Were it therefore possible that means could be devised by which the quantity of water necessary for the daily supply of London could be deprived of its excess of earthy carbonates in a manner sufficiently economic, comprehensive, and effectual, the citizens of the metropolis would enjoy the advantage of a tolerably pure soft water, free from those inconveniences which attend the use of the present hard-water supply. Confining myself wholly to a chemical view of the subject, the principal disadvantages attending the use of hard river waters are-- First, The precipitation of earthy matter on the inside of vessels in which the water is heated. This furring of the vessel, as it is called, leads to its more rapid destruction, and has also the inconvenience of rendering it more difficult to cleanse, so that the flavour and odour of the various substances cooked in it are not readily removed. From the non-conducting power of the earthy crust, an increased consumption of fuel is also required for the due heating of the vessel. Secondly, The admixture of the earthy salts with the various articles of food submitted to the action of hot water. Thirdly, Diminished solvent power, as required for the purposes of the chemist, the brewer, and for many domestic purposes, as in the making of tea, soups, &c. Fourthly, Diminished cleansing power, both as regards the direct solvent action of the water, and also as causing the decomposition of soap, and consequent increased consumption of that article. I must, however, remark that the annual loss reported to arise from this cause appears to me considerably overrated, since water is rarely used for the washing of linen until previously boiled, and the common practice of adding carbonate of soda to the water completely destroys the ill effects resulting from the hardness of the water. The additional expense of the carbonate of soda, thus added, is too trifling to merit notice; but when this salt is used in excess, as is generally the case, it produces the more serious evil of materially impairing the strength of the fabric submitted to its action. The only real advantage which hard water possesses over soft (and in the present state of things one of considerable importance), is, that it does not act upon or erode the lead of the pipes and cisterns in which it is contained. There are also some particular cases of minor importance in which hard water is preferred; thus dyers prefer hard water for rinsing of their goods, soft water extracting too much of the colour; but these cases are comparatively rare, and might be easily accomplished by an artificial hardening of the water.