IN the days, not so long ago, when wood cisterns were built into very confined places, a plumber often showed more ingenuity in wriggling himself out of a cistern, after he had lined it with lead, than in getting into it; for not only would he be cramped in every limb from working many hours in attitudes which could hardly be described as kneeling, sitting, or standing, but he would have a narrower space to get through, by the thickness of the lead he had fixed upon the edge of the cistern. And when he had oozed out of such a place, through a trapdoor, hatch-door, or between joists and floors and ceilings, he would often be in such a plight as to be mistaken for a chimney-sweep (except that no sweep could ever have worked himself into such a position), for handling lead is not like handling linen, any more than working with soil and grease is like working with a needle and thread. But cisterns are not now so treated. They are brought out into larger places, where they can be seen and cleansed when so desired; and, instead of wood cisterns lined with lead, the cisterns chiefly used now are made of galvanized sheet iron. (See Chap. XXXVII., Art. 4.)

2. Wood cisterns, or tanks of any shape or size, can be lined in their places with sheet lead of any weight per superficial foot, for lasting a few years or for centuries, and for storing water, which does not act on lead (Chap. XXXVII., Art. 7), there is no other kind of cistern which can be so absolutely depended upon, or which is so generally convenient. The strength of the bottom should be 1 lb. or 2 lbs. per sup. ft. stronger than the sides; but 7 lbs. bottom and 6 lbs. sides make a good cistern, though I prefer the bottom to be of 8 lbs. lead, and the sides and ends of 6 lbs.

3. For lining tanks for chemical purposes, the sheet lead should be manufactured from refined pig lead, and instead of soldering the angles, the edges of the lead should be burned. (Chap. V.)

4. In taking the dimensions of a cistern for cutting out the lead - when the angles are to be soldered - all the sizes wanted are the length, width, and depth of the wood cistern inside. The lead for the bottom should be cut out 1 in. larger each way - in length and width - than the cistern, to allow for squaring, straightening, and turning up at the edges - for wedging in at the angles of the four sides; e.g., a cistern 6 ft. by 5 ft. and 3 ft. 6 in. deep would require a piece of lead for the bottom 6 ft. 1 in. by 5 ft. 1 in. These dimensions, added together, will give the length of the first side and end (though the first side and end to be put in is wanted 1 1/2 in. longer than the last, to allow for the return edges on to the wood, the two pieces are generally cut in equal lengths, to save time and trouble); thus, 6 ft. 1 in. by 5 ft. 1 in. = 11 ft. 2 in. This allows for squaring and straightening the ends, and for returning about three-quarters of an inch at each end on to the wood sides, for securing the lead in its position. The width is obtained by adding 3 in. to the depth of the cistern, to allow for straightening the edges, turning 3/4 in. on the bottom (though many plumbers use an inch for this) and 2 in. to cover the top edge of the cistern.

5. Before lining a cistern, see that all the holes are cut in it for the various pipes, especially the hole in the bottom for the waste-pipe, taking care that the hole for the latter is made of sufficient size to allow the end of the pipe to be well opened out to receive the brass washer-and-waste, the hole being counter-sunk for making the soldered joint flush with the lead bottom, so that the cistern may be quite emptied.

6. I will follow the order of lining a wood cistern, and speak of the sides first. Unroll the lead upon the floor adjoining the cistern to be lined, or if the cistern is in a roof and there is no floor, then upon some boards, and dress out any irregularities in its surface, and, before chalk-lining out the sizes, see that the cistern is perfectly square; for carpenters, like other people, do not always work on the "square." When a side and end are in one piece, such as we have been considering, and as is the practice, except in very large cisterns, when a separate piece is used for each side and end, line out the sizes with a chalk-line upon the lead, allowing a margin of about 3/4 in. to stand on the bottom, and also for the returns at the two ends. The line for turning up the end, for forming the upright unsoldered angle, should be marked with a chalk-line, and never scratched with a sharp tool.

Having marked out the side and end, take a piece of quartering, or "straightedge," and turn up the edge for standing on the bottom. This is easily done by kneeling on the piece of quartering, to keep it stiff, and turning up the edge with the aid of a chipping-knife and dresser. Then break up the end by placing the piece of quartering upon the line for the upright angle (the angle which is not to be soldered) and boss up the bottom corner a little, for fitting tightly into the angle of the wood cistern. Some plumbers stupidly cut this corner, and in such a way as to leave a hole just where the Folder can run in, and so get themselves into difficulties when soldering the cistern. In putting this piece of lead into its place in the cistern, bulge the centre part of the side and end inwards a little towards you, as you stand in the cistern, so as to be able to drive the angles of the lead tightly home. Be very careful with the turned-up angle, the unsoldered angle, and see that it fits tightly into the angle of the cistern, before securing the lead at the ends; for if the lead is not well home in such angles, when the side and end are fixed, and the dresser is used for driving it home, as is often done by unskilled men, the lead is very much weakened. I have known 6 lbs. lead reduced to 4 lbs. in such angles, and even for the edge of the dresser to be driven right through the lead, and the angle to require soldering. A nail in the return edge of the under-lap, about 3 in. down from the top, is all that is wanted to secure the lead in its place. The edge of the lead is readily turned over the top of the cistern with a few sharp strokes of the dresser and fastened (the inner edge of the wood being rounded off a little before lining the cistern), and the stand-up part of the angle is easily bossed back. When forming this angle, the part to be bossed over the edge of the cistern should never be cut in, with the edge of the dresser or any other tool, or it will not boss over freely.