Why is hard water subject to become putrid, and generally turbid?

Because of the vegetable or animal matter which it contains; and from the suspension of earthy impurity; when drank, it is flat, from the absence of air. Brande.

Why does potash or soda render hard water soft?

Because a decomposition is thus effected, and the carbonate of lime, a very insoluble salt, precipitated. Why is hard water ill adapted for washing?

Because it contains sulphate of lime, which, by a double decomposition,separates the materials of soap Why is river water much softer and more free from air and earthy salts than spring water ?

Because river water, by the agitation of a long current, and in many cases an increase of temperature, loses both common air and carbonic acid, and, with the last much of the lime or magnesia which it formerly held in solution. The specific gravity hereby becomes less, the taste not so harsh and agreeable; and out of a hard spring, by mere exposure to the atmosphere or the action of the soil, is often made a stream of sufficient purity for most purposes where soft water is required. A. Booth.

Why is the Thames water of such extreme softness ? Because, from observations at and below London bridge, as far up as Kew and Oxford, it is supposed that the waters seldom change, being probably carried up and down with the turn of the tides for an indefinite period of time.

Why are the objections to Thames water removed by filtration?

Because its impurities have no influence in permanently altering the quality of the water, which is good; and, as they are only suspended, mere rest, especially such as is given by filtration, will restore the water to its original purity.

Why is water raised from beneath the surface of the earth by a pump?

Because the atmosphere presses equally upon the whole surface of the water in the well, until the rod of the pump is moved; but, by forcing the rod down, the bucket compresses the air in the lower part of the pump-tree, which, being elastic, forces its way out of the tree through the valve; so that, when the bucket is again raised, that part of the pump-tree under the bucket is void of air; and the weight of the atmosphere pressing upon the body of water in the well, forces up a column of water to supply its place; the next stroke of the pump-rod causes another column of water to rise; and so long as the bucket fits the pump tree close enough to produce a vacuum, a constant stream of water may be drawn from below.

Why are filtering stones usually made of porous freestone?

Because they are the nearest imitation of the natural process by which the purest waters rise through sand or siliceous rock.

Why is the temperature of cold springs in general pretty uniform?

Because they take their origin at some depth from the surface, and below the influence of the external atmosphere.

Why is the same spring water which appears warm in winter deemed cold in summer?

Because, though always of the same heat, it is in summer surrounded by warmer atmosphere and objects.

Why does not water freeze in pipes two or three feet under ground, when it is frozen in all the smaller branches above?

Because the earth conducts heat slowly, and the severest frosts penetrate but a few inches into it;

while the temperature of the ground a few feet below its surface is nearly the same all the world over. Why are leaden cisterns unsafe for holding water for culinary purposes?

Because, if the water has stood in them for several days undisturbed, a small coating of white rust may be seen at the upper edge of the water. On every fresh addition of water this rust is washed off; and, if there be the slightest degree of acidity in the vessel, the rust of lead will be dissolved in the water, and thus an insidious poison will be conveyed into the stomach. This rust, or oxyde, as it is chemically called, is produced by the lead combining with the oxygen of the water.

Why are water-pipes, bottles, &c, often burst by water freezing in them?

Because of the expansion of the particles of the water, which, when they crystallize and assume the solid state, unite by certain sides in preference to others, arranging themselves so as to require more space, and having numerous vacuities, the bulk of the whole must necessarily be enlarged.

Why is ice lighter than water?

Because of the air-bubbles produced in the ice while freezing.

Why is soda-water so called?

Because it contains, when well prepared, a very small portion of carbonate of soda, which corrects acidity in the stomach.

Why is soda-water from the fountain' inferior to

that sold in bottles?

Because the former is merely water impregnated with carbonic acid gas by a forcing pump, and consequently liable to be contaminated by copper, zinc, or lead, according to the vessels in which the condensation is carried on.

Why is it difficult to pour from a vessel which has not a projecting lip?

Because, in pouring water from a mug or bottle lip, the water does not at once fall perpendicularly, but runs down along the inclined outside of the vessel, chiefly in consequence of the attraction between this and the water.

ICE WELLS.

Why is ice broken before it is stored in wells?

Because it may reunite in the interior; in a long frost it diminishes considerably in bulk, as it forms itself into a compact mass, by freezing in the well. Why should ice be taken from the sides of the well, and the centre left till the last?

Because, if the ice is first taken from the middle, you disturb the body, and the air thus introduced will destroy more than you consume.

BOILING.

Why does water boil in a vessel on a fire?

Because the parts of the liquid next the fire get heated, and rise up through the colder parts which are heavier; and this is found to be the principal manner of communicating heat to all parts of a liquid for, if the heat is applied at the top, it can only with great difficulty be conducted through the liquid either sideways or downwards; but when applied below, the parts, as they are heated, become enlarged and lighter; they rise to the top, and heat the others in their progress, while those others, being still somewhat heavier, sink down, and are heated fully in their turn. By degrees, the whole liquid gets so hot that the parts next the bottom are converted into steam or vapour, which rises through the rest of the liquid in bubbles to the top, and there flies off till the whole liquid is evaporated.

Why does the spout of a kettle emit a thick cloud or vapour?

Because the steam from the water is then cooled according to its distance from the spout; whereas steam is so transparent as hardly to be seen near the mouth.

Why should a tea-kettle be removed from the fire when the steam from it appears cloudy?

Because the water is then beginning to be condensed, the steam when the water first boils being perfectly transparent.

Why does a kettle containing water, boiling on a fire, in part resemble a still?

Because the water at the bottom of the kettle, or next the source of heat, combines with heat, and forms vapour, which is discharged from the spout in steam. By fixing a long tube of glass or metal to the spout, the steam will be condensed, and drops of water will run from the other end. But the tube which corresponds with the worm in the still, becoming as hot as the steam, it can abstract no more heat, and then the condensation ceases. Hence the necessity of keeping the tube cool, which may be done by its passing through cold water. Thus, the whole water in the kettle may be boiled away, but reproduced in the tubes, and collected from it without the loss of a drop. This process is not only the principle, but very nearly the practice of distillation, as it is called, and the simple apparatus here described is nearly the model of a still. Donovan.

Why should the bottom of a tea-kettle be black, and the top polished?

Because the bottom has to absorb heat, which is aided by rough and blackened surfaces; and the top has to retain heat, which is ensured by polished ones.

Why is a crust so frequently seen on the insides of tea-kettles and boilers?

Because of the hard water boiled in them, which