With respect to the fall of drain pipes Dr Parkes says, “one in forty-eight is frequently given, or three quarters of an inch in every
yard; a fall of one in sixty-five in drains of six inches diameter, and one in eighty-seven in drains of eight inches diameter, will give a velocity of 220 feet per minute.
In order that drain pipes may be properly cleaned it is desirable to have them so made that they can be opened at intervals by means of lids or caps. The following cuts represent a few of the many kinds of pipes adapted for this purpose.
In addition to this method of cleansing them, drain pipes should be regularly flushed out at least once a month. House pipes are usually cleaned out by means of a flexible bamboo, or by jointed rods fitted with screws and rollers, which serve to loosen sediment. A frequent examination of all house pipes and traps should be made, and every joint and bend of the former well looked to. Unfortunately, however, they are so frequently covered in, that this is impossible.
Where it can be done all skirting boards and covers under which the pipes and traps are concealed should be removed. When, however, this cannot be managed the following plan of examination into their condition may be followed:—Pour water down the pipe, and observe if there be any smell; if there be, the pipe is full of foul air, and requires ventilation; or else the trap is defective, and the bad smell is due to sewer gas. Or, instead of pouring down water, a lighted candle or a piece of smouldering brown paper may be held over the entrance of the pipe, or the grating over a trap, when the air will be driven back. If the condition of the pipe be tested by throwing water down it, it should be noticed whether the water runs away at once or whether it is checked in its progress. This is all that, under the circumstances, can be done inside the house; but though an examination of the pipe is precluded inside, it may be possible to remove the earth on the outside, and so to get down to and open the drain with which the pipe communicates. Under these circumstances water mixed with lime should be poured down the house pipe; if the milky-looking water is long in making its appearance, and runs only in driblets, the drain requires flushing; if the milky-looking water is much coloured and mixed with dirt, then the pipes and trap are foul, or there is a sinking or depression in some part of the drain where the water is lodging.
Afterwards a pailful of lime and water should be poured down the pipe, which should be afterwards flushed by pouring water down it until the water flows off nearly clear.
Referring to the construction and position of the pipes which carry off the waste water, soil, &c., from our houses into the drains, Dr Parkes writes—“Builders are always anxious to conceal tubes, and thus carry them inside the walls, or in the case of hollow walls, between the two. The consequence is that any escape of air must be into the house. I have known a case in which the leakage of a closet pipe carried down in a hollow wall constantly contaminated the air of a house. It would be infinitely better to run the pipes at once through the wall to the outside. Few persons have any idea of the carelessness of plumbers’ work—of the bad junctions, and of the rapidity with which pipes get out of order and decay. When a leaden pipe carrying water is led into a water-closet discharge pipe, it is frequently simply puttied in, and very soon the dried putty breaks away, and there is a complete leakage of gas into the house. Even if well joined the lead pipe will, it is said, contract and expand, and thus openings are at last formed. Dr Fergus, of Glasgow, has directed particular attention to this in the case of lead closet pipes, which become easily perforated, and which have only a limited duration of wear.” See Traps, Sewers.
DRAUGHT. Syn. Haustus, L. A single dose of liquid medicine, usually dispensed in one-and-a-half-ounce or two-ounce phials. Draughts are almost exclusively extemporaneous compounds, and differ from ‘mixtures’ only in containing one dose; whereas mixtures contain several. The latter have now very generally superseded draughts among all but the higher classes, when the dose is to be frequently repeated. Draughts possess the advantages of extreme convenience, and, from only one phial being opened at a time, of preserving the preparation better than when it is exposed to the air by the frequent removal of the cork. They are usually taken from a wine-glass, which they about 2⁄3rds fill.
In the preparation of draughts the same precautions are observed as are pointed out under