diffusion of drain-pipes over 150 square miles of country, and for a reservoir which should contain storage of water equivalent to a very long metropolitan consumption. The later examination, made by Mr. Napier and confirmed by others, tends and appears to show, that these large sources of expense may be avoided; that the waters may be collected of unusual purity and softness, where they have united themselves into rivulets of considerable volume; that the gauged and estimated discharge of these rivulets is sufficient day by day for the needs of the metropolis, according to the largest construction of those needs; that capillary drain-pipes and very extensive storage-room may thus be dispensed with; and that under the modification of arrangement suggested by these facts, some very large reduction might be inferred for the total estimate of this comprehensive plan. Many of these particulars are already before the public; but in a matter of so much importance to the health of the City, as that of participating in a supply of pure water, collected and distributed on the soundest principles, and sold at the cheapest rate, I did not think it would become me, as your Officer of Health, to remain an indolent auditor. I have felt it my duty to inform myself, so far as I could, on the real merits of this scheme, and on its probable relation hereafter to the sanitary condition of the metropolis. I have spent three days on the site of the proposed sources, and many other days in informing myself on all the bearings of the subject. I have likewise collected water from a proposed tributary of the future supply, which has been analysed, and which shows (as my Appendix will illustrate to you) a remarkable and rare excellence. On one occasion of visiting the country, I was accompanied by Mr. T. Taylor, and we made on the spot a sufficient number of extemporaneous examinations, to assure us that the essential features, shown in the more elaborate analysis, are (as geological considerations would lead us to believe) the general characters of water throughout the district. On any other than the sanitary relations of this subject I can have nothing officially to say; but, confining myself to these relations, I may certify to your Hon. Court that the water in question is, in my judgment, of a quality admirably suited for domestic purposes; that its distribution through the City of London would conduce to the health and comfort of the population; and that the principles, proposed by the Board for its collection and conveyance, appear to me such as sanitary science, in its present condition, should counsel for the water-service of the metropolis.