PLUMBERS are so partial to water, that however deficient they may be in other branches of plumbing knowledge, they ought not to be deficient in the knowledge of water and its storage. As I have said in "Dulce Domum," I believe "many illnesses which are now put down solely to bad drainage would, if it were possible to ascertain the actual facts, be attributable to the bad state of the water." Although analysts, like doctors, disagree, the plumber should not trust to his own opinion of a water; but, in all doubtful waters, he should throw the responsibility of determining the wholesomeness - the fitness or unfitness - of a water upon a public or duly qualified analyst, to whom samples should be sent (in Winchester quarts) for analyzing.
2. As a supply of water cannot at all times be relied upon, even where there is a "constant supply" from the water company's main, a sufficient storage should be provided to meet the requirements of the household during the longest time the water would be likely to be turned off. This inconstancy would generally depend upon circumstances - upon the source of the supply, the state of the mains, and the resources of the authorities, and also upon the locality and the altitude of the storage cisterns. In some cases it might not be more than an hour or two, in others it may continue over many hours, especially where the mains are under repairs or alterations. As far as my experience goes, it would hardly be safe to provide for less than a day's (twenty-four hours) consumption.
The magnitude of the water supply in London is appalling: "London is said to require a daily supply of more than 150 1 million gallons of water. Of this about 15 million gallons come from deep wells in the chalk, the rest from other sources, principally from the Rivers, Thames and Lea."
3. It seems a pity that lead-battened cisterns should have gone out of use, for they showed a nice piece of workmanship, and they generally lasted longer than any other handmade thing in or about a house. The one illustrated in fig. 161 has been in constant use for more than two centuries in the old and new buildings of the oldest banking-house in London; and it is still doing duty, and will perhaps last another century or two.
Fig. 161. - View of an Old Lead-Battened Cistern.
4. Though lead-lined cisterns are very suitable for storing water for supplying water-closets, slop-sinks, and urinals, water for dietetic purposes, especially if it is of a character to act on lead (Chap. II., pp. 8, 9), should be stored in slate cisterns, or in white enamelled earthenware cisterns; or, where a storage of 200 or 300 gallons is required, in cisterns made of fire-clay and salt-glazed. But most people are content to store the water in galvanized wrought-iron cisterns, chiefly, I believe, because they are so readily made to suit almost any position, and also because they are not so liable to damage as slate cisterns. But though the action of water on galvanized iron is not so-great as on lead, such cisterns are by no means free from action, especially when charged with water which would act on lead. In such cases where large tanks are necessary, and the water would act on lead and therefore on galvanized iron, the tanks should be made of cast-iron plates or wrought-iron, and be bolted together and strongly lime-whited inside.
1 The Official Return for June, 1891, gives 190 millions.
Messrs. T. and W. Farmiloe's titancrete cistern or tank is made of almost any capacity, varying from 10,000 gallons to 20 gallons. Above a certain size it is better built on the spot. It is composed of an iron and wire frame, entirely-embedded in a special concrete, which, it is alleged, does not affect water. I have had no experience of these tanks.
5. I have seen lead-lined cisterns which have been in use for more than half-a-century, if not absolutely free from any action of water on them, so good and perfect that their surfaces, except perhaps in a few places in the soldered angles, have shown no signs of any action. But, on the other hand, I have seen lead-lined cisterns which have only been in use a year or two so acted upon, that in places they have lost half their original substance. (Chap. II., pp. 8, 9.)
6. In new lead-lined cisterns, with some waters, a film is formed over the face of the lead, which is most valuable, as it prevents, to a very great extent, any further action of the water upon it. And in cleaning out such cisterns, great care should be taken not to scratch off any part of this film.
7. In my "Lectures" I gave some extracts, by permission of Dr. Sedgwick Saunders, from his translation of M. Belgrand's essay on "The Action of Water upon Lead Pipes," and which I reproduce here.
"Lead has been employed in the manufacture of conduit pipes ever since the distribution of water in towns was first established by the Romans, the first aqueduct, the Appian, according to Varro,1 being constructed in the year of Rome 442.
"From that period leaden pipes have been in constant use; all the water services in the interior of ancient towns being made of that metal.
"In Paris the leaden branch-pipes connecting dwelling-houses with the main supply number about 39,500, and their average length may be put at 40 metres,2 and their total length at 1,580,000 metres.
"In the case of houses that are occupied, the longest period for the water to remain in the leaden pipes can be estimated thus: -
Houses having unlimited supply 9 hours during the night. from 5 to 10 min. during day.
Gauged supply from 3 to 6 hours at the most.
"As will be seen further on, the time the water is in contact with the interior surface of the pipe is too short for the lead to be attacked.
"I have already stated that in the net-work of main pipes there are about three kilometres3 of lead piping. These are from time to time removed, and on examination their interior surfaces are invariably found to be perfectly smooth and without any trace of corrosion.