air when water is discharged into the drain, and also when there is a slight difference of temperature between the drain and the outside air. For the egress of drain, a tube should be provided from the top of the drain, or top of the highest branch, and carried up the building, taking care to finish at the top, where the air discharged cannot enter the house or building by a window, open-eaved roof, or a chimney down draught.

I do not think it well for special ventilating-shafts to be made for the public sewers through, or by means of, private house drains. I would also advise that the work should be done separately, by, and at the expense of, the local authority; and in drains treated as before described, the fixing, between the air inlet supply, or between the connection of the first branch inlet drain and the connection with the sewer, a horizontal siphon-pipe dip, with vertical pipe springing from the centre of the dip, and carried up to the surface, properly sealed and covered at the top for occasional clearance. This trap, if perfectly well made, will effectually resist sewer or drain-air pressure, and completely cut off or separate the drain from the sewer air.

The multiplication of air inlet- and outlet-tubes to branch drains, and air inlets and outlets to siphontraps, is, I believe, fraught with much mischief, and the reservoir space for drain air is needlessly increased; the cost and difficulties of proper maintenance are also increased. So many extra risks of smell arise from the imperfect jointing, fitting, and from the apparatus getting out of order, or being ignorantly and carelessly put out of order. The more complicated the apparatus, the greater the facility for the hand engaged upon the work to leave something undone or imperfect.

The drain inspector's occasional call will not enable him to detect many points where defects may be left. Simplicity, and not complication, in the work of house-drainage is needful for an approach to perfection. In order to attain this, reduce the drain inlets to the smallest possible number; have no surface inlet to drain in kitchen, scullery, passage, or cellar, or any place where rain-water or other water will not occasionally flow to keep the trap charged (and the floors of these places are better washed with mop and flannel when necessary); let the drain be made sound, and thoroughly sealed at every joint, laid on the shortest and most direct line possible, from point to point, and every inlet sealed from back drain air with a simple and effective trap. If an outlet-trap be fixed, to separate or cut off the sewer from the drain air, then an exit-tube for ventilating the drain should be provided. This trap causes an entirely new condition of things within the drain. During the reception of inflowing water, the weight of the water is exerted and expended upon the drain air-strictly, producing pressure on every trap; and this means woe to the weakest trap, unless strong enough to resist the force-instead of expending itself on the drain air and sewer air together.

By far the majority of houses drained have no outlet-traps; the drain and branch drain air are one, and in connection with the sewer air volume, the sewer air being changed through untrapped inlets, and again changing and renewing the air in the drain through the outlet and along its course, both changes being aided by variation of water-flow and atmospheric and drain temperature, either or both of which cause a change of air in the sewer or drain.

siphon a well-made dip-trap. Water traps are generally unsiphoned from one or other of the following causes.

1. A sudden discharge of water, passing the small outlet of a branch drain, acting on the injector principle upon a quarter or half-inch dip.

2. Evaporation of water in the trap, assisted by the overheating of the material of which the trap is made under a hot sun.

3. Siphonic withdrawal of the water by string, straw, cotton, wool, or paper hanging partly in the water and partly over the overflow, and down into the drain or pipe.

Drain air escapes into or about the house, not because there is no special air supply to, or special air exit from the drain, but because of some defect in the drain, trap, or draining apparatus. In such cases no special air supply or air exit will remedy the mischief. They may dilute the drain air escaping through the defect, but the poison will still come out, in weaker, but still in dangerous form. The remedy must be applied to the actual defect.

JAMES LOVEGROVE, Assoc. M. Inst. C.E. Town Hall, Hackney, Dec. 7th, 1880.

SANITARY INSPECTION IN RURAL
DISTRICTS.

At the Sanitary Congress, lately held at Exeter, some remarks were made with regard to sanitary inspectors not altogether favourable to that body.

I am quite prepared to acknowledge generally the truth of these comments; but, with a view to effect an improvement in the condition and circumstances of inspectors, I venture to ask you to allow me to call attention to this subject.

The position of inspectors in rural unions is most unsatisfactory. They are miserably paid, considering the great expense of horse keep or hire incurred in carrying out the work; and they are also virtually removable by the authority at will. The rural world is not yet aroused to the necessity of sanitary improvements and greater cleanliness amongst the cottage occupiers. Many of the guardians, as I know well, are altogether opposed to anything of the sort, on the ground of interference with the liberty of the subject-more, on that of the expense (though small) incurred. All the interest in these matters is confined to a small body of more enlightened men on the board.

The appointment of inspecting officers being compulsory upon the authorities by the Public Health Act, it results that the very lowest salary which will produce a candidate is fixed, regardless entirely of capabilities for the office. The appointment is, in most cases, given to very young men, of no experience whatever, who merely accept it as providing them a bare subsistence until something better turns up, or to old, worn-out, superannuated men, from motives of charity. Sanitary knowledge, commonsense, and efficiency are the last considerations-the smallness of the salary the first. Many inspectors are as good as told, "We are forced to appoint you; but the quieter you keep yourself, the better we shall like you. I have seen salaries fixed as low as £40 per annum. What else can that mean?

There is nothing in the circumstances to tempt men to train themselves for such appointments, or to make themselves acquainted with sanitary requirements when they are appointed. There is no chance of improvement in their position, and no hope of

T

'POLE'S SYPHON WATER-CLOSETS.' At page 157 of your issue for Oct. 15th, Alderman Bennett says:-'I wish it to be understood that the syphon referred to is the only trap between the closet and the main sewer. There should be no second trap of any kind, as gas generated between two traps may have sufficient pressure to force its way into the house closet the instant a lever is raised, or water poured in. This remark applies to most closets.' In Alderman Bennett's statement that his closet-trap is the only trap between the house and the sewer-there being no trap on his housedrain-he acknowledges a breach of the law, and renders himself liable to be taken to task (as he ought to be) by the Local Government Board, or other constituted authority. As to his other assertion, 'that there should be no second trap of any kind, as gas generated between two traps may have sufficient pressure to force,' etc., he only exposes his own ignorance, for with a ventilated trap such as the 'Buchan's Trap' shown in illustrations on pages 115 and 116 of your issue for September 15th, 1880, or any other traps having a ventilating pipe properly put in between them, no such pressure to force' as Alderman Bennett imagines can exist: his reasoning therefore is a total fallacy, and like his sanitary practice, a dangerous mistake. If Alderman Bennett will turn back to page 116, and look at the illustration on the second column, he will see how to put in two traps without any chance of gas accumulating or 'pressure to force' being able to arise. W. P. BUCHAN.

21, Renfrew Street, Glasgow, 27th Nov. 1880. P.S.-Permit me to add that the word 'siphon' should always be spelt 'siphon', as it is of Greek origin. Syphon' is wrong.—W. P. B.

་

FILTRATION OF WATER IN THE

MILITARY SERVICE.

I desire to make one or two corrections with reference to Mr. Bischof's paper on 'Filtration of Water in the Military Service' in the last number (November) of the SANITARY RECORD. In particular, he has mistaken some of the expressions used in my report in the A.M.D. Blue Book. He says, 'Let us refer to page 211, number 2. Here, under the heading "Continuity of Action," carferal is simply omitted. There is, indeed in the report (p. 205, seventh series) a single experiment, intended to prove the continuity of action, by the filtration of twenty (?) gallons.' Here Mr. Bischof confounds 'continuity of

action' with 'durability of filtering power'. Perhaps I did not make my meaning clear, but by continuity of action' I meant continued permeability', and absence of 'clogging'. As the carferal showed no tendency to clog, it was unnecessary to mention it. As regards the experiment on the filtration of twenty gallons, which Mr. Bischof thinks worthy of a note of surprise, (if not exactly of admiration), he has not stated the case quite accurately. It was not an experiment on the filtration of twenty gallons, but an through a filter which had been previously treated inquiry into the condition of ordinary water passed with an excessively impure solution. The mixture put into the filters represented an amount of impurity equal to that of many thousands of gallons of orgood water were passed through, and the twentieth dinarily impure water. Then twenty gallons of fairly gallon examined, to see how the filters had dealt with the impurity, and if they had yielded any other water. The experiment was doubtless an imperfect one, though hardly so preposterous as Mr. Bischof makes it appear.

I may add that my report was a qualified one, and that I indicated my intention of continuing the experi

ments.

That the authorities should have made their decision 'precipitately' as Mr. Bischof seems to think, is not my fault, and I was not even informed of the fact until a long time after, indeed, I believe I first learned it from Mr. Bischof himself. Mr. Bischof complains that 'no attempt is made to establish any superiority of carferal over spongy iron, excepting by the supposed greater rapidity of action of the former.' This is quite true, but then it is the whole point at issue. Spongy iron is an excellent filtering medium, but it is slow, and was complained of as inconvenient for service purposes. Carferal was sent to me to report upon, and I did so.

I think constructions have been put upon my report which are not justified, but of course each one who reads it must judge for himself on that point. Dec. 10th, 1880. F. DE CHAUMONT.

The following is the letter referred to at page 230 as appearing in the Daily News.

SMOKELESS COAL.

SIR, Perhaps you will allow a housekeeper who has made a trial of the smokeless coal to give her experiences. My kitchen range is a closed kitchener, with large ovens on each side. The grate has been lined with fire brick to diminish the consumption of fuel. For two days last week I had smokeless coal, which I obtained through the National Health Society, burnt in the range for experiment, and with the following results. I found that the fire lights easily and quickly, and soon becomes clear and bright; the ovens are heated in half an hour, the hot plate is quickly hot enough to boil saucepans and kettles all over the surface, the flues remain perfectly clean. Also the consumption of fuel is much less than when ordinary bituminous coal is burnt in the range, as the heat given out is very intense, and the fire so quick that about twenty minutes less time than usual is required for roasting joints. To conclude, my cook was delighted, and immediately begged that I would order in some tons of smokeless coal. I have an extensive view of chimneys from my study windows, and for these two days, whilst all my neighbours' kitchen chimneys were sending forth thick volumes of smoke (more particularly between 7 and 8 a.m. and 4 and 5 p.m., the hours when kitchen fires are

being made up and when yellow fogs frequently descend upon London), no sign of smoke was seen issuing from my own kitchen chimney, though I knew that baking and washing were going on downstairs, and that a fire was burning, at the extravagance of which I should have stood aghast if ordinary bituminous coal were being used. In the household fireplace I find that the smokeless coal will not light well unless there is a strong draught; this can be produced by having a temporary blower fitted to the grate, which can be hung on till the fire has burnt up, and then put away, or a few pieces of ordinary coal can be used to commence the fire with. When these are red-hot, the fire can be built up with smokeless coal, which soon becomes a clear incandescent mass, sending out a great heat. The fire requires to be made up about three times a day, it does not require poking, but gradually burns away, leaving very few cinders. I have used the smokeless coal in my house in the ordinary register grate, the large Queen Anne fire baskets with no register in the chimney, and hence no artificially-induced draught, and in the Abbotsford grate, and in all with equal success. The heat given out is so intense that it is a wise precaution to have the grates lined with fire-bricks, both to lessen the size of the fire and to prevent the sides of the grate being burnt away. There is a widely-expressed fear that cooks and housemaids may object to the use of smokeless coal, on the ground that it will give them some extra trouble in lighting fires. There is no extra trouble in any grate with a good draught, as in a kitchener, or any grate fitted with a blower, and the amount of dirty work saved in clearing out soot flues, sweeping chimneys, and general house-cleaning, is so immense that in a very short time, housemaids and cooks will come to see that there is a great economy of time and labour in the use of smokeless coal. Since my experiment of last week, I have succeeded in obtaining some tons of smokeless coal, and now burn it regularly in the kitchen, but having unfortunately filled my cellars in the summer with bituminous coal, I am, against my inclination, still obliged to burn the latter in the fire-place.

A CAREFUL HOUSEKEEPER.

REVIEW.

How to Prevent the Spread of Fever. A Popular Lecture by the Medical Officer of Health to the Borough. Printed at Nottingham.

It does not appear on the title-page of this lecture when, or before what audience, it was delivered, nor indeed, that it has ever been delivered at all. Whether, however, it has been actually presented to a popular audience, or is only a lecture in the potential sense, viz., that it is adapted for delivery to such an audience, we are ready to testify to its suitability for such a purpose, and should be glad to hear that the information which it contains had been utilised for the benefit of other places than Nottingham. The lecture does not, of course, contain anything that is at all novel, but it exhibits the nature of the commoner forms of infectious disease, and enforces the precautions which are necessary to prevent their spread, in a way which, as the Article hath it, is easily understanded of the people. The author points out in particular the limitations with which the term preventable is applicable to different forms of disease, and shows that in the case even of those which can be prevented by the direct action

of the sanitary authority, a large amount of cooperation is required on the part of the public. It is to the nature of this co-operation that the lecture is mainly directed, especially in regard to scarlet and typhoid fevers, and small-pox. The advice which is given as to the precautions necessary in the first of these cases is excellent. One point in particular is emphasised which is too generally neglected, and that is the tenacity with which infection clings to the hair of scarlatinal patients, and the necessity of frequent and thorough washing of the head during convalescence. We have no doubt, from our own experience, that the neglect of this precaution is a a most frequent source of communication of the disease in cases where in other respects the means that have been adopted to arrest infection would appear to have been satisfactory. For this reason it would seem desirable to extend the plan of oiling the skin, as recommended by Dr. Budd, during the desquamative stage, to the hair, and to insist upon the latter being cut as short during this stage as is possible. There is one point with regard to scarlet fever to which no allusion is made in this lecture, though it is, in our opinion, scarcely second in importance to any, and that is the necessity of extreme suspicion being observed with regard to even the slightest case of sore throat in children under any circumstances, and above all when scarlet fever is in the neighbourhood. It would be difficult to exaggerate the frequency with which extensive outbreaks of this disease have been distinctly traced to a mild and apparently unsuspicious case of sore-throat. Genuine sore-throat is so rare a phenomenon in an ordinarily healthy child that in most cases, when it does occur, some specific cause for it is to be suspected; and though it may not be accompanied by distinct evidence of connection with scarlatinal poison, it is always best to deal with it as if it were. It is to the neglect of this precaution, not only by the public, but, we regret to say, by a large number of the medical profession, that the difficulty of dealing with scarlatinal epidemics is mainly due; for it is these slight cases of infectious sore-throat, often so trivial as not to prevent the child being sent to school, that spread the disease in the most insidious way.

We observe that the author of this lecture commits himself to the position that typhoid fever can 'in all cases be traced to the drinking of polluted water, the inhaling of sewer-gas, or air tainted with infectious bowel discharges.' This view is, no doubt, sufficiently in accord with the opinions of a large number of trustworthy authorities to justify its being maintained; but we feel sure that those who entertain it will be found, as a rule, to have derived their experience chiefly in urban districts, and that observers who have been enabled to study this disease, as it so frequently occurs in isolated and otherwise healthy conditions in rural spots, will not feel so ready to accept it as an exhaustive solution of the problem of the genesis of a disease which shades off so insensibly into uncomplicated low fever on the one hand, and into simple diarrhoea on the other. Nor do we think that it is at all desirable to inform the public, as the author of this lecture does, that typhoid fever is not infectious, even with the qualification that is added, that it is not so 'in the sense that either scarlet fever or small-pox are infectious.' Such a statement would seem to imply that the difference between the infectiousness of these diseases is one of quality rather than, as it is, one only of relative intensity. That the infection of

DR. SIEMENS'S GAS STOVE.

WE reprint the following description, by Dr. C. W. Siemens, F.R.S., of his new gas stove, from Nature of November 11th:

The growing obscurity which distinguishes the winter atmosphere of London has disposed men to consider whether it is an indispensable evil connected with the use of coal in great centres of population, or whether means can be found of providing the warmth and comfort which the copious use of mineral fuel affords us without having to pay the penalty of dispensing with the solar ray, of finding ourselves and everything we touch covered with soot, and of occasionally having, even at midday, to grope our way with a feeling akin to suffocation.

I am decidedly of opinion that the evil is one which not only admits of remedy, but that its cure would result from a closer attention to the principles of economy in the use of fuel.

A gas-grate that was arranged in my billiard-room in the usual fashion, consisting of three air gas pipes

These

with apertures distributed over the fire-grate, and covered with pumice-stone, presented certainly a cheerless appearance, and filled the room (notwithstanding a fair chimney-draught) with fumes, rendering the benefit of the fire a doubtful one. fumes could not have passed into the room from the upper surface of the pumice-stone, owing to its proximity to the chimney; but a little consideration made me come to the conclusion that these gases really proceeded from the ash-pan into the room. The products of combustion set up by the gas flames ascend no doubt so long as they are intensely hot, but in giving off their heat to the inert pumice-stone they rapidly cool, and being heavier than atmospheric air, descend through the grate between the lines of gas flames, and thus reach the apartment. Moreover, the gas burnt towards the back of the fireplace takes scarcely any part in providing a red radiating surface in front of the grate, serving only to baffle the draught passing towards the chimney from the room. The first condition to be realised in an efficient