1. IN seamless lead pipe for soil-pipe, rain-water-pipe, cold water wastes, and services - where the water would not act on them, or acting would not hurt anybody - the plumber rejoices in the use of a pipe, which, for soundness, wholesomeness, durability, compactness, appearance, and the reliability of its wiped solder joints, as well as for the ease with which it can be made to follow any course, not only compares favourably with any other known pipe, but is, in fact, as proved by experience, superior to earthenware, stoneware, zinc, copper, cast-iron, or wrought-iron pipe.

2. It is peculiarly the plumber's duty to see that the lead pipe he fixes - soil-pipe, waste-pipe, ventilation-pipe, or service-pipe - is of an even thickness all over, for if one pipe manufacturer does not so make it another does. It may cause some extra trouble and expense to get such pipe, but now that it is so manufactured it would be manifestly unfair to the owner of a property to fix a pipe which, while equal to lasting a century on one side, could not be relied upon for a quarter of a century on the other. Where there is no anxiety on the plumber's part to seek out good soil-pipe manufacturers, and where the pipe he uses inside a house is of an uneven thickness, the strength of the pipe should be increased say from 8 lbs. lead to 10 lbs. lead, so that the pipe in its weakest part may be equal in thickness to sheet lead weighing 8 lbs. to the superficial foot. (Chap. II.)

3. A lead soil-pipe 1/8 in. thick - i.e., equal to sheet lead weighing 8 lbs. to the superficial foot, and of a true and even thickness all over - can be so fixed that it shall last a century and more; and during the whole of that period it need not cost its owner, or rather its successive owners, one farthing. And when the time comes for its renewal it will fetch, as old lead, one-third of its original cost, unless past history is no guide for the future.

4. When soil-pipes are of lead the work of fixing them can be carried on with less forethought and more expeditiously than with either cast-iron or wrought-iron pipe. In the case of either of the latter, however carefully the work may have been set out at first, a deviation from the original plan in some of the fixtures, or a deviation in the course of a pipe - which in a building of some magnitude, where growing minds are at work upon it, will be sure to occur - would probably call for a bend, or a junction, or a special pipe, which would lead to waste of time until such parts were furnished. In the case of the former, plenty of lead pipe being on the job, or within ready reach, no deviation in the course of a pipe need delay operations for a minute, for the plumbers could bend or branch it, to suit the altered circumstances, as they progressed with their work.

5. The duration of a stack of iron pipe exposed to the influences of the atmosphere, even if it be of the water-main strength, is much shorter than that of a lead pipe, though in many cases it would be cheaper to fix the latter than the former. No matter what means may be adopted for protecting iron pipe from rusting, I know of none that will prevent iron pipe from oxidizing in some of its parts after a time, and when exposed to the London atmosphere. But where iron pipe is used, whether for soil-pipe, rainwater-pipe, waste-pipe, or drains, it should have a protective coating inside and out; for in iron pipes there is not only a corrosive action going on outside, but there is also a corrosive action going on inside, i.e., such pipes deteriorate from within as well as from without.

6. For fixing cast-iron soil-pipe outside a house on the faces of external walls, I prefer the pipe to be galvanized, and afterwards coated with Dr. Angus Smith's solution, and then painted outside to suit the colours of the adjacent iron rain-water-pipes. The joints in such cases are stronger if made with Spence's metal than with most of the "cements" used; but where not exposed to the heat of the sun, in the longest and shortest hours of the day, they can be well and soundly made by caulking in a ring or two of spun yarn, and filling up the remainder of the socket with marine glue by the aid of a blow-pipe or blowing lamp.

7. For fixing inside a house the pipe should be of greater strength, with stronger, wider, and deeper sockets, so that the joints may be made with blue metal, i.e., that two or three rings of spun yarn may be caulked into the socket, and the socket filled in with molten lead, and caulked, as shown at B, fig. 110. As such a pipe would be too expensive to galvanize, it should be properly coated inside and out with "Dr. Angus Smith's solution," though there is a difference of opinion as to which of several methods is the best one. As far as my experience goes, no known or tried method can be absolutely depended upon to prevent oxidation when iron pipe is exposed to the atmosphere.

8. Cast-iron soil-pipes and waste-pipes for fixing inside a house should be very carefully examined before they are coated, to see that they are free from all defects, from flaws and fractures, as the coating would cover over small defects and screen them from sight. The pipes both inside and outside should also be cleaned before they are dipped into the cauldron; and immediately before fixing a pipe in its place it should be sounded and well tested, to see that it is free from fracture. Captain de Place, of Paris, has invented a mechanical contrivance called a "sciseo-phone," to detect the presence of flaws in metals.

Fig. 110. - Section of a Caulked Lead Joint.

The pipes should also be well examined, to see that they are of an even thickness all over, except of course in the hub or socket, and for an inch or two below the socket, which should be of much greater thickness; but in no part of the pipe should the thickness be less than 1/4 in. before it is coated.