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ment which is a precautionse in improving
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and its saturated soil is undoubtedly most objectionable. But in all the outcry against the malaria of Washington we hear little of the whisky, and the late hours, and the dissolute life to which, probably, a more just estimate would ascribe the greatest proportion of its morbidity and of its mortality.
These remarks are by no means intended to belittle the office of proper systems of drainage in improving the public health, but rather as a precaution against that general disappointment which must follow the demonstration of the patent fact that perfect drainage is not the only requirement of perfect living. With this limitation, too much importance can hardly be attached to the subject; nor can too much earnestness be employed in urging forward every movement which looks to the removal of filth and of undue soil-moisture.
It cannot be pretended that the conditions of sanitary perfection are known; but we may safely claim that the intelligent investigations of the past few years have led to a very important increase of our positive information on the subject. There is no doubt that some of the well-accepted theories of the present day are destined to be set aside by future investigation ; but, on the whole, they constitute a very good and reliable foundation for systematic work. They contain a sufficient element of certainty to justify local Boards of Health in establishing rules and regulations, the enforcement of which, whatever their imperfections and it is to be remembered that such rules have to be prepared for universal application, not alone for those who desire and are willing to pay for the best work,-cannot fail to bring about a marked improvement in the condition of life of all classes of the people.
The assumed basis for the best present practice,- most of which will probably stand the test of time,- may be fairly stated as follows:
All ordinary domestic waste matters, whether offensive or inoffensive, when first produced, become to about the same degree offensive when putrefied. They also become to about the same degree dangerous, save that some may carry specific germs of disease, which are absent from others. All such matters should, therefore, be removed entirely beyond the house and beyond the limits of population before their putrefaction sets in. The objections attaching to the decomposition of these substances attach in like manner, but in less degree, to such of their elements as adhere to the walls of the channels through which they are removed ; i. e., it is important not only to consider the removal of the great bulk of our filth, but also to guard against evils arising from the decomposition of the adhering particles which mark the course it has followed.
The removal of waste matters by transportation in water has such preponderating advantages over all other systems of treatment,-including the earth closet,- that it is not worth while, for general practice, seriously to consider any other than the water-carriage system. The removal of solid matters in a stream of water requires a sufficient depth in the flow to carry the solids along, and a sufficient velocity to prevent sedimentation. As these elements-depth and velocity - must always work together, the size of the channel through which the stream runs is most important. An amount of water that would fill a large pipe half an inch deep, would fill a sufficiently smaller pipe an inch deep. Ordinary focal solids are readily transported in water an inch deep, while in water of only half that depth their buoyancy would be too much reduced, and the amount of their surface receiving the impulse of the flow would be too small for their prompt transportation; so that, unless the velocity were so great as to break down the mass, they would remain in the chan. nel. Some of the substances reaching our drains are of too firm a consistence to be broken down by the velocity of ordinary streams, and these often form the nucleus about which fouler things gather to create accumulations. Therefore, it is important, with regard to all drains which do not run full, that their diameter be so restricted as to give the required depth to their flow. There is another consideration of equal importance which must always be kept in view: the velocity of the stream remain. ing the same, the depth of the flow will be in proportion to the diameter of the pipe and to the quantity flowing through it. Therefore, as the quantity supplied in ordinary house drainage is fixed, the diameter of the pipe must be so restricted that, at the velocity with which it flows,- varying according to the rate of inclination, the given fixed volume will secure the required depth. It is not, of course, possible to maintain at all times a cleansing depth of flow in any house drain; but it is possible, by regulating the diameter of the conduit in accordance with the volume flowing at the time of greatest use, and with the rate of inclination, to make sure that at some time during the day, and
generally several times during the day, there shall be a sufficient depth of current to wash away what the straggling flow may have left behind.
In those parts of the house drainage where the conduit is filled with water, it is necessary to give, at least at frequent intervals, a sufficiently rapid movement to the whole mass to carry away whatever may have been deposited in these filled portions by slighter discharges. Practically, this observation applies mainly to the case of traps, where a bend is introduced in the course of the pipe to hold water, as a "seal" to separate the air of the outer drain from the air of such pipes as are open to the interior of the house. In this case, velocity has to be given not only to water occupying a portion of the pipe, but to its full contents, so that the diameters of traps should be, other things being equal, considerably less than the diameters of the pipes leading to them and from them.
One of the most serious difficulties met with in practical work is what is known as “siphonage,” that is, the sucking out of the water of traps by the rarefaction of the air in the outer pipe, caused by the passage of liquids or air through it or across its mouth. The tendency to siphonage is greater in small traps than in large ones, the same suction being brought to bear on a smaller volume (weight) of trapping water. No satisfactory device of general application has yet been discovered by which this difficulty may be overcome with certainty and without entailing other effects equally to be feared. The present custom exacted or sanctioned by local Boards of Health is to carry a vent pipe from the upper bend of the trap to the open air, so that when the air of a pipe becomes rarefied, the balance shall be restored by admitting air through the vent pipe, leaving the water of the trap undisturbed. Theoretically, this practice has much to commend it; practically, it seems to me to have grave objections, which it will require our best endeavor to remove. Our best hope lies in the devising of some other means for securing a safe trap.
However completely we may succeed in preventing deposits in waste-pipes and drains, we cannot prevent the adhesion to their walls of more or less of the soapy, greasy, and slimy matters carried by their flow. With a perfect adjustment of diameters, and with the proper appliances for frequent flushing, such adhesions may be reduced to a minimum. However small the quantity so adhering, it is sure to enter into decomposition, and it is well known, or, rather, it is generally believed, that the extent to which such decomposition becomes noxious or innoxious is regulated only by the degree to which fresh air is admitted to it at all times. All waste-pipes and drains must have such a connection with the outer atmosphere as shall insure a supply of oxygen for complete decomposition at all points, and a reasonably rapid dilution and removal of the gaseous products of the process.
Concerning fixtures within the house, it is to be remembered that each additional one constitutes another channel of communication between the air of the house and that of the drain. The possibility of efficient protection at these openings is, at least, so well secured, that we need not hesitate to establish such fixtures as are required for comfort and for reasonable convenience; but there remains just so much question in the matter as to justify the recommendation that a luxurious profusion of plumbing fixtures had better be avoided.
The two vital points still to be settled are: First, an absolutely effective means for maintaining the integrity of traps; and, second, such an arrangement of vessels, traps, and waste-pipes as will insure the complete discharge beyond the house walls of all matters delivered into the waste-pipes without the possibility of their being long retained in traps or elsewhere on their way. Thus far we are at sea as to the first of these requirements. Some endeavor to satisfy it by trap ventilation, and others by the use of mechanical traps, both of which methods, as now carried out, have demonstrable defects. The uncertainty here involved constitutes to-day the chief unsolved problem in the work of house drainage. It is here more than anywhere else that the most skillful and experienced judgment is required in the arrangement of plumbing work.
The water-closet has undergone a transformation since im. proved drainage began to attract attention in this country, which has brought it within measurable distance of practical perfection. The universal condemnation of the pan-closet by every respectable authority, if we except the Boards of Health of the larger cities, and there are good reasons for their present inaction,-is secured. Just apprehension as to its dangers is widely disseminated and deeply implanted. Its introduction in new work must soon be prohibited, and its retention
in old work cannot last very long. The defects which are most marked in this apparatus exist in a modified degree in some other closets which still meet with favor; but the march of improvement is entirely in the direction of closets which have no moving parts, which require a very copious use of water with. out waste, and of which the outlet channels are free from enlargements, or recesses not subject in every part to a thorough cleansing every time they are used. The simplest of these, and in many respects one of the best, is the plain “hopper” with a bent trap below it supplied with such a volume of flushing water as to ensure complete washing. Another common fault recognized and appreciated by all authorities is the supplying of closets by valves directly connected with the house supply. The importance of the interposition of a flashing cistern is getting to be well and generally understood. On the whole, we may say that, so far as water-closets are concerned, the interests of the public are taking care of themselves in a most satisfactory manner. Economy and indifference will necessarily retain in use the great mass of improper apparatus until it shall have worn itself out; but new construction and renewal of old work will in time overcome existing difficulties.
The majority of even the best houses are now very badly drained, and are subject to the production of “sewer-gas” at many points between the outer wall of the house and the fixtures within it. Occupants are generally careless or ignorant of this fact, and the verdict of “my plumber” is still considered by the average house-owner a sufficient certificate of good sanitary condition. Large traps, clogged with accumulations of putrefying kitchen-waste, soapy compounds, focal matter, etc., are still the rule rather than the exception. Defective pipes and more defective joints, involving often the escape of drainage drippings, or of drainage exhalations, exist very widely. Most drains still run under the cellar-floor, and such drains are almost invariably very faulty. All of these things, however, are slowly being changed, and the change is, practically, always in the right direction. In some cases where the local sewerage is very bad there is doubtless a certain amount of contamination of houses by the gases resulting from decomposition in the sewer. Few modern sewers, however, are seriously open to this charge, and proper ventilation of soil-pipes is, when accompanied with good plumbing work, a sufficient protection against danger from this
VOL. CXXXVII.—NO. 320.