III. Suggested Alterations in the Act of Parliament.

Finally, gentlemen, considering that you are about to procure a renewal of your Act of Parliament, and that you contemplate strengthening it with such additional clauses as may render it effective for the eradication of all preventable disease within the City of London, I would ask permission, in this point of view, to submit to you in a connected series, such modifications as in my judgment would contribute to that purpose. Most of these I have already had the advantage of suggesting to your Committee on Health; and to many of them I have adverted by anticipation, in previous passages of my Report. I would beg to enumerate the desiderata under the following heads, viz.

1. A clause, which would give you control over the supply and distribution of water, would enable you in your corporate capacity to contract with any person or any company for the total service of the City; and would authorise you to defray the expenses of such contract by certain specified rates.

2. A clause empowering you to require, that every trade or manufacture practised within the City shall be carried on with such precautions, and with such available improvements, from time to time, as shall reduce to the lowest practicable amount whatever nuisance or inconvenience to the neighbourhood is apt to arise therefrom.

3. Such change in the definition affixed to your 91st clause as would render this operative for the regulation and improvement of a larger number of houses; and such addition to the clause as would enable you, on the joint certificate of your Officer of Health and Surveyor, to enforce the making of additional windows, where requisite for the proper ventilation of houses.

4. A clause permitting and empowering you, on sufficient medical testimony, to remove, or to call upon the Board of Guardians to remove, from any lodging-house, within the new definition of your Act, any person diseased with fever or other infectious malady, whose continuance there would endanger the lives of other inmates.

5. A clause prohibiting the occupation of under-ground cellars for the purposes of dwelling.

6. A clause prohibiting the keeping of cattle in or under dwelling-houses.

7. A clause vesting in the Commission a right to purchase houses by jury valuation, in any case where they shall determine that such houses are permanently unwholesome and unfit for human habitation, or that their alteration or removal is necessary for the public health.

8. A clause enabling the Commission to control all further encroachments on spaces which are now open within the City; so that on ground now unoccupied by buildings, no future erection shall be made, except with the sanction of the Commission.

9. A clause to protect the purity and wholesomeness of human food, as sold within the City, by affixing penalties to its exposure for sale in any adulterated, decayed, or corrupted condition, which may impair its fitness for consumption.

These are the heads under which it has appeared to me that the most useful additions might be made to your Act of Parliament, in matters within the scope of my official observation. There are some other minor modifications, which I have submitted to your Committee of Health, and which, as they relate merely to detail, it is unnecessary for me to bring before you. All the recommendations which I have made on this subject result from a careful scrutiny of the operation of your present Act, during the two years that I have had the honour of serving you. Each separate paragraph of my enumeration founds itself upon a distinct recollection of occasions, sometimes numerous, wherein, for want of such enactments, nuisances which you were anxious to suppress have eluded your authority, or advantages which you were desirous to realise have stood beyond your attainment.

It was in the nature of things that this should be so; for the period has been one of experiment. When the City Sewers Act became law for a period of two years, every one interested in its success must have felt the advantage of that limited duration, and have rejoiced in the opportunity, thus afforded, of rendering it eventually the most perfect embodiment of sanitary law.

Parts of the Act have abundantly fulfilled your intention. In the all-important particular of house-drainage—in the enforcement of water-supply, so far as circumstances rendered possible—in the effective preservation of exterior cleanliness—in the abatement of innumerable nuisances—in the provision and maintenance of sewerage and paving and lighting throughout the City—the public has seen your Hon. Court exercising very large powers with very unusual success. And this, let me add, during a time of no ordinary difficulty: a time when, day by day, the vast importance of sanitary improvement has been gaining ground among the educated classes of the country, as a deep and settled conviction; a time when the feelings of all classes have been powerfully excited, and when the metropolis especially has been convulsed with alarm, in the anticipation and in the aspect of a pestilence.

In some other respects the Act has been less operative, and for an obvious reason. To legislate for health was new to you. It was only through the gradual investigation of officers, appointed under the Act, that you could become adequately informed of those sanitary requirements on which your ultimate legislation for the City must found itself. Only by their slow experience, only by failure as well as by success, was it possible that correct knowledge could be obtained of the powers really needful for fulfilling your sanitary intentions.

In carefully watching the fluctuations of health amid your population; in investigating the causes which determine them; and in testing, on every occasion, how far these causes are amenable to the control of your Act of Parliament, I have arrived at the conclusions submitted to you in the present and in my previous Report.

To excuse the length at which I have addressed you, I have but another word to say. My apology consists in the assurance, which again I lay before you, that in spite of all your exertions, untimely and preventable death still prevails most largely in the population under your charge. If the deliberate promises of Science be not an empty delusion, it is practicable to reduce human mortality within your jurisdiction to nearly the half of its present prevalence.

It is the sad prerogative of my Profession to have such knowledge of death as cannot lie within your experience. Knowing all that is implied in each one separate instance of its visitation—how much pain and sorrow, often how much bereavement and destitution, we, perhaps better than others, learn to appreciate that vast amount of social misery which has its symbol in the high death-rate of a population. It is from this practical point of view that I have ever estimated the importance of your functions, and have fixed the obligations of my own humbler office. Notwithstanding all that Medicine can achieve, to succour the body as it struggles against actual disease—notwithstanding those resources of drugs and handicraft, by which the physician or surgeon opposes death or mitigates pain in the detailed exercise of his art, all past experience, and every transaction of our daily practice, confirm the popular adage that prevention is better than cure. If this be true in any particular case, much more is it true in the largest application. While Curative Medicine—ministering step by step to the individual units of a population, can produce only minute and molecular changes in the health of society; Sanitary Law, embodying the principles of Preventive Medicine, may ensure to the aggregate masses of the community prolongation of life and diminution of suffering: in the working of some single enactment, it may affect the lives of generations of men, and may moderate in respect of millions the sources of orphanage and poverty.

Surely, it is no common epoch in the history of the metropolis when you are appealing to the Legislature, on behalf of the Corporation, for the grant of additional powers towards the accomplishment of so great a beneficence. To me it has always been an act of the deepest and most anxious responsibility to address you; and it would ill have become me now, in the attempt to discharge so grave a duty, if I had spared any pains or withholden any conviction.

While endeavouring in this, and in my previous Report, faithfully and in detail to depict for you the actual condition of human life within the City, and while seeking to deduce for you, from reason and experience, those sanitary principles which are applicable for its improvement, I have had no trivial or easy task; and you will pardon me, I hope, both if I have incompletely surmounted the difficulties of so large a subject, and if, by the length of my Report, I have made too great claims on your indulgence.

I have the honour to remain,
&c., &c.

Note to Column I.

Speaking generally, this column may be taken to express the number of houses in each Ward. Exception must be made, however, in respect of the four wards marked with asterisks; for in them the real number of houses somewhat exceeds the number of assessments. This discrepancy depends on the fact that, in the specified wards, a court containing several houses is often assessed by composition as a single property. Mr. Daw informs me that in order to correct on this score the numbers which stand opposite the Wards in question, addition should be made as follows:—to Bishopsgate Without, 80—raising its number to 1100; to Cripplegate Without, 150—raising its number to 1112; to Farringdon Without, 100—raising its number to 3633; to Portsoken, 150—raising its number to 1408. This would raise the total number to 16,384, which is about the estimated number of houses in the City. From the results of the last census it appeared that the population of the City was distributed as follows:—within the district of the City of London Union on an average of 7·1 persons to each house; within the district of the East and West London Unions on an average of 8·8 persons to each house.

Comparative prevalence, in the several Wards of the City, of such Deaths as particularly depend on local circumstances.

I.II.III.IV.V.VI.VII.VIII.IX.X.XI.XII.
Number
of
Assess-
ments.
vide
[Note].		WARDS.Total
for the
biennial
period,
from
Oct. 1,
1848,
to
Sept.
28,
1850.		Separate
Totals
of the
two years
ending
respec-
tively
Sept. 29.		Cholera,
Dysentery,
Epidemic
Diarrhœa.
Year
ending
Sept.		Fever, &c.
Year
ending
Sept.		Small Pox,
&c.
Year
ending
Sept.		Erysipelas,
Puerp.
Fever,
Pyæmia,
&c.
Year
ending
Sept.		Scarlet
Fever,
Cynanche
Maligna,
&c.
Year
ending
Sept.		Diarrhœa,
Pneumonia,
&
Bronchitis
of Infants.
Year
ending
Sept.		Infantile
Zymotic
Dis.
Hooping-
cough,
Croup,
Measles,
&c.
Year
ending
Sept.		Hydro-
cephalus,
Con-
vulsions,
&c.
Year
ending
Sept.
184918501849185018491850184918501849185018491850184918501849185018491850
184Aldersgate Within3015151...11.........142372242
572Aldersgate Without17912257324155154314...27121391619
809Aldgate102663631772...2252189952010
133Bassishaw7523......1......1.....................11
314Billingsgate3328515...2.........2...3...214......4
334Bishopsgate Within60431720...13......112...356553
*1020Bishopsgate Without3292319888718134535103411932153531
251Bread Street221662...3.........11......63......42
205Bridge181264..................121312112
536Broad Street4229137...41......1...33467132
194Candlewick131217.................................2...31
499Castlebaynard103752828...551...1...4...611105207
341Cheap322210413.........212...53...253
626Coleman Street6642241383......2...3...10962127
294Cordwainer55...2.......................................3...
158Cornhill422..............................2......1...1
471Cripplegate Within8050308...41......223...128771412
*962Cripplegate Without299207928611156373317...332931151921
232Dowgate2520512............2......112...1141
961Farringdon Within1531173667...941111411517921110
*3533Farringdon Without84561323237019484021013123410567233315738
409Langbourn29121731121......211123227
166Lime Street8441...........................11...221
*1258Portsoken1438261295714...2219114101210918
343Queenhithe59362314124211172544416
611Tower4622249...43......131238...147
253Vintry141135...21............1...1...1...52
235Walbrook2415931...2............2243115...
City of London Union251871...72......1...21331...31
15904The Deaths from all
causes within same
period were 6551		 -27951932863825541661181733444013532285243196124264219
480
16384 27958792845084167528320483
I.II.III.IV.V.VI.VII.
Number
of
Assess-
ments.
vide
[Note].		WARDS.Total
for the
biennial
period,
from
Oct. 1,
1848,
to
Sept.
28,
1850.		Separate
Totals
of the
two years
ending
respec-
tively
Sept. 29.		Cholera,
Dysentery,
Epidemic
Diarrhœa.
Year
ending
Sept.		Fever, &c.
Year
ending
Sept.		Small Pox,
&c.
Year
ending
Sept.
18491850184918501849185018491850
184Aldersgate Within3015151...11......
572Aldersgate Without1791225732415515
809Aldgate102663631772...
133Bassishaw7523......1......
314Billingsgate3328515...2.........
334Bishopsgate Within60431720...13......
*1020Bishopsgate Without32923198887181345
251Bread Street221662...3.........
205Bridge181264...............
536Broad Street4229137...41......
194Candlewick131217...............
499Castlebaynard103752828...551...
341Cheap322210413.........
626Coleman Street6642241383......
294Cordwainer55...2...............
158Cornhill422..................
471Cripplegate Within8050308...41......
*962Cripplegate Without29920792861115637
232Dowgate2520512............2
961Farringdon Within1531173667...9411
*3533Farringdon Without845613232370194840210
409Langbourn29121731121...
166Lime Street8441...............
*1258Portsoken1438261295714...2
343Queenhithe5936231412421
611Tower4622249...43......
253Vintry141135...21......
235Walbrook2415931...2......
City of London Union251871...72......
15904The Deaths from all
causes within same
period were 6551		 -27951932863825541661181733
480
16384 279587928450
I.II.VIII.IX.X.XI.XII.
Number
of
Assess-
ments.
vide
[Note].		WARDS.Erysipelas,
Puerp.
Fever,
Pyæmia,
&c.
Year
ending
Sept.		Scarlet
Fever,
Cynanche
Maligna,
&c.
Year
ending
Sept.		Diarrhœa,
Pneumonia,
&
Bronchitis
of Infants.
Year
ending
Sept.		Infantile
Zymotic
Dis.
Hooping-
cough,
Croup,
Measles,
&c.
Year
ending
Sept.		Hydro-
cephalus,
Con-
vulsions,
&c.
Year
ending
Sept.
1849185018491850184918501849185018491850
184Aldersgate Within...142372242
572Aldersgate Without4314...27121391619
809Aldgate2252189952010
133Bassishaw1.....................11
314Billingsgate2...3...214......4
334Bishopsgate Within112...356553
*1020Bishopsgate Without35103411932153531
251Bread Street11......63......42
205Bridge...121312112
536Broad Street1...33467132
194Candlewick..................2...31
499Castlebaynard1...4...611105207
341Cheap212...53...253
626Coleman Street2...3...10962127
294Cordwainer........................3...
158Cornhill............2......1...1
471Cripplegate Within223...128771412
*962Cripplegate Without3317...332931151921
232Dowgate......112...1141
961Farringdon Within11411517921110
*3533Farringdon Without13123410567233315738
409Langbourn...211123227
166Lime Street............11...221
*1258Portsoken219114101210918
343Queenhithe1172544416
611Tower131238...147
253Vintry......1...1...1...52
235Walbrook......2243115...
City of London Union1...21331...31
15904The Deaths from all
causes within same
period were 6551		 -444013532285243196124264219
480
1638484167528320483

Letter by Mr. Thomas Taylor, Lecturer on Chemistry at the Medical School of the Middlesex Hospital, on the Chemical Qualities of certain Waters.

4, Vere-street, Oxford-street,
November, 1850.

Dear Sir,

Having, by your desire, submitted the following samples of water to chemical analysis, I now beg leave to lay before you the result; and also, at the same time, to reply to certain questions which you likewise proposed.

The samples of water taken for examination were derived from the following sources:—

A. This water was taken from an upright pipe in a court-yard of the Guildhall. It was slightly opalescent, inodorous, and tasteless; numerous small particles floated in it, which took a considerable time to subside. The matter deposited was of a rust colour, and consisted of peroxide of iron, with a little sulphate and carbonate of lime, and organic matter. It is to be observed that, as the water from this pipe is seldom used, these impurities collect in the pipe, and are therefore in some measure accidental, although, prior to collecting the water, a considerable quantity had been allowed to run away. The water was allowed to free itself from these impurities by subsidence, before being submitted to analysis.

By evaporation to dryness, an imperial gallon left a solid residue, weighing 17·33 grs., which consisted of—

Carbonate of lime, with a little oxide of iron11·12
Carbonate of magnesia0·60
Sulphate of lime1·56
Chloride of sodium2·40
Silicic acid0·37
Organic matter1·19
17·24

When heated, this water became turbid; and, by continued boiling for two hours in an apparatus so arranged that the whole of the steam was condensed and returned to the water, 10·95 grs. of the earthy carbonates, coloured by oxide of iron, were deposited.

The relative hardness of this water, as determined by the soap test, distilled water being taken as unity, was 13·3.

B. The second sample of water was taken from a small tap in the house of Mr. Hall, Bishopsgate-street. The tap was attached to the main.

This water was without smell or taste, and free from floating matter. After standing some time, it deposited a very small quantity of oxide of iron. Although clear and transparent, it was not bright.

It contained 19·10 grs. of solid matter in the imperial gallon. The solid matter consisted of—

Carbonate of lime, with a little oxide of iron14·58
Carbonate of magnesia0·44
Sulphate of lime1·54
Chloride of sodium1·71
Silicic acid0·32
Organic matter0·72
19·31

Like the preceding water it became turbid when heated to the boiling point, and by continued ebullition for two hours, 12·90 grs. of carbonate of lime, coloured by oxide of iron, were precipitated.

Hardness in reference to distilled water as unity = 19.

C. This water was taken by ourselves from a spring-head near Haslemere, Surrey. The spring issued from the foot of a low sand-hill covered with bushes, and was received into a natural basin about four or five feet in diameter, the bottom of which was lined with pebbles and small gravel. From this basin the water flowed into a large shallow pond.

The temperature of the spring at its source was 49° Fahr., that of the air being 56° Fahr.

This water was perfectly clear and brilliant, but not sparkling. It had no appreciable taste, but was peculiarly soft and agreeable. It did not contain carbonic acid in a free state, for when mixed with a solution of chloride of calcium and of ammonia not the slightest turbidity was produced. When boiled it did not lose its transparency, nor produce any deposit, until concentrated to about one-sixth of its volume, when glittering scales of hydrated silicic acid separated.

An imperial gallon, when evaporated to dryness, left a solid residue, which weighed 5·24 grs.

This residue was perfectly white when dried at 300° Fahr.; when heated to low redness, it charred slightly at the edges. The quantity of organic matter was therefore exceedingly small.

Hardness in reference to distilled water as unity = 2·4.

On analysis, an imperial gallon was found to contain—

Carbonate of lime2·00 
Chloride of sodium1·46 
Sulphate of soda0·407
Silicic acid1·143
Organic matter0·23 
5·24 

Traces of an alkaline nitrate were also detected.

During the short visit I made with you to Farnham, we examined several other springs near to their sources. In their general characters these waters closely resembled the preceding sample, all of them being remarkably soft, clear, transparent, inodorous, and free from any excess of organic matter, or of oxide of iron.

By your desire two samples were subsequently sent to me; one marked ‘Barford,’ the other ‘Boorley.’

The water marked Barford contained 6·30 grs. of solid matter in the imperial gallon; when evaporated, scales of silicic acid separated from it in the same manner as from the water taken at Haslemere. Neither of these waters contained any trace of carbonic acid. Their relative hardness (distilled being unity) was—Barford 2·4, Boorley 1·5.

D. The fourth sample of water was drawn from the pump near the church in Bishopsgate-street.

This water was selected as exemplifying the general composition of the shallow well-water of the City of London, when the well is situated near to a burial-ground, as is frequently the case with the parochial wells.

The water from this well is perfectly bright, clear, and even brilliant; it has an agreeable soft taste, and is much esteemed by the inhabitants of the parish, although, as will be seen by the subjoined analysis, it is an exceedingly hard water, and the large quantity of earthy salts it contains renders it unfit for all culinary and for most domestic purposes.

When heated to the boiling point, this water becomes turbid, and by continued boiling of an imperial gallon of the water for two hours, 23·03 grs. of solid matter were deposited, consisting of 22·15 grs. carbonate of lime, and 0·88 carbonate of magnesia, with a trace of phosphate of lime.

An imperial gallon of this water, when evaporated to dryness and the residue dried at a temperature of about 300° Fahr., left a residue which amounted to 88·07 grs. From another sample of the same water taken a month afterwards, 84·53 grs. of solid residue were obtained.

By an analysis, an imperial gallon of the water gave—

Carbonate of lime28·97
Carbonate of magnesia2·61
Sulphate of lime17·85
Chloride of sodium16·95
Nitrate of potass12·40
Nitrate of soda1·50
Nitrate of magnesia4·92
Nitrate of ammonia4·01
Silica0·80
Phosphate of limetraces
Organic matter
90·01

The residue left by evaporation was of a light brown colour; when calcined at a low red heat it became slightly charred; but I could not, with any degree of certainty, determine the precise quantity of organic matter it contained: it was certainly very small.

The excess of solid matter, as shown by the analysis, over the quantity obtained by evaporating the water to dryness, is owing to the decomposition of the nitrate of ammonia.

The quantity of alkaline and earthy nitrates in this water is very remarkable. These salts are doubtless derived from the decomposition of animal matter in the adjacent churchyard. Their presence, conjoined with the inconsiderable quantity of organic matter which the water contains, illustrates in a very forcible manner the power the earth possesses of depriving the water that percolates it of any animal matter it may hold in solution; and moreover shows in how complete and rapid a manner this process is effected.

In this case the distance of the well from the churchyard is little more than the breadth of the footpath, and yet this short extent of intervening ground has, by virtue of the oxidizing power of the earth, been sufficient wholly to decompose and render inoffensive the liquid animal matter that has oozed from the putrefying corpses in the churchyard.

The result of these analyses confirms the general statement that the water derived from the sandy districts of Farnham and Bagshot is of eminent purity, and therefore peculiarly fitted for all those purposes of domestic and manufacturing economy which require the use of a very soft water.

When regarded in conjunction with the analyses made by other chemists, of the water taken from the streams, pools, and other collections of water in the same locality, it also points out that, if it be desirable to secure the water in its utmost state of purity, it should be collected at its very source, before it has had time to become impregnated with the various mineral and saline ingredients of the different soils through which it would have to pass. The total absence of free carbonic acid in these waters is a very remarkable fact, and one which I believe has not been hitherto noticed.

It will also be perceived that the principal solid constituent of the water supplied by the New River and the East London companies is carbonate of lime, held in solution by an excess of carbonic acid, an opinion already expressed by several chemists. These waters also contain an appreciable quantity of oxide of iron.

When the water from these sources is boiled, or simply brought to the boiling temperature, the excess of carbonic acid is driven off, and the carbonate of lime being thus deprived of its solvent, the greater portion of it, together with the oxide of iron, is thrown down in the form of an insoluble crystalline powder, while the water is rendered comparatively soft and pure.

Were it therefore possible that means could be devised by which the quantity of water necessary for the daily supply of London could be deprived of its excess of earthy carbonates in a manner sufficiently economic, comprehensive, and effectual, the citizens of the metropolis would enjoy the advantage of a tolerably pure soft water, free from those inconveniences which attend the use of the present hard-water supply.

Confining myself wholly to a chemical view of the subject, the principal disadvantages attending the use of hard river waters are—

First, The precipitation of earthy matter on the inside of vessels in which the water is heated. This furring of the vessel, as it is called, leads to its more rapid destruction, and has also the inconvenience of rendering it more difficult to cleanse, so that the flavour and odour of the various substances cooked in it are not readily removed. From the non-conducting power of the earthy crust, an increased consumption of fuel is also required for the due heating of the vessel.

Secondly, The admixture of the earthy salts with the various articles of food submitted to the action of hot water.

Thirdly, Diminished solvent power, as required for the purposes of the chemist, the brewer, and for many domestic purposes, as in the making of tea, soups, &c.

Fourthly, Diminished cleansing power, both as regards the direct solvent action of the water, and also as causing the decomposition of soap, and consequent increased consumption of that article. I must, however, remark that the annual loss reported to arise from this cause appears to me considerably overrated, since water is rarely used for the washing of linen until previously boiled, and the common practice of adding carbonate of soda to the water completely destroys the ill effects resulting from the hardness of the water. The additional expense of the carbonate of soda, thus added, is too trifling to merit notice; but when this salt is used in excess, as is generally the case, it produces the more serious evil of materially impairing the strength of the fabric submitted to its action.

The only real advantage which hard water possesses over soft (and in the present state of things one of considerable importance), is, that it does not act upon or erode the lead of the pipes and cisterns in which it is contained.

There are also some particular cases of minor importance in which hard water is preferred; thus dyers prefer hard water for rinsing of their goods, soft water extracting too much of the colour; but these cases are comparatively rare, and might be easily accomplished by an artificial hardening of the water.

The following Table indicates the relative hardness of the different waters as determined by the Soap test; distilled water being taken as unity, as proposed by Professor Brande. It also shows the effect of boiling in reducing the hardness of the water. The numbers express the direct quantity of an alcoholic solution of soap, which an equal bulk of each water requires in order to form a lather remaining permanent for from five to ten minutes.

Distilled water1·0
Water fromHaslemere2·4
Boorley1·5
Barford2·4
Water of the New River Company13·3
Dittoafter being boiled4·7
Water of the East London Company19·0
Dittoafter being boiled5·6
Water from the well in Bishopsgate-street47·4
Dittoafter being boiled26·0

The experiments which I have recently made on the action of pure water upon lead, clearly point out the necessity of keeping the pipes always full, especially in those instances in which the water has a tendency, however slight, to erode the lead. As the importance of this part of the question does not appear to have been sufficiently appreciated by the advocates of a constant instead of an intermittent supply, I will briefly recount the facts of the case, although I do not offer them as presenting anything particularly novel. If a piece of bright lead be placed in a stoppered bottle, completely filled with recently distilled water, so that the access of air be wholly excluded, the lead is but very slightly acted upon, and it is only after the lapse of three or four days that its surface becomes spangled with a few minute crystals of carbonate of lead.

If the stopper of the bottle be now removed, the lead still remaining beneath the surface of the water, the erosive action of the water on the lead proceeds more rapidly, but still slowly. But if now a portion of the water be poured off, so as to leave the lead only partially immersed, rapid action on the lead immediately commences. In the course of thirty-six or forty-eight hours, its surface becomes coated with crystalline scales of carbonate of lead, which, falling off, are succeeded by others, so that after the lapse of a few days an abundant deposit of carbonate and hydrated oxide of lead is found at the bottom of the vessel. If the experiment be made with distilled water that has been previously agitated with air, so as to completely aërate it, the lead is more rapidly acted upon, even in a closed vessel, thus clearly showing how much the action of the water upon the lead depends upon the presence or absence of atmospheric air.

Now, in a minor degree, this is precisely what takes place in a leaden pipe conveying water capable of eroding lead. While the pipe is full, comparatively but little action occurs; but when the pipe is filled alternately with air and with water, it is placed under the most favourable circumstances to ensure a rapid erosion of its substance, and consequent contamination of the water.

The rush of water necessarily produced by an intermittent flow must also detach portions of carbonate of lead from the sides of the pipe, even in those cases where the water has no very decided action on lead, and it is therefore far from improbable that in this manner the poison of lead is occasionally conveyed into our kitchens, and becomes mixed with our food.

According to your desire, I have examined the action of the waters from the above-mentioned sources on clean lead, and have arrived at the following conclusions:—the water from Haslemere has a slow though decided action upon the metal, no effect taking place until the lead had been partially immersed for four or five days. After that time, a small deposit of carbonate of lead was perceptible at the bottom of the vessel, although none could be detected in solution. The absence of carbonic acid in the water from Haslemere, Boorley, and Barford, would in all probability prevent their acting upon lead, were atmospheric air at the same time excluded. A piece of lead that had been kept for a week in a closed bottle filled with water from Haslemere did not exhibit the least trace of carbonate of lead, nor could the presence of lead be detected in the water.

It is scarcely necessary to add, that the water as drawn from the pipes of the New River and East London Companies does not exhibit the least solvent action upon lead; when, however, purified by boiling, and placed in contact with lead, crystals of carbonate of lead were observable after the lapse of three days in the water of the New River Company, while, owing to its greater hardness, the water of the East London Company did not exhibit any traces of carbonate of lead until the expiration of more than a week, and even then only in a slight degree. The same waters purified by the patented process of Clark did not exhibit so decided an action upon lead as when purified by boiling; but after evaporating to dryness the water in which lead had been immersed for three weeks, and dissolving the residue in dilute nitric acid, the presence of a minute quantity of lead was rendered evident.

It therefore appears that if leaden pipes, and especially if leaden cisterns, are to be employed in the distribution and storage of water, on the system of interrupted supply, it will be a necessary safeguard, that the water thus conveyed and stored should not be of less hardness than from six to seven degrees, compared with distilled water as unity; and conversely, it also follows, that if the inhabitants of the metropolis are to gain the advantage of using a still purer and softer water, it will be requisite to do away with the existing leaden pipes and cisterns, and to substitute for them some material which shall not communicate any poisonous or noxious ingredient to the water. As matters now stand, we escape daily poisoning by the use of water loaded with earthy salts, and are thus compelled to drink an impure water on account of the impurity of our vessels. Would it not be better, and is it impossible, to drink the pure element from a pure cup?

I remain, dear sir, with much respect,
Yours obediently,
Thomas Taylor.

To John Simon, Esq., F.R.S.,
Officer of Health to the City of London.