obtained with stoneware or earthenware pipes, owing to the difficulty of preserving perfect accuracy of form during the process of burning." "In the Stanford joint tightness is obtained by casting upon the spigot and in the socket of each pipe, by means of moulds prepared for the purpose, rings of a cheap and durable material, which, when put together, fit mechanically into each other, and by making these rings of a spherical form, a certain amount of movement or settlement may take place without destroying the accuracy of the joint. In laying these pipes, therefore, all that is necessary is to insert the spigot of one fairly and firmly into the socket of another previously laid, and the joint is complete and perfectly water tight. A smearing of some kind of grease is frequently found to be of advantage." Half-socket or access-pipes are sometimes useful, where it becomes necessary often to inspect the house drain. They should be located close to angles, bends, junction branches, running traps, etc. They are not much used in this country, owing, probably, to the fact that, should the main drain run over one-half full, sewage may leak out through the access-pipes into the soil. In laying drains, care should be taken to avoid, as much as possible, trees. The roots of these are frequently found to penetrate and often choke the pipes, and are certainly a dangerous obstruction to the flow in the drain. If the line of the drain must necessarily pass near trees, the use of iron pipes is recommended. The coating of the pipes with coal tar on their outside, the use of asphaltum for joints, and sometimes the surrounding of the drain with a strong layer of concrete are said to be effectual protection against roots of trees. As a I now must speak of the grade of the drain, as this is a matter of prime importance. Upon the inclination of a pipe depends the velocity of the water flowing through it. If this velocity should be insufficient, deposits will occur, and the drain will in time become choked. Pipes of 4 inches diameter should have a velocity of flow of from 3 to 44ft. per second; those of 6 and 9 inches diameter should have a velocity of not less than 2 to 3ft. A velocity of 2ft. per second should be considered the minimum allowable in house drains. general rule the inclination of a house drain should be as great as attainable, and must be, wherever local conditions will permit, continuous. It is not unfrequently found by uncovering old drains that, in order to save digging, they are laid very flat-nay, often level— from the point where they leave the house to nearly their junction with the sewer, at which place they are turned with a steep pitch downwards, and often enter the sewer at its crown. By distributing the whole available fall over the total length of the drain a much better grade would have been secured. In order to lay a drain with a true grade, especially where the fall is little, a level should be used. The elevation of bottom of pipe, where it leaves the house- at a depth of not less than 3 feet in the New England States, as a protection against frost-should be ascer tained, as well as the elevation of the junction with the sewer (or else inlet to cesspool or flush tank). A profile of the ground along the line of the drain should also be determined by levelling. Thus, the proper available fall can be determined, with a little additional trouble, it is true, which, however, will be well repaid by securing a much better quality of the work. A fall of from 1 in 40 to 1 in 60 is desirable for pipes of 4 or 6 inches diameter, but this cannot always be had. I would consider a grade of 1 in 100 as the least to be given to small house drains, in order to keep them self-cleansing. When laid with such fall and running full or half-full, a six-inch drain has a velocity of 34 feet, a four-inch drain a velocity of nearly 3 feet, which is sufficient to carry along such suspended matters as only ought to enter a house drain. Where the available fall is less than 1 in 100, special flushing apparatus, such as Field's flush tank, McFarland's tilting tank, or Shone's hydraulic syphon ejector should be used. The former seems to many preferable, as it is free from all movable parts which are liable to get out of order, unless carefully and continually watched. I have thus fully explained the right method of laying drain pipes, because, even with the best plumbing inside of the house, it is of the greatest importance to have the outside drains of good quality, properly laid, and properly jointed. The next question to be considered is: What is the proper size for house drains? This will, of course, depend to some extent upon the grade of the drain, the size of the house and number of its occupants, the amount of water used per head per day, and finally, unless the rain falling upon the roof is stored in a cistern, upon the amount of rain-fall to be carried off in a certain time. This rain is a most beneficial scourer for drains, and unless the sewage of the dwelling is to be disposed of by irrigation, or the sewers of the town built according to the "separate system," which excludes the rain-fall from the channels carrying sewage, I should strongly advise to deliver it into the same channel, which carries away the foul wastes of the habitation. Even with this double purpose in view the house drain need not be very large, and the closer its size is proportioned to the volume of water it must carry the more self-cleansing will it be. This is easily understood, for the same stream that fills a 4-inch drain half-full will spread out at the bottom of a 9-inch pipe, and, having less velocity, will be unable effectually to remove sediment [see Diagram II in Appendix I]. For an ordinary city dwelling a drain four inches in diameter is ample, even including all the rain-fall. For a larger lot and residence a six-inch drain is all that is needed, even if the fall should be only 1 in 100. As a general rule, house drains have been constructed. of too large a diameter, and one often meets with the objection that a four inch pipe will clog up with grease in a short time, or will be obstructed by solid substances. To this, I answer, that in regard to grease the only safe way, where it is allowed to waste, or in case of large boarding-houses and hotels, is to keep it altogether out of the drain (which can be easily accomplished by a suitable grease trap). Grease congealing in a drain is sure to clog it, no matter how large it is made. The stoppage would be only a question of time, and nothing could be gained by postponing this inevitable result. In regard to obstructions by solid matters, I may assert that nothing which passes through the strainer of a sink or from the water-closet bowl can possibly obstruct the drain. What may enter through carelessness of servants or of the householder, such as "sand, shavings, sticks, coal, bones, garbage, bottles, spoons, knives, forks, apples, potatoes, hay, shirts, towels, stockings, floor-cloths, broken crockery, etc.," to quote from Mr. J. Herbert Shedd's Report on the Sewerage of Providence, cannot rightfully be expected to be carried away in a drain. To guard against such obstructions, the drain should be made accessible, especially near bends, junctions and the main trap. Let us now consider the question of the proper size of drains by applying the well-known laws of hydraulics to it. The Diagram I, in Appendix I, showing discharge, velocity, size and inclination of drains or sewers, has been calculated from Weisbach's formula for discharge of pipes, supposed to run half full. Table No. 1, in the same Appendix, has been calculated by Robt. Moore, Esq., C. E., late Sewer Commissioner of St. Louis, from Weisbach's formula for flow of water through open culverts. It gives the size and velocity in house drains, laid at different inclinations, and for various sizes of lots, the rain-fall being 2 inches per hour, and the pipes running full. Table No. 2 (ibidem) from the same author, gives diameters of drains and sewers, capable of discharging 1250 gallons per house (of 25 feet front) per day, running three-fourths full at various rates of inclination. It should be said that the smallest sizes of the tables (below 3 or 4 inches diameter) are given only for the sake of completeness, and not as sizes to be recommended for actual use. We shall assume, for an example, an ordinary city lot of 25 x 150 ft. =.0861 acres. The rain-fall to be provided for may be 2 inches per hour. Though such storms are not frequent, provision should be made for them in the calculation of the size of house drains, as the rain falling on roofs and on paved yards reaches the drain very soon after having fallen. A rainfall of 1 inch per hour per acre very nearly yields 1 cubic foot per second, therefore 2 inches per hour give 2 cub. ft. per sec. per acre. The number of cubic feet of rain from the above lot is therefore .0861 × 2.1722 cub. ft. per second or 60 × 1.722 10.332 cub. ft. per minute. = = We further assume 6 persons to the house, and 75 gallons per head per diem, which is a very liberal allowance. The waste water of the house is therefore 6 x 75 450 gallons per day. If one-half of this amount is estimated to run off in 8 hours, the maximum per hour would be about 28 gallons or 0.0624 cub. ft. per minute. This quantity is so insignificant compared with the rainfall that we may safely neglect it. If the drain has a fall of 1 in 60, and shall not run over one-half full, Diagram I shows that a pipe 4 inches in diameter is sufficient to carry off 10 cub. ft. per minute. Should the drain be allowed to run three-quarters full, and have a fall of 1 in 100, a diameter of 3 inches would suffice, according to Table 1. As a second example, I shall take a large lot, say 80 × 150 ft. .2755 acres. The quantity of rain to be discharged will be, under the same suppositions as above, 2 × 60 × .2755 acres 33.06 cub. ft. per minute. The diagram I gives the necessary size of pipe, for a fall of 1 in 50, to be a little over 6 inches, supposing the drain to run half-full. For a drain, running full, Table 1 gives the necessary diameter 5 inches. These two examples are believed sufficiently to explain the use of the diagram and table appended. If the rain should be excluded, it will be seen from Diagram I that a 4-inch pipe, laid at a grade of 1 in 100, and running half-full discharges 7.5 cub. ft. per minute, or 10800 cub. ft. per 24 hours. Assuming 75 gallons or 10 cub. ft. per head per 24 hours, and doubling this to provide for a maximum flow, it will be seen that this quantity is equal to the sewage of 540 persons or of 90 houses (6 persons to a house). 10800 20 For such calculations Table 2 of the Appendix becomes useful. It will be seen from it that a 6-inch drain, running three-quarters full, laid with a fall of 1 in 50, is large enough for the sewage proper of 400 houses, assuming 1250 gallons per house per day, which is an ample allowance. The foregoing explanations have, I believe, sufficiently proved that no house drain needs to be larger than six inches under ordinary circumstances. Any increase of size beyond this would tend to be a detriment rather than a benefit. DRAINS INSIDE OF THE HOUSE. The earthernware drain should end at about 5 to 10ft. outside of the foundation walls of the house. From this point towards the inside of the house the drain should be of iron. The joint between iron drain and earthernware pipe should be made with pure hydraulic Where the iron pipe passes through the wall, a relieving arch should be built over it. Settlement of walls often occurs, and is liable to crack the pipe or even break it, unless the above provision is carried out. It is quite evident that, under no circumstances whatever, this part of the house drain should consist of vitrified pipe. Important as it is to have the drains outside of the house free from sediment or leakage, it is still more so to have all the pipe joints inside of the dwelling perfectly air and water tight, for if any defect should exist here, sewer gas will leak into the cellar and pervade the whole house. For this reason we sometimes find the cardinal rule laid down that no drains should run under a house, but should be taken outside of it as soon as possible. This is not practicable, as a general rule, in the case of narrow city lots. Fortunately, however, we can, with perfect safety, run the drains across the basement or cellar floor of a dwelling, provided we choose the only safe material, i. e. iron pipes. A good mechanic is able to make with these a perfectly air and water tight joint. The best course of the iron drains in the house is along the ceiling of the cellar, or along one of the foundation walls. In other words, wherever practicable, the iron drain ought to be kept in sight, in order to enable anybody to detect a leaky joint at occasional inspections. Sometimes fixtures located in the cellar, such as servants' water-closets, laundry tubs or sinks, make it necessary to lay the iron drain below the cellar floor. In this case it should be laid with proper fall in a trench, the sides of which are walled with brick work, and the base of which should consist of a layer of from 4 to 6 inches of concrete, thoroughly rammed and properly graded. The trench should be made accessible by closing it with movable covers of iron or wood. If the drain is carried in sight, I would much prefer supporting it by strong iron hooks from the cellar wall, instead of suspending it by iron hangers from the main joists of the floor above. For, with the latter arrangement, a slight lowering or bending of the beams supporting the iron drain, would tend to loosen the joint between watercloset trap and soil pipe, as the latter is rigidly connected with the drain, thus creating a source of danger from leakage of sewer gas. As regards the proper inclination of iron drains in the cellar the rules given for the outside drains should be observed. The principles stated for the size of the outside drain apply with equal force to the inside drain. If no leaders enter the drain at its upper end or along its course through the house, a 4-inch pipe is ample for any ordinary sized dwelling; a 6-inch drain is very seldom required. As a good precaution for repairs or cases of obstructions of the |