SUPPLY OF WATER. 



it unsuitable for cooking vegetables, owing to the 

 tendency of that salt to form an insoluble com- 

 pound with their legumine. In the brewing of 

 pale ale it is necessary to use water that is 

 permanently hard from the presence of sulphate 

 of lime ; but sweet ales and porters are produced 

 better from soft waters, as they extract a greater 

 amount of matter from the malt. It may be 

 stated generally, that for the purposes of washing 

 and cooking, a water of less than 6 is soft, but 

 above this point the hardness becomes objection- 

 able. At 8, the water is moderately hard ; at 12, 

 it is very hard ; at 16, the hardness is excessive ; 

 and much above this, it is intolerable. 



To make these observations more intelligible, 

 we may mention a few instances of known waters, 

 with their place in the scale. In Keswick, the 

 water is under half a degree of hardness ; in 

 Lancaster, it is i; and in Manchester, 2. The 

 water of the Dee at Aberdeen, which is used for 

 the supply of the town, is i of hardness. The 

 water of Loch Katrine is of remarkable purity, 

 having only two grains of solid matter of all kinds 

 in the gallon, and i of hardness. The waters of 

 the Welsh mountains, from which it was proposed 

 to supply London, have on an average less than 

 2. The river Clyde, which formerly supplied 

 Glasgow, is 4^, and may also be reckoned a soft 

 water. The Thames at London, as well as the 

 New River, is about 14, while many of the tribu- 

 taries of the Thames rise as high as 16 ; but 

 being all chalk-waters, they may be materially 

 softened by boiling. Springs from the chalk 

 commonly range from 16 to 18 ; but particular 

 springs are to be met with in some parts of the 

 world four or five times as hard, from the presence 

 of bicarbonate of lime. The water of the Treasury 

 pump in London has from 50 to 60 of hardness. 



Leadin Water. Injurious effects have frequently 

 arisen from the contamination of water with lead, 

 derived from leaden pipes and cisterns. Some 

 kinds of water are known to act powerfully on a 

 leaden surface, and others scarcely at all ; but the 

 qualities and circumstances on which the action 

 depends have never been satisfactorily determined. 

 Distilled water, and soft lake and river waters in 

 general, act most decidedly, but by no means in 

 proportion to their softness. The presence of air 

 in the water seems one essential condition, and 

 light also increases the action. The conditions 

 which determine the character of water as regards 

 its action on lead have hitherto been involved in 

 much obscurity, notwithstanding that they have 

 repeatedly been the subject of investigation. The 

 government Commission of 1851, on the water- 

 supply of the metropolis, established the fact, that 

 the presence of dissolved oxygen, and the ab- 

 sence (?) of more than 3 volumes of carbonic acid 

 in 100 volumes of water, are among the conditions 

 necessary to cause the water to attack lead. The 

 result of experiments on this subject proved that 

 the presence of a minute quantity of phosphoric 

 acid, such as could be got by momentary contact 

 with animal charcoal while passing through a filter 

 of that material, completely prevented the softest 

 water acting on lead, without at the same time 

 sensibly increasing its hardness. Even although 

 a soft water like that of Loch Katrine attacks lead 

 powerfully, both while in a bright and also in a 

 tarnished condition, it does not seem necessarily 

 to endanger the lives of the community who use 



it, as, although the process may go on consider- 

 ably at first, the protecting film which soon coats 

 the surface of the inside of pipes and cisterns 

 seems to prevent further attacks. This is known 

 to be the case at Manchester, where the water 

 acts slightly on new pipes ; but the action soon 

 ceases, and no evil effects are ever recorded as 

 resulting from its use. The reason why Loch 

 Katrine water acts on lead, and the water of St 

 Mary's Loch does not do so, although of very 

 nearly the same degree of hardness, is, that the 

 solution of peat or moss, to which it owes its 

 yellow tinge, has been discovered to have the 

 curious effect of preventing its action on lead. The 

 truth of this is easily tested by pouring distilled 

 water (which, in its pure condition, would attack 

 lead almost instantaneously) over a piece of peat ; 

 this water, after being left in contact with the peat 

 for a few hours, will be found not to act on lead in 

 the least. In experiments of this class, the bottle 

 containing the lead and water should not be com- 

 pletely closed, as the free ingress of air is necessary 

 to complete the test satisfactorily. Still, there are 

 opposing facts to shew that this protective action 

 is not always to be relied on ; and that water that 

 has passed through any considerable length of 

 lead pipe, or stood for some time in a short one, 

 or in a cistern, should never be used without care ; 

 a ninth part of a grain of lead per gallon has been 

 known to derange the health of a whole com- 

 munity. 



Organic Impurities. The contamination of 

 water by vegetable and animal substances takes 

 place in various ways. The most obvious and 

 abundant source of this class of ingredients is the 

 sewage and refuse of towns ; and next in order 

 may be ranked the contact with soils rich in 

 organic matter. Among organic impurities may 

 be classed offensive gases, such as carburetted, 

 sulphuretted, and phosphuretted hydrogen ; vege- 

 table fibres in a state of rottenness ; putrefying 

 products of the vegetable or animal kingdoms ; 

 starch, muscular fibre, &c. ; urea and ammoniacal 

 products ; vegetable forms algae, confervae, fungi, 

 &c. ; animalcules infusoria, entomostraceae, 

 annelidas or worms, &c. Water falling on a 

 growing soil, and running off the surface to lie in 

 stagnant ponds, is in very favourable circum- 

 stances for being tainted with vegetable and 

 animal life. The surface-water of a district over- 

 grown with peat-moss has usually a peaty flavour, 

 as well as a dark yellowish colour. The infusion 

 of peat does not breed animalcules, being a strong 

 antiseptic ; but it is an objectionable ingredient, 

 nevertheless. Lime removes the peat most effec- 

 tually, but there is both expense and risk in apply- 

 ing it If fine clay is mixed with peaty water, 

 shaken up, and allowed to settle, the yellow tint 

 disappears entirely, being carried down by the 

 particles of clay during subsidence. It is perhaps 

 doubtful whether any specific unwholesomeness 

 can be justly attributed to peat-water. The in- 

 habitants of Stornoway in Lewis, and Lerwick in 

 Shetland, have no other supply but that from a 

 peaty district, but no complaints are heard of 

 deterioration of health in consequence of its use. 



Chalk-water, which, as it issues from a spring, 

 is perfectly free from organic matter, has a source 

 of contamination within itself. When exposed to 

 light and air, the duplicate dose of carbonic 

 acid that keeps the chalk dissolved, becomes 



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