Now publishing in Weekly Numbers, at 14d. each; in Monthly Parts, at 7d.; THESE Papers are mainly addressed to that numerous class whose minds have been educated by the improved schooling, and the popular lectures and publications, of the last twenty years, and who may now be presumed to crave a higher kind of Literature than can be obtained through the existing cheap periodicals. They will embrace History, Archæology, Biography, Science, the Industrial and Fine Arts, the leading topics in Social Economy, together with Criticism, Fiction, Personal Narrative, and other branches of Elegant Literature. The series will thus com- prehend the usual field of the Quarterly Reviews and higher-class Magazines, while its period of publication and price must render it Title and Contents to Vols. I. II. III. IV. V. and VI. may be had of the Booksellers, W ATER, in consequence of its intimate connection with so many of the tastes, conveniences, and necessities of life, becomes a subject of universal and never-failing interest. Its position in the landscape as sea, lake, and running stream, affects the sense of beauty; to the eye of the naturalist engaged in classifying and describing the contents of the globe, it is a substance having numerous properties and relations; it is a grand example of the mechanical laws and gravitating power impressed upon all material things; and as an agent in the economy of the world, it enters largely into the operations of production and change. It is the highway of the world, the cheap defence of nations, the boundary of possessions, the element of existence to an immense living population. Lastly, it is an indispensable requisite and manifold convenience of the every-day life of human beings: alike to the uncivilised and civilised, to the roaming tribes of the wild, and the settled inhabitants of our crowded cities. The uses of water in daily life lead to the adoption of means for providing it in proper quantity, quality, and readiness to every place of human habitation; and among the various arts that make up our civilisation, this has a leading position of importance. Of late years, great improvements have been introduced into the department of the public water supply, and efforts continue to be made towards still farther improvements. Our object in the present Paper is to touch upon the chief points of information connected with the sources and qualities of water, and the public arrangements for the supply of town populationsrestricting ourselves solely to the condition and requirements of our own country. No. 49. VOL. VII. 1 SOURCES OF WATER SUPPLY. The great masses of liquid constituting the seas and oceans of the globe, are unfit for many of the purposes of water, on account of the excess of soluble matter they contain, dissolved out of the solid crust of the earth, and concentrated by the evaporation of ages. Sea water, besides its principal ingredient, common salt, contains salts of lime and magnesia in considerable amount, and cannot be used for drinking, cooking, or washing. But the process of evaporation or distillation constantly going on over the whole liquid surface of our planet, yields to the atmosphere a pure supply-and this descending as rain, may be collected in situations where it is not permitted to acquire the disqualifying ingredients of the ocean liquor. Sometimes a water contracts impurities at one part of its course, and is freed of them at another part: the connection with the solid earth is not wholly a cause of deterioration. The chief sources of supply may be described as surface-collection, rivers, and springs: Surface Collection. Water descending in rain may be ranked as a species of distilled water, and if collected on clean surfaces, it will be the purest which nature can supply. In its descent through the atmosphere, it brings with it a quantity of common air, together with any other gases that may be afloat, and also the fine particles of dust raised by the wind, and continually present in the lower stratum of the aërial ocean. A certain small amount of impurity is thus contracted before it reaches the ground; but what is of still more consequence, water in this condition has an intense attraction for the saline and other soluble matters which it finds on the surface. What are termed organic impurities, or the corrupting ingredients derived from vegetable and animal bodies, living or dead, are taken up in large quantities by rain water, so that a very short time suffices to taint the fresh-fallen shower. Hence the water caught on house-tops, although admirably adapted for washing, is not usually pleasant for drinking: part of the unfitness, however, arises from its wanting the proper degree of coolness. Rain water collected on shipboard is noted for its tendency to rapid putrefaction. Surface water, therefore, with its freedom from saline ingredients, has the disadvantage of possessing a strong affinity for organic impurities, these being diffused over every surface in the neighbourhood of living beings. But surface water, considered as a source of supply, is not the same as the rain water gathered from house-tops. If we resort to a barren district of rock or sand, destitute of vegetation, and remote from the pollution of towns, we may obtain water such that, notwithstanding the solvent power of the fresh-fallen rain, hardly any organic impurity has entered into its composition. Accordingly, water in this condition may be a highly proper source of supply. It cannot be said of any surface beforehand that it is eligible as a collecting-ground; very careful examination of the water actually collected, especially in the hot months of summer and autumn, is required to determine this point. The grand advantage of this mode of supply is the absence of salts in solution, rendering the water soft in respect of washing, and free from any peculiar taste of soda, magnesia, iron, or other mineral impregnation. The disadvantages are-first and principally, the presence of organic impurities; next, the necessity of impounding reservoirs so large as not only to secure that the excess of the wet months may avail for the deficiency of the dry months, but even that the excess of a wet year may be transferred for the supply of an unusually dry year; and lastly, the impossibility of obtaining water sufficiently cool for drinking in the warm season. Notwithstanding these general defects, it happens in various places that a surface supply is the best that can be had, and is, on the whole, satisfactory. Rivers. The water obtained from running streams is in part what has flowed immediately from the surface, and in part the water of springs, shallow or deep. In any case, a considerable amount of contact with the ground has been permitted, and in consequence saline matter is liable to be dissolved in a greater or less degree. The extent of the impregnation, as well as the kind of material dissolved, will depend on the rocks and strata of the river basin. Water flowing from granite rock, as the river Dee in Aberdeenshire, has a very small quantity of dissolved salts. Slate formations are also favourable to the purity of the water flowing over them. Sandstone is very inferior in this respect, while the limestone and chalk covering large districts of the country impart a nearly constant amount of lime-salt to all the running streams. The lime is not unfrequently accompanied by magnesia; and when this last substance is present in great quantity, it marks out a distinct and peculiar species of water. River waters, besides the qualities they derive from their primitive sources, are apt to contain mud and matters in suspension, and are thus deficient in the clearness and transparency so essential to the satisfaction of the eye in a drinking water. The agitation which a running river undergoes prevents stagnation and such decay of organic matter, sometimes with an offensive smell, as occurs in canals; but it also deprives the water of some air and free carbonic acid, which renders it, according to the opinion of many, less fresh to the taste. Moreover, the water partakes of the extremes of summer and winter temperature, and in the hot months can hardly be free of organic impurities and insects. But, on the other hand, the supply from one of our large rivers is boundless and unfailing; and it conveys the surface drainage and spring effusions of a large tract of country without incurring any trouble or expense as to the original sources. With far more of mineral impurity than surface water, river water will usually present less of vegetable and animal impurity, in consequence of the tendency of the mineral impurity to increase, while the organic impurities diminish, by time and exposure. Springs. When water falling on the surface of the ground sinks into the soil, descending downward by slow percolation till it encounters an impervious bottom, and rises up at some convenient opening by the force of hydrostatic pressure, the outgush is called a spring. Beds of sand and gravel, as well as the surface-coating of soil, allow a free passage to water; but its course |