Good workmanship is as important as, if not indeed more important than, good arrangement. It seems a very simple proposition to say that all waste-pipes, whose office it is to carry foul liquids out of the house, should be made tight in material and in joint. It is a remarkable fact, however, that leaky joints in soil-pipes and in drains are by no means rare. Probably there are few houses, very few, in which they do not occur. The soil-pipe is put together by inserting the small end of each section into the bell at the top of the section below it, practically like putting the outlet of one funnel into the larger upper portion of another. There may be abundant space for leakage at every joint from the top to the bottom of the house, without there being the least show of the leakage of water. The foul air within the pipe may escape freely through a dozen openings, while the heavier liquid flow takes its easiest and most direct course downward from the point of one pipe through the bell of the one below. When we come to the horizontal run of the soil-pipe in the basement, if an imperfection of the joint occurs on the lower side there is an obvious drip, which continues at least until closed by rust. Similar imperfections in other parts of the joint would not be so manifested. It has recently been demonstrated that there is no safety in the construction of soil-pipes short of that absolute assurance which can be secured only by an efficient test. Plugging all the outlets of the soil-pipe and filling it with water, the slightest leak will be exposed.