accompanied by a surplus of water or by corresponding reduction in the working expenses of the supply.

With respect to the first proposition, that the prevention of waste is or may be accompanied by vast sanitary benefits, arising from the more efficient action of existing drains, as well as from the dryness of the subsoil of dwellings, I would call attention to the very prevalent notion that a town cannot have too much water, and that all the water which can be passed into the mains should, if possible, be given to it, as it is conducive to cleanliness, and as the sewers require it. The prevention of waste is assumed to be equivalent to stinting the supply, when in reality it may have the contrary effect. Take the common case of a town demanding twentyfive gallons per head per day for domestic purposes. Now, ten gallons per head per day is probably the maximum quantity actually used for such purposes. Of the remaining fifteen gallons a large proportion is lost by defective fittings and misuse, and flows down a few isolated drains to the sewers. But the maximum waste due to this cause considerably exceeds the average, and it exists where the pressure on the mains is greatest, viz., in the lower parts of the town, so that the greater part of such waste water enters the sewers near their outfalls, where it is useless; while at their upper ends, where water is most required, the supply to the sewers from this cause is trifling. Among the sewers of a town many are, or ought to be, permanently self-cleansing, and without entering upon the consideration of the various circumstances which conduce to so desirable a condition, I may say that all sewers which are not self-cleansing, with the reasons why they are not self-cleansing, should be systematically tabulated, and if want of water be the cause,

which is certainly not always, and, I think, not usually so, the cure is very simple when you have a surplus of water, formerly wasted, to use for this most beneficial purpose.

Imagine the influence on a single system of sewers, if only a quarter of a gallon per head per day of the population whose drains fall into it were used for flushing that system.

I will give, as an example, a single existing case, and in most towns there are many cases more striking. The sewer system to which I refer carries away the refuse of 52,000 persons. There are in it about 250 dead ends of branch sewers, of which probably 100 require artificial flushing to keep them absolutely free from deposit. A quarter of a gallon per head per day will give 4,000 gallons for each of those sewer ends every month, a quantity which—whether flushing direct from the mains, or the tank system, which is by far the best, be adopted — is more than ought ever to be used. It would in short fill a 3-foot by 1 foot 10 inch sewer to the crown for 145 feet of its length.

But the private drains also require flushing. It is certain that the dribble of waste water will never flush them; the small pipes of ordinary water-closets kept running all night will never do it; but the regulating cistern, delivering its two gallons through a 14-inch pipe, will do it most effectually, and that cistern will help you greatly in your work.

Of course there are other private drains, but the dribble of waste water, if it exists, is no advantage to them.

I have spoken of the proportion of the lost 15 gallons due to defective fittings and misuse, and I now come to the remainder of that quantity which leaks from innumerable defects in public and private service pipes. This water sinks into the subsoil; it renders healthy soils unhealthy; it makes the houses damp, and certainly militates against the cleanliness of the lower orders; but its influence for harm does not end here; part of it reaches the sewers, and even though it may get into them it can only do so by damaging the brick-work and mortar. The second proposition and its corollary is to the effect that the prevention of waste by the system hereafter described is practicable, and that it is, apart

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from all sanitary considerations, by far the most economical mode that can be resorted to for increasing available water supply, while it will always diminish the working expenses in case of supply by pumping from wells; while towns and districts at present supplied on the intermittent system, when the total supply is more than sufficient to meet the necessities of the people, which is the case when more than ten to fifteen gallons per head per day is taken for domestic purposes, may obtain constant supply, accompanied by a surplus of water, or by a corresponding reduction in the working expenses of the supply. I think I may satisfy you as to the truth of this statement by giving an example of the cost of the work in a district of Liverpool where the consumption was 20 per cent. below the average before the prevention of waste under the new system was commenced, and the pipes in which, being very old, required in a great number of instances to be entirely renewed. Add to this the fact that the corporation relaid at their own cost all defective private service pipes not within the dwellings, and you can understand that I have good grounds for saying that while the saving was a minimum, the cost was a maximum. The district in question contains 31,000 persons; the saving of water between former constant and present constant supply was 21.38 gallons per head per day, and between former intermittent and present constant 7.42 gallons per head per day; and the saving of water between former and present constant service was obtained at a cost to the corporation of less than a farthing per 1,000 gallons. In districts containing a better class of property the saving is often greater while the work to be performed in obtaining that saving is far less. When we consider this in connection with the fact that water obtained from new works usually costs 5d. or 6d. per 1,000 gallons, we must admit the last proposition as an established fact.

The inducements to undertake systematically the preven

tion of waste have been laid before you in what appear to me their most striking aspects; but to those who have taken up the subject in practice many other important features, which I am unable to consider in a short paper, suggest themselves. I will, therefore, at once describe to you the method by which the prevention of waste and restoration of constant service is being rapidly carried on in Liverpool.

I believe a suggestion to place meters upon water mains has been made in former times; but it remained for Mr. J. H. Wilson, the chairman of the Liverpool Water Committee, to propose the systematic adoption of the plan, and to see it carried out with the most complete success, and with results far surpassing anything that could be anticipated.

The system I now practise, and the reasons for it, may be better explained if I premise that the piston meters at first used, and which were placed upon the 3 and 4 inch service mains, indicated the necessity for obtaining not merely the total consumption for the twenty-four hours, but the minimum consumption during the night, and, if possible, the consumption at short intervals during the whole twenty-four hours. It is evident that such results could only be obtained from the ordinary meters by constantly watching and even counting the strokes. A short experience of the system, notwithstanding its great success, showed the enormous advantages which would accrue from the use of a meter so arranged as to draw a diagram representing graphically the exact quantity of water flowing through any main at every instant during the twenty-four hours. The great cost and wear and tear of all meters which I have tried was an additional incentive in my endeavors to produce such an instrument.

The best form of the waste-water meter may be described as follows:

It consists essentially of a vertical tube lined with brass,

and equal in diameter at the upper end, where it is connected with the inlet from the main to the diameter of that main, but larger at its lower end. In the tube is a horizontal disc of the same diameter as the main, with a vertical spindle on the centre of its upper face, from the end of which the disc is hung by a fine wire passing out at the top of the tube through a brass gland; this wire is connected above with a counter balance weight which, when the water is at rest, retains the disc at the top of the tube, which it completely fills.

It is obvious, then, that if water is caused to flow through the instrument, the disc will find somewhere in the tube a position which it will retain until the velocity of the water changes. The lower end of the conical tube being about double the area of the main, no obstruction to the flow can take place, such as must necessarily be the case in all piston meters, while the motion for any given increment of velocity near the top, or place of minimum flow, can be made equal to or even greater than that due to an equal increment at the bottom or point of maximum flow, so that its senitiveness it not diminished at low velocities, a feature which is unattainable in any meters constructed on the turbine or analogous principles.

In order to insure the absence of any friction sufficiently great to prevent the disc and wire from reaching the exact point at which they would stand if perfectly free during the continuance of each particular velocity, I found it desirable to abandon the use of a stuffing-box, properly so called, and to substitute a single brass gland, the hole in which fits the wire accurately, but not tightly. This wire, being an alloy of iridium and platinum, maintains its condition for any length of time, and the small quantity of water which oozes past it is allowed to drain away.

The absolute accuracy and freedom with which the meter acts has been proved by the strictest tests. The vertical