Different potable waters have unequal solvent powers on this metal. In some places the use of leaden pumps has been discontinued, from the expense entailed upon the proprietors by the constant want of repair. Dr. Lamb[19] states an instance where the proprietor of a well ordered his plumber to make the lead of a pump of double the thickness of the metal usually employed for pumps, to save the charge of repairs; because he had observed that the water was so hard, as he called it, that it corroded the lead very soon.
The following instance is related by Sir George Baker:[20]
"A gentleman was the father of a numerous offspring, having had one-and-twenty children, of whom eight died young, and thirteen survived their parents. During their infancy, and indeed until they had quitted the place of their usual residence, they were all remarkably unhealthy; being particularly subject to disorders of the stomach and bowels. The father, during many years, was paralytic; the mother, for a long time, was subject to colics and bilious obstructions.
"After the death of the parents, the family sold the house which they had so long inhabited. The purchaser found it necessary to repair the pump. This was made of lead; which, upon examination was found to be so corroded, that several perforations were observed in the cylinder, in which the bucket plays; and the cistern in the upper part was reduced to the thinness of common brown paper, and was full of holes, like a sieve."
I have myself seen numerous instances where leaden cisterns have been completely corroded by the action of water with which they were in contact: and there is, perhaps, not a plumber who cannot give testimony of having experienced numerous similar instances in the practice of his trade.
I have been frequently called upon to examine leaden cisterns, which had become leaky on account of the action of the water which they contained; and I could adduce an instance of a legal controversy having taken place to settle the disputes between the proprietors of an estate and a plumber, originating from a similar cause—the plumber being accused of having furnished a faulty reservoir; whereas the case was proved to be owing to the chemical action of the water on the lead. Water containing a large quantity of common air and carbonic acid gas, always acts very sensibly on metallic lead.
Water, which has no sensible action, in its natural state, upon lead, may acquire the capability of acting on it by heterogeneous matter, which it may accidentally receive. Numerous instances have shewn that vegetable matter, such as leaves, falling into leaden cisterns filled with water, imparted to the water a considerable solvent power of action on the lead, which, in its natural state it did not possess. Hence the necessity of keeping leaden cisterns clean; and this is the more necessary, as their situations expose them to accidental impurities. The noted saturnine colic of Amsterdam, described by Tronchin, originated from such a circumstance; as also the case related by Van Swieten,[21] of a whole family afflicted with the same complaint, from such a cistern. And it is highly probable that the case of disease recorded by Dr. Duncan,[22] proceeded more from some foulness in the cistern, than from the solvent power of the water. In this instance the officers of the packet boat used water for their drink and cooking out of a leaden cistern, whilst the sailors used the water taken from the same source, except that theirs was kept in wooden vessels. The consequence was, that all the officers were seized with the colic, and all the men continued healthy.
The carelessness of the bulk of mankind, Dr. Lambe very justly observes, to these things, "is so great, that to repeat them again and again cannot be wholly useless."