. ”

“ We know the difficulty we have to procure good drinking water, and though it may be filtered, there will remain natural salts, which are found in different degrees in all water upon the globe. We know the rain, which is perfectly [Pg 604] pure when condensed from the clouds, absorbs carbonic acid, etc., from the atmosphere. We have shown how this water as soon as it comes upon the earth attacks the rocks, and as it progresses carries away lime. ”

“ Chapters three and four deal with the artificial and natural purification of water. These are the most important portions of the book to the engineer and taxpayer, taking up the question of water supply in its economic and commercial aspects, both as regards the general town supply and also in reference to individual household filtration. The physical forces and forms with which we have to reckon are next considered under Rain, Ice, Snow, and River and Stream Water. ”

“ The rain, which is pure water, except for the little particles of various things floating in the air which it brings down with it, soaks into the ground, forming springs, and helps to swell the ponds and lakes and rivers, and so it gets mineral and other substances in it again, especially salt, which is found in small quantities in all spring-water, and this impure water is carried to the ocean again to be purified ”

“ Hard water will become thick and foul sooner than soft water.
139. To purify Water for drinking.—Filter river water through a sponge, more or less compressed, instead of stone or sand, by which the water is not only rendered more clear, but wholesome; for sand is insensibly dissolved by the water, so that in four or five years it will have lost a fifth part of its weight. Powder of charcoal should be added to the sponge when the water is foul, or fetid. Those who examine the large quantity of terrene matter on the inside of tea-kettles will be convinced all water should be boiled before drunk. ”

“ The constituent parts of pure water, in volumes, are two parts of hydrogen and one of oxygen, and by weight one part hydrogen and eight parts oxygen. When pure it is transparent, tasteless, inodorous, and colorless, except when seen in considerable depths. But having such high solvent powers and affinity for almost every substance in nature, one can account for suspicions that science places on all waters, for it is never free from impurities. And well it may not, if doctors are to be believed, for they tell us, that chemically pure water is not best for man ”

“ All waters which have been in contact with the soil dissolve out of it numerous inorganic and organic substances. Waters are described as hard or soft, hardness being the popular expression for the property of not easily forming a lather with soap. It is due to the presence of salts of lime and magnesia. Hard waters, if their hardness be not excessive, are agreeable and wholesome for drinking, but not well adapted for laundry or bathing purposes. They tend to harden vegetables cooked in them, and do not make as good tea as soft water. ”

“ The tide flows up the river many miles past the waterworks, carrying up with it the filth from the sewers. The supply of water was, to be sure, obtained when the tide was down, but as the banks of the river are clothed with sedges in many parts, and its bottom deep with mud, the water can never be free from sewage. ”

“ Can you imagine these water-particles, just above any pond or lake, rising up and getting entangled among the air-atoms? They are very light, much lighter than the atmosphere; and so, when a great many of them are spread about in the air which lies just over the pond, they make it much lighter than the layer of air above, and so help it to rise, while the heavier layer of air comes down ready to take up more vapour. ”

“ While if the land be so water-logged that the level at which water can be obtained by digging is brought near to the surface, the water containing salts from below is drawn upwards by means of capillary attraction, and once more evaporation takes place, leaving the salts in the soil. ”

“ When the receiver is full of the sand, sea water is poured on the top, and this, in its way down, carries with it the salt left by evaporation. When it runs out below at a small hole, it is a very strong brine ”

“ The consequence of the ancient evaporation, by which the great Pleistocene lake was reduced to its present modest dimensions, and of the ceaseless modern daily evaporation, is the impregnation of the waters of the lake with salts and other mineral substances to a remarkable degree. Ocean water contains on an average 4-6% of salts: Dead Sea water contains 25%. ”

“ Multiplying in myriads, and being too small and weak to resist the elements, they are constantly swept about in currents of water or air, and in the moisture on the surfaces of moving animals, etc. Well-authenticated observations show that with the evaporation of ponds and other waters containing swarms of these little animals, many encyst themselves within delicate capsules formed of an exudation, which hardens the body-surface ”

“ In considering the principles of well supplies it is important to bear the following facts in mind. The crust of the earth, so far as it is permeable and above the sea-level, receives from rainfall its supply of fresh water. That supply, so far as it is not evaporated or absorbed by vegetation, passes away by the streams or rivers, or sinks into the ground. If the strata were uniformly porous the water would lie in the rock at different depths below the surface according to the previous quantity and distribution of the rainfall. ”

“ The evidence of the action which takes place in the absorption of oxygen from the atmosphere by salt water and its effect on dissolved sewage solids is conflicting, but in general fresh water is a better diluting medium than salt water. ”

“ Water, in the chemical meaning of the word, is a liquid composed only of hydrogen and oxygen, and leaving no residue when evaporated. Such water is not found in nature; it can only be obtained by distillation of well or river water. The water which falls in long continued rain, or is obtained by melting snow, is most nearly like distilled water; it contains only small quantities of dissolved substances, and generally such as would be without influence in colour making. ”

“ We have seen, that evaporation proceeds much more rapidly from a surface of water, as a pond or river, than from a land surface, unless it be fully saturated, and that evaporation from the water exceeds the whole amount of rain, about as much as evaporation from the land falls short of the amount of rain. ”

“ The great beds of salt, deep in the earth, are usually accumulations left there by water that is drawn from brine lakes, from which the liberated water often escaped as pure spring water at the surface of the earth. It does not escape by evaporation, at least not until it reaches the earth's surface. ”

“ Rain-water, collected at a distance from towns and upon surfaces kept clean, is next in purity to that of deep wells; that collected from roofs and stored in underground tanks is rarely good enough for dietetic purposes. ”

“ There is no outlet above ground, no stream flowing from it, and it is, of course, a stagnant water, with no other circulation than than which springs from the changes in temperature and from the gas and petroleum that are constantly rising through the pool. ”

“ For first, the most excellent Governour, by His Divine Providence, hath most wisely ordained and appointed, that a salt water of this kind, which men could in no wise be without, should break forth out of the Earth, and it is thus effected: The Sea-water every where passing through the passages and clefts of the Earth, in some places is dried up by the Central fire, and coagulated into hard and great pieces, which being digged up by men, and dissolved by the help of Water, and freed from its fæces, is boiled up in fit Vessels, and reduced into a pure Salt. ”

“ When the ground water is at the low mark the shallow well becomes dry; as the water rises it flows into the well. When the water has reached the high mark the intermittent spring becomes a flowing spring. The pressure of the ground water is great enough to produce flowing wells down on the level.
Not all wells, by any means, will furnish a pure water supply. There are many factors to consider from the viewpoint of the pollution of well water and these will be considered in due time. When water reaches an impervious strata it remains at that level and moves in a horizontal plane. ”