e/f
IA.
WATER AND WATER SUPPLIES
WATEE
AND
WATEE SUPPLIES
JOHN C. THEESH,
\\
D.SC. (LONDON); M.D. (VICTORIA); D.P.H. (CAMBRIDGE);
MEDICAL OFFICER OF HEALTH TO THE ESSEX COUNTY COUNCIL. LECTURER
ON " PUBLIC HEALTH," KING'S COLLEGE, LONDON. EDITOR OF THE
"JOURNAL OF STATE MBDICINE." HON. SEC. INCORPOR-
ATED SOCIETY MEDICAL OFFICERS OF HEALTH.
FELLOW OF THE INSTITUTE OF CHEMISTRY.
MEMBER OF THE SOCIETY OF
PUBLIC ANALYSTS, ETC.
SECOND REVISED EDITION.
PHILADELPHIA:
P. BLAKLSTON'S SON & CO.,
1012 WALNUT STREET.
1900.
Printed in England.
Entered at Stationers' Hall.
PREFACE
IT is now fully recognised that an abundant supply of
pure water is an absolute necessity for the preserva-
tion of health, and that one of the chief duties of all
Sanitary Authorities is to see that all the inhabitants
of their districts have, within a reasonable distance,
an available supply of wholesome water wherever
such can be obtained at a reasonable cost.
The main object of this little work is to place
within the reach of all persons interested in public
health the information requisite for forming an
opinion as to whether any supply or proposed supply
is sufficiently wholesome and abundant, and whether
the cost can be considered reasonable.
It does not pretend to be a treatise on Engineer-
ing, yet it is hoped that it contains sufficient detail
to enable any one who has studied it to consider in-
telligently any scheme which may be submitted for
supplying a community with water, whether that
community be large or small.
Whilst all our large towns have obtained more or
less satisfactory supplies of water for their inhabitants,
the great bulk of the population living in villages and
rural districts generally is still dependent upon im-
properly constructed and unprotected shallow wells,
vi WATER SUPPLIES
or even upon more questionable sources for its supply.
The cause is not far to seek. Neither the Sanitary
Authorities nor the rural populations are as yet fully
alive to the importance of a good water supply, and
have no knowledge of how to set about remedying
the present conditions even if regarded as unsatis-
factory. There is also a widespread and generally
erroneous impression that scattered populations cannot
be supplied with water from sources at a distance at
a reasonable cost. To prove the fallacy of this im-
pression particulars are given of a few typical schemes
which have been successfully carried out in thinly-
populated districts, and it is hoped that the example
set by these enterprising authorities will be widely
followed.
The supply of water to rural districts is a
question which has engrossed the attention of
Medical Officers of Health ever since such officials
were appointed, but too often they have been satisfied
with merely reporting that water supplies were un-
satisfactory. Such reports are not sufficient to over-
come the apathy of Sanitary Authorities or to
arouse any great interest in the subject in the
districts concerned. The Medical Officer must not
only prove that the present supplies are inadequate in
quantity or unwholesome in quality, or both, but in
conjunction with the Surveyor he must be prepared
to formulate a scheme and to prove that it is practi-
cable. To enable him to do this is one of the objects of
this work. The practical experience gained in large
rural districts in which it has been my privilege to
submit such schemes and see them carried to a success-
ful completion, is embodied in various chapters, and
PREFA CE vn
I hope will prove of value to all who are interested
in the well-being of our rural populations.
A brief rtsumt of the law relating to water supplies
is given in the final chapter, and I have to thank my
friend, A. Freeman, Esq., Clerk to the Maldon Rural
District Council, for many suggestions, and for revising
everything therein relating to the law.
All schemes for establishing public water supplies
in districts hitherto dependent upon water from ques-
tionable sources are certain to meet with considerable
opposition, but District Councils and their officers
may take heart from the experience of others. Carry
out the work satisfactorily, and those who were loudest
in opposition will ere long frankly acknowledge the
value of the boon conferred.
JOHN C. THRESH.
CHELMSFORD, January 1896.
CONTENTS
CHAPTER I
WATER, ITS COMPOSITION, PROPERTIES, ETC.
Composition of water Pure water not found in nature Effect of
temperature Maximum density Latent heat Expansion during
act of freezing Boiling point influenced by atmospheric pressure
Evaporation of water, snow, and ice Solvent powers Common
constituents of natural waters Hardness Action on metals Lead
poisoning Hygienically pure water Mineral waters Portable
waters, classification of. . . . . . Pages 1-11
CHAPTER II
RAIN AND EAIN WATER
Distillation Moisture contained in the atmosphere Evaporation,
from the ocean, from land surfaces, etc. The causes of rain
Rainfall, by what influenced, how determined Constituents of
rain water, effect of proximity to ocean, towns, etc. Pollution
during collection and storage Amount available from roofs, and
specially prepared surfaces Rain-water separators Storage for
domestic purposes Rainfall source of all water supplies Natural
waters in order of purity Composition of rain water
Pages 12-27
CHAPTER III
SURFACE WATER
Characteristics of, from various geological formations Effect of soil and
cultivation of ground surface Ponds, lakes, and reservoirs Lakes
as natural reservoirs, Loch Katrine, Lake Vyrnwy, Thirlmere
Aberystwith water supply Glasgow water supply Analyses of
upland surface waters Analyses of public water supplies derived
from uplands and moorlands .... Pages 28-40
x WATER SUPPLIES
CHAPTER IV
SUBSOIL WATER
Bogs, marshes, and swamps Pervious and non-pervious subsoils
"Pockets" of gravel Permeability, imbibition, and saturation of
rock Variation in level of subsoil water and the causes thereof
Amount of water held by various rocks Movement of subsoil
water Proportion of rainfall which percolates into subsoil
Water, how obtainable from subsoil Quantity obtainable, how
ascertained Shallow- well water Subterranean rivers Budapest
and Perth examples of towns supplied from subsoil Quality of
subsoil water How 7 polluted Koch on "subsoil water " Towns
in Massachusetts supplied with subsoil water Effect of towns,
villages, etc., on subsoil water Example, village of Writtle,
Essex Analyses of shallow-well waters from various geological
sources Analyses of public and other supplies derived from
subsoil . . . . . . . Pages 41-54
CHAPTER V
NATURAL SPRING WATER
Perennial, intermittent, and variable springs Origin of springs Cold
hot, ascending and descending springs Artificial springs The
natural springs of Clifton, Batii, Buxton, Matlock, and Chelten-
ham Springs, how? gauged Causes of variation in flow Dr.
Whitaker on the King's Lynn water supply Bristol supplied
from springs Utilisation of springs Character of spring water
from various geological sources Analyses of spring waters
Pages 55-69
CHAPTER VI
DEEP-WELL WATERS
Difference between "shallow" and "deep" wells Artesian wells-
Subterranean reservoirs or rivers Source of deep -well water-
Chief water-bearing strata Supply obtainable from deep wells,
how affected : by extent and character of outcrop, average rainfall,
continuity of water-bearing strata, selection of site Advantages
of underground water supplies Effect of proximity to other wells
Supply to Long Eaton, Castle Donington, and Melbourne
Supply of deep-well water for the City of London Report of
Royal Commission on metropolitan water supply Deep wells in
the Colonies, United States Recent analyses of deep-well waters
Pages 70-85
CONTENTS xi
CHAPTER VII
RIVER WATER
Catchment basins Drainage areas Effects of towns, villages, manu-
factories, etc. , within a drainage area Self-purification of rivers
The Seine, Thames, Tees, etc. Flow of streams Amount of
water available, factors influencing Maximum, minimum, and
mean rainfall Seasonal variation of rainfall, effects of Portion
of rainfall reaching rivers Stream gaugings, different methods
of Towns deriving their water supplies from rivers
Pages 86-103
CHAPTER VIII
QUALITY OF DRINKING WATERS
Colour of pure and impure waters Taste and odour, by what in-
fluenced Effect of mineral, animal, and vegetable impurities
Turbidity, to what due Organisms found in water Soluble con-
stituents of potable waters, inorganic and organic -What con-
stitutes a good potable water ... . . Pages 104-121
CHAPTER IX
IMPURE WATER AND ITS EFFECT UPON HEALTH
Constituents which may cause diarrhoea Diseases caused by mineral
constituents : goitre, diarrhoea, plumbism, etc. Diseases due to
specific organisms : malaria, enteric or typhoid fever, cholera,
yellow fever, oriental boils, Zoo - parasitic diseases : Bilharzia,
/uuniatobia, Filaria sangtiinis, Filaria dracunculus, etc. Diseases
of animals caused by impure water . . . Pages 122-159
CHAPTER X
THE INTERPRETATION OF WATER ANALYSES
The inorganic, organic, and bacterial constituents, relative importance
of Erroneous conclusions may be drawn from both chemical and
bacteriological analyses Significance of chlorides, nitrates and
nitrites, ammonia, phosphates, organic matter Albumenoid
ammonia Organic carbon and oxygen Oxygen absorbed Sir
Charles Cameron on the value of chemical analyses Intermittent
pollution Variation in quality of water from one and the same
source Table of analyses, showing bow little dependence can be
xii WATER SUPPLIES
placed upon the results of a chemical analysis Remarks on the
waters referred to in the Table of Analyses The bacteriological
examination of water Microbes found in water and their signifi-
cance Standard of purity, absurdity of Importance of the
examination of the source of the water . . Pages 160-192
CHAPTER XI
THE POLLUTION OF DRINKING WATER
Pollution at its source Surface and river waters Subsoil water Deep-
well water Pollution arising during storage Pollution during
distribution Pages 193-214
CHAPTER XII
THE SELF-PURIFICATION OF RIVERS
Rivers, how polluted Natural purification Oxidation, sedimentation,
effect of sunlight, organisms, etc. Can a sewage-polluted river
water ever be rendered perfectly safe for a public water supply ?
Pages 215-224
CHAPTER XIII
THE PURIFICATION OF WATER ON THE LARGE SCALE
Sedimentation Filtration, efficiency of, how determined Dr. P.
Frankland's experiments at the London Waterworks Table
showing effect of subsidence Experiments conducted by the
Massachusetts State Board of Health Effects of (a) rapidity of
filtration, (b) thickness of filtering media, (c) fineness of filtering
media, (d) scraping the surface of filter, etc. Conclusions based
upon Massachusetts experiments Dr. Koch on the "conditions
necessary for efficient filtration" The Altona Waterworks-
Action of sand Construction of filter beds Size and number of
beds required Table showing area of filter and rate of filtration
at different works Natural filtration Filter galleries Atkins'
scrubbers American filtering machines Polarite, spongy iron,
magnetic carbide, and other filtering materials ; where used ;
efficiency of Sand washing " Softening " purifies water
Pages 225-246
CHAPTER XIV
DOMESTIC PURIFICATION
Low-pressure filters High-pressure filters Table filters Cottage
filter Efficiency of filters Distillation Aeration Purification
by the addition of chemicals .... Pages 247-255
CONTENTS xiii
CHAPTER XV
THE SOFTENING OF HARD WATER
Softening by boiling; by addition of chemicals Clark's lime process
Atkins' process Southampton Waterworks The "Porter-Clark "
process The Stanhope water softener The Howatson "Softener "
Stroud Waterworks Cost of various processes Saving effected
by using soft water in houses, institutions, and towns
Pages 256-271
CHAPTER XVI
QUANTITY OF WATER REQUIRED FOR DOMESTIC AND
OTHER PURPOSES
Variation in rural and urban districts Purposes for which water is
required Various estimates of amount required for different
purposes Constant versus intermittent supplies Tables showing
amount supplied in various towns Newcastle and Wolverhampton
records Daily supply by London Water Companies Waste of
water Unnecessary consumption Prevention of waste Saving
effected by Deacon's meters at Liverpool, Exeter, and elsewhere
Amount of water required in tropical climates Daily quantity
required by various animals .... Pages 272-283
CHAPTER XVII
SELECTION OF SOURCES OF WATER SUPPLY AND AMOUNT
AVAILABLE FROM DIFFERENT SOURCES
Various sources Finding water Water "finders" Selection of site
for wells Drainage area The Stockport water supply Amount
yielded by various water-bearing formations . Pages 284-304
CHAPTER XVIII
WELLS AND THEIR CONSTRUCTION
Shallow wells How usually constructed Improved methods of
constructing Tube wells Koch's advice with reference to shallow
we ll s Abyssinian tube wells Amount of water yielded by
various tube wells Cost of sinking wells Cost of driving tubes
Deep wells Pumping directly from tubes Pumping from storage
reservoir Multiplication of tube wells to increase supply Defects
in tube wells Yield of water from deep wells Deep wells in
Queensland, South Australia, Victoria, Cape of Good Hope,
United States, and other countries . . . Pages 305-331
xiv WATER SUPPLIES
CHAPTER XIX
PUMPS AND PUMPING MACHINERY
Various types of pump Lifting pumps Plunger or force pumps
Centrifugal pumps Bucket and plunger pump Quantity of water
delivered by each stroke of pump "Efficiency " of pumps
Height to which water can be raised (a) by manual labour, (b) by
donkey working a gin, (c) by horse working a gin, by one horse-
power engine Wind engines Water as a motive power Rams,
turbines, and water- wheels : Fuel engines Hot-air engines Oil
engines Gas engines Steam engines Horse-power required
Pages 332-356
CHAPTER XX
THE STORAGE OF WATER
Impounding reservoirs Settling reservoirs Service reservoirs Classi-
fication of waterworks Effect of storage Covered versus open
reservoirs Capacity of storage reservoirs to compensate for the
inequality of hourly consumption and provide reserve in case of
fire Rain-water tanks Bouse cisterns . . Pages 357-368
CHAPTER XXI
THE DISTRIBUTION OF WATER
The "constant" system The "intermittent" system Conduits and
aqueducts, size of, fall required Various kinds of mains Eytel-
wein's formula Depth of mains Dead ends, advantages and
disadvantages House service pipes, lead, tin-lined lead, wrought
iron, galvanised iron Regulations made under the Metropolis
Water Act, 1871 Pages 369-380
CHAPTER XXII
THE LAW RELATING TO WATER SUPPLIES
Land and water rights, voluntary and compulsory purchase of Sale
of rights by limited owners Roadside waste land, ownership
of Precautions to be taken when purchasing lands, springs,
etc. Rights of riparian proprietors Water flowing in definite
channels Underground water Waterwork Clauses Acts Water
rates and rents Cost and maintenance of waterworks, by whom
borne Parish Councils and water supplies The Public Health
Act 1875 The Public Health (Water) Act 1875 The Limited
CONTENTS xv
Owners Reservoirs and Water Supply Further Facilities Act, 1877
Important legal decisions affecting water supplies
Pages 381-399
CHAPTER XXIII
RURAL AND VILLAGE WATER SUPPLIES
General neglect to provide rural supplies, causes of Advantages of
public supplies Description of typical works, with cost of works,
cost of maintenance, water rates levied, etc. Spring water raised
by hydraulic ram Gravitation works Spring water raised by
steam pump Subsoil water raised by steam pump Subsoil water
gravitation works Spring water raised by water-wheel Deep-
well water raised by windmill Spring water pumped by turbine
Deep-well water raised by an oil engine Spring water raised
by a gas engine Table of rates Charges for domestic supply of
water in various towns .... Pages 400-417
APPENDIX
1. Crenothrix, cause of disagreeable odours in water 2. Zinc-
contaminated water, effect upon health 3. Plumbo-solvent
action of moorland water 4. Pollution of water in reservoir,
outbreak of typhoid fever 5. Pollution of water supply by
melting snow, outbreak of typhoid fever 6. Pollution of water
in mains 7. Pollution of a deep well near Edinburgh 8. Typhoid
fever in the Bolan Pass 9. Self-purification of streams
Pages 418-422
o*
UNIVERSITY
WATEE SUPPLIES
CHAPTEE I
WATER, ITS COMPOSITION, PROPERTIES, ETC.
FEOM the time of Aristotle until the close of the eighteenth
century, water was regarded as an elementary substance, that
is, one which could not be split up or decomposed into any
simpler forms of matter. In 1781 an English chemist, Henry
Cavendish, discovered that when two gases, oxygen and
hydrogen, were mixed together in certain proportions (two
of hydrogen to one of oxygen) and an electric spark passed
through the mixture, combination took place and water was
formed. Many other ways have since been devised for
causing these gases to combine and for demonstrating that
water is the product formed. By other methods also water
can be decomposed and made to yield the two elements which
alone enter into its composition when pure. For example, if
a strong current of electricity be passed through water,
bubbles of gas are given off from each terminal or pole. At
the one pole the gas consists of pure oxygen, at the other of
pure hydrogen, and the volumes obtained are two of the
latter to one of the former. As oxygen is sixteen times as
heavy as hydrogen, the composition of pure water is as
under :
By volume. By weight.
Oxygen ... 1 part . . 8 parts.
Hydrogen ... 2 parts . . 1 part.
B
2 WATER SUPPLIES
Pure water is a chemical curiosity. The moisture which
bedews the tube in which the mixture of hydrogen and
oxygen has been exploded is water in its purest form. If,
however, it be exposed to the air or be allowed to stand in
contact with any substance (save perhaps some of the less
oxidisable metals, as platinum and gold) it will absorb
gases from the air or dissolve some of the material of the
vessel in which it is placed, and from a chemical point of
view is no longer pure. Pure water does not occur in nature,
even rain water caught in mountainous districts far from the
smoke of towns or the haunts of men contains traces of
impurities taken up from the air. When the foreign sub-
stances are present in so small quantities as not appreciably
to affect the physical properties of the water, or to render it
unfit for domestic and manufacturing purposes, it is popularly
spoken of as " pure," and it is in this sense that the term
" pure water " will in future be used throughout this book.
Pure water, when viewed in small quantities, appears to be
perfectly colourless, but when viewed in bulk, as in the white
tiled baths at Buxton, and in certain Swiss lakes, it is seen to
possess a beautiful greenish-blue tint. A very small amount
of suspended or dissolved impurity is sufficient to obscure
this colour. Impure waters almost invariably exhibit a
colour varying from green to yellow and brown when
examined in suitable tubes about two feet in length, but, as
will be seen later, it does not always follow that a water with
a brownish tint is too impure for domestic use. Pure water
is absolutely devoid of odour and is destitute of taste. The
purest is insipid, but if such a water be aerated by agitation
with air or by nitration through a porous, air -containing
medium, the insipidity disappears. Practically, water is
incompressible, but the volume of a given weight varies very
considerably with the temperature. With very few exceptions
all fluids expand when heated and contract when cooled.
The most important exception is water between certain
temperatures. As the effect of heat upon water has a direct
WATER, ITS COMPOSITION, PROPERTIES, ETC. 3
bearing upon certain points connected with water supplies,
it is necessary briefly to consider the action of change of
temperature. If a quantity of pounded ice, with a little
water, be placed in a glass beaker in which two thermometers
are placed, one at the bottom and the other near the surface
of the mixture, it will be found that both indicate the same
temperature, C. If now some source of heat be applied to
the beaker, it will be observed that neither thermometer will
indicate any increase of temperature until the last particle of
ice is melted. The heat, as such, has disappeared, its effect
upon the ice being not to raise its temperature but to liquefy
it. The same fact can be proved by another simple experi-
ment, which enables us also to measure the amount of heat
which disappears or becomes latent. If one pint of water, at
the temperature of C., be mixed with one pint of water at
79 C., the temperature of the mixture will be the mean,
39 '5 C. If, however, ice at C. be substituted for the cold
water, the whole of the ice will melt, but the temperature of
the resulting fluid will not be 39'5 C. but 0. Water at 0,
i.e. at its freezing point, may be said to be ice plus heat.
This heat, which becomes latent during the process of lique-
faction, is again given off when water freezes. As the surface
of a sheet of water freezes, the water, in the act of solidification,
gives up a certain amount of heat. This raises the tempera-
ture of the remaining water, and so the process of freezing or
solidification is retarded. Were not this the case, during
winter water would freeze with great rapidity, and the ice so
formed would as rapidly melt when the weather became
warmer. Such a condition of things would render all but
the tropical and sub-tropical regions practically uninhabitable
during certain portions of the year. As soon as the tempera-
ture sank below zero, ice would so quickly form that our lakes,
reservoirs, streams, etc., would contain only solid ice. Snows
would melt so rapidly with a slight increase of temperature
that most disastrous floods would follow. This sudden
freezing also would result in the bursting of every water
4 WATER SUPPLIES
main and pipe, since water in the act of solidification expands
considerably, eleven pints of water when frozen forming
twelve pints of ice, or, in other words, water expands one-
eleventh of its volume in the act of freezing. The effects of
this expansion are disastrous enough to water mains and
pipes when the freezing process is retarded by the heat given
off by the water as it solidifies ; but if the solidification took
place suddenly, as soon as the temperature fell slightly below
zero, the expansion, being uniform in every direction, would
burst every pipe or vessel in which the water was contained.
The force so exerted in the act of freezing is enormous.
Thick iron shells filled with water and securely plugged are
easily burst by exposure to the cold of a Canadian winter's
night.
Water is at its maximum density at 4 C. If cooled below
that temperature it expands ; if the temperature is raised it
also expands. It thus differs from nearly all other liquids,
which at all temperatures between their freezing and boiling
points expand when heated and contract when cooled. If a
jar of water be exposed in an atmosphere below zero, and two
thermometers are placed in the water, one at the bottom and
the other near the surface, it will be found that the thermo-
meter at the bottom records a continuously lower temperature
than the one near the surface until 4 C. is reached. Up to
this point the colder water, being heavier, has continued to
fall to the bottom of the jar. Below this temperature the
upper instrument will record the lower temperature, proving
that at temperatures below 4 water becomes specifically
lighter. If such were not the case the water at the bottom
of the vessel would continue the colder and would be the first
to freeze. Solidification would take place from below
upwards. The result would be that during a severe winter
our streams and lakes would become one mass of ice, which
all the heat of the ensuing summer would be unable to melt.
To quote Professor Roscoe, " If it were not for this apparently
unimportant property our climate would be perfectly arctic,
WATER, ITS COMPOSITION, PROPERTIES, ETC. 5
and Europe would in all probability be as uninhabitable as
Melville Island." As it is, in large lakes and rivers the
temperature of the deep water never falls below 4 during the
winter, and the surface water when cooled to zero begins to
freeze, and at the same time to liberate its latent heat, which
raises the temperature of the layer beneath, and so retards the
cooling process. That the habitability of such a large portion
of the globe should depend upon these exceptional properties
is a remarkable fact.
At the sea-level water boils at 100 C. When the atmo-
spheric pressure is decreased, as in ascending a mountain, or
when the water-containing vessel is placed under the receiver
of an air pump and a portion of the air exhausted, the boiling ^
point is lowered. On the summits of the highest mountains <ij
water boils at so low a temperature that meat cannot be
thoroughly cooked in it, and in the vacuum produced by a -
properly-constructed air pump water can be made to boil *-*
rapidly at ordinary temperatures, and as during evaporation ^g
heat is lost, the temperature is reduced so low that the water *-* C
freezes as it boils. If boiled in an open vessel water rapidly v _
and visibly evaporates, but this evaporation takes place in- EC
visibly at all temperatures, the more slowly the lower the ^
temperature. Even snow and ice slowly disappear by evapor- fcd
ation during winter. The rate of evaporation from an exposed ^ <
surface depends upon several factors, the more important *-
being the temperature, the velocity of the air in contact with
the surface, and the dryness of the air. On a dry, hot, windy
day evaporation is rapid ; on a damp, cold, calm day evapora-
tion approaches its minimum. The bearing of these facts
upon the subject of rainfall and the storage of water will be
discussed in subsequent chapters.
Water has remarkable solvent powers. The number and
variety of substances which it can take into solution greatly
exceed that of any other fluid. Some substances, such as
sugar and salt, it dissolves in large quantities and with con-
siderable rapidity ; others, such as the constituents of most
6 WATER SUPPLIES
rocks, it only dissolves in small quantity and very slowly.
Many gases, such as ammonia and hydrochloric acid, it absorbs
with avidity, taking up many times its own volume ; others,
such as nitrogen and oxygen, the two principal constituents of
the atmosphere, it only dissolves in small proportions ; whilst
of others, such as carbonic acid, it can dissolve about its own
volume. This property of absorbing or dissolving gases is a
most important one. It explains how water may become
contaminated by mere exposure to an impure atmosphere, as
when an uncovered cistern is placed in a water-closet, or
when an overflow pipe is directly connected with a drain.
One of the most important constituents of nearly all natural
waters is carbonic acid gas. This gas is always present in
the air, and all rain waters contain some of it, but still
more is taken up by the water as it percolates through
ground covered with vegetation. The presence of this gas
increases the solvent powers of the water, enabling it to
dissolve carbonate of lime (chalk and limestone) and carbonate
of magnesia very freely. If a sample of tolerably " hard "
water be placed in a flask and gently heated, bubbles of gas
will be observed to form in the water, rise to the surface and
burst. These bubbles are the gases (oxygen, nitrogen, and
carbonic acid) which were previously held in solution by the
water. The carbonic acid, being most soluble, is not wholly
given off until the water boils. As this gas is removed the
water will become more or less turbid from the deposition of
minute solid particles of carbonate of lime or of this substance
with carbonate of magnesia. One gallon of pure water will
only dissolve from two to three grains of these carbonates,
but when the water contains carbonic acid it may dissolve
twenty or more grains. The whole of this excess is thrown
out of solution if the water be boiled so as to expel the acid.
If the water now be filtered or decanted from the deposited solid
matter, and again boiled until the whole has evaporated, a
grayish-white residue will be found on the bottom of the
vessel. This consists of the mineral (and possibly some organic)
WATER, ITS COMPOSITION, PROPERTIES, ETC. ^
substances which the water had held in solution. The amount
will vary with the character of the water. Rain water leaves
a very slight residue, whilst that yielded by sea water is very
abundant indeed. If this residue be free from organic matter
(usually derived from decaying animal or vegetable substances),
it will undergo little or no change in colour when heated to
redness ; whereas, if organic impurity be present, it will char
when heated, the residue becoming brown or even black.
The common constituents of natural waters may be classi-
fied as follows :
Gaseous. Carbonic acid, oxygen, and nitrogen.
Solids, (a) Mineral. Carbonates of lime and magnesia.
Sulphates of lime, magnesia, and soda.
Chloride of sodium (common salt).
(&) Organic. Products of decomposition of animal and vege-
table matter.
Besides the matters in solution many waters contain others in
suspension, and these again may be divided into inorganic
(mineral), such as clay, fine sand, debris of rocks, etc., and
organic, such as the lower forms of animal and vegetable life,
living or dead. The nature of the mineral constituents will
be more fully discussed in the chapters relating to waters
from different sources, and the organic impurities in the section
devoted to the quality of waters.
Waters containing very small quantities of lime and magnesia
salts are called "soft," since they lather freely with soap,
whilst waters containing larger quantities are termed "hard,"
since they form a curd with soap, a more or less considerable
quantity of the soap being wasted in decomposing the lime
and magnesia compounds before a lather will form. The
hardness is usually expressed by chemists in degrees, each
degree corresponding to one grain of carbonate of lime, or its
equivalent of other lime or magnesia salts in the gallon of
water. As previously stated, the carbonates are thrown out
of solution by boiling, and the water then becomes softer in
proportion to the amount of these salts so removed. This
8 WATER SUPPLIES
removable hardness is called " temporary," whilst the hardness
remaining after boiling, and which is due chiefly to the
presence of sulphates of lime and magnesia, is called " per-
manent." Waters under 5 or 6 of hardness may be con-
sidered "soft," those exceeding 12 "hard." The advantages
and disadvantages of "soft" water will be fully discussed
later, when all the points bearing upon the selection of a
source of supply are being considered.
Water not only takes up gases from the air, mineral and
organic matter from rocks and soil, but certain waters act
upon and dissolve traces of the metals lead, iron, and zinc
of which cisterns and pipes are generally made. A chemically
pure water would probably have no action whatever upon
these metals if also chemically pure ; but as natural waters
are never absolutely pure, nor the metals free from impurities,
under certain conditions chemical or electrolytic action is set
up, and the metals are acted upon. The presence of any of
these metals in a drinking water is objectionable, but traces
of lead are far more dangerous than traces of iron or zinc,
since lead is not only more poisonous, but is also a cumulative
poison that is, the lead tends to accumulate in the system,
and as the quantity stored increases so also does its poisonous
action become more marked. The medical officer to the Local
Government Board, in his report for the year 1890, stated that
" upwards of 600,000 persons in the West Riding of Yorkshire
alone appear, from the statements of medical officers of health,
to be at one or another time liable to lead-poisoning by the
drinking-water supplied to their populations." The districts
of Lancashire and West Yorkshire appear to suffer more than
others from this form of poisoning, and certain medical
inspectors were deputed to conduct such "chemical and
bacteriological" studies as were most likely to lead to the
discovery of the conditions under which waters can acquire the
power of dissolving lead. Unfortunately the cholera scare
has interfered with the investigation, and it is not yet com-
pleted. Any discussion as to the cause of this action would
WATER, ITS COMPOSITION, PROPERTIES, ETC. 9
at present be profitless, since by those who have studied the
subject the most diverse opinions are expressed. Dr. Sinclair
White found that all the waters he examined which acted
upon lead were distinctly acid, and at Sheffield the solvent
action of the water varied directly with the acidity. When
this acidity was neutralised in any way, as by the addition of
limestone (carbonate of lime), or carbonate of soda, the water
no longer attacked the metal. He believes that the acid is
derived from the decaying peat on the moors upon which the
water is collected. Other observers think that the acidity is
due to sulphuric acid, which is formed in the air in immense
quantities in districts where certain iron and other ores are
smelted, and where inferior kinds of coal (containing pyrites)
are consumed. Mr. Power (Medical Inspector to the Local
Government Board) suggests that the action is due to the
presence of some micro-organism in the water ; others attribute
it to the absence of silica or carbonate of lime. Dr. Garrett,
as the result of a long series of experiments, considers the
action as "primarily an oxidising one," dependent upon the
presence of nitrates or nitrites. A very minute quantity of
these substances, he says, appears capable of setting up this
action, which is further assisted by the presence of chlorides.
Acid waters freely dissolve oxide of lead so formed, hence
"the power exhibited ... by waters of acid reaction, of
taking lead into solution when they are placed in contact with
the metal, is easily explained." Whatever may be the nature
of the action which takes place, the waters which act most
freely on lead are " soft " waters, such as rain water, upland
surface-water, and the waters of certain lakes ; and if the
uplands from which the water is collected be covered with
peat, the plumbo-solvent action of the water will at certain
seasons be most energetic. Few hard waters exert any action
upon lead. Every sample of such waters which I have
examined either contained no carbonate of lime, or less than
three grains per gallon that is, the hardness was entirely, or
almost entirely, of a " permanent " character. Certain ex-
io WATER SUPPLIES
ceptionally soft deep -well waters found in Essex have no
action upon lead, but though almost free from carbonate of
lime, they contain a considerable amount of carbonate of soda,
which renders the water alkaline, and so produces the same
effect as the carbonate of lime. The introduction into any
water of four or five grains of carbonate of lime per gallon
(as by filtration through beds of chalk or limestone), or its
equivalent of carbonate of soda, effectually prevents any action
upon lead ; not only so, but such waters cause the formation
of a deposit upon the surface of the metal of some compound,
which resists for a time the action of the untreated water.
Whilst the presence of lead can only be discovered by the
application of chemical tests to the water, or surmised from
the symptoms of lead poisoning amongst those who use it
(since it affects neither the taste nor appearance), the
presence of iron derived from the action of the water upon
a pipe or cistern is detected at once by the water exhibiting
a more or less marked turbidity and depositing upon standing
a little rust-coloured sediment. The amount of iron actually
in solution is always infinitesimal, the compound of iron
formed by the action of the water (or its gaseous and saline
constituents) upon the metal being practically insoluble,
and if filtered such water is in no way deleterious to health.
The unfiltered water, however, has an unsightly appearance
(from the suspended oxide) and will iron-mould clothes if
used for washing. The action diminishes after a time as the
pipes become coated with oxide, but probably never entirely
ceases. As this action can be entirely prevented by using
pipes or cisterns coated inside with some "protective"
(vide Chapter XXI.), such should always be used.
Waters which act on lead appear also to have the power
of acting upon zinc, and of forming poisonous compounds
which dissolve freely in the water. As the physical characters
of the water are not altered, the presence of the metal may
remain unsuspected, unless some obscure form of illness leads
the medical attendant to have it examined. When water
WATER, ITS COMPOSITION, PROPERTIES, ETC. n
which contains an appreciable amount of zinc is heated in an
open vessel, before it commences to boil an iridescent film is
observed upon the surface, sometimes giving rise to the im-
pression that the water is " greasy." Such waters should
not be stored in zinc or galvanised iron vessels, or passed
through galvanised iron pipes.
Waters containing no deleterious organic matters, and only
such mineral matters as neither from their quality nor quantity
are objectionable, may be considered as pure from the hygienic
point of view. If the mineral matters are in excess, or dele-
terious or objectionable organic substances are also present,
the water is impure. Where the mineral constituents are,
either from their quantity or quality, sufficiently potent to
confer medicinal qualities upon the water, it is called a mineral
water. Such waters, if containing iron, are "ferruginous'
or " chalybeate " ; if containing odorous sulphur compounds,
" sulphuretted " ; if containing sulphate of magnesia or other
mild purgatives, " aperient," etc. Such waters are, of course,
useless for domestic purposes, and therefore require no further
reference here.
Potable waters may be divided into the following classes,
according to the source from which they are directly obtained :
Rain water.
Surface water (including lake and pond waters).
Subsoil \vater.
Deep-well water.
Spring water.
River water.
Each of these sources will be separately considered.
CHAPTEK II
RAIN AND RAIN WATER
WHEN water is boiled in a suitable vessel and the steam
passed through some form of cooling apparatus the vapour is
condensed, and water flows from the open end of the cooled
tube. This is the process of distillation, and water so obtained
is called " distilled water." As the water approaches the boil-
ing point the less soluble gases are evolved, but the more soluble
ammonia (if present) distils over with and is contained in the
first portions of the distilled water. The saline constituents
of the water, being non- volatile, remain behind in the vessel in
which the water is being boiled. As stated in the last chapter,
water slowly evaporates into the air at all temperatures, and
at 10 C. (50 F.) 1 cubic yard of air can contain 150 grains of
water, at 21 C. (70 F.) about twice this amount, and at C.
(32 F.) about half. If, therefore, 1 cubic yard of air satur-
ated with moisture at 21 C. be cooled to 0, it would deposit
about 225 grains of water in the form of dew or rain. The
ocean has been compared to a boiler, the sun to a furnace, and
the atmosphere to a vast still. The cooler air of the higher
atmosphere and of colder zones acts as the condenser, causing
the precipitation of the distilled water as rain. About three-
fourths of the earth's surface, or 145,000,000 of square miles,
is covered with water, three-fifths of which is south of the
equator. The surface of the water is heated by the direct
rays of the sun, and evaporation is rapid, especially in tropical
regions. Somerville estimates that "186,240 cubic miles of
RAIN AND RAIN WATER 13
water are annually raised from the surface of the globe in the
form of vapour, chiefly from the inter-tropical seas. The
evaporation over the surface of the ocean is so great that, were
it not restored, it would depress its level about 5 feet annually."
Ansted says that " about 7000 Ibs. weight of water are
evaporated every minute, on an average, throughout the year
from each square mile of ocean." l Besides this evaporation
from the ocean, evaporation is constantly going on from the
surface of the land, the amount varying with the season and
climate, the nature of the soil, and the character of the vegeta-
tion. When discussing the amount of water obtainable from
various watersheds, this question of evaporation will receive
further consideration. According to Somerville " the vapour
from the great reservoirs at the equator and the southern
hemisphere is wafted by the south-east trade wind in the upper
regions of the atmosphere till it comes to the calms of Cancer,
where it sinks down and becomes a south and south-west surface
wind, and then the condensation begins that feeds all the great
rivers of the world." Moisture-laden air if cooled sufficiently
will give up a portion of its water in the form of mist (cloud)
or rain, the amount of water condensed varying with the degree
of saturation of the air in the first instance, and the extent to
which the temperature is reduced. This cooling is produced
in three ways (a) by the ascent into the higher regions of
the atmosphere, the temperature falling about 3 C. for every
thousand feet ascended, (6) by contact with cold surfaces, as of
the sides of mountains, and (c) by admixture with colder air.
The first cause is by far the most important, the last can only
under comparatively rare circumstances be the cause of rain.
The importance of the second is sometimes overrated, since to
it is often attributed the excessive rainfall in hilly districts
and mountainous regions. The effect of the hills is principally
to direct the air currents impinging upon them upwards, and
1 ' ' All the coal which men could dig from the earth in many centuries
would not give out enough heat to produce, by the evaporation of water,
the earth's rain supply for a single year." Symons' Met. Mag., vol. v.
14 WATER SUPPLIES
therefore into colder regions. The lowest stratum of air only
can be chilled by contact with the ground. As Eaton 1 points
out, " if this contact with the cold ground were sufficient to
cause rain, we should invariably have rain when in the winter
months a warm and saturated south-west wind succeeded a
frost, as long as the ground remained unthawed, instead
of a thin surface fog, as usually obtains." In the British
Islands the westerly are the chief rain-bearing winds. As the
west coast is mountainous, such winds are directed upwards
by contact with the hillsides ; the cold produced by the ex-
pansion first condenses the vapour into cloud and finally into
rain. Most of the rain is deposited on the western slopes ;
the clouds, having passed over the range of hills, tend to sink,
become warmer, and disappear. Thus the westerly winds are
comparatively dry by the time the opposite coast is reached,
and as easterly winds blowing over the European Continent
usually contain but little moisture, the rainfall on the east
coast is far less than that upon the west. In England, east of
a line extending from Shields to Beading and north of the
Thames, the average rainfall per annum is only about 23 inches ;
along the south coast it is about 35 inches ; whilst in the
mountainous districts of Cumberland, Westmoreland, Wales,
and Devonshire, the average exceeds 75 inches. Up to about
2000 feet the amount of rainfall increases with the elevation ;
above this level, the clouds having already deposited most of
the moisture they originally contained, the amount decreases,
or at least no longer increases. Where the hills do not reach
2000 feet, and where they are cut through by valleys, more
rain is deposited on the lee side of the hills and over the country
opened out by the valleys. The following gaugings by Mr.
Bateman, taken along the line of the Bochdale Canal across
the Pennine Chain 2 " show to a marked degree the abstrac-
tion of moisture caused by the intervention of a range of
hills."
1 Proc. Brit. Met. Soc. 1861.
2 De Kance The Water Supply of England and Wales.
RAIN AND RAIN WATER 15
ANNUAL RAINFALL.
At Rochdale . . . 34*25 inches At foot of western slope.
White Holmes, Blackstone \ 120Q f , , e gea i j
edge . . . . f
Toll Bar ,, 5316 ,, 1000 feet above sea-level.
Blaek House ,, 51 '80 ,, 1000 feet above sea-level.
Sowerby Bridge . . 29 '85 ,, 300 feet above sea-level
at foot of eastern side of the hills.
Over some five-and-a-half millions of square miles of the land
surface of the globe rain seldom or never falls (the deserts
of Sahara, Gobi, Kalahari, the interior of Australia, etc.)
Near the equator the rainfall is almost perpetual. At
Cherraponjee, in the Khasia Hills, in Assam, the average rain-
fall is over 400 inches. Probably the wettest district in
England is the Stye Pass, in the Cumberland Hills, where
about 200 inches falls annually, the average over the whole
of England being about 30 inches. Speaking generally, the
rainfall varies with the latitude, altitude, distance from the
sea, direction of the prevailing winds, extent of forests, and
position with reference to mountain ranges.
The rainfall also varies greatly at certain seasons. Over
nearly the entire sub-tropical region winter is the rainy
season. According to Scott l the exceptions are " the eastern
coast of the great continents, as China and the eastern
states of the Union, which enjoy a sort of monsoon rain in
the height of the summer. Natal in Africa and the Argentine
Kepublic come under the same category. All these countries
receive abundant rains at the period most favourable for the
growth of crops. . . . The countries with winter rains and
summer droughts must have recourse to irrigation to water
their fields." In other regions farther north, rain falls at all
periods of the year, as in the British Isles. On the west
coast most rain falls in January, but on the opposite coast
September, October, and November are the wettest months.
The mean monthly rainfall at Kew r , Greenwich, and in
1 Elementary Meteorology,
16
WATER SUPPLIES
Massachusetts for various periods is given in the subjoined
table :
Kew.
Kew.
Greenwich.
Massachusetts. 1
1813-72.
1865-80.
1881-90.
January
1-9
2-2
1-3
37
February
1-5
17
1-3
3'6
March .
1-5
1-3
1-3
3-9
April .
17
1-85
1-3
3-3
May .
2-1
1-6
1-6
3-3
June .
2-0
2-1
1-6
3-3
July .
2-3
2-4
2-2
3'8
August
2-3
2-2
1-6
4-1
September
2-35
2-5
17
3-0
October
27
2-5
1-9
37
November
2-3
1-9
2-0
3-9
December
1-9
2-2
1-4
3'5
The variation in the rainfall in any given district in different
years and in different parts of the year has an important
bearing upon the question of water storage, and will be
considered in the section treating of that subject.
A precise knowledge of the amount of rainfall is absolutely
necessary where the total amount of water falling upon a
given area has to be ascertained, and this knowledge can only
be obtained by careful collection and registration. Such
records also, if properly kept, are of the greatest service in
enabling approximate estimates to be made of the amount of
water which can be collected, and for comparing the rainfall
over different areas. It is very desirable, therefore, that some
uniform plan of collection and registration should be adopted.
The Royal Meteorological Society gives to its observers the
following instructions (Hints to Meteorological Observers, with
Instructions for Talcing Observations) :
" Rain-gauge. The rain-gauge should be made of copper,
and have a circular funnel of either 5 or 8 inches diameter,
with a can or bottle inside to collect the water. It is very
1 Average deduced from long-continued observations in various parts
of the State. Report on Water Supplies, 1889-90.
RAIN AND RAIN
desirable that it should be of the Snowdon pattern that is,
with a 6-inch cylinder and a sharp brass rim (Fig. 1).
" It should be set in an open situation, away from trees,
walls, and buildings at the very least as many feet from
their base as they are in height and it should be so firmly
FIG. 1. Snowdon Rain-gauge.
fixed that it cannot be blown over ; the top of the rim should
be one foot above the ground, and must be kept quite level.
" The measurement of the rainfall is effected by pouring
out the contents of the water of the bottle or can into the
glass measure, which must be placed quite vertical, and read-
ing off the division to which the water rises ; the reading is
to be taken midway between the two apparent surfaces of the
water. The glass measure is usually graduated to represent
tenths and hundredths of an inch, and holds 0'50 inch of rain-
fall. Each division represents the one-hundredth of an inch,
c
1 8 WATER SUPPLIES
the longer divisions five-hundredths, and the long divisions,
having figures attached, tenths of an inch. If there be more
than half an inch of rain, two or more measurements must be
made, and the amounts added together. The complete amount
should always be written down before the water is thrown
away. The gauge must be daily examined at 9 A.M., and the
rainfall, if any, entered to the previous day ; if none be found,
a line or dash should be inserted in the register. It is desir-
able that very heavy rains should be measured immediately
after their occurrence, entering the particulars in the remarks,
but taking care that the amount is included in the next
ordinary registration.
" Snow. When snow falls, that which is collected in the
funnel is to be melted and measured as rain. This may
quickly be done by adding to the snow a measured quantity
of warm water, and afterwards deducting the quantity from
the total measurement. If the snow has drifted, or if the
funnel cannot hold all that has fallen, a section of the snow
should be obtained in several places where it has not drifted
by inverting the funnel, turning it round, lifting and melting
what is enclosed. The section should, if possible, be taken
from the surface of a flat stone."
In mountainous districts, and for waterworks purposes, in
which it is only necessary to make weekly or monthly obser-
vations, a special form of rain-gauge must be used. 1 Mr.
Symons' pattern is admirably adapted for this purpose (Fig.
2). The cylinder in which the water is collected will contain
48 inches of rain, and by aid of a graduated rod and float,
readings may be taken to one-tenth of an inch. The rod is
detached and only introduced when an observation is being
made. In districts where the annual rainfall does not exceed
40 inches, the collecting cylinder may be of smaller capacity.
If the area of the mouth of the funnel be twice that of the
cylinder, the float will rise 2 inches for each inch of rain,
and the accuracy of the readings is increased.
1 MM. Richard Fr eres of Paris make a self-registering rain-gauge.
RAIN AND RAIN WATER
One inch of rainfall corresponds to nearly 4f gallons per
square yard, or 22,620 gallons per acre. If 1 inch of rain
fell upon some impervious surface, such as a roof, covering
say 10 square yards of
ground, the amount of
water which could be
collected, providing none
were lost by evaporation
or from any other cause,
would be 46| gallons.
To obtain anything ap-
proaching this amount,
however, the rain would
have to be heavy and con-
tinuous. If it fell in a
series of slight showers
spread over any consider-
able interval, and especi-
ally in hot weather, only
a very small proportion
indeed would be collected
nearly all would be lost
by evaporation. When the
rain falls upon more or less
pervious soil covered with
vegetation, it is only the
heavy rains or long-con-
tinued showery weather
which yields sufficient
water to percolate into
the subsoil to feed the
springs and raise the level FlG ' *-** aal Mountain
of the subsoil water (vide Chapter IV.). The total rainfall
and the rainfall available for water supplies are therefore not
identical terms.
Rain water collected from a clean, impervious surface in
20 WATER SUPPLIES
the open country is the purest of natural waters. In passing
downwards through the air, however, it not only takes up a
proportion of the gaseous constituents, but also washes the
air from all floating impurities, whatever their nature. The
rain which first falls always contains the largest proportion of
these impurities. In the neighbourhood of towns the rain
contains soot, sulphuric acid, and other matters derived from
the combustion of coal, together with ammoniacal salts,
nitrates, and albuminous matters derived from decomposing
animal and vegetable substances, and the exhalations from
the bodies of men and animals. Minute traces of these
substances, together with common salt (derived from the sea)
and various micro-organisms, are found in all rain waters.
One gallon of rain contains on an average 8 cubic inches
of gases, of which about one-third is oxygen and two- thirds
nitrogen. The carbonic acid amounts only to about two
per cent of the mixed gases.
Dr. Angus Smith, in his work on Air and Rain, states
that rain from the sea contains chiefly common salt ; that the
sulphates increase inland before large towns are reached, and
seem to be the products of decomposition, the sulphuretted
hydrogen from organic compounds being oxidised in the
atmosphere ; that the sulphates rise very high in large towns
because of the amount of sulphur in the coal used as well as
to decomposition; that when the sulphuric acid increases
more rapidly than the ammonia, the rain becomes acid ; that
free acids are not found with certainty where combustion or
manufactures are not the cause ; and that ammoniacal salts
increase in the rain as towns increase : they come partly from
coal and partly from decomposed organic substances. The
observations of Dr. Miguel at Montsouris, Paris, on the
micro-organisms found in rain, prove that bacteria, pollen,
spores of fungi, protococci, etc., constantly occur, and are
especially numerous in the warmer months ; and in the first
showers after a long spell of dry weather over 100,000 such
organisms may occur in a single pint of rain water.
RAIN AND RAIN WATER 21
The foregoing remarks refer only to water collected directly
in clean vessels. If the rain has fallen upon a roof it may
become seriously contaminated by the excrement of birds,
decaying vegetable matter, soot, and dust ; in fact some of
the filthiest waters used for domestic purposes which I have
examined have come from rain-water tanks. The solid
organic matters are washed from the roof or other collecting
surfaces into the tanks ; these undergo further putrefactive
change, the products formed entering into solution and accen-
tuating the pollution. When properly collected, rain water
can be stored and utilised for all domestic purposes. Since
it never contains more than a trace of lime salts in solution,
it is exceedingly soft and well adapted for washing. Its taste
is mawkish and objectionable, but this can be remedied by
filtration ; in fact it can be rendered quite palatable. Rain
water, especially in certain districts where manufacturing
towns abound, is frequently distinctly acid, and then acts
freely on various metals. It is not safe, therefore, to store it
in lead, zinc, iron, or galvanised iron tanks. Slate tanks may
be used, but if the joints are made with white or red lead,
the angles where the lead is exposed should be filled in with
cement. This not only prevents the lead being acted upon,
but renders the jointing more secure and facilitates cleansing.
Earthenware can be used for small cisterns. Large storage
tanks may be built of brick, and, if underground, should be
well puddled outside with clay. The bricks should be set
with hydraulic lime mortar and the inside of the tank lined
with Portland cement. The object of these precautions is not
only to prevent the rain water wasting by leakage, but also
to prevent ground water gaining access. Access of surface
water must also be guarded against by roofing over in a
similar manner. By proper collection and storage of the
rainfall it is often possible to obtain a fairly abundant supply
of good water for a farm, dwelling-house, or even a group of
houses. To effect this, three conditions are necessary : (1)
The tank must be of sufficient size to store all the available
22 WATER SUPPLIES
rainfall, and must be properly constructed. (2) The first
portion of every shower which washes the roof or other col-
lecting surface, and is therefore always filthy, must not
be allowed to enter the storage tank. (3) There must be
some efficient system of filtration. The area covered by the
average country cottage may be taken at 35 square yards,
and the available rainfall collected from a roof cannot safely
be estimated at more than half the total rainfall. Much is
lost by evaporation ; many slight showers do not yield enough
water to reach the tank, and in very heavy showers much is
often lost by the water running over the eaves troughing, or
over the ends of the cottage where there is no spouting.
Assuming the rainfall to be the average, from 15 to 18 inches
could be collected. This would yield for the year about
3200 gallons, or 9 gallons per day. It is evident that this
would not be sufficient to meet all requirements ; but even
in the worst districts there are ponds or brooks from which
water could be obtained for slopping purposes. With a
larger roof area, of course a larger amount of rain water
would be available ; but as few cottages cover an area of
40 square yards, 9 gallons would be the maximum supply.
In the eastern counties, where the rainfall is only from
20 to 25 inches, even this amount cannot be obtained, but
in districts where the rainfall exceeds the average more could
be collected. The amount of water required on farms is
necessarily larger than in cottages, but even the increased
collecting area from the roof of the house and outbuildings
would not give a relatively more abundant supply.
As the water is in constant use, the storage tank need not,
of course, be so large as to hold at one time the whole of the
amount collected during the year. It will be sufficient if it
is one-fourth or one-third this size that is, if it hold a rainfall
of at least 4 inches. To do this, the tank must have a capa-
city of 3 cubic feet for each square yard covered by the roof
(not of actual roof area). For a country cottage, under the
conditions assumed above, the storage space must be 105 cubic
RAIN AND RAIN WATER 23
feet. This would be approximately furnished by a tank 6
feet square and 3 feet deep, or by a circular tank 4 feet 8
inches in diameter and 6 feet deep, or 5 feet in diameter and
5 \ feet deep. For larger roof areas the size of the storage
cistern can easily be calculated.
To separate the first portion of the rain water, Roberts'
Rain- Water Separator may be used. " It rejects the dirty
and stores the clean water. It is made of zinc, upon an iron
frame, and the centre part or canter is balanced upon a pivot.
It is self-acting, and directs into a waste pipe the first portion
of the rainfall, which washes off and brings down from the
roofs soot and other impurities. After rain has fallen a
certain time the separator cants and turns the pure water into
the storage tank." The vertical form is used where a single
stack pipe carries the water from the roof to the tank. One
length of the stack pipe is removed, and the separator is in-
serted and fastened to the side of the house. When a build-
ing is provided with several stack pipes connected by an
underground pipe leading to the tank, the horizontal form
should be used. Various sizes of the apparatus are made,
costing from 3 to 6, and it can be fixed by any intelligent
workman. 1
Fig. 3 shows the vertical separator in the position that it
retains when running foul water into the waste pipe during
the first part of a shower, while the roof is yet dirty.
Fig. 4 represents it when it has canted and has begun to
pass the pure water into the storage tank.
One cannot but regret to see in rural districts, where water
famines occur almost every summer, so little effort made to
utilise the rainfall. Any kind of old cask or tank is con-
1 The author some time ago ordered one of the vertical separators to
be affixed to a farmhouse. Shortly afterwards he received a complaint
that very little water was collected, and that it was filthier than before.
Upon examination he found that the workman had so fixed the separator
that the washings of the roof went into the tank, whilst the pure water ran
into the drain.
WATER SUPPLIES
sidered good enough in which to store the rain, and little or
no care is taken to so securely cover the receptacle 'as to pre-
FOUL
PURE
FIG. 3.
vent impurities getting in. Separators are not yet generally
used, and therefore the water which is collected is more or less
filthy from the first. Occasionally there is some pretence to
filtration, the stack pipe discharging over a bed of sand and
RAIN AND RAIN WATER 25
gravel with or without charcoal. For filtration to be of any
service the filtering material must be so fine as to allow the
water to pass through but slowly. As a rule, the more rapid
the nitration the less the purification (vide Chapter XIII.) ; and
if a small filter is to transmit a heavy rainfall it is evident that
it must be too coarse to be more than a strainer. If finer
material were placed in such a filter chamber, a considerable
portion of every heavy rainfall would run to waste. Where
a separator is used comparatively little sediment is formed
in the tanks, and the water is sufficiently clean and bright for
every purpose save that of drinking. For table purposes it
should be passed through some good form of filter, or the
separated rain water may be collected as it falls in the
receptacle to a filter, and allowed to slowly percolate through
the filtering media into a collecting tank, from which it
can be drawn in any convenient manner. The filter should
be fitted with a loose cover, so that whenever necessary the
top layer of sand can be removed and replaced by fresh, or the
filter be otherwise cleaned. The receptacle receiving the
water from the "separator" should be sufficiently large to
hold | an inch of rainfall upon the whole collecting area.
If, instead of merely utilising the roofs of buildings for
collecting rain, the surface of a portion of ground be rendered
impervious, any quantity of water may be obtained. In many
cases a plot of ground could be selected at such an elevation
as to supply the mansion, farm, or cottages with water by
gravitation, so saving all the expense of pumps and pump-
ing. Mr. Eardley Bailey Denton, M.I.C.E., writing in The
Field, 18th June 1887, says, " 1 inch of rain falling on the
surface of an acre is equivalent to 22,622 gallons; and sup-
posing that half an acre of land be set apart and rendered
impervious for the collection of rain falling on it during the
six winter months, the amount collected where the rainfall
is least, as in the east of England, during that period would
be about 170,000 gallons (assuming the winter rainfall to be
15 inches), or enough to satisfy the wants of nearly 100 persons
26 WATER SUPPLIES
for a period of three months (an exceptionally long drought) at
20 gallons a head daily, an ample quantity for all individual
and household purposes. Tanks can be built at a cost vary-
ing from 3 to 5 per 1000 gallons, and on the chalk formation,
where scarcity is soonest felt, at even less cost. In most
cases a collecting area can be selected free from contamination.
The area upon which the water would be collected need
merely have a concrete floor with cement surface, railed off
to prevent stock running over it, and the storage tank may be
constructed underneath." The above estimate of the amount
of water which could be collected does not appear to be ex-
cessive, and many mansions are now being satisfactorily sup-
plied in this manner. To purify the water a simple filter at
the end of the suction pipe in the underground tank, supple-
mented also by a filter along the course of the house supply,
is recommended. This second filter is fixed below the house
cistern in an accessible position, so that the contents can be
easily cleaned. Unfortunately this plan is too expensive for
groups of cottages that is to say, the cost per house would
exceed that which a Sanitary Authority can compel the owner
to expend in obtaining a supply (about ,8 per cottage). The
roof area of most mansions is so much greater per inhabitant
than the roof area of cottages, that a much more abundant
supply is procurable. Probably 20 square yards per person
is an average in a mansion. This would yield about 1500
gallons per year, or 4 gallons per head per day. The house
cistern should be capable of holding about a week's supply,
and be filled up every day. The need for a cistern so large
is due to the fact that the demand for water is very unequal,
three or four times as much being used some days than
others.
The rainfall is the source of all our water supplies ; but
unless caught upon artificially-prepared surfaces, such as roofs
and specially-prepared cemented surfaces, it is not called rain
water. That which falls upon rocks, either bare or with
little vegetation, when collected is called "upland surface
RAIN AND RAIN WATER 27
water " ; that which falls upon and is collected from moors is
" moorland water " ; that which runs off the surface of pasture
lands, "surface water from cultivated ground "; that which
percolates through the surface soil into a pervious subsoil is
" subsoil water " ; whilst that which travels through the sub-
soil under impervious strata, so that it can only be reached
by boring through such strata, is " subterranean or deep- well
water." Where an impervious stratum comes to the surface
and throws out the subsoil water from the pervious stratum
above, a land spring is formed, whilst subterranean water
thrown to the surface in any way forms an "ascending or
deep spring." The waters in streams may be derived from
any one or more of these sources ; river water is usually a
mixture of all, together with sewage and other impurities
received from the towns and villages along its course.
Speaking generally, deep springs yield the purest waters,
and rivers the most impure ; they may be arranged in order
of purity as follows :
Deep-spring water.
Subterranean or deep- well water.
Upland surface water.
Moorland water.
Subsoil water (if distant from any aggregation of houses).
Land springs.
Surface water from cultivated ground.
River water.
Subsoil water under villages and towns.
The R.P.C. give a lengthy Table of Analyses of care-
fully-collected rain water (78 samples), and of rain water as
ordinarily collected and stored in tanks (8 samples). The
following are the means of their results.
Fresh rain water. Tank water.
Total Solids . . 2 76 16 "8 qrs. per gallon.
Nitric Nitrogen . '004 '78
Chlorine . . . '43 1'6
Hardness . . '42 7-9,,,,
Free Ammonia . '50 1 '1 5 pts. per million.
CHAPTEK III
SURFACE WATER
IGNEOUS, Metamorphic, Cambrian, Silurian, and Devonian
rocks resemble each other in being practically impervious, and
very slightly acted upon by water ; and the districts where such
rocks are exposed are usually wild and mountainous, and in
Great Britain at least have a rainfall much above the average.
Bain falling upon such surfaces rapidly runs off, forming
rivulets and streams, pools and lakes, the water from which
differs but little from that of the rain from which it is derived.
Certain limestones of the Silurian and Devonian systems,
though very compact and hard, however yield an appreciable
trace of carbonate of lime to the water, causing it to have a
hardness of from 6 to 10 or more degrees. The hardest
rocks undergo a process of weathering, by the exposure
of their surfaces to the action of the air and water. By
the alternate freezing and thawing of water in the minute
interstices, the superficial layers become disintegrated and
yield a little soluble matter to the rain falling thereon. If
the surface be very steep, the debris is washed away as formed ;
if not, it gradually accumulates, until there is sufficient to
enable lichens and mosses to flourish. The decay of these
plants furnishes mould or humus, upon which larger and more
highly-organised plants may grow, and these by their death
and decay furnish the beds of peat so common in certain
districts. The rain falling upon such plant-covered surfaces
is in part retained, some being returned to the atmosphere by
SURFACE WATER 29
evaporation from the surface of the soil, and from the fronds
and leaves of the plants covering it, the remainder slowly find-
ing its way to lower levels, and ultimately into the streams
and pools. Only during heavy rains will any quantity run
directly off the surface. From the bare rocks, since the rain
immediately flows away, comparatively little is lost by evapora-
tion or absorption ; rivulets and streams are quickly formed
and almost as quickly disappear. Where the rocks are
covered with vegetation the streams are more permanent,
though fluctuating greatly. Much of the water, being retained
for a time in the spongy mass of vegetable debris clothing the
rock, is enabled to take up a certain amount of organic
matter, sufficient frequently to impart a brownish colour and
a peculiar bitter " peaty " flavour. These impurities are
solely of vegetable origin, and unless excessive in quantity
appear to have no injurious effect whatever upon the health.
The igneous rocks of Devon and Cornwall yield a water
containing very little inorganic matter ; but as peat is
abundant in these districts, the organic matter derived
therefrom may be considerable. Containing little or no
carbonate of lime, they usually act freely upon lead
(vide Tables of Analyses).
The Metamorphic, Cambrian, Silurian, and Devonian rocks,
exposed in Wales and neighbouring counties, Westmore-
land, Cumberland, Devon, and Cornwall, yield water very
similar from a hygienic point of view to that from the
igneous rocks. The metamorphic rocks (quartz, mica
schist, gneiss, granite, and crystalline limestone) may
be said to be absolutely impervious, as may also the
slates of the other series. The sandstones, however, are
more or less porous, and absorb some portion of the rain-
fall. The calcareous rocks of the Silurian and Devonian
systems are exceedingly compact, and the water from
their surface is but little harder than that from the non-
calcareous rocks.
30 WATER SUPPLIES
The non - calcareous carboniferous rocks (Yoredale rocks,
millstone grits and coal measures) occur in South Wales,
Derbyshire, Yorkshire, Lancashire, and North Stafford-
shire, and are but slightly pervious. A considerable
proportion of the rainfall on the slopes of the hills finds
its way into the rivulets and streams, some of which are
utilised for feeding reservoirs for supplying many of our
manufacturing towns with water. Certain of these
waters are exceedingly soft, the average hardness only
being 6. They are therefore admirably adapted for use
in steam boilers and for most manufacturing purposes.
They are frequently peaty and turbid, but when
carefully filtered usually form satisfactory domestic
supplies. In certain districts the water is frequently
acid, and then acts powerfully on lead. It is water
from these sources which has produced the extensive
prevalence of lead -poisoning in the Lancashire and
Yorkshire towns.
The calcareous carboniferous rocks (carboniferous or mount-
ain limestone and limestone shales) of Northumberland,
North Yorkshire, Lancashire, and Mid-Derbyshire yield
a water of a moderate degree of hardness, not so well
adapted for many manufacturing purposes, but not too
hard for domestic use, and free from any solvent action
upon lead. The beds of limestone and sandstone in the
coal measures are more freely acted upon by water,
and that derived from the surface may be excessively
hard, even exceeding 50. 16 is given as the average.
When the hardness is excessive the water is, of course,
unsuitable for domestic use and for most manufacturing
purposes.
The secondary rocks " stretch across England from the mouth of
the Tees to the mouth of the Exe, with a branch running
to the mouth of the Mersey." The lias, new red sand-
stone, conglomerate sandstone, and magnesian limestone
formations yield from their uplands a water closely
SURFACE WATER 31
resembling that from the mountain limestone (Tables I.
and II. include analyses of waters from all the above-
mentioned formations).
Where any of these formations are covered with soil in a
state of cultivation, the surface water is often much altered
in character, especially if the soil be calcareous. The hardness
is then considerably increased. All are liable to contain larger
traces of organic matter, some of which will be of animal
origin. Nitrates, which are present in infinitesimal amount,
if at all, in water from barren rocks, are always found, and
may occur in considerable quantities, if the soil be manured.
The chlorides also will increase in proportion to the number
of men and animals living upon the gathering ground.
In this country the amount of chlorine in the rainfall varies
so considerably with the distance from the ocean, prevailing
direction of the wind, etc., that it is only over very localised
areas that this factor can be utilised for determining whether a
water be polluted or not ; but on continents like North America,
large areas (whole States in fact) are so slightly affected by
these conditions that the amount of chlorine may be used
for ascertaining and calculating approximately the amount of
pollution. In Massachusetts the whole of the surface of the
country, with the exception of a very small portion, is non-
calcareous, and the surface waters vary but little in composition
if unpolluted, the amount of chlorine decreasing continuously
from the coast inland. In a report on the State water supplies,
1887-1890, the Commissioners state that "in a general way
four families or twenty persons per square mile will add, on an
average, "01 of a part per 100,000 of chlorine to the water
flowing from this area, and that a much smaller population will
have the same effect during seasons of low flow." They
therefore tabulate the ninety surface waters of the State that
are used for public drinking supplies according to whether
the amount of chlorine they contain is in excess of the normal
or not. In twenty-six there was no excess of chlorine ; in
twenty-three the excess was so slight that they could not say
32 WATER SUPPLIES
that they were in the least polluted by household waste. The
excess of chlorine in the others indicated that they contained
from one to five per cent of water, containing as much salt as
ordinary sewage. The average composition of the above
three groups is included in the Table of Analyses, page 38.
The other indications of pollution in drinking waters from
upland surfaces and.other sources will be fully considered later.
Surface water may not only be discoloured by draining from
peat-clothed rocks, but may also be turbid, especially after
rain. When stored in reservoirs, it occasionally, especially in
the late summer and autumn, acquires a disagreeable odour
and taste, from the presence of algae and other low forms of
vegetable life. The Massachusetts Commissioners found that
polluted waters were most frequently so affected, and especially
if stored in shallow ponds, lakes, or reservoirs. Pure water in
deep lakes and reservoirs, though by no means exempt, rarely
acquires bad tastes or odours.
Pools are collections of water of limited extent in the
hollows of the rocks in hilly districts, and the water may have
the ordinary character of surface water from the particular
formation. Usually, however, they contain accumulations of
dead and decaying vegetable matters, which render them
impure. Ponds are usually artificial reservoirs formed by
making an excavation in the impervious subsoil, or by lining
with some impervious material, such as clay, a cavity made in
the pervious superficial stratum, and storing water which has
drained from the ground around. Such waters are rarely fit
for domestic use, not only on account of the vegetable matters
contained therein, but on account of their liability to pollution
by cattle, by manure on the ground within their drainage area,
etc. Being shallow, the whole mass of water may be frozen
during a severe and continued frost, and any contained fish
will perish ; afterwards when the ice melts these will decompose
and foul the water. Several instances of this kind have come
under my notice in districts where the inhabitants depend
upon ponds for their supply of water.
SURFACE WATER
33
Suspended matters in surf ace waters may be removed by con-
tinued storage in large reservoirs or lakes, when time is given
for the whole to subside, or by filtration through sand, which,
however, is troublesome and somewhat expensive. The Massa-
chusetts Commissioners point out " that when water is taken
from the ground near streams and lakes it is often to a large
extent surface water so thoroughly filtered that it cannot be
distinguished from the natural ground water. This method
of purification by natural filtration is an excellent one to
adopt where there is a sufficient area of porous ground adjoin-
ing the surface water source."
The advantages of converting lakes into reservoirs for
storing water over the construction of artificial reservoirs are
so great that several towns have already adopted this plan.
Glasgow is supplied with water from Loch Katrine ; Liverpool,
and several other towns, from Lake Vyrnwy in Wales ; and
Manchester from Thirlmere in Cumberland. As an example
of a smaller town Aberystwith in North Wales may be
quoted ; it derives its supply of water from that portion
of the rainfall on Plynlimmon which runs into the Llyn
Llygad Rheidol Lake. The following account is taken in
part from evidence given at an inquiry held by the Local
Government Board, and contains many points of interest.
The inquiry was held to sanction a loan of 16,000 to
carry out the work. At the present time the town has a
resident population of 10,000, and in summer a considerable
number of visitors reside there. The scheme was completed in
1883, and the town has no wan abundant supply of water of
unexceptionable purity.
" The source of supply is the Llyn Llygad Rheidol Lake,
situated on Mount Plynlimmon, 16-J miles from Aberystwith,
and about 1650 feet above the sea. The wild nature of the
country renders the possibility of pollution remote. The
area of the lake is 11 J acres, its greatest depth 60 feet, and
the available storage capacity, supposing the bank is raised,
as proposed, 1 foot, and only 15 feet of water is drawn off, is
D
34 WATER SUPPLIES
nearly 40,000,000 gallons. This is equivalent to eighty days'
supply for a population of 25,000 at 20 gallons per head
(that is, for about twice the present population (1892),
summer visitors included). This would be if no rain were to
fall on the mountain for that length of time a supposition
hardly ever likely to be realised. Plynlimmon rises about
2500 feet above the sea, and is the highest peak in this part
of Wales. The warm winds from the south-west and west,
coming laden with moisture, impinge on the mountain, and
their temperature being suddenly reduced, copious falls of
dew and rain take place. The lake is actually fed with rain
that falls on the very summit of Plynlimmon, and it would
only be in a most extraordinary season of drought that no
rain would fall for more than 2-J months. The area draining
into the lake is 133 acres. The actual rainfall is unknown,
but Mr. Symons (the first authority on the subject) puts it
at over 75 inches. At Nantiago Lead Mine, 800 or more
feet below Plynlimmon, it was 92 inches in 1878, so that it
may be 120 inches or even more at the summit of the mountain.
The very moderate rainfall of 60 inches only is assumed. Very
little would be lost by evaporation, the slopes of the mountain
being so great that the water runs off most rapidly; and
very little would be lost by percolation, as the mountain
consists of Bala rock, the upper member of the lower Silurian
beds, a hard and more or less impermeable formation. If,
then, 60 inches only be taken as the available rainfall over
133 acres, the quantity flowing into the lake would be over
180,000,000 gallons, very nearly a year's supply at 500,000
gallons daily. If the available rainfall be 100 inches per
annum (as indicated by gaugings of the outflow from the
lake), the supply would be 300,000,000 gallons yearly. The
water will be carried from the lake to Aberystwith in an
iron main 8 inches in diameter. Such a main, with the
minimum gradient obtainable for it, will deliver more than
half a million gallons daily. The water, before being dis-
tributed in the town, will be discharged into a service
SURFACE WATER 35
reservoir, two-thirds of a mile from the town and 130 feet
above the highest building in the place. The general
pressure throughout the town will be equal to a head of 200
feet. The capacity of the reservoir will be 1,000,000 gallons.
From the service reservoir the water will be distributed to
the town by a 10-inch main." The following is an abstract
of the estimate :
Cast-iron pipes, 34,117 cwts., at 5s. per cwt. 8529 5
10-inch main from service reservoir, 2338 cwts. 584 10
Excavating trenches for pipes, and refilling
28,804 lineal yards at prices varying from
2s. in rock to 6d. in soft soil per yard . 1514 8 7
Laying pipes and jointing them . . . 1214 8
Extra for junctions and special pipes . . 110
Carriage of pipes 1055 14
Sluice valves, flushing valves, air cocks, etc. . 188 9
Posts to indicate line of main . . . 25
Pressure-reducing tanks or break valves, and
fixing ditto 217 10
Works at the lake for drawing off the water . 185
Service reservoir, with valves, pipes, etc., complete 2019 11 6
Contingencies, law charges, and engineering
at 7i per cent 1173 4 6
Total . . . 16,816 13 3
The works were duly executed, but the estimate was exceeded
by about 1000, a detour with the water main having to be
made on account of the peaty nature of the ground. It will
be noted that no land had to be purchased, and that no com-
pensation water had to be provided, both important matters
for consideration when a public water supply is being
provided.
At the Congress of the British Institute of Public Health
held last year (1893), in Edinburgh, the engineer to the
City Waterworks gave a description of the Loch Katrine
Waterworks supplying Glasgow. The paper contains much
that is interesting, and to it I am indebted for the follow-
36 WATER SUPPLIES
ing particulars. When the scheme was first propounded,
Glasgow had a population of 350,000, and it was estimated
that it would increase to 760,000 in 1900, and that the
consumption of water would then be 30,000,000 gallons per
day. The works were estimated to bring 50,000,000 gallons
per day. However, both these estimates have proved
erroneous, since the population now being supplied with water
is 860,000, and the consumption of water has risen from 40 to
50 gallons per head, so that 43,000,000 gallons are now used
every day. The increased quantity used is attributed to
several factors : the introduction of baths into the houses of
the well-to-do working classes ; the compulsory fitting up of
water-closets in even the smallest class of houses; the increase
of public urinals, watering-troughs for cattle, drinking and
ornamental fountains ; the introduction of several large public
swimming baths. Loch Katrine is 368 feet above the sea.
The area of the loch is 4| square miles, and its drainage area
36 J square miles. By means of a small masonry dam at the
outlet the loch has been raised 4 feet above the old summer
level, and can be drawn down 3 feet below that level. In
this range of 7 feet there is comprised a storage of
5,623,000,000 gallons, or 102 days' supply. The surround-
ing hills rise to a height of from 2300 to nearly 3000 feet ;
and as a result of this and the proximity of the district to
the west coast, which first receives the moist south-west winds
of the Atlantic, the rainfall is very large. At Glengyle, at
the top of the loch, the fall is frequently over 100 inches per
annum, and the driest year during the last 40 years (1880)
yielded 69 inches. The loch is so deep that the water never
freezes except in shallow and sheltered bays. Temperature
observations made in 1885 and 1886 show that the water
reached its lowest temperature of 38'7 F. near the bottom,
in March, whilst at the top it was 38*1, and that during the
rest of the year the surface water was warmer than the deep
water. Geologically the district round the lake consists of
metamorphosed mica schist of the lower Silurian system,
SURFACE WATER 37
yielding very little mineral matter to the rain falling upon
it. The district is practically uninhabited, and by a pay-
ment of 17,600 to the proprietors of the land they have
surrendered all rights of feuing and of erecting houses, or
of allowing additional steamers or boats to ply on the lake.
There is much peat on the hill tops, and in times of flood the
streams are highly coloured, but the relatively large size of
the loch and its great depth have an important influence in
removing the peaty stain. Analysis shows that it is a very
pure water, exceedingly soft (hardness under 1). Notwith-
standing this no case of lead-poisoning through using it has
ever been reported. A service reservoir 8 miles from
Glasgow holds eleven days' supply. The aqueduct was
expected to pass 50,000,000 of gallons per day, but the
effect of the roughness of the channel in retarding the flow
(friction) was much more than had been anticipated, and the
flow is only 42,000,000. The total cost of the works, in-
cluding 11 J miles of tunnelling, 10 J miles open cutting and
bridges, 13 J miles cast-iron syphon pipes across valleys, and
piping within distribution area, has been close upon
1,500,000. This also includes works carried out at other
lochs to provide 40,000,000 gallons of compensation water.
An extension of these works is now being carried out which,
it is estimated, will allow of 100,000,000 gallons of water
per day being drawn from the loch for the supply of the
city, at an additional cost of 1,150,000. The domestic
water-rate, which in 1856 was Is. 2d. per 1 of rental, has
been reduced to 6d. per 1.
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CHAPTEE IV
SUBSOIL WATER
THE subsoil or stratum immediately underlying the surface
soil may be of a pervious or impervious character. If pervious
a considerable portion of the rain falling upon the soil will
pass down into it, if impervious only a relatively small
portion will percolate, the larger portion running off as sur-
FIG. 5. A, Pervious subsoil ; 4', Portion saturated with water ; B, Impervious
stratum ; c, Spring.
face water. Where such an impervious rock occurs covered
only with the spongy debris of vegetation, saturated with
water, we have bogs, marshes, and swamps. The district
will probably be malarial and the water of a dangerous
character. Where a pervious subsoil of sand, gravel, chalk,
limestone, sandstone, or other rock overlies an impervious
rock such as clay, granite, hard limestone, etc., a portion of
nearly every rainfall enters the subsoil, and being held up
by the impervious layer below tends to accumulate. The
water thus held in the interstices of the rocks lying imme-
diately beneath the soil is "subsoil" or "ground" water.
Where the pervious subsoil fills in a hollow in the more im-
42 WATER SUPPLIES
pervious stratum, as in so-called pockets of gravel, the ground
may become waterlogged that is, completely saturated
with water. If, however, at any one or more points the edge
of the containing basin is depressed, water will overflow, form-
ing a spring. Such overflow will only take place when the
water in the porous rock has its surface level raised above that
of the outlet. The portion below this will still remain stagnant.
Where the porous subsoil rests upon a flat or sloping imper-
vious substratum, the subsoil water will be constantly in
motion, travelling towards the lowest point, where the imper-
vious rock outcrops. There it will either issue as a spring,
FIG. 6. .(, Pervious rock ; n, Subsoil water ; c, Spring ; />, Stream ;
E, Clay or other impervious stratum.
or act as the invisible feeder of a stream or lake. " The
action of the soil in regard to water is in reality of a three-
fold nature : it may transmit water as wine is transmitted by
a strainer ; it may imbibe the moisture just as ink is soaked
up by blotting-paper ; and it may hold or be saturated by
water, as a sponge immersed in water is saturated by liquid
which flows from it when the sponge is lifted out. Thus we
have to distinguish between the permeability, the imbibition,
and the saturation of a rock. The amount of surface water
which percolates through the soil depends upon the permea-
bility ; the amount retained as moisture of the soil depends
upon the imbibition ; the amount which can be held by the
subsoil as ground water depends upon the saturation." l Clay
exhibits in a high degree the property of imbibing water, but
1 Miers and Crosskey, The Soil in relation to Health.
SUBSOIL WATER 43
it is only very slightly permeable. Coarse gravels, on the
other hand, are exceedingly permeable, but imbibe little, and
have little storage capacity. The coarser the grain of any
rock, the more freely will water traverse it, and the
springs which it feeds will be more quickly affected by the
rainfall. The water which penetrates the subsoil will either
eventually flow out as springs (which will become dry unless
the rain falls with sufficient frequency to keep up the supply
of ground water), or if, from the contour of the impervious
stratum below, the springs and outcrop are not at the lowest
level of the water-bearing stratum, a certain amount of water
will always be retained, forming, as it were, an underground
reservoir. If, by pumping or otherwise, water be drawn
from this reservoir, the outflow from the outcrop will be
decreased by the amount so removed, and if sufficient be
pumped the springs will cease to flow. The level of the water
in the subsoil varies in different places and in the same place
at different times. Where the porous stratum is of great
thickness the water-level may be at a considerable depth,
depending chiefly upon the elevation of the outcrop. The
level also will vary with the rainfall, rising when the amount
percolating is in excess of that flowing from the springs, or
being artificially removed from wells, and falling when the
percolation is less that the outflow. The rapidity with which
the rise and fall follow the variations in the rainfall depends
on the permeability of the subsoil and its depth. Prestwich
states that on the chalk hills it takes from four to six months
for the rainfall to reach the water-level if at a depth of 200
to 300 feet. On gravel and sand, with a water-level only a
few feet from the surface, the rain would be absorbed and
percolate much more rapidly, but probably would not affect
the ground water level for many days. The varying level of
the river into which the ground water is discharged will also
affect its height, since when the river is in flood the ground
water will be held back and rise. The fluctuation will be
most marked in wells near the river, and least in those at a
44 WATER SUPPLIES
distance. When the ground water enters the sea even the
rise and fall of the tide may cause the height of the water to
vary. The amount of water which can be retained in a rock
varies considerably. 'Chalk and sand can hold about one-
third their bulk of water ; oolite one-fifth ; magnesian lime-
stone one-fourth ; compact sandstone and pebble beds one-
eighth ; granite one-fortieth. Expressed in other words, one
cubic yard of chalk or sand saturated with water would
contain from 50 to 60 gallons of water, and an area of one
acre 3 feet thick would contain about 260,000 gallons.
Except in depressions in the impervious substratum which
have no outlet, the water in the subsoil is in constant motion,
travelling towards the outflow. The rate of this movement
is affected by the porosity of the ground, its slope, freedom
of outlet, and many other factors. At Munich, Professor
Pettenkofer finds that the subsoil water moves towards the
Isar at a rate of about 15 feet per day, whilst at Berlin the
movement towards the Spree is barely perceptible. At Buda-
Pesth the mean rate, according to Fodor, is 174 feet daily.
The height of the subsoil water can be ascertained from the
level of the water in the wells, and its variations will be indi-
cated by the rise and fall of the water-level. This under-
ground sheet of water may be of considerable extent, but its
surface is not necessarily or even usually horizontal. It will
slope towards the outlet, not uniformly, but with a curved
surface. When water is abstracted at any point, as from a
well, a portion of the water in the subsoil around drains into
the well to replace that removed. The water-level for a
certain distance is lowered, the curved surface sloping less
and less as it recedes from the well (Fig. 13). The extent of
area drained will vary with the degree to which the level of
the water in the well is depressed, and with the permeability
of the subsoil. Usually the radius of this drainage area is
taken as twice the depth of the well, but it may under certain
circumstances be much more than this.
The whole of the rain falling upon a pervious soil does not
SUBSOIL WATER 45
percolate into it. Some will run off the surface, the amount
varying with the slope and the nature of the surface ; some
will be lost by evaporation, not only from the surface of the
ground, but also from the leaves of herbs and trees. Dr.
Dalton, at Manchester, found that only 25 per cent of the
rainfall percolated to a depth of 3 feet. Mr. Dickenson,
at King's Langley, on a grass -covered gravelly loam, found
that 42 '4 per cent reached that depth. Dr. Gilbert and Mr.
Lawes, at Rothamstead, found that about 37 per cent was
collected at a depth of 20 inches, 36 per cent at 40 inches,
and 29 per cent at 60 inches. Since the loss by evaporation
in the summer is very great, little or no water may reach
the underground reservoir during the warmer months (April
to September). At Nash Mills, Hemel Hempstead, as an
average of twenty-nine years' observations, the percolation in
summer was found to be about 14 per cent, in winter 61 per
cent, during the whole year 37 per cent. The soil here was
chalky. On loose sands and gravel a much larger proportion
would undoubtedly percolate, whilst in sandstones probably
only about 25 per cent, and in limestones even a smaller
quantity, would reach the ground water. The most favour-
able watershed is one which is fairly level, sandy or gravelly,
and having few or no outlets ; so that nearly all the water
which percolates goes to increase the underground supply.
Where the outlets are free, naturally the store of water will
never be so large, since it is being constantly drained away.
Water is obtained from the subsoil by driving tubes or
by sinking wells, and these may have galleries driven in
various directions to increase the supply. The permanent
yield of such a well will depend upon the area of the water-
shed by which the water is collected and the porosity of the
subsoil. During dry weather the pumping operations will
lower the level of the water and provide space for the water
which will percolate during the wet season. To obtain a
permanent supply of a fixed quantity of water, the proportion
of the rain falling upon the contributing area which can be
46 WATER SUPPLIES
collected must be equal to the quantity which it is desired
to abstract. If the area of the watershed draining towards
the proposed well be known, and the rainfall, the depth of
ground water required to furnish a given daily supply may
be approximately calculated. Let us assume that the rain-
fall records prove that 120 days' storage is required, and that
the amount of water to be raised daily is 250,000 gallons,
and that the subsoil is sand or gravel. Such a subsoil, when
saturated, will contain about 35 per cent of water ; but the
whole of this cannot be removed, only about 25 per cent will
run out when the water-level is lowered. In order to obtain
this 250,000 gallons daily it will be found by calculation
that it is necessary to have storage equivalent to 40 acres of
ground, in which the water-level can be lowered 9 feet. If
a superficial examination renders it probable that this amount
of storage is available, a series of tests must be carried out
to confirm it. For this purpose a number of test wells are
driven during the dry season, and the change produced by
long-continued pumping observed. The depth to which the
water surface is lowered at the wells and at various distances
from the wells will furnish the engineer with the required
information.
The water from so-called shallow wells is subsoil water,
and in most villages and nearly all rural districts such wells
are the chief source from which water is derived. As a well
only drains the ground for a limited distance around, where
a larger supply is required other wells must be sunk or
galleries be driven in various directions below the ground
water level. On gently sloping ground a chain of wells
may be sunk and connected together. In a valley through
which flows a stream liable to pollution, pure water may
sometimes be obtained by sinking wells along the foot of the
hills, and so intercepting the ground water on its way to the
stream. If the bed of the stream is formed of permeable rock,
it will be saturated with water flowing slowly in the same
direction as the stream. Such a subterranean river may even
SUBSOIL WATER 47
convey more water than the visible stream. In the Thames
valley it is estimated that the flow beneath the river con-
siderably exceeds that of the river itself. In seasons of
drought the subterranean flow may continue long after the
bed of the stream has become dry, and at such times water
may often be obtained by sinking a well. In galleries sunk
along the course of streams or near the borders of lakes,
where the subsoil is pervious, when the level of the water in
the galleries is lowered below that of the surface of the
stream by pumping or in any other way, water may flow
from the river or lake into the galleries. Percolation out-
wards through the silt or mud at the bottom of rivers and
pools can only take place slowly, and no definite measure-
ments have ever been obtained of the amount. Where the
quantity of water removed from the galleries does not reduce
the level below that of the free water surface, the whole
supply is derived from the ground water intercepted on its
way to the stream, and only when the level is reduced below
the free water surface is the supply supplemented by back-
ward percolation.
The quality of subsoil water will vary with the character
of the subsoil and the proximity to human habitations. In
the chalk, lias, oolite, sandstone, and limestone districts
the water will be hard, but the most ancient rocks, the
Yoredale and millstone grits, and sands and gravel generally,
yield soft water, if uncontaminated. The living earth has
such remarkable powers of purification and filtration, and
the subsoil beneath is so effective a filter, that natural ground
water is almost free from germs (often it is absolutely free)
and from organic matter. This natural process of purifica-
tion will be described more fully in a later section. As
usually derived from shallow wells, the subsoil water is
almost invariably subject to contamination. The Commis-
sioners appointed to examine the Domestic Water Supply of
Great Britain reported that the most dangerous water is
"shallow well water, when the wells are situated, as is
48 WATER SUPPLIES
usually the case, near privies, drains, or cesspools. Such
water often consists largely of the leakage and soakage from
receptacles for human excrements ; but, notwithstanding the
presence of these disgusting and dangerous matters, it is
generally bright, sparkling, and palatable." In Table IV.
the highest and lowest results are given of the analysis of
large numbers of waters from various geological sources.
The majority of the samples, however, were very impure, and
the lowest results only can be considered typical of pure
water from these sources. Table III. contains recent analyses
of a number of town water supplies derived from the subsoil.
It will be observed that in many cases nitrates (as indicated
by the nitric nitrogen) are present in considerable amount,
and as these salts are derived from the oxidation of organic
matter, such as sewage, manure, decaying vegetables, etc.,
waters containing such quantities of nitrates are often looked
upon with considerable suspicion, and some chemists,
relying upon their analytical results alone, absolutely con-
demn these waters as dangerous to health. Koch, 1 com-
paring the processes of artificial and natural filtration, says :
"As a rule, the soil is of a material much more finely
granulated than the comparatively coarse-grained sand of
the filter, and it is fair to expect that the subsoil water, after
passing the sufficiently thick layers of this finely granulated
soil, will be either very poor in micro-organisms, or quite
free from them. This is confirmed by the investigations of
C. Fraenkel, who has shown that subsoil water, even in a
soil which has been much and for a long period contaminated,
as is the case in Berlin, is quite free from germs. In other
places the same results have followed from investigations
made on this point. We have, therefore, no reason to
keep out of consumption the subsoil water, which can be
found nearly everywhere. On the contrary, we cannot find
a better - filtered water and one more protected against
infection. The only difficulty is to bring this perfectly
1 Water Filtration and Cholera. Translated by A. J. A. Ball.
SUBSOIL WATER 49
purified water into consumption without its being later on
again contaminated and infected. In this respect great errors
are still most inexplicably made everywhere." Wells as
ordinarily constructed yield polluted water because no
attempt is made to keep out surface water. Not only can
the pure water enter at the bottom of the well, but the less
perfectly purified can enter at the sides, and the impure surface
water can gain access at the top. Often the wells are left
open, and so unprotected that filth can be washed in with
every rainfall, or, if covered, the dome is not water-tight, nor
the ground above solid, nor of such a character or of such a
depth as to purify the water passing through it. Drains of
most primitive construction are often placed near to carry
away the waste water from the purnp, but used also for slop
water of all kinds. Waters from such wells are notoriously
liable to become infected, and have often caused outbreaks
of typhoid fever and cholera. The proper construction of
wells and the alteration of existing wells, so as to render
them safe, are subjects of such vital importance that they
will be discussed in a special chapter. Koch is so convinced
of the absolute nature of the security from the danger of
infection afforded by the use of subsoil water properly
collected and stored, that he has proposed that the Berlin
waterworks should be so altered as to supply the city with
subsoil water only. Budapest derives its water supply from
the subsoil along the banks of the Danube, in which a chain
of wells is sunk, and the outbreak of cholera in 1893 was
attributed to the use of this water.
In the State of Massachusetts, forty-two towns varying
in population from 2000 to 25,000 have public water
supplies taken from the ground. The largest supplies
are taken from localities in the vicinity of large bodies or
streams of water. At Newton nearly 2,000,000 gallons of
water are pumped daily from galleries extending for about
three-quarters of a mile along the course of the river. At
Waltham a well 40 feet in diameter is believed to be cap-
E
50 WATER SUPPLIES
able of yielding 1,500,000 gallons daily in a dry season.
Maiden and Revere may be cited as examples of towns sup-
plied exclusively with subsoil water, not supplemented by
water percolating from lakes or streams. 1 "At Maiden the
amount pumped in 1890, 746,446 gallons daily, represented
a collection of 9 '7 inches (or 20 per cent of the total rainfall
of 49 inches) upon a direct watershed estimated at T61
square miles. At Revere the pumping for the year, 465,491
gallons daily, represented a collection of 12*5 inches (25 per
cent of the total rainfall of 50 inches) upon a watershed
of 0'78 square mile." But "it is probable that the amount
which has been pumped is more than could be pumped after
one or two years of low rainfall. At Revere particularly,
experience has shown that the storage capacity of the ground
is very large, so that when the water-table is reduced to a
very low level during the summer, the ground will not fill
before the next summer, unless the amount of rainfall is
above the average."
Where it is desired to obtain water from the porous subsoil,
the direction of the flow of the ground water must be ascer-
tained. This will be towards the springs, lakes, streams, or
rivers forming the outflow. The ground water will have its
highest level at the point most distant from the outflow, but
most water will be obtainable near the outflow, unless the
porous subsoil rests in a depression in the impervious rocks
beneath, when most water can be procured where the depres-
sion is greatest. In an inhabited district the purest water
will be found on that side which is farthest from the outflow,
since all the impurities entering the subsoil will be carried in
the direction of flow of the underground water. For this
reason a pure water may sometimes be found at one side of
a house, when that from the opposite side is polluted. Where
a patch of gravel is bounded by streams on two sides, the
ground water will be travelling in both directions, and that
at one side may be much less impure than that from the
1 Report of State Board of Health, 1890.
SUBSOIL WATER 51
other. Thus in Fig. 6, if the village stand upon one side of
the hill, it will affect only the ground water at that side, the
water on the opposite side escaping contamination. The
extraordinary extent to which the subsoil water can be
affected by pollution from inhabited houses, highly cultivated
land, etc., is indicated by the analyses given in Table IV.
When examining recently the water from a gravel patch
about one square mile in extent, and with a population of
about 1400 persons upon it, I found that the water along
three sides of the patch was remarkably constant and
uniform in composition, and very free from organic impurity,
whilst that from the neighbourhood of the village, and
between the village and the river, the principal outflow, varied
considerably, and was more or less impure. In Table III.
the analyses, Writtle, Nos. 1, 2, and 3, are of waters taken
from the gravel at the three first-mentioned sides ; Nos. 4, 5,
and 6 are of water from wells in the village. The difference is
entirely due to the soakage of slop-water, sewage from defec-
tive drains, sewers, cesspit, and cesspools, into the subsoil.
In some cases the filth had been very fully oxidised before
reaching the well, in others this oxidation was not nearly so
complete. Such waters are, of course, quite unfit for domestic
use. Where the surface soil has been removed, as in the
neighbourhood of inhabited houses, the purifying influence
of the living earth is, of course, lost, and where the porous
stratum of subsoil is thin, the purification by oxidation and
filtration is but limited. Where both these conditions occur,
the subsoil water must of necessity be very impure. Koch's
eulogy of the subsoil as a source of water supply must there-
fore be limited to those districts in which the population is
scattered, and the subsoil of sufficient depth to secure efficient
filtration and purification. Where both these conditions
obtain, the ground may yield a water of the highest quality,
but where these conditions are not fulfilled, there will always
be impurity and risk.
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CHAPTER V
NATURAL SPRING WATERS
SPRING waters have always been held in high repute as sources
of domestic supply, and justly so, since springs yield as a rule
waters of a high degree of organic purity. As they gush from
the ground also they can easily be utilised, no form of machine
being necessary to raise the water. Although usually so free
from organic matter, many springs contain inorganic con-
stituents of such a quality, or in such quantity, as to confer
upon them medicinal properties which man has not been slow
to utilise. Numerous springs of this kind are known which
have enjoyed a high reputation for their curative properties
from time immemorial. Some again yield water of delightful
coldness throughout all seasons of the year, whilst others yield
warm, hot, and even boiling water. Certain springs also
appear to be perennial, the flow being constant, or apparently
so, even during periods of excessive drought, when streams
have ceased to flow and wells to yield. For these reasons the
origin of springs had always been, until within a compara-
tively recent period, a cause of wonder and speculation. The
facts brought to light by the study of geology and hydrology
have, however, robbed them of much of their mystery ; but
the source of certain constituents and the cause of the high
temperature of the water yielded by many springs still give
rise to much discussion. The overflowing water varies in
volume from that of the tiniest rivulet to that of a river of
considerable magnitude, yielding millions of gallons per day
56 WATER SUPPLIES
as the Sorgue and Loiret in France, the Manifold and Hamps
in Staffordshire, and the river Aire at Malham Cove in
Yorkshire. The pressure on the water may only be just
sufficient to cause it to overflow upon the ground, or it may
be so great, and applied in such a direction, as to throw
it vertically upwards for even 50 or 100 feet above the level
of the surrounding surface. Not only also do springs arise
in valleys and depressions on the earth's surface, but some-
times upon or near the summits of hills of considerable eleva-
tion. Such springs, if of any large volume, are often of great
value, since the water can be conveyed by gravitation to any
point at a lower level where a supply is required.
Springs are so varied in character that it is difficult to
classify them. According to the temperature of the water,
we have cold springs, hot or thermal springs, and boiling
springs or geysers. According to the direction of flow, we
have descending springs and ascending springs ; and according
as they arise from superficial or buried strata, we have land
springs and deep springs. The latter division is the most
suitable for our purpose, though certain springs in mountain-
ous districts can scarcely be included under either class.
These are springs originating from elevated lakes, or by the
melting of the snow and ice of glaciers. In the Alps such
springs abound. The Dauben See, a lake on the Gemmi, at
an elevation of 7000 feet, has no visible outlet ; but about
1000 feet lower upwards of fifty springs are found, which
appear to be fed by the lake. By the melting of glaciers
resting on fissured rocks, the water traverses the fissures and
issues as springs in the valleys below. Land springs proper
occur where the impervious stratum supporting the pervious
subsoil outcrops, providing the outcrop be at a lower level
than that of the subsoil water. Where the patch of pervious
ground is small in extent and of little depth, the springs
arising therefrom will be "fleet," or variable, markedly
affected by the rainfall, ceasing to flow during a drought and
flowing freely after heavy rains. The constancy of flow
NATURAL SPRING WATERS 57
increases with the extent of the collecting surface and the
depth and permeability of the subsoil. The freedom of outlet
also is a factor, for if very free the volume of the spring will
be more readily affected by the rainfall than if the outlet be
more restricted. Where the porous subsoil fills up a hollow
in the impervious rock beneath, the ground water level may,
during long-continued droughts, sink below the level of the
outcrop, and it may require a series of wet years to again
raise the level to such a height as to cause the springs to
flow. Many such " intermittent " springs are known, e.g. the
Caterham Springs and the Hertfordshire Bourne. The latter
appears at intervals of four to seven years (Dr. Attfield).
Springs of this character are obviously quite unsuitable for
public water supplies, as they are not to be depended upon
for any lengthened period. Deep and ascending springs are
usually much more constant than land and descending springs,
since they are fed from subterranean sources often of vast
extent. The water also has undergone more complete filtra-
tion, and any organic matter originally contained in the water
becomes completely oxidised, so that such springs generally
yield water of a high degree of organic purity. The rain which
feeds the springs may fall upon the absorbing surface many
miles away. Passing into the pervious rock, it follows the direc-
tion of this stratum, which first dips downwards under some
impervious formation, and later outcrops at a lower level than
that of the absorbing surface. In the chalk and other fissured
rocks the water travels chiefly, if not almost exclusively, along
the lines of fissure, and where the rock is soluble these fissures
may become enlarged, until in time caverns are formed, some
of which are of great extent and form subterranean reservoirs
of water. At great depths water probably meets with car-
bonic acid gas under pressure, which it absorbs. As the
temperature of the earth increases with the distance from the
surface (on an average the temperature increases 1 C. for
every 106 feet descended), this elevated temperature and the
excess of carbonic acid increase greatly the solvent powers of
58 WATER SUPPLIES
the water, and possibly explain the formation of such vast
caverns, and also the greater richness of most of these springs
in mineral constituents. Water may be thrown out, not only
at the natural outcrop of such a pervious stratum, but by
faults, or by the filling up of fissures with some impervious
material impeding the natural flow of the water and directing
it upwards to the surface.
Artificial springs are formed wherever a communication is
made between the surface of the ground and the water im-
prisoned under pressure in a pervious stratum lying between
two impervious formations. Where the pressure is sufficiently
FIG. 7.
great the water overflows. This .is the principle of the
Artesian well, which, however, will be considered later as a
variety of " deep " well. In some cases, however, nature has
provided such a communication between the surface and the
water beneath, by means of a fault, giving rise to a deep or
ascending spring.
Fig. 7 shows how such a spring may be formed. A
represents the superficial stratum of impervious rock, C
the deep impervious formation, B the intermediate pervious
bed collecting the rainfall on its exposed surface at an eleva-
tion considerably above the surface at the point of faulting,
D. It is obvious that the depression of the layer A
prevents the water stored in B passing beyond the fault,
and it must therefore accumulate until the whole of that
NATURAL SPRING WATERS 59
portion of B to the right of the fault becomes saturated,
unless some means of escape is provided. The violence,
however, which produces a fault necessarily causes irregulari-
ties in the disrupted surfaces, and the fissures may extend
from the surface down to B. As the water-level in the
latter rises it will fill these crevices, and finally, when the
level reached is above that of the ground at D, a spring
will result. Of course the fissures above alluded to may
extend downward so as to restore the connection between the
two portions of the pervious stratum, in which case no spring
will be formed, unless B outcrops at both sides above the
level of D. In the latter case the spring will be fed from
both sides, and therefore be of increased volume. If the
layer A be of clay, or a rock of similar nature, fissures would
not be formed, and the fault would not therefore give rise to
a spring. The most favourable conditions exist when A
is a hard rock and C is of a clayey nature. The two
portions of B will then be completely disconnected, and
the imprisoned water must travel along the line of fault
towards the surface. The springs at Clifton and Matlock
are thus produced, and probably also the equally noted springs
at Buxton, Bath, and Cheltenham.
The amount of water yielded by such springs depends
upon the amount of rainfall absorbed by the collecting sur-
face, and is therefore proportional to the area of such surface.
The character of the water depends upon the nature of the
rocks with which it comes in contact in its underground
course. For example, if it passes through beds of rock salt,
it will take up large quantities of that substance ; if through
beds of gypsum, it will contain much sulphate of lime.
Whether the quantity of water yielded by a spring or
springs will be sufficient for the supply of a town or village
can only be ascertained by actual measurements of the flow
made at intervals through a considerable period, but it may
be surmised from other evidence as to the constancy of the flow.
A careful study of the geology of the district is also necessary,
60 WAITER SUPPLIES
and a knowledge of the situation, area, and character of the
gathering ground, and of the rainfall thereupon, is also
essential. It must not be forgotten also that where the
water chiefly travels through fissures in the rocks impurities
may be carried long distances without undergoing oxidation
or other change which will render them harmless. In the
account of epidemics produced by polluted waters, examples
will be given of such pollution and of disease produced
thereby. The flow from natural springs is rarely so copious
or so constant as to render them suitable sources from which
to supply towns of any magnitude. Bristol originally derived
the whole of its supply from springs at Chewton Mendip,
which yielded a minimum of 2,000,000 gallons of water a
day for a long period. The fluctuations increased, and at
length became so serious that the supply had to be
supplemented from other sources. Deep springs are ob-
viously preferable to land springs, both on account of their
greater constancy and lesser liability to pollution. The
water also is usually more brilliant, sparkling, and palatable,
and is generally preferred for domestic purposes, unless the
hardness is excessive, to water from any other source.
Amongst rural communities a preference is usually shown for
natural springs with natural surroundings, and objections are
often raised to any works of an artificial character being
carried out for protecting the water, or for doing anything
more than is absolutely necessary to enable vessels to be filled.
Where a community is to be supplied, a reservoir is necessary,
but the capacity need rarely exceed that of twenty-four hours'
supply. A larger reservoir is only required when the flow at
certain periods is in excess of the demand, whilst at other
periods it is insufficient to meet all requirements. The
amount of storage necessary to obtain a constant and ample
supply must be determined from a consideration of all the
circumstances affecting the particular case.
Springs can often be utilised very economically for supply
ing mansions and small villages with water, even when the
NATURAL SPRING WATERS 61
latter are at a greater elevation than the former, providing
the flow be sufficient to work a ram, turbine, or other similar
form of pumping-engine. As only a small proportion of the
water is lifted by the fall of the remainder, this surplus water
will be available for supplying houses at a level lower than
that of the overflow from the ram or turbine. In this way
the water yielded by a spring on the side of a hill may be
utilised for supplying water to the inhabitants on the hill
above as well as to those in the valley beneath.
The following quotations from a report by W. Whitaker,
F.R.S., on the " Best Source for a Water Supply to the Town
of King's Lynn," contain many points of interest, since they
bear upon a number of questions which have to be considered
when a scheme for supplying a town with water is being
discussed (King's Lynn is a town at the mouth of the Wash,
with a population of 18,265): "Lynn is one of those
towns which cannot get its water supply within its own
borders. A thick bed of clay underlies the marsh-silt that
forms the surface, not only of the town itself, but also in the
greater part of the neighbourhood, where this (and other
alluvial beds) have a wide spread along the main valley, with
comparatively narrow inlets up the tributary valleys.
" These clays have been proved, by a boring in the northern
part of the town, to go down to a depth of about 680 feet,
and then, without reaching the bottom, leaving it uncertain
how much deeper clay may go. Now if a bed usually of a
water-bearing character should occur at some little further
depth, it is doubtful whether a large supply would be got, at
all events by boring, for it is often found that a thick mass
of overlying beds tends to close the fissures, etc., in underlying
beds that, nearer the surface, are quite permeable. It can
readily be understood that the weight of a mass of clay some
700 feet is very great, and is likely to have an effect on any
limestone or sand beneath.
" Clearly, therefore, it is needless to consider the question
of boring for deep-seated water in the town. Very small
62 WATER SUPPLIES
quantities of water might possibly be got, from occasional
and local sandy beds in the clays ; but these would be useless
for a public supply.
"Having then to go outside the municipal boundary, it
is natural to consider, firstly, the nearest source of supply.
This is the lower greensand (as it is somewhat unfortunately
called, green being generally an exceptional colour in it), a
formation which in this part of the country consists of
variously-coloured sand, sometimes cemented (by iron oxide)
into the ferruginous stone known as carstone, and occasionally
with a thin bed of clay in the middle part.
" It has a fairly broad outcrop (to over five miles) eastward
of Lynn ; but this is much indented by alluvial deposits up
the valley-bottoms, and there are also many cappings of drift
clays over the higher parts and down some of the slopes, even
to their bases. Nevertheless, the formation being for the
most part highly permeable, much water must sink into it.
"The underlying Kimmeridge clay crops out in places on
the west, by the border of the alluvial lands, the gentle dip
of the beds being easterly ; but there are no powerful springs,
and consequently, to get a large supply of water from the
lower greensand, it would not do to sink near Lynn that
is, toward the boundary of the formation but wells would
have to be made a good way to the east, so as to command
the underground flow of water from a large area."
Dr. Whitaker then expresses doubt as to whether one or
even two wells would yield a sufficient supply, as in sands
underground galleries cannot be cut, as in limestones, chalk,
etc. Wells sunk in sand also often get silted up and then
require clearing out. The lower greensand is usually ferru-
ginous, and does not therefore yield a water of high quality.
Passing on to the chalk formation and the water obtainable
therefrom, Dr. Whitaker says :
"Much of the water falling on the chalk sinks into it,
and of this a part finds its way downward, until at some
depth the chalk is saturated and can hold no more. The
NATURAL SPRING WATERS 63
level of saturation varies roughly with that of the ground,
being higher at the hills on the east than at the slope toward
the outcrop of the underlying gault ; the reason of the
difference of level being the frictional resistance to the flow
of the water through the chalk. The underground water-
slope in the chalk of the immediate neighbourhood being
westward, the springs are therefore merely the natural outflow
of the water -charged chalk, the water finding its way out
at the lowest available places, the slowness of percolation
through the rock making the springs constant, though of
course varying in amount, instead of their being very great
at one time (after heavy rain) and dry at another, as would
be the case if the water flowed through quickly.
"The water of these springs is, by nature, of the best
quality ; its only defect can be hardness, and this can be got
rid of to any reasonable extent, if needful ; but alas ! nature
has not been left alone ; man has changed the state of things,
and not for the better ! Of the three chief sources, two have
been polluted in a most unlucky way (one by a churchyard,
and the other by the filth of a farmyard).
" The intermediate spring at Sow's Head is away from all
buildings. I agree with Mr. Silcock (the Borough Engineer)
that it is to the chalk that Lynn should go for its water supply.
" Of the two schemes that he has brought before you to
get this water, I must own to a partiality for the bigger one,
for getting the water by means of a well and galleries, some-
where near and above Well Hall, which would intercept the
water on its way to the spring, and for pumping it to a
reservoir at the brow of the hill, about midway to Lynn,
which certainly seems to be about the best site for a reservoir,
there being a mass of boulder clay over the top of the hill.
"As, however, there seems to be no likelihood of large
increase in the population of Lynn, the question of cost must
lead one to look favourably on the other scheme, for taking
water by gravitation from the Sow's Head Spring, after opening
it out.
64 WATER SUPPLIES
"I have no doubt that the work of cutting back and
opening out that spring would result in a goodly increase of
the outflow but unfortunately we have no means of saying
how large that increase would be, and so it would hardly do
to adopt that scheme absolutely without some further know-
ledge. I think therefore that Mr. Silcock has wisely asked
that some preliminary work should be done, at no great cost,
to try the power of that spring. Of course with a spring
supply you can only take what the spring gives you, whereas
in pumping from a well you draw in water from around,
creating an artificial inflow."
An excellent example of the utilisation of a natural spring
for the supply of water to a number of small villages is the
works recently carried out in the Chelmsford Rural Sanitary
District by the Authorities' Surveyor, Mr. I. C. Smith. Dan-
bury Hill is one of the highest points in Essex. It is capped
with gravel of varying depth. On the common, on the
southern slope, is a spring of water which is the natural outlet
for the water in most of the gravel on that slope, and which
I estimate to have an area at least half a mile square. The
average annual rainfall here is a little over 20 inches, and
if 10 inches of this passes into the subsoil this patch of gravel
should yield over 1 00, 000 gallons of water per day. The spring
is of great repute, and in exceptionally dry years, when all
other sources around have failed, the water is said (on the
evidence of the oldest inhabitants) to have flowed as freely as
ever. When first gauged the spring was found to be yielding
about 50,000 gallons per day, or half the estimated yield of
the collecting area, but when cleared and opened out the flow
increased to about 70,000 gallons. The water is collected
in a reservoir of about 15,000 gallons capacity, and then flows
through a chamber in which a " ram " is fixed, and by this
means some 8000 gallons of water are pumped per day to a
tank on the top of the hill 180 feet above the spring, and
about a mile distant. This tank (of 4000 gallons capacity)
supplies the village of Danbury by gravitation. The water
NATURAL SPRING WATERS 65
is again impounded, and then supplies by gravitation por-
tions of four other parishes. The total length of mains is
about 13 miles, and the total cost 3600.
Few large towns depend solely upon springs for their
supply of water. Bristol at present obtains water from
springs in the triassic conglomerates and carboniferous lime-
stone of the Mendip Hills. The total yield is about 5,000,000
gallons per day (23 gallons per head of population). In dry
weather the supply is insufficient, and arrangements are being
made to impound the water from additional springs.
In the Massachusetts Report on Water Supplies little
reference is made to springs, since apparently no town is
supplied from such a source. In the 1891 Report, however,
it is stated that large quantities of spring water is sold
throughout the state, " particularly in cities and towns where
the regular water supply is thought to be unsatisfactory, or
where the water, as is not infrequently the case with surface
water supplies in the summer time, has an unpleasant taste and
odour." " There is also a large amount consumed in bottled
form, as soda water and other effervescing drinks." They
examined waters from forty-five springs, and found most of
them of the highest purity. Even those samples taken from
populous districts and near sources of pollution showed that
a high degree of purification had been effected by filtration
through the ground.
The character of spring water depends chiefly upon its
geological source. The water from a deep spring will naturally
be characteristic of the stratum in which it is stored under-
ground, and be little if at all affected by the more superficial
formations through which it merely passes on its way to the
surface. Bearing this in mind, the quality of the water
obtainable from springs arising in various geological strata
may be described in very few words. In all cases it is assumed
that the water is free from pollution.
1. Granite, Gneiss, and Silurian Rocks. Usually excellent
F
66 WATER SUPPLIES
in every way, their purity and softness rendering them
admirably adapted for drinking, cooking, and washing
purposes. The hardness rarely exceeds 7, and is usually
much less.
2. Devonian Rocks and Old Red Sandstone. Very wholesome
and palatable. The hardness varies considerably (2 to
21). Usually they are fairly soft, but some samples
are too hard for washing purposes.
3. Mountain Lim estone. Bright, colourless, and very palatable,
but usually too hard for washing purposes. The average
hardness is about 14, but it may exceed 30. In some
the hardness is chiefly "temporary," in others "per-
manent."
4. Yoredale Rocks, Millstone Grit, and Coal Measures.
Generally wholesome. Average hardness about 10,
but varies from 2 to 18 or more.
5. New Red Sandstone. Yields water abundantly, and of
great purity bright and sparkling. When not too hard
it is excellently adapted for all domestic purposes. The
" permanent " hardness usually exceeds the " temporary,"
and the total hardness varies from 6 to 24, the average
being about 13.
6. Lias. The water from this formation is usually so hard
(the average is over 20) that unless artificially softened
it is not well adapted for domestic purposes. As the
hardness is generally of the "temporary" character, it
can easily be reduced by any of the lime processes.
7. Oolites. Springs abound on this formation, and are often
of immense volume. The water is excellent in quality,
though invariably rather hard. The average hardness
is 17, the extremes about 12 and 27. The hardness is
almost entirely "temporary,'' and when excessive can
readily be removed.'
8. Greensands, Upper and Lower. Although very palatable
and wholesome, the water furnished by these sands
varies much in character. The hardness may be less
NATURAL SPRING WATERS 67
than 1 or upwards of 25. As a rule it is chiefly
temporary.
9. Chalk. The water from chalk springs bears justly a great
reputation for purity, brightness, and wholesomeness,
though often the hardness is too great for washing pur-
poses. It varies from 8 to 22, with an average of 17.
Of course it is almost entirely due to carbonate of lime
and can be readily removed where necessary.
10. Gravel and Drift. Varies to an astonishing degree.
The Bagshot gravels and sands usually furnish a soft
water, whilst some gravels yield water of excessive hard-
ness. Land springs alone are formed in these superficial
deposits, and the water generally contains more or less
of the products of the oxidation of manurial matters
which have been applied to the surface.
According to the Rivers Pollution Commissioners, the
chalk, oolite, lower green sand, and new red sandstone
are the best water-bearing strata in the kingdom ; their
water-holding capacity is very great, and the quality of the
water excellent. Where they dip below any "impervious
formation they are still charged with water and easily access-
ible to the boring rod." The most constant and largest
springs are derived from the chalk, oolite, new red sand-
stone, millstone grit, and mountain limestone. In the two
latter formations the water is contained chiefly in fissures
(this is probably the case also with the chalk), and the flow
from the springs therefore is more likely to be markedly
affected by prolonged drought,
68
WATER SUPPLIES
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NATURAL SPRING WATERS
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CHAPTER VI
DEEP-WELL WATERS
THE term " deep " in reference to wells is somewhat ambigu-
ous, since different writers attribute to it different meanings.
By some, any well over 50 feet in depth is called "deep,"
whatever the character of the stratum in which it is sunk,
or the strata through which it passes. By others the term
is used without any reference to actual depth, but to imply
that the well is sunk through some impervious stratum into
a water-bearing formation lying beneath. Such writers
regard all wells as " shallow," whatever their depth, if they
are sunk into and yield water from a superficial stratum.
Water in the interstices of a rock overlaid by an impervious
formation must have travelled some distance (often many
miles) from the outcrop upon which the rain furnishing it
fell ; hence nitration and oxidation is as a rule very perfect.
But where a pervious formation is so thick that the water-
level is 50 feet below the ground surface, it is evident that
in percolating to this depth the water will have become so
purified as to approach the subterranean water above referred
to in character. Such being the case, it is best to consider
such deep superficial wells as "deep." Deep wells passing
through impervious into pervious and water-bearing strata
are best designated as Artesian, although this name is often
reserved for those deep wells from which water actually
overflows. The first wells of this character were probably
sunk in China ; they were common in the East at a very early
DEEP- WELL WATERS 71
period. Centuries ago they were also sunk in the province of
Artois in France. One such well there has undoubtedly
yielded a continuous supply of water since the year 1126
A.D. At Grenelle in this province a large boring was com-
menced in 1835, and was carried to a depth of about 1800
feet before the water-bearing sand was reached. The water
then rushed in and rose some 60 feet above the surface of
the ground, the flow being nearly 1,000,000 gallons per day.
FIG. 8.
With the imperfect appliances of that period, the well took
six years to bore. Artesium being the ancient name for
Artois, all such wells have since been called Artesian. The
various kinds of deep well are illustrated by the above
diagram, Fig. 8.
The water-level in the formation c being at d, it is evident
that a well sunk at A would not pass through the superficial
impervious stratum b, yet would be deeper than the well sunk
at B, passing through this formation to reach the same source
of water. The level of the ground at C being considerably
below the water-level d, water would overflow from the well
at C. The latter, therefore, is a true Artesian well, or we
may call it an overflowing Artesian well to distinguish it
from B.
Very little consideration will render it obvious that per-
72 WATER SUPPLIES
vious strata which lie below the sea-level must retain within
them all the water absorbed at their outcrop. Formations of
this character, with extensive exposed surfaces, passing under
other more superficial strata, may store enormous amounts of
water, and if they do not reach too great a depth, which is
rarely the case, water may be obtained from them by boring
or sinking a well. The greater the depth to which the
boring passes, the greater the supply of water obtainable.
Thus in Fig. 8, as soon as the water-level in c became de-
pressed by pumping from A, B, or C, below the bottom of
A, that well would cease to yield. If the water-level became
still more depressed B also might fail, whilst C would
continue to furnish a supply. This only applies when the
pumping at the lower level is withdrawing more water than
is passing into the outcrop from the rainfall. When such is
not the case, the effect of one well upon another, if some
distance apart, will be inappreciable. If the whole of the
pervious stratum c be not saturated with water, the conditions
will be different, water will be travelling in the direction
from A to C, either towards the sea, some river, or spring,
(unless, as occasionally may occur, there be no outlet), and the
movement of the water present in the rock may be looked
upon as analogous to that of a subterranean river, or as that
of water in a cistern supplied at the top and being drawn off
at the bottom. According to the cistern theory, pumping
will reduce the level of the water without stopping the
'leakage" from the bottom, whilst on the river theory
pumping will chiefly affect the leakage, since abstraction of
water from any point in a river must decrease the flow of
water past that point. The two views were ably argued
before the Royal Commission on Metropolitan Water Supply,
and after hearing the evidence of Sir John Evans and Mr.
Whitaker in favour of the " cistern " theory, and of Baldwin
Latham in favour gf the " river " theory, the Commissioners
reported as follows :
" We are of opinion that the analogy of a cistern is in-
DEEP- WELL WATERS 73
accurate and misleading when used in relation to streams at
a considerable distance from the points where pumping is
carried on. A waterworks well is itself a typical cistern ;
the pumps are not unfrequently submerged many feet, and
when pumping commences it is the bottom water that is
withdrawn, and in consequence of losing its support the upper
water is proportionally lowered. . . . But in addition to this
vertical and horizontal lowering (of the water surface) in the
open well, there goes on simultaneously a lowering of a
different character in the chalk around the well.
" Immediately adjoining and outside an unlined chalk well,
the water lowers pari passti with that inside, but the same
horizontal plane is not continued outwards. The water cannot
pass through the crevices in the chalk to the well without a
certain amount of fall or slope, this being necessary to
overcome the friction of its passage. Hence the surface of
the water in the emptying chalk rises from the well in all
directions at a gradient more or less steep, in relation to the
openness or closeness of the passages. These slopes will
nowhere probably form a symmetrical or regular cone-shaped
depression having the well as its centre, but slopes at varying
angles modified by circumstances are undoubtedly required if
the supply to a well is to be maintained whilst pumping is
going on.
"It is only necessary to follow out this idea to a distance of
miles from the well to realise clearly that the cistern theory
is untenable. In the open well the upper water is supported
directly by that below it, and when the support is removed
the surface is immediately and vertically depressed. Out in
the body of the chalk the upper water is only partially sup-
ported by that below it, and mainly by the chalk in and upon
which it lies and flows ; and this being so, the analogy of a
river is much more apt and accurate than that of a cistern.
Mr. Baldwin Latham and other witnesses were therefore more
nearly right than Sir John Evans, when they said that pump-
ing from a well tapping an underground stream flowing in a
74 WATER SUTPLIES
known direction mainly affected the water below the well,
and had little effect on that above the well."
The same reasoning applies not only to the chalk, but also
to all porous underground strata containing water under
similar conditions.
But few deep wells are sunk into the Devonian rocks,
millstone grit, coal measures, or magnesian limestone, the
probability of obtaining water therefrom being in most cases
very problematical. The new red sandstone, oolites, and
chalk are the great subterranean water-bearing strata, the
lias, greensands, Hastings, and Thanet sands having smaller
outcrops, and being much thinner, and not so certainly con-
tinuous, yield much more limited supplies. The new red
sandstone is an exceedingly effectual filtering medium, and
from the great extent of this formation vast quantities of
the purest water are stored in it, and often can be rendered
available at a comparatively slight expense. The oolites,
according to the R. P. C., " contain vast volumes of magnifi-
cent water stored in their pores and fissures . . . and it
cannot be doubted that a considerable proportion of this
could be secured for domestic supply in its pristine condition
of purity at a moderate cost." The chalk formation is one of
the most absorbent ; therefore a large proportion of the rain-
fall upon its outcrop passes into it and becomes thoroughly
filtered and purified. The R. P. C. found the deep-well waters
from the chalk "almost invariably colourless, palatable, and
brilliantly clear." " The chalk," they say, " constitutes
magnificent underground reservoirs, in which vast volumes of
water are not only rendered and kept pure, but stored and
preserved at a uniform temperature of about 10 C. (50 F.),
so as to be cool and refreshing in summer, and far removed
from the freezing-point in winter. It would probably be im-
possible to devise, even regardless of expense, any artificial
arrangement for the storage of water that could secure more
favourable conditions than those naturally and gratuitously
afforded by the chalk, and there is reason to believe that the
DEEP-WELL WATERS 75
more this stratum is drawn upon for its abundant and ex-
cellent water the better will its qualities as a storage medium
become. Every 1,000,000 gallons of water abstracted from
the chalk carries with it in solution, on an average, 1 j tons
of chalk, through which it has percolated, and this makes
room for an additional volume of about 110 gallons of water.
The porosity and sponginess of the chalk must therefore go on
augmenting, and the yield from the wells judiciously sunk
ought within certain limits to increase with their age." Strange
as it may appear, this does not apply to waters from the chalk
in certain districts which, instead of being hard, as is usually
the case, are exceptionally soft, containing sometimes not
more than two grains of chalk in solution in each gallon.
Such exceptions prove that the underground sheet of water
is not continuous. As previously explained, this is occasioned
chiefly by faults interrupting the continuity of the strata, and
such faults may seriously affect the supply obtainable from
any particular well. Besides such faults, various foldings
and irregularities often occur, dividing and subdividing the
subterranean reservoir, cutting off more or less completely one
compartment from another, and limiting the supply. Before
sinking a deep well, therefore, many points have to be care-
fully considered if the possibilities of failure are to be reduced
to a minimum.
The chief are :
1 . The extent and character of the absorbing area or out-
crop, whether bare or covered with drift, whether
level, undulating, or hilly ; its elevation above the
district proposed to be supplied by the wells ; the
density of the population upon it, or discharging
their sewage thereon. Notwithstanding the purify-
ing action of porous rock, it is not desirable to have
a dense population upon the outcrop, as in the course
of time the water may become affected. Many wells
have had to be closed for this reason. At Liverpool,
76 WATER SUPPLIES
for instance, several deep wells belonging to the
Corporation became polluted by the population on
the collecting area, and had to be abandoned.
Where the subterranean water is chiefly collected in
and travels through fissures this danger is accentu-
ated. The extent of the absorbing area is often
difficult to determine, as implicit reliance cannot be
placed on maps. The sections at the surface, by
which the geological structure was determined at
the time of the survey, are occasionally misleading.
2. The average rainfall for a number of years. This being
known, and the nature of the surface determined, a
rough estimate of the amount of water absorbed may
be formed (vide Chap. XVII.). But the outcrop may
receive the drainage of a neighbouring impervious
area, or, on the other hand, the contour or surface of
the outcrop may be such as to throw off an unusual
proportion of the rainfall, or much of that absorbed
may flow away from springs. The levels of the
springs must be studied to ascertain the direction of
flow of the underground water, and their positions may
lead to important inferences with reference to the
continuity or otherwise of the water-bearing stratum,
the presence of faults, crumplings, or other irregu-
larities.
3. The continuity of the water-bearing strata and their super-
ficial area and thickness. The maps issued by the
Geological Survey show the position and throw of all
known faults, but trial bores have frequently to be
made to ascertain whether others exist, unless their
absence is proved by existing wells. The study of
data obtained from recorded well sections, or by the
results of trial bores, will give an idea of the thick-
ness and extent of the porous stratum. The thick-
ness may vary considerably. Thus the chalk at Norwich
is nearly 1200 feet thick, in Wiltshire 800 feet, in
DEEP- WELL WATERS 77
Surrey 350 to 400 feet, in East Kent 800 feet, at
Harwich 888 feet, at Kentish Town 640 feet. The
lower greensand which lies beneath the chalk has a
thickness of probably 600 feet in the Isle of Wight,
but it rapidly thins away and appears to be absent
under London. As an instance of the difficulties
met with in determining the extent of an under-
ground water-bearing deposit, and of the unrelia-
bility of maps, Mr. Hodson, C.E., states 1 that when
investigating "an area of lower greensand, which the
Ordnance Survey showed as occupying an area of
about 8| square miles, of which the outflow lay to
the south-west, a careful examination proved that a
main anticlinal existed which brought up an under-
ground ridge of impervious Weald clay, which,
although not apparent on the surface, effectively
divided the underground sheet of water, and diverted
to an outflow on the south-east the water absorbed
on 3J miles of the watershed, leaving only 5| miles
as possibly available. In addition to this the evi-
dence afforded by the springs conclusively showed
that other smaller anticlinals existed, which held up
the water as in a series of troughs, which made it
very doubtful whether more than one square mile
could be commanded by any particular well ; whilst
to complete the uncertainty, notwithstanding the
most persistent efforts, it was impossible to discover
all the lower greensand area given by the map, and
a large district clearly marked as upper greensand was
just as clearly gault."
4. The selection of a site for the well. Underground
water not flowing in a well-defined channel, there are
no laws conferring prescriptive rights of property ;
hence if a well be so placed that its supply of water
1 A paper on Underground Water Supplies, communicated to the
Incorporated Association of Municipal Engineers, May 1893.
78 WATER SUPPLIES
is affected by the pumping from another well, there
is no remedy at law. A site, therefore, should be
chosen so as to tap the water at a point where it is
least likely to be influenced by other wells (vide
page 72). The multiplication of deep wells in and
around London has lowered the water-level consider-
ably, and in many parts of Essex, wells which were
sunk fifty years ago, and then overflowed, only yield
water when raised by pumps. In many instances,
where the wells had ceased to yield, the deepening
of the reservoir (or sunk portion of the well) or the
lengthening of the pump pipe has restored the
supply.
The advantages of underground water supplies wherever
obtainable, as compared with impounding schemes, are that
large reservoirs are not required, very little land is wanted,
no compensation water has to be provided, or water rights
acquired from neighbouring landowners, filter beds are un-
necessary, and the possibility of the water becoming polluted
is much less. Against these advantages must be placed the
cost of pumping; but "in these days of modern high-class
pumping machinery," Mr. Hodson says, " the additional cost
is so trifling as not to be worthy of serious consideration ; in
fact, the expenses of pumping to a moderate height with good
machinery are even less than the annual charges for interest
and working expenses of filter beds alone." These remarks,
of course, apply only to comparatively large centres of popula-
tion. The expense of boring a well to any considerable depth
prevents such supplies being obtained for single houses or
small communities, except in certain districts where no other
source is available. The mode of construction, cost, etc.,
will be discussed in the section on "Wells and Well
Sinking."
The distance within which one deep well can affect another
in a continuous stratum depends upon many circumstances,
DEEP-WELL WATERS
79
such as the porosity of the rock, presence of fissures and their
direction, etc. In London there are wells within very few
yards of each other, the supplies from which appear to be
unaffected by their contiguity. On the other hand the
Windsor Well, 210 feet deep, belonging to the Liverpool
Corporation, is said to have affected the surrounding wells to
a maximum distance of If miles.
In the Lea valley the underground water-level has been
carefully ascertained. From Chadwell springs to Cheshunt
there is a fall of 4 feet per mile ; from Cheshunt to Waltham
Abbey 18 feet per mile, and from Cheshunt to Hoe Lane 11
feet per mile. Between Hoe Lane and Walthamstow the fall
averages 9 feet, whilst between here and the city the fall varies
from 22 to 32 feet per mile. The increased fall south of
Cheshunt is doubtless due to the pumping under London,
which is abstracting more water in a given time than can
pass through the chalk, compressed as it is by great thickness
of clay above it. The effect, therefore, of the excessive ab-
straction of water from the deep wells in London is affecting
the water-level, or plain of saturation, to a distance of 10 or
12 miles north of the city.
The following well sections, typical of those in and around
London, are taken from Whitaker's Geology of London :
BANK OF
COLD BATH
COVENTGARDEN
ENGLAND.
FIELDS.
MARKET.
Thick-
ness.
Depth.
Thick-
ness.
Depth.
Thick-
ness.
Depth.
River Gravel and made
ground
26
26
24
24
25
25
London Clay
111
137
45
69
135
160
Woolwich and Reading
Beds .
Thanet Sand .
5Si
39"
195
234i
55
8
124
132
J-100
260
Chalk
100
33H
20
152
98
358
8o
WATER SUPPLIES
SOUTHEND WATER-
WORKS, ESSEX.
WALTHAM CROSS, HERTS.
STREATHAM
COMMON,
SURREY.
Thick-
ness.
Depth.
Thick-
ness.
Depth.
Thick-
ness.
Depth.
Surface Soil
3
3 (Gravel)
13|
134 (Mould)
2
2
London Clay
414
417
64^
78
178
180
Sands .
181
598
64
142
195
285
Chalk .
302
900
~~
142 +
285 +
The average depth of tube wells in London is about 400
feet, and in most instances the deep-well pump has to be
fixed from 200 to 300 feet from the surface. Messrs. Isler
and Company, who have bored many of these wells, state that
the yield obtained varies from 1800 to 7200 gallons per hour
from single bore holes. At Sleaford, in Lincolnshire, Messrs.
Le Grand and Sutcliff recently bored a well for Messrs. Bass
and Company's maltings. At a depth of 156 feet in the
limestone beds of the lower oolite water was reached, and
rushed out of the bore pipe 3 feet above the surface at the
rate of over 12,000 gallons per hour, or nearly a ton of water
per minute. By enlarging the boring and sinking to 177
feet the yield was increased to 30,000 gallons per hour.
The towns of Long Eaton, Melbourne, and Castle Doning-
ton have combined and obtained a supply of water from a
deep well in the millstone grit at Stanton Barn. The scheme
was devised by and carried out under the immediate super-
vision of Mr. George Hodson, C.E. A well 70 feet deep
was sunk, and from the bottom of this 750 yards of headings
were driven, about 6 feet high by 5^ feet wide. Two bore
holes, each 10 inches in diameter, were sunk to a depth -of
about 300 feet, and lined with perforated steel tubes where
they passed through water-bearing beds. The yield of water
from these was found to be nearly 900,000 gallons per day.
The population to be supplied is about 16,000, but it is
estimated that in thirty years this will have increased to
DEEP- WELL WATERS 81
25,000. The engineer is of opinion that the above yield
FIG. 9. Illustrates the overflow from an Artesian well recently bored at Bourn,
Lincolnshire, by Messrs. C. Isler and Company, for the supply of the town of
Spalding. The overflow is at the rate of about 5,000,000 gallons per day, and
is probably the most prolific underground spring yet tapped in England. The
boring is only 134 feet deep.
allows an ample margin for periods of drought and all other
G
82 WATER SUPPLIES
contingencies. From the well the water is pumped into a
covered reservoir on a hill at such an elevation that the three
towns mentioned can be supplied by gravitation therefrom.
The pumps and pumping machinery are in duplicate, and are
capable of raising 60,000 gallons of water per hour. The
total cost of the completed works for the three districts was
a little under 45,000.
From time to time proposals have been made to further
increase the supply of deep- well water for the City of London,
and the whole subject has recently been fully investigated and
reported upon by a Royal Commission. It is calculated that
40,000,000 gallons a day is obtainable from wells in the Lea
valley, or 27,500,000 more than is at present being pumped ;
from wells in the Kent Company's district 27,500,000 gallons,
or 11,000,000 a day more that at present. The data and
reasoning upon which such estimates are based may be illus-
trated from that portion of the Commissioners' Report
referring to the Lea valley.
1. The area of the collecting surface is estimated at 422
square miles, a portion consisting of bare chalk, or chalk
covered with permeables, the remainder of chalk covered with
partially or wholly impermeable beds draining on to the chalk.
2. The mean annual rainfall of a long term over this area
is 26 '5 inches, the average of three consecutive dry years is
22 '8 inches, and the fall in the driest year 19 inches.
3. In the Thames valley the average annual evaporation
is 16 inches, and in the driest year 14. Assuming the same
to hold in the Lea watershed, the evaporation on an average
of three consecutive dry years would be about 14*8 inches,
leaving 8 inches to run off into the rivers or to percolate into
the ground. Of that which gets into the ground a portion
is returned to the river. From measurements made as to
the yearly discharge at Field's Weir, above which the river
receives the whole of the drainage of this area, the mean
discharge represents 4 '6 inches flowing off. Deducting this
from 8 inches, the amount left to percolate is 3 '4 inches, which
DEEP- WELL WATERS 83
would yield, from an area of 422 square miles, 3,304,000,000
cubic feet per annum, or 56,000,000 gallons per day. But the
whole of this water as it travels past the wells down the
valley cannot be intercepted.
"In the driest of three years, therefore, especially if it
came to the last in the cycle, 56,000,000 would clearly not
be obtainable, probably not more than 47,000,000, but we
believe that the Companies, after providing reasonably for
all below them, might, under the worst conditions, reckon on
obtaining 40,000,000 gallons a day."
Professor Boyd Dawkins believes that the body of the
chalk contains such a store of water that it would equalise
the rainfall, so that the amount available even during three
consecutive dry years would be little short of that obtainable
with an average rainfall. With this opinion the reporters
disagree, since they consider that the only available water is
in the fissures and crevices of the chalk, and that when these
are drained the water held in the body of the chalk by capil-
larity oozes out so slowly as to be practically useless.
In the subjoined table are given the analyses of a number
of public water supplies derived from deep wells in various
strata. With one or two exceptions they are quite recent.
Deep -well water differs little from spring water from the
same geological source. An exception, however, occurs in
certain districts where the chalk lies at a great depth beneath
the London clay, and yields a very soft water containing
carbonate and chloride of sodium. This is well adapted for
domestic purposes, but not for use in high pressure boilers, nor
for irrigation. Boilers in which it is used quickly leak, and
the saline constituents have a prejudicial effect upon many
forms of plant life.
The utilisation of subterranean water obtained from bored
wells is in many of our colonies converting deserts into fruit
gardens, and rendering habitable large extents of country in
which life was previously impossible on account of the scarcity
of water (vide Chap. XVIII.).
8 4
WATER SUPPLIES
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CHAPTER VII
RIVER WATER
THE whole surface of any given country can be divided into
"catchment basins," each such basin including an area of
land surface draining into a particular river. The district
so drained is also called the watershed of the river, and it
may vary in extent from a few square miles to thousands of
square miles. The watershed of any large river flowing directly
into the ocean may be said to include and be greater than
the watersheds, drainage areas, or catchment basins of all its
tributaries. The actual point at which a river takes its rise
is often difficult to decide. If it originates at the natural
outlet of a lake or from a powerful spring, the point at
which it comes into existence is obvious. If, however, it is
formed by the meeting of the waters of two or more rivulets
of tolerably equal length and flow, then the claims of any
one of the streams to be the parent stream may be disputed.
A stream may arise from a spring, and for some short distance
may consist of pure spring water, but its volume is soon
increased by surface and subsoil water, so that all river
waters may be said to consist of mixtures of waters in
varying proportion from all three sources. As these waters
will -also vary with the geological character of the district,
and the nature of the subsoil and surface, it is obvious that
the waters of different rivers will not only differ from each
other, but that water from the same river taken at different
points, or even from the same point at different seasons, may
RIVER WATER 87
vary considerably in composition. Where the water of a
tributary differs much in appearance from that of the parent
stream, the difference can often be observed for some distance
below the point of entrance of the smaller stream. In some
instances the effect of such admixture is very marked. Upon
Axe Edge in Derbyshire a highly calcareous stream joins
a ferruginous one. Before combining, both are clear ; after
mixing, the stream becomes red and turbid, deposits an
ochrey substance upon its bed, and only again becomes
pellucid after flowing a considerable distance.
Unfortunately, in all inhabited districts the rivers not
only receive the natural drainage, but are also the ultimate
receptacles of all the polluted waters (sewage) artificially
collected from manufactories, groups of houses, and from
towns within their watersheds. Notwithstanding the Rivers
Pollution Act, nearly every stream of any size in this country
is at the present time so befouled, the defilement in many
instances being so great, that the rivers are practically open
sewers. Where the sewage is . chemically treated before
being allowed to pass into the streams, most of the suspended
impurities are removed, and possibly a portion of those
previously held in solution. If the sewage be disposed of
by broad irrigation or by intermittent downward filtration
through land, it is still further purified, most if not all the
organic matters being removed or destroyed by oxidation.
From highly cultivated land also a certain amount of filth
may reach the streams, especially during heavy rains, when
much of the rainfall not only dissolves impurities but carries
with it into the river other matters in suspension. This
rapid inrush of water disturbs the mud and deposit at the
sides and in the bed of the stream, and for a time increases
the rapidity of flow, and renders the water turbid and still
more impure. Rivers rising and flowing through very thinly-
populated districts may yield water to which no possible
objection can be taken, from a hygienic point of view, water
which may be admirably adapted for all domestic and other
88 WATER SUPPLIES
purposes, and which it is in the highest degree improbable
will ever act as the carrier of the germs of disease. Many
rivers, however, are utilised as sources of public water
supplies which are continuously receiving sewage from towns
or villages at points above the intake. The Thames is such
a river, and the Royal Commission which recently inquired
into the water supply of the Metropolis reported that there
was no evidence of the pollution causing any injury to the
health of those drinking the water, and even advocated the
increased utilisation of the Thames for the supply of water
to the capital. The utilisation of rivers as water supplies is
so dependent upon the possibility of the water being puri-
fied, that, although the subject will be discussed later, some
reference must be made to it here. The self-purification of
rivers is by one set of observers regarded as an indisputable
fact, whilst by others it is regarded as a myth. The Royal
Commission on Water Supplies in 1869 reported that when
sewage was diluted in a stream with not less than twenty
times its volume of water, that the polluting matter was com-
pletely oxidised and destroyed during a flow of " a dozen miles
or so." The Rivers Pollution Commissioners in 1874 reported
that, as there was no proof of this, they had undertaken a
series of observations and experiments and had arrived at
a diametrically opposite conclusion. After describing the ex-
periments, etc., they conclude that " whether we examine the
organic pollution of a river at different points of its flow, or
the rate of disappearance of the organic matter of sewage or
urine when these polluting liquids are mixed with fresh
water and violently agitated in contact with air, or finally,
the rate at which dissolved oxygen disappears in water
polluted with 5 per cent of sewage, we are led in each case
to the inevitable conclusion that the oxidation of the organic
matter in sewage proceeds with extreme slowness, even when
the sewage is mixed with a large volume of unpolluted water,
and that it is impossible to say how far such water must
flow before the sewage matter becomes thoroughly oxidised.
RIVER WATER 89
It will be safe to infer, however, from the above results, that
there is no river in the United Kingdom long enough to effect
the destruction of sewage by oxidation." In the same Report
is quoted the opinion of Sir Benjamin Brodie, F.R.S., " that
it is simply impossible that the oxidising power acting on
sewage running in mixture with water over a distance of
any length is sufficient to remove its noxious quality." This
Royal Report notwithstanding, it is an undoubted fact that in
many rivers some purifying action is taking place, and with
great rapidity. Thus the river Seine, after becoming horribly
polluted as it runs through Paris, gradually improves in
appearance, and about 30 miles below the city is actually
found upon analysis to be purer than it was before it received
the sewage of the city. The water of the Thames at Hampton
Court contains no more organic matter than it does at points
higher up, before it has received the sewage of the towns
along its course. The bacteriological examination of river
waters does not enable us to arrive at any definite conclusion,
and the Royal Commission on Metropolitan Water Supply,
after hearing much evidence last year, says that, " After all,
the main evidence on which we have to base our judgment
is that furnished by London itself. For more than thirty
years the inhabitants of London have been drinking water
taken from the Lea and the Thames above Teddington, at
points either the same as those at which the present intakes
are situated, or at points where the chances of contamination
were greater, and the population that has been thus supplied
has varied from some two and a half to five millions. Here,
then, we have an experiment on a gigantic scale, largely
exceeding in compass the aggregate experience of all the
other places in which outbreaks of fever have been subject
to inquiry, and an experiment made, moreover, under the very
conditions, or at any rate under no more favourable condi-
tions than those that are still in operation in London. What
has been the practical issue of this prolonged and wide
experience ? Every medical witness that has appeared before
90 WATER SUPPLIES
us, whether his general feeling was favourable or unfavour-
able to the water, has told us unhesitatingly that he knows
of no single instance in which the consumption of this water
has caused disease. This is the unanimous testimony of the
medical officers of health, of the water analysts, and of the
bacteriological experts, of all, in short, whose attention has of
necessity been directed to the subject." The Commissioners
therefore think that the risk of disseminating disease, even
by admittedly polluted river water, is, under conditions
similar to those which obtain in the Lea and the Thames,
and where the water is equally carefully collected and
filtered, so small as to be negligible. The serious outbreaks
of typhoid fever in the Tees valley in 1890-91, which were
investigated by Dr. Barry, a Local Government Board inspector
of great experience, were attributed by him to the pollution
of the river Tees by sewage. The Medical Officer to the
Local Government Board, in his introduction to this Report,
says, " Seldom, if ever, has the fouling of water intended for
human consumption, so gross or so persistently maintained,
come within the cognisance of the medical department, and
seldom, if ever, has the proof of the relation of the use of
water so befouled to wholesale occurrence of enteric fever
been more obvious and patent." These outbreaks were
carefully considered by the Metropolitan Commissioners, and
they concluded that Dr. Barry's evidence connecting them
with the polluted Tees water was not conclusive.
Amidst such a conflict of opinion it is safest to suspend
one's judgment ; but even the most ardent advocate of the
use of river water will admit that it should receive as little
sewage as possible, and that the sewage should be previously
subjected to the most effective system of purification. Storage
reservoirs also should be provided, sufficiently large to allow
of the average daily supply being furnished without taking
in any part of the flood- water, and the filters should be kept
in a thoroughly efficient condition. That the neglect to
maintain these conditions might result in an outbreak of
RIVER WATER 91
typhoid fever or cholera seems possible if not even probable,
and the fact .that a town using polluted water has remained
free from such epidemics for a series of years is no proof
that such immunity will be perpetual. In the section
treating of "Diseases disseminated by Potable Waters"
many examples will be quoted in which polluted river water
has been proved, so far as actual proof is possible, to have
been the cause of serious outbreaks of both typhoid fever and
cholera.
The amount of water which can be taken from a river for
supplying a town varies according to (a) the area of the
watershed, (b) the topography and geological character of
the ground, (c) the average rainfall, and the rainfall during
a, consecutive series of dry years, (d) the distribution of the
rainfall throughout the year, (e) the amount of water which
must be supplied for " compensation " purposes, and (/) the
facilities for obtaining storage.
The available watershed, of course, includes only that
portion of the whole watershed which feeds the river above
the point at which the water will be abstracted. This can
only be ascertained by actual measurement, though approxi-
mate estimates may be made from hydrographical maps on
which the river basins are defined.
The contour of the ground surface also affects the supply,
for upon this depends greatly the rapidity with which the
rainfall, especially when heavy, will flow over the surface into
the stream. The character of the surface and of the subsoil
will also affect the amount which will flow directly into the
river, and the amount which will percolate and pass into the
river at a lower level. All the above also will be factors in
determining the amount of evaporation, or, in other words,
of determining the available rainfall. The surface drainage
area does not always correspond with the true drainage area,
since there may be springs within the surface area fed from a
source without that area ; and, on the other hand, rain which
falls on the surface area may pass by underground channels
92 WATER SUPPLIES
beyond the limits of the watershed. All these possibilities
have to be borne in mind, and the locality carefully examined
to ascertain whether such conditions exist, and to what extent
they will affect the water supply.
The way in which the rainfall in any particular district
can be ascertained has already been described. The minimum
rainfall for a year, or a series of years, can only be determined
from records continuously taken for many years ; but it is
found that, under ordinary circumstances, the maximum
rainfall exceeds the average by one-third, whilst the minimum
falls short of the average by the same amount. The mean
rainfall during the three driest consecutive years is usually
about one -fifth less than the average. Thus, where the
average rainfall for a series of years is 30 inches per annum,
the maximum will be about 40 inches, the minimum 20 inches,
and the mean for the three driest consecutive years 24 inches.
Where careful daily gaugings of a stream have been made for
a few years, the proportion of the rainfall finding its way into
it can be ascertained, and by calculation the amount which
would pass into the river, with the minimum rainfall, can be
approximately determined. The following table, compiled
from the 22nd Annual Jteport of the State Board of Health of
Massachusetts, shows the rainfall received and collected during
a series of years on the Sudbury River watershed.
During the sixteen years, 1875-90 inclusive, the average
rainfall was 45 '8 inches. The calculated maximum rainfall
on this area is 61 '1 inches, and the minimum 30'5 inches.
The observed maximum and minimum were 57 '9 and 32*8
inches respectively. The mean rainfall for the three driest
years (1882-84) was 38 '8, whilst the calculated mean is 36 '6
inches, so that doubtless the calculated amounts will closely
approximate to the truth when the records for a much longer
period of years are available. The percentage of rainfall col-
lected does not vary directly with the rainfall, and neither
the smallest nor largest proportion collected corresponded
with the lowest and highest rainfalls ; but the results do not
RIVER WATER
93
vary to such an extent as to render it difficult to determine
approximately the minimum amount available. The cause
of this variation is due in part to the seasonal variation in
the rainfall, and in part to the variation in the amount
evaporated.
Year.
Rainfall.
Rainfall collected.
Per cent collected.
1875
45-49
20-42
44-9
1876
49-56
23-91
48-2
1877
44-02
25-49
57-9
1878
57-93
30-49
52-6
1879
41-42
18-77
45-3
1880
38-18
12-18
31-9
1881
44-17
20-56
46-6
1882
39-39
18-10
45-9
1883
32-78
11-19
34-1
1884
47-13
23-78
30-5
1885
43-54
18-92
43-4
1886
46-06
22-82
49-5
1887
42-70
24-23
56-7
1888
57-46
35-75
62-2
1889
49-95
29-06
58-2
1890
53-00
27-00
50-9
Mean for 16 yrs.
45-80
22-67
49-5
A knowledge of the seasonal rainfall and the seasonal
variation in the flow of the stream is also absolutely neces-
sary, since upon these factors depend in a great measure the
amount of storage which will be required to collect the
water during periods of abundance for use during periods of
drought. During the sixteen years' records of the Sudbury
River, the mean daily flow during the month when the river
was lowest was only 60 gallons per acre of the watershed ;
during the driest three months it was 1 48 gallons ; during
the driest twelve months, 777 gallons ; whilst the mean daily
flow for the whole period was 1686 gallons. From these
records the reporters to the Massachusetts State Board of
Health have calculated a table showing the "amount of
storage necessary to make available different quantities of
water per day from each square mile of watershed, where the
94
WATER SUPPLIES
conditions are similar to those which exist at Sudbury River."
To obtain 100,000 gallons per day per square mile, the storage
reservoir must be capable of holding 2,200,000 gallons per
square mile of watershed; to obtain 1,000,000 gallons per
day, the reservoir must hold 540,000,000 gallons. For
intermediate quantities the original table must be consulted. 1
Of course these results can only be used where the conditions
which obtain resemble somewhat those of the watershed
under consideration. The following table for the river
Thames is calculated from data given in the Report of the
Royal Commission on Metropolitan Water Supply :
Year.
Rainfall.
Rainfall collected.
Per cent collected.
1883
28'4
13-3
46-8
1884
22-9
7'0
30-8
1885
29-15
8-3
28-5
1886
31-1
11-1
35-7
1887
21-3
8-2
38-5
1888
28-45
8-9
31-3
1889
25-6
9-1
35-5
1890
22-8
5-7
25-0
1891
33-3
9-8
29-3
Average of 9 yrs.
27-0
9-05
33-5
If this table be compared with the corresponding one for the
Sudbury River, it is evident that a considerably larger pro-
portion of the rainfall is available from the watershed of the
Sudbury than from that of the Thames.
Mr. Beardmore calculates that during summer, the Thames,
Severn, Loddon, Medway, and Nene, which flow over a variety
of geological strata, only carry off less than one-eighth of the
rainfall, whilst the Mimram and Wandle, which arise in and
now through chalk districts only, yield nearly half the total
rainfall. Certain rivers are much more constant in their flow
than others, the result depending chiefly upon the conforma-
tion of the watershed and the character of the subsoil. If
the stream be fed chiefly with surface water the variation
1 State Report 1890, page 342.
RIVER WATER 95
will be very considerable, whilst if fed chiefly from the Hub-
soil the flow will be comparatively uniform. All these factors,
therefore, have to be taken into consideration when estimating
the available supply and the amount of storage necessary.
Where there are riparian owners having a right to the use
of the water for any purpose, as for manufacturing, or as a
motive power, further complications are introduced. Sufficient
water must be allowed to pass down the river to satisfy all
their reasonable requirements. Only the amount in excess of
this can be appropriated, and as during seasons of drought
they may require the whole flow of the river, the impounding
reservoirs must be large enough to store water during seasons
of abundance sufficient to tide over these periods when none
can be collected.
The quantity of water which must be stored to equalise
the supply during the longest period of drought which may
possibly occur can only be determined when the average daily
demand is approximately known, and the whole of the con-
ditions above referred to have been carefully investigated.
The number of days' storage required varies in this country
from 120 to 300; the smaller quantity only being required
on the western side, where the rainfall is heavy and the
number of rainy days considerably above the average. In
the eastern counties, where exactly the opposite conditions
obtain, about ten months' storage may be necessary.
The amount of storage required may be calculated from
the rainfall statistics only, or from the stream gaugings, but
both must be considered if the result is to be reliable. The
gaugings may be effected by various methods : (a) by means
of sluices ; (b) by aid of current metres ; (c) by means of
weirs ; (d) by gauging the surface velocity. Where a rough
approximation only is desired, a straight portion of the stream
may be selected which is tolerably uniform in width and
section, and where the water flows smoothly, or where by a
little labour such uniformity may be produced. By plumbing
the depth at different points across the stream and measuring
OP THB
UNIVERSITY
9 6
WATER SUPPLIES
the width, the cross section can easily be calculated. The
length of the selected portion, 20 yards or more, must be
marked off, and the time noted which it takes a chip or float
to traverse this length in mid-stream on a calm day. The
mean velocity of the whole body of the water may be taken
as '75 that of the surface velocity. These data are sufficient
to give the volume required.
For example, the area of a section of a stream is found to
be 45 square feet, and the time taken by a float in traversing
a distance of 60 feet is 80 seconds. Required the flow in
gallons per day.
45 x 60 x 75
80
= 25 '3125 = flow in cubic feet per second.
25 '3125 x 60 x 60 x 24 x 6 '25 = 13,668, 750 gallons per 24 hours.
The ratio of the mean to the surface velocity is not a constant,
and its value is variously estimated by engineers from the
results of actual experiments. It varies with the rapidity of
flow, the nature of the channel, depth of water, or form of
cross section, but the first named is probably by far the
most important factor. Mr. Beardmore adopts the formula
U = V + 2'5 - \/5V where U equals the mean, and V the surface
velocity per minute. This formula gives the following values
for U :
Surface Velocity
in Feet
per Minute.
Mean Velocity.
Value of U
in terms of V.
5
2-5
5
10
5'5
55
20
12-5
625
50
36-5
73
100
80-2
802
200
170-9
855
Where greater accuracy is required and the stream is large, a
current metre may be employed.
" Having fixed on the station where the cross section of a
RIVER WATER
97
large river is to be taken and the velocities ascertained, take
a number of soundings across the stream, at 8, 10, or 12
points, according to the breadth. These lines of sounding
divide the section into a number of trapezia, and the area of
each of these is to be calculated. Then, at a point half-way
between each of the two lines of sounding, is to be fixed a
small boat containing the current metre (Fig. 10), by means
of which 5, 6, or 7 velocities are to be determined in the same
vertical line. The arithmetical mean of these is then to be
FIG. 10.
multiplied by the area of the trapezium to which they apply.
The sum of these products is evidently the discharge of the
river it is equivalent to the total sectional area multiplied
by the mean velocity " (Hughes's " Waterworks," quoted from
D'Aubuisson's Traite d' Hydraulique a Vusage des Ingenieurs).
In artificially constructed channels of uniform cross section,
such as canals, culverts, and pipes (the two latter may be
running full, but must not be under pressure), various formulae
have been devised for estimating the flow from the fall per
mile and the hydraulic mean depth. 1 Beardmore's modification
of Eytelwein's formula is the one usually employed
1 The hydraulic mean depth is the sectional area of the water divided
9 8 WATER SUPPLIES
where U equals the mean velocity in feet per minute, II the
hydraulic mean depth, and H the fall in feet per mile.
Example. In a circular channel of 2 '5 feet diameter,
having a fall of 5 feet per mile, and running exactly half full
of water, what is the flow in cubic feet per minute 1
R=g. H = 5. U = 55V2x5x = 137'5.
2'5 2 x '785
The area of a section of the water is ---- 9 --- = 2*453 feet.
This, multiplied by the velocity, 137 '5, gives a yield of
337 '3 cubic feet per minute.
Streams of any magnitude are usually gauged by engineers
by the aid of artificially constructed weirs. Theoretically
the velocity with which the water passes over the weir is that
which a body would acquire in falling through a distance
equal to the difference between the surface level of the water
above the weir and the surface of the weir itself. A body
falling from rest acquires at the end of one second a velocity,
y, which is approximately 32 feet per second. The mean
velocity at the end of any number of seconds, t, will be
-, the space traversed, s, in that time will be --,
and the velocity at the end of that period tg. Eliminating t,
we find that v 2 = 2sg = 2 x 32 x s, therefore
V = 8\/3.
Theoretically, therefore, the velocity with which water passes
over the actual surface of the weir is eight times the square
root of the difference in level above referred to. But this is
the lowermost stratum of the water only, the strata above
having a less velocity, decreasing upwards as the square root
by the wetted perimeter. In circular pipes miming full, 3'14( equals the
wetted perimeter, and f j *785 the cross section of the water ; K therefore
equals d.
RIVER WATER
99
of the depth from the surface level. The mean velocity of all
the strata will be that of the particles at the depth of the
lowermost, therefore
Unfortunately friction has to be taken into account, and as
this varies with the shape of the weir, its width, etc., the
above formula has little more than theoretical interest.
Numberless experiments have been recorded and many
formulas deduced therefrom for weirs of different kinds.
Here, however, it is only necessary to refer to the one most
frequently employed, that derived from Mr. BlackwelPs
experiment made on the Kennet and Avon Canal on
the flow of water over 2 -inch planks. Let Q equal the
quantity of water flowing over the weir in cubic feet per
minute, then
Where w = the width in feet, s the depth of water in inches,
and c = a constant multiplier, found by experiment and
given in the following table (quoted from Slaggs' Water
Engineering) :
Depth s=l inch
= 2 inches
-3 ,,
= 4 ,,
= 5 ,,
= 6 ,,
= 7 ,,
= 8
= 9
Value of c 3 '50
,, =4 '25
=4-44
,, =4-44
=4-62
,, =4-57
=4-61
=4-48
,, -4-44
For depths of 3 inches and upwards c may evidently be
taken as 4 '5. As an example, it is required to calculate the
flow over a weir of 5 feet in width, the level of which is 6
inches below the even surface of the water.
Since 5 6, c = 4'5 and w = 5
Q = 4 '5 x 5 x \7fr*
Q = 333 cubic feet per minute,
100
WATER SUPPLIES
Under certain circumstances, as where a lock gate and
sluice are available, the flow may be determined from the area
of the sluice and the vertical distance between the centre of
the sluice and the level of the water in the stream. Theoretic-
ally the velocity of the water passing through the sluice would
be 8 Js, but from friction and other causes it is always less
FIG. 11.
than this. With very small sluices of from 1 to 16 square
inches area, Poncelet and Lesbros' factor, '62 may be taken
as approximately correct. If therefore the area of the sluice
A be known, the flow per second will be
Q = A x -62 x 8 \/s = approximately 5 A\A'-
If A and s be expressed in feet, Q will be the flow in cubic
feet per second.
Where the river is of considerable dimensions, and it is
RIVER WATER 101
desired to record the variations in the flow automatically, a
tide-gauge may be used (Fig. 11).
By aid of such an instrument the rise and fall of the float is
recorded on a revolving cylinder, so that not only the extent
of the variations, but the exact time at which they occurred
is registered.
Where the amount of water to be abstracted from a river
is very small compared with its volume, of course all these
elaborate investigations are unnecessary. In such cases also,
storage will only be required to supply the town during periods
when the river is in flood and the water turbid.
In exceptional cases only can river water be abstracted
at a point sufficiently high to supply a town by gravitation.
Usually the water is pumped into storage reservoirs, from
which it flows on to the filter beds, and it may again require
to be pumped after filtration into service reservoirs at such an
elevation as to permit of the water supplying the town by
gravitation. Service pipes may be attached to the rising
main if houses have to be supplied en route. When pumping
is going on the flow will be from the pumping station to the
houses, but when the pumping ceases the flow will be in the
contrary direction, from the service reservoir. The water
taken from the Thames and Lea for the supply of the
metropolis is all pumped into service reservoirs in order to
obtain the necessary pressure, the height to which it is lifted
being on an average about 200 feet.
Limited supplies of water can be obtained from streams
having a good fall, by aid of rams, turbines, or water-wheels,
when the place to be supplied is at too great an elevation to
be supplied directly by gravitation. These automatic pumping
machines will be described in a later section.
A large number of towns in England derive their water
supplies from rivers. In the Tees valley, Darlington, Stock-
ton, Middlesborough, and several smaller towns are supplied
from the Tees ; Durham is supplied from the Wear, Carlisle
from the Eden, Eipon from the lire, York from the Ouse,
102 WATER SUPPLIES
Knaresborough from the Nidd, Leeds from the Wharfe and
Washburn, Doncaster from the Don, Wakefield in part from
the Calder, Ely from the Ouse, Newark from the Trent, 1
Leamington from the Learn, Shrewsbury, Worcester, and
Tewkesbury from the Severn (Gloucester also occasionally),
Plymouth from the Mew, Sandown (Isle of Wight) from the
Yare, etc. On account of the prevalence of typhoid fever in
certain of these towns (Stockton, Darlington, Middlesborough,
York, and Newark, for example) the possibility of obtaining
water supplies from other sources is being discussed. On the
other hand, certain towns are contemplating improving their
present supplies by resorting to rivers. Cheltenham, for
example, is completing works for augmenting its present
supply by drawing from the Severn at Tewkesbury. It is
now supplied in part by private wells, of which there are
over 2000, in part by spring and surface water collected in
reservoirs belonging to the town (this water when stored
has a tendency at certain seasons of the year to acquire a
disagreeable odour from the growth of vegetable matter,
chiefly Chara), and in part by the head waters of the Chelt,
which is also impounded in a reservoir. This reservoir will
hold 100,000,000 gallons, and is usually full to overflowing
about the end of March; it then loses water pretty continuously
until November, when again the feeders exceed the draught.
100,000 gallons a day have to be turned down the Chelt as
compensation water. The closing of surface wells, and the
increasing demand for water for water-closets and for flushing
sewers, and other municipal purposes, has on several occasions
run the reservoirs so low as to cause considerable anxiety.
There is within five or six miles of the town a perennial supply
of pure water from springs, which form the head waters of
the Thames, but Parliament has refused to allow them to be
diverted for the use of the town. In 1881 powers were
obtained for bringing water from the Severn at Tewkesbury,
and for supplying that town and the villages en route. The
1 Vide Chapter IX.
RIVER WATER 103
severe drought of last year (1893) caused these works to be
proceeded with. The Medical Officer of Health says that
the water is wonderfully good, and the volume magnificent.
That it receives the sewage of several towns along its course
is acknowledged, but that there is any evidence of this pollu-
tion at Tewkesbury is denied. Worcester has taken its supply
from the Severn for forty years, and although the filtration
is said to be far from perfect, it has suffered nothing. This
town, however, pours its sewage into the river at a point
seventeen miles above the Cheltenham intake, and a mandamus
has been issued to compel the town to purify its sewage.
Between Worcester and Tewkesbury very little sewage enters
the Severn. With the Worcester sewage diverted or puri-
fied, the Medical Officer and engineer consider that the
Severn water, properly collected and filtered, will afford an
abundant and perfectly wholesome supply to Cheltenham,
and more especially as the towns already deriving their
water supplies from the Severn are not unduly affected
by typhoid fever. The recent report of Dr. Barry on the
typhoid epidemic in the Tees valley has, however, caused
considerable alarm, and an agitation has been raised in the
town to protest against the works being proceeded with. A
promise, therefore, has been made that the river water shall
only be laid on for manufacturing and municipal purposes,
and not turned into the mains for general consumption
unless and until the present sources of supply absolutely fail.
This compromise will probably be accepted as satisfactory
by all parties.
Table VII. (Chapter X.) contains the analyses of several
typical samples of river water, including the filtered waters
supplied by the various London companies, during August
1892, derived from the rivers Thames and Lea.
CHAPTEE VIII
QUALITY OF DRINKING WATERS
MTJCH lias already been said about the suitability of waters
from various sources for domestic use, and fortunately it may
be taken as being generally true that the best water for drink-
ing purposes is also the best for cooking, washing, and other
domestic requirements, and also for probably all manufacturing
processes. A high degree of purity is not necessary in the
latter case; hence a water which may be totally unfit for
drinking may still be of value for many other purposes ; but
as dual supplies introduce complications, and usually mean
additional expenditure, it is an undoubted advantage to have
a single supply equally well adapted for all uses. As health,
however, is of paramount importance, a pure water supply
is an absolute necessity for domestic use, and it is only where
the supply is limited, or the water is unfitted in some way
(as by being too hard), or is too expensive for manufacturing
purposes, that there will be any demand for an additional
supply. In many towns the requirements of manufacturers
are met by the laying of special mains conveying water from
a river, or some other source, yielding water too impure for
domestic use, yet perfectly well adapted for their special
requirements. Such water may also be utilised for flushing
sewers, etc. On the sea-coast sea- water is sometimes used
for flushing sewers, etc., especially where it is cheaper to
pump it than use the domestic supply, or where the latter is
not too abundant.
QUALITY OF DRINKING WATERS 105
The characteristics of a good potable water are freedom
from colour, odour, taste, turbidity, and excess of saline
matter and the total absence of all injurious substances,
whether of animal, vegetable, or mineral origin.
Colour. A hygienically pure water is almost invariably
quite colourless when viewed in small bulk, as in a tumbler,
though when looked at in a reservoir, or in a tube about 2 feet
long, it will have a faint bluish tint.
Professor Tyndall showed that when a powerfully condensed
FKI. 12. Tubes for comparing the colours of potable waters.
beam was caused to traverse a sample of water, the amount
of light scattered depended upon the quantity of impurity
present. But " an amount of impurity so infinitesimal as to
be scarcely expressible in numbers, and the individual par-
ticles of which are so small as wholly to elude the microscope,
may, when examined by the method alluded to, produce not
only sensible, but striking, effects upon the eye." Experi-
menting with sea-water, he found that a blue colour corre-
sponded with a high degree of purity. A yellow-green water
in the luminous beam appeared exceedingly thick with very
fine particles, and a bright green water, though much more
pure than the yellow-green, was far more impure than the
blue. A green or yellow tint usually indicates the presence
of vegetable or animal matters ; a brown tint is almost invari-
ably due to peat ; whilst a reddish tint indicates the presence
of iron. Surface waters from hills and moorlands often con-
tain peaty matter in solution and are discoloured thereby, but
this discoloration forms only a sentimental objection to the
io6 WATER SUPPLIES
water, unless excessive, and the peat does not appear in any
way to affect the health of those who use it. Such waters
are usually very soft and well adapted for manufacturing
purposes generally, but there are some processes, as the
making of the finest qualities of paper, in which the use of
peaty water is objectionable. Some bleaching action takes
place when such water is freely exposed to sunlight and air,
as in lakes and large reservoirs. From observations made
in Massachusetts it was found that water " must be stored
several months to cause any material reduction in colour,
and from six months to a year in order to remove practically
all of it." A filter of sand and loam removed the whole of
the colour from the water of the Merrimac River for two
years. During the third year the filtered Avater was occasion-
ally coloured ; during the fourth and fifth year the effluent
from the filter "was very slightly but uniformly coloured."
New sand would therefore appear to be a more efficient
colour-remover than sand which has been in use as a filtering
material for a length of time.
Where the water has a reddish or reddish brown tint due
to the presence of iron, access of air causes it quickly to
acquire an opalescent appearance, from the formation of a
more highly oxygenated and insoluble compound of iron.
This deposits slowly and the water loses its colour. The
objectionable character of such water for washing purposes
is well known.
Odour. Absolutely pure water is odourless, and, with
rare exceptions, so are all hygienically pure waters. Peaty
waters, especially when warmed and shaken in a bottle with
air, give off a peculiar and characteristic odour. Waters from
certain sources, though quite free from pollution, have an
odour of sulphuretted hydrogen (rotten eggs). Where this
is strong and persistent the water is classified amongst
mineral water as "sulphuretted." In some parts of Essex
the water derived from veins of sand beneath the boulder
clay has a faint but decided odour of this gas; the smell
QUALITY OF DRINKING WATERS 107
entirely disappears upon leaving the water exposed to the
air for a short time in a bucket or tank. In these districts,
however, the inhabitants will drink any kind of ditch or
pond water rather than this, so convinced are they that such
a smell can only proceed from the vilest sources. With
these exceptions any water giving off an odour when warmed
must be considered impure, and therefore inadmissible as a
domestic supply. Odorous waters appear to be much more
commonly met with in some districts than in others. In
Massachusetts, out of 1404 samples of drinking water
examined, from reservoirs, ponds, lakes, rivers and brooks,
only 275 were entirely destitute of odour, 458 had a " vege-
table or sweetish " odour, 202 a " grassy " odour, 84 a
"mouldy" odour, 146 an " aromatic " odour, 47 a "fishy"
odour, 92 a "disagreeable" odour, and 100 an "offensive"
odour. Mr. G. N. Calkins, who has made a special study of
this subject, concludes that there are three classes of odours : (1)
odours of chemical or putrefactive decomposition, (2) odours
of growth, and (3) odours of physical disintegration the two
latter being probably due to odorous oils. Theoretically,
the odours of a water may be due to dissolved or suspended
matters of mineral origin, but no such substances are known
to affect great bodies of water. Decaying vegetable matter,
he thinks, is responsible for the " vegetable and sweetish "
odours, and dead animal matter for the " offensive " odours.
The " grassy " and " mouldy " odour cannot yet be explained.
The "aromatic" and "fishy" odours are more important,
since they are prone to develop at certain seasons of the
year in waters which at other periods are quite destitute of
smell. These are invariably surface waters which have been
stored for some time in open reservoirs.
The fishy odour is said to be due to various Infusorians,
one of which, the Uroylena Americana, has during the past
two or three years infested several of the drinking waters of
the State.
Professor Remsen, who investigated the cause of the
io8 WATER SUPPLIES
"cucumber" odour 1 of the Boston water in 1878, attri-
buted it to the decomposition of a fresh -water sponge
(Spongilla fluviatilis). Mr. Rafter attributed the disagree-
able fishy odour and taste of a water which he examined to
the presence of Volvox globator, and I have observed a
similar coincidence in a public water supply in this country.
From time to time an organism "barely visible to the
naked eye," globular in form, greenish yellow in colour, and,
on superficial examination, closely resembling Volvox globator,
has been found in several of the Massachusetts water supplies,
and recently it appeared in great abundance in the ponds
supplying Norwood and Plymouth. The water in the ponds
had no marked odour, but as delivered from the taps in the
towns it had a most objectionable smell. This colony-forming
infusorian was found to belong to the genus Uroglena.
Three species are described, but one only, the Uroglena
Americana, appears to impart an odour to water. When in
a state of disintegration it liberates an oil -like substance
with an intensely disagreeable smell. As this species has
frequently been mistaken for Volvox, possibly in cases
where bad odours have been attributed to the latter they
were really due to the Uroglena. Such appears to have been
the case at Middleton and Meriden, Connecticut, in 1889.
The organism was found in great abundance in the reservoirs,
but was absent in the tap water, and the latter alone had
any odour. Apparently while traversing the water-mains
the delicate structure becomes completely disintegrated,
liberating the strongly smelling oily constituent. Bursaria
gastris gives a sea- weed like odour, Cryptomonas furnish a
"candied violet" odour, Asterionella and TaheUaria (Dia-
toms) an " aromatic " odour. 2
At Bolton (Lancashire) the water supply in July 1891
gave rise to some alarm, as it had somewhat suddenly acquired
1 "Odours in Drinking Waters": Report of Massachusetts State
Board of Health, 1892.
2 Vide Appendix, "Report of Rotterdam Crenothrix Commission."
QUALITY OF DRINKING WATERS 109
a " fishy " odour and taste. Dr. Adams, the Medical Officer
of Health, attributed the disagreeable odour to various forms
of fresh-water Algae, but more especially to Conferva Bom-
bycina, since this species when decomposing yields foetid
gases, "the smell of which resembles that of fish not in very
fresh condition." He regarded the growth as being fostered
by the presence of phosphates derived from manure and
sewage on the watershed area. As fishes feed on such vege-
table matters, Dr. Adams advised stocking the reservoir with
fish, an experiment which has been tried elsewhere, with
doubtful results. At Cheltenham, in September 1891, the
water derived from an uncovered reservoir fed by springs
was found to have acquired this fishy odour and flavour.
These springs supply three reservoirs, A, B, and C. A is
covered over, B and C uncovered. The open reservoir, C,
was the one in which the water was affected, and it was
found when emptied that upon the sides and bottom there
was a considerable growth of Chara foetida. Dr. Garrett, the
Medical Officer of Health, says : " This plant is infested at all
times with parasites, but during the time its cells are break-
ing down, the entire bulk of water contained in the reser-
voir swarms with living organisms, varying in size from the
Entomostraca that are easily visible to the naked eye, to the
most minute Protococci and other unicellular organisms which
require a high power of the microscope to be distinguished."
Species of Volvox were very numerous ; species of Nostoc and
filaments of Oscillator iacece were also found. Paramecia,
Vorticellce, Rotiferce, Anguillulce, were also observed. The
cleansed reservoir was dressed with lime and the water again
turned in. All went well until the corresponding week of
the following year, when the water from the same set of
reservoirs again developed the fishy odour and flavour. This
time, however, it was reservoir B which was chiefly
affected, though the water in C was not destitute of odour.
The water in the covered reservoir, A, remained free from
algoid growth and was odourless. In C Chara was again
no WATER SUPPLIES
developing, whilst in B the growth was abundant. This,
Dr. Garrett thinks, proves conclusively that the Chara is the
cause of the trouble. It is worthy of remark, however, that
he found Lyngbya muralis parasitic on this plant, and that
Dr. Farlow of Harvard University, in the Bulletin of the
Bussey Institution for 1877, ascribes a peculiar suffocating
odour as being due to the presence of this species of Nostoc
in potable waters. A similar odour, he says, is produced by
other species of Lyngbyce and Oscillator ice, whilst Beggiatoa
(the so-called sewage fungi) gives off a sulphurous odour,
and decaying Nostoc a more disagreeable odour of pig or
horse-dung. Pari jxissu with the development of the fishy
odour in the Cheltenham water, the amount of organic
matter (as measured by the organic ammonia and the
permanganate required for oxidation) also increased therein,
and to distinguish this from pollution entering the reservoir
from without, Dr. Garrett calls it " natural " contamination.
The Cheltenham water supply is naturally very pure and has
a hardness of 7 to 11 degrees. In this latter respect, there-
fore, it differs from the other waters which have been men-
tioned as similarly affected, since all are surface waters of
the softest character. At Gloucester, however, which also lies
in the Severn valley, and which is supplied with a water from
a similar source, there have been from time to time complaints
due to the same cause. Invariably these odours develop in
the autumn, but in certain years only, hence we may reason-
ably infer that the climatic conditions have been especially
favourable for the growth of the particular organism or
organisms which by their metabolic changes, or by their
degeneration or decay, give rise to the foul- smelling com-
pounds which taint the water. The drinking of such
waters is not recorded to have caused any illness, or any
disagreeble effects beyond a sensation of nausea. The water,
however, cannot be considered to be wholesome, and if there
is no alternative supply it should be well filtered and boiled
before use. Boiling alone will, in some cases, entirely remove
QUALITY OF DRINKING WATERS in
the odour, whilst in others it appears to accentuate it unless
the organisms producing it have been previously removed
by nitration.
Small eels have been found in water-mains, and these by
their decomposition have been known to impart a disagree-
able odour to the water drawn therefrom. 1
A recent case of somewhat similar character occurred in
a small Essex hamlet obtaining its water supply from a
pond. The water acquired a disgusting odour in the early
summer, and I found that during the previous winter, which
had been very severe, the water had been frozen into one
mass of ice. After the thaw a quantity of dead fish had been
removed, but apparently some had remained in the pond, and
with the advent of still warmer weather these were decom-
posing rapidly, and the products of the putrefactive processes
were tainting the water. In another case a water flowing from
a disused mine acquired a most offensive odour ; from the
microscopical and chemical examination of the water I con-
cluded that some animal had fallen down the shaft, which was
on the hill above, and had been killed, and that its body was
decomposing and polluting the water. Dead animals (from
mice to babies) have been found in cisterns and tanks used
for storing water when the development of some peculiar
flavour has caused them to be examined. That putrid animal
matters often contain poisons of the deadliest character is
well known, hence waters containing any products of such
decomposition should be looked upon as especially dangerous.
Taste. Smell and taste are often confounded, for many
substances possessing very strong odours, and generally
reputed to have equally characteristic and powerful tastes, are
really tasteless. Vanilla, garlic, and assafcetida may be cited
as examples. If the sense of smell be lost, or be held in
temporary abeyance by closing the nostrils, it will be found
that these substances are perfectly insipid and flavourless.
1 "Eels iii Water -Mains of the East London Waterworks," Local
Government Board Report, 1887.
ii2 WATER SUPPLIES
Doubtless many of the waters which have just been referred
to as having fishy, aromatic, or other odours and tastes, are
really tasteless. But odourless waters may affect the sense
of taste. Thus a very small quantity of iron gives water an
astringent inky flavour, whilst an excess of common salt
makes the water saline or brackish. Eain water has a
peculiar flavour, and freshly distilled water is most insipid.
Without having a distinct flavour, however, waters vary much
in palatability. A well-aerated, moderately hard water, such
as is derived from wells in the chalk and oolite, and from
deep springs, is the most palatable. Upland surface waters
and stored or aerated rain waters are moderately palatable,
whilst fresh rain water and most polluted waters are least
palatable. Some shallow well waters containing very large
amounts of oxidised sewage matters are exceedingly palatable,
and every analyst and medical officer can recall instances in
which such waters have been held in high esteem for their
brilliancy, pleasant flavour, and sparkling character, until
something has occurred which caused the water to be ex-
amined and its true nature discovered. Whilst a good water,
therefore, should be palatable, it does not follow that because
a water is very palatable that it is also very pure and well
adapted for domestic purposes.
Turbidity. A good drinking water should be quite bright
and free from all suspended impurities. Substances in a very
minute state of division render water opalescent, and settle
very slowly, if at all. Larger particles of mineral substances,
living organisms visible to the naked eye, and vegetable and
animal debris, cause a greater or less turbidity according to
the amount present. Very often a water which looks quite
clear in an ordinary tumbler is found to be opalescent or
turbid when viewed in a tube 1 or 2 feet in depth.
Insoluble mineral matters usually deposit rapidly; clay,
however, causes a turbidity which disappears very slowly and
is sometimes very difficult to remove even by filtration. A
public water supply with which I am acquainted was always
QUALITY OF DRINKING WATERS 113
more or less turbid. It was derived from chains of wells
sunk in loam and sand, and after heavy rains the amount of
suspended clayey matter gave the water a most unsightly
appearance. Many endeavours had been made to clarify the
water, including treatment with alum, and filtration through
sand, vertical sheets of flannel, etc., but without ensuring
really satisfactory results. At my suggestion filter beds were
constructed of polarite and sand, and the water ever since
has been delivered to the consumers in a perfectly clear and
almost brilliant condition.
The nature of the suspended matter can often be dis-
tinguished by the unaided eye, and the trained observer may
draw important inferences from such an examination ; but
more frequently the aid of the microscope has to be invoked
to determine the character of the deposit. Finely -divided
mineral matter brought down by rivers in flood times is said
to be capable of causing diarrhoea (vide Chap. X.). Dead
organic matter, or debris, may be derived from decaying plants
and animals. The presence of cotton, linen or silk fibre, of
potato starch, spiral cells of cabbage and similar plants,
fragments of paper, etc., indicate contamination with sewage,
and therefore that the water is of a dangerous character.
Whatever the source, any considerable quantity of such im-
purities necessarily impairs the quality of the water.
The varieties of living organisms found in water are in-
numerable. Many are so minute as to require the highest
powers of modern microscopes for their detection, and their
identification is a matter of great difficulty and ofttimes im-
possible. These bacteria are probably found in all natural
waters ; but, generally speaking, the purer the water the
smaller the number ,of bacteria it will contain. The purest
deep -well waters are almost certainly entirely devoid of
bacteria whilst held in the pores of the subterranean rocks
from which they are derived, but as raised to the surface of
the earth a few of these ubiquitous organisms invariably gain
access either from the air or from the materials with which
I
H4 WATER SUPPLIES
the water comes in contact, and then commence to multiply
with inconceivable rapidity. In other waters the number of
bacteria present varies, roughly speaking, with the degree of
pollution, few being found in the purest waters, whilst a
single drop of sewage-polluted water may contain hundreds
of thousands of them. Professor P. Frankland, who has made
a special study of this subject, says : " As regards the nature
of the bacteria found in natural water, they are for the most
part bacilli, micrococci being comparatively rare, whilst
spirilla are not unfrequently discovered, more especially in
impure waters. Upwards of 200 different forms or species
of micro-organisms have been already found in water, and
although by far the majority of these are presumably per-
fectly harmless, a number of well-known pathogenic forms
have also been discovered." Amongst these are the bacillus
of typhoid fever, of cholera, of tetanus, of anthrax, and of
tubercle. Singularly enough these pathogenic organisms retain
their vitality longer when introduced into sterile water than
when added to a natural water containing the ordinary water
bacteria. Exposure to sunshine appears to have a most destruc-
tive effect upon all bacteria, but Professor Frankland thinks
" it can only be in very shallow bodies of water, and in the
superficial layers of deep ones, that it can exercise its power."
The minuteness of these organisms is such that it is
probable that they never occur even in polluted waters in
such quantities as to render it opalescent to the unaided eye.
Doubtless their presence would be revealed in the track of
Professor TyndalPs concentrated ray of light, just as particles
of dust are revealed by a sunbeam.
The presence of the spores and mycelia of the higher fungi
indicates impurity probably derived from sewage, since the
latter invariably contains phosphates, without which these
forms cannot live.
Algae, diatoms, and desmids are found in open wells, ponds,
lakes, and running streams, and, as we have seen, some forms
are believed to be the cause of the peculiar odours some-
QUALITY OF DRINKING WA TERS 115
times developed in practically stagnant water. Apart from
this, their presence is of little importance, more especially as
they are easily removable by nitration. These forms of
vegetable life (unlike most fungi) do not depend upon decay-
ing vegetable and animal matter for their sustenance, whilst
the lower forms of animal life, next to be referred to, can
only exist in waters containing such substances, and which
therefore are more or less impure.
The lowest forms of animal life are only found in waters
containing organic matter in solution. This organic material
may, however, be merely derived from decaying vegetable
matter, such as is found in the water of bogs and marshes,
but these, nevertheless, cannot be considered as wholesome
for drinking purposes. Ciliated animalcule also abound in
stagnant water, and Hassall noticed that in the Thames
Paramecia were abundant below Brentford, where the river
was polluted with sewage, whilst they were rare higher up
the stream where the water was comparatively pure. The
higher forms of life do not necessarily denote impurity, but
the presence of worms or of their ova or embryos is especi-
ally objectionable, since these may be forms which can live
and develop in the human system and produce harmful effects
(vide Chapter IX.).
The Soluble Constituents of Potable Waters. The sub-
stances in solution may be of mineral or organic origin, the
former derived from the" rocks with which the water has been
in contact, and the latter from disintegrating or decomposing
animals and plants, from manured soils, sewage, etc.
Organic matter of any kind is objectionable. That which
is derived from peat merely is least, that from sewage most
obnoxious. In passing through soil, however, organic matter
becomes more or less completely oxidised, the carbon into
carbonic acid gas, and the nitrogen into ammonia, nitrous or
nitric acid, the two latter of which, acting upon the carbonate
of lime present in all soils, form nitrites and nitrates, liberating
an additional amount of carbonic acid. This dissolves in the
ii6 WATER SUPPLIES
water, and gives the sparkling character so often observed
in water from shallow wells sunk in polluted subsoils. This
process of purification will be discussed more fully in a later
section, whilst the significance of the presence of ammonia
and of nitrites and nitrates substances which in themselves
are perfectly harmless will be better treated of when the
interpretation of the results of analyses is being considered.
Although dissolved organic matter is objectionable, it is only
when present in some quantity, as in water from swamps and
marshes, and water highly polluted with sewage, that the
organic matters themselves are likely to have any baneful
effects. Even sewage-polluted water may be imbibed for
years without producing any appreciable effect upon the
health ; but sooner or later the specific poison of typhoid
fever, cholera, diarrhoea, or other disease is introduced
by the sewage, and an outbreak almost inevitably follows.
Polluted waters, and the diseases which have been at-
tributed to their use, will be considered in the next chapter.
The total amount of saline matter permissible in a drinking
water depends in a great measure upon the nature of the
salts. No hard and fast line can be drawn, but the best
waters rarely contain more than 20 grains of mineral matter
per gallon. When 100 grains is reached the water becomes
rather of the character of a "mineral" than a "potable"
water. The analyses already given show the wide variation
which exists in the amount of inorganic matter contained in
water used for public supplies, both when obtained from similar
and from diverse sources. Thus the exceedingly pure lake
water supplied to Glasgow contains less than 5 grains of solid
matter per gallon, whilst the equally pure water supplied from
deep chalk wells to many towns in Essex contains from 70 to
100 grains of saline matter per gallon. These deep-well
waters, like many others derived from more superficial sources
near the coast or the banks of tidal rivers, contain a consider-
able amount of common salt, but where the amount is not
sufficient to more than suggest the presence of this ingredient
QUALH^Y OF DRINKING WA TERS 1 1 7
to the taste, it appears to be quite harmless. More than this
would probably not be tolerated, though it might be exceed-
ingly difficult to prove that it was otherwise obnoxious.
These saline deep-well waters also contain much carbonate
of soda, in certain cases sufficient to exert a prejudicial effect
upon plants when used for watering purposes, yet apparently
without the slightest influence upon the human organism.
With reference to the alleged influence of the hardness of
water upon health, the Rivers Pollution Commission, the
Royal Commission on Water Supply, and other Commissions,
received and considered a large mass of evidence. A Com-
mission appointed in 1851 to consider the London water
supply, reported that "an aerated water is manufactured and
safely consumed to some extent, which contains 92 grains of
carbonate of lime per gallon, instead of 12 or 14 grains, as
in Thames water. The portion of lime and magnesian salts
in the water drunk must indeed be greatly exceeded in
general by the quantity of the same salts which enters the
system in solid food. The only observations from which an
inference of the lime in water in deranging the processes of
digestion and assimilation in susceptible constitutions has
been conjecturally inferred, have been made upon waters con-
taining much sulphate of lime and magnesia, as shallow-well
water, or the hard selenitic water of the new red sandstone,
and have no force as applied to the Thames and its kindred
waters, as the earths exist in these principally in the form of
carbonate." A French Commission reported that the evidence
received tended to prove that in hard water districts the
inhabitants had a better physique than in the soft water
districts ; and a Vienna Commission reported in favour of a
moderately hard water for a similar reason. The Rivers
Pollution Commissioners prepared tables of death-rates of a
large number of towns divided into three groups : (1) those
supplied with soft water ; (2) those supplied with moderately
hard water ; and (3) those supplied with hard water, and
concluded that, "Where the chief sanitary conditions prevail
u8 WATER SUPPLIES
with tolerable uniformity, the rate of mortality is practically
uninfluenced by the softness or hardness of the water supplied
to the different towns ; and the average rate of mortality in
the different water divisions varies far less than the actual
mortality in the different towns of the same division." The
evidence received by this Commission also showed that in
the British Islands the tallest and most stalwart men were
found in Cumberland and the Scotch Highlands, where the
water used is almost invariably very soft. It appears to be
impossible to prove that, so far as health is concerned,
either soft or hard water has the advantage ; but there is a
general consensus of medical opinion in favour of soft water.
The opinion so often expressed that hard waters tend to pro-
duce gravel and calculus appears to have no foundation in
fact at least no proof of such affections being more common
in hard water districts than in soft has ever been forthcoming.
That hard water tends to produce digestive derangements is
believed by many medical practitioners, but my own impres-
sion is that such derangements, if they ever occur from this
cause, are only temporary, and are induced in those who,
having been long accustomed to the use of soft water, for
some reason have changed to a hard water. After such a
change it is conceivable that the system may take a time to
accommodate itself to the altered circumstances. In a recent
number of The Asclepiad, Sir B. Ward Richardson refers to
the use of hard water in certain fashionable watering-places,
and attributes to it an injurious effect upon the health of the
visitors. The first few days of quiet and change produce a
beneficial effect, then dyspeptic symptoms set in flatulence,
constipation, pain in the stomach, sleeplessness, etc. ; the
person then becomes low-spirited and possibly somewhat
hysterical, the kidneys get out of order, and much pale-coloured
urine is passed. All these symptoms, Dr. Richardson believes,
in nine cases out of ten, are due to the hardness of the water
and nothing else. That hard water is superior to soft on
account of its greater palatability is probably also a fallacy.
QUALITY OF DRINKING WATERS 119
The palatability depends more upon the degree of aeration,
and as a rule hard natural waters are better aerated than soft
waters. The insoluble lime soap formed when washing in
hard water is difficult to remove from the pores of the skin,
and it causes, more especially in those not accustomed to its
use, an unpleasant sensation, as though the skin were not
thoroughly clean, and may cause a roughness of the cuticle
and affect the complexion. It has even been suggested that
the insoluble soap or curd, by clogging the pores or outlets of
the sweat glands, interferes with the proper discharge of the
functions of these glands and gives rise to pimples. By
horse trainers soft water is preferred, hard water being
credited with producing a " staring " coat, which is certainly
not indicative of perfect health.
For washing purposes the superiority of soft water is un-
doubted. Apart from the use of soap, the detergent qualities
of a water containing very little calcareous matter in solution
are more marked than in waters containing a large proportion
of these substances ; but when soap is used, all the latter have
to be removed before the soap dissolves in the water, and so
a certain amount is wasted. The first action of the soap is
to soften the water, and that this is a very expensive method
can easily be demonstrated. Each degree of hardness removed
in the washing process means the waste of 1 2 Ibs. of best hard
soap per 10,000 gallons of water. With a water of 20 of
hardness, therefore, 1 Ib. of soap is wasted for every 40
gallons used, or, in other words, it costs the user 6d. to 7d.
to soften each 100 gallons of such hard water when used for
washing purposes. As a matter of fact the expense is
probably much greater, since the insoluble curd adheres to
the articles being washed, and requires additional time and
labour and soap to remove it. Where a hard water only is
available for a public supply it is much cheaper, as we shall
see in the sequel, to soften the water by the use of certain
chemicals before supplying it to the consumers.
For other domestic purposes also soft water possesses
120 WATER SUPPLIES
many advantages. Before a Royal Commission Dr. Holland
stated that soft water extracted the strength of tea twice as
well as hard ; and Professor Clark gave the opinion that, as
the result of his experiments, hard water was quite unfitted
for making tea. Too much stress, however, cannot be laid
on this evidence, since the increased solvent power of soft
water is mainly upon the tannin and astringent principles,
the most objectionable constituents of the tea-leaf, and waters
whose hardness is due to the presence of carbonates, become
much softer when well boiled from the deposition of the lime
salts as a fur upon the sides of the kettle. Monsieur Soyer,
the famous cook, said that hard water gave cabbages, greens,
spinach, asparagus, and especially French beans, a yellow
tinge, and that the boiling process had to be prolonged,
entailing an additional expenditure for fuel. For boiling
meat or making soup it was not so good as soft water, the
latter appearing to open the pores of the meat, whilst hard
water compressed them. Soft water extracted the flavour of
both vegetables and meat, and the juice or gravy of the latter
much better than hard water. Soft water evaporated one-third
faster than hard water. For cooking purposes he would in
every way " give the preference to soft water." The furring
of kettles and boilers is also an objection to the use of hard
water. A furred vessel requires more heat, and therefore
increases the amount of fuel used and of time required to
raise the water to any given temperature. The metal of
which the vessel is composed gets unnecessarily hot, and if
at such a time the fur should crack and the water come in
contact with the superheated metal, it may determine a
fracture. In boilers used for working engines by steam such
an accident has often caused an explosion. For such pur-
poses, therefore, hard water is very unsuitable.
But are there no objections to be urged on the other side
to the use of soft water for domestic purposes 1 With one
exception there is apparently no disadvantage in the use of
the softest of waters. The exception is the proneness of
QUALITY OF DRINKING WATERS 121
certain soft waters to act upon metals, to dissolve lead and
zinc, and to corrode iron pipes. This subject will be again
referred to in Chapter IX., and when treating of storage cisterns,
mains, and service pipes. The objection only applies to waters
with a temporary hardness of less than 2 or 3 degrees ; but
such waters are at the present time being supplied to enormous
populations, and the extent of its deleterious effect upon the
consumers is only just beginning to be realised.
To sum up : The ideal of a potable water is one which is
colourless and odourless, and which is free from all organic
matter, and from all but the merest trace of the products of
the oxidation of such matter, and which, while containing just
sufficient carbonate of lime to prevent action upon metals,
contains but little of any other saline constituent. That
whilst a small amount of organic matter, if of peaty origin,
is not very objectionable, the slightest trace of unoxidised
sewage is an indication that the water is dangerous. That
for all domestic and manufacturing purposes a soft water is
preferable to a hard water. That a hard water, in which the
hardness is chiefly due to the presence of carbonates, that is,
in which the hardness is chiefly temporary is preferable to a
water which is permanently hard from the presence of
sulphates. That hard waters, in which the hardness is due to
the presence of magnesian salts (the sulphate more especially),
are more objectionable than those in which the hardness is
due to lime salts. That deep -well waters containing a
moderate amount of common salt and of carbonate of soda,
appear to be quite free from objection for domestic purposes.
It should, however, be added that such waters, especially if
they contain chloride of magnesium, as they usually do,
injuriously affect "boilers," causing them to leak at the
rivets and corroding the taps, so entailing expense in repairs
and shortening the life of the apparatus. For this use,
therefore, they are not to be commended.
CHAPTER IX
IMPUKE WATER AND ITS EFFECT UPON HEALTH
A HYGIENICALLY pure water has already been defined as one
in which the inorganic and organic substances present in it
are so small in amount as not appreciably to affect its
physical properties, or render it unfit for domestic purposes.
Accepting this definition, it is obvious that there is no sharp
line of demarcation between the pure and impure. Often
the difference is one of quality rather than of quantity, and,
as will be found when the interpretation to be put upon the
results of chemical and bacteriological examinations are being
considered, opinions often differ as to what should be
considered as pure and safe, and as impure and unsafe. Even
waters which are merely hard, but otherwise of excellent
quality, are, as we have seen, strongly suspected to cause
dyspeptic symptoms in certain individuals, more especially if
not previously accustomed to their use. The effects produced
upon health by impurities of mineral origin differ from those
produced by living organisms, which are capable of multiplying
within the system and causing specific disease. Dead organic
matter appears often to be innocuous in itself, but is believed
to cause diarrhoea occasionally. As this affection is also often
produced both . by soluble and insoluble mineral impurities,
it may appropriately be considered first.
Diarrhoea. A water containing an excess of sulphate of
magnesia, lime, or soda, or of chloride of magnesium, will be
more or less aperient in its action, the effect depending in
IMPURE WATER, ITS EFFECT UPON HEALTH 123
part upon the amount of the salts present, and in part upon
the constitution, etc., of the person drinking it. Finely-
divided mineral matter such as clay, scales of mica, etc.,
often found in turbid river water has been repeatedly
known to cause diarrhoea, probably by irritation of the mucous
membrane lining the alimentary canal. Suspended vegetable
debris has also been credited with producing the same effect.
Pond water containing much vegetable matter (infusion of
dead leaves, algee, etc.), is well known to have a tendency to
produce diarrhcea, especially amongst families who have not
previously drunk such water. Sewage-polluted water has
frequently caused outbreaks of this disease sometimes with
decided choleraic symptoms. These outbreaks, however,
must be distinguished from those of true cholera, which can
only be induced by specific pollution. The autumnal
diarrhcea so prevalent in certain districts appears to have
little, if any, connection with the water supply ; but it has
been asserted that water stored in reservoirs or cisterns
during hot weather has a tendency to cause diarrhoea,
especially if the temperature of the water reaches 60 F.
The various ways in which water may be polluted and
cause diarrhoea are exemplified in the following cases,
selected out of many found recorded in the reports of medical
officers of health, in medical journals and elsewhere :
During the Mexican War (1861-62) the French troops,
when at Orizaba, were compelled to drink water impregnated
with sulphuretted hydrogen, and suffered from diarrhoea and
flatulency ; the eructated gases had the offensive odour of
rotten eggs.
At Salford Gaol, some'years ago, an outbreak of diarrhoea
occurred amongst the prisoners using water which passed
through a certain tank. The warders, who used water from
the same source, but which had not been stored in the tank,
were not affected ; and when the prisoners were supplied
with the same water as the warders, the diarrhoea ceased.
Upon investigation it was found that a pipe terminating
124 WATER SUPPLIES
immediately over the surface of the water in the tank was
in direct communication with a drain. Probably, therefore,
the water had absorbed drain air, and possibly micro-
organisms, and so become polluted.
Early in 1891 an epidemic of diarrhoea occurred at Lincoln.
The symptoms were severe, but in no case fatal. Dr.
Harrison, the Medical Officer of Health, says in his report :
u I consider it was due to the contaminated state of the
drinking water. The disease attacked people in Lincoln,
Bracebridge, and the County Asylum, where, out of 750
inmates, 73 suffered. ... In Upper Bracebridge, within 50
yards of the asylum, no case of diarrhoea was reported.
These people were exposed to the extreme cold, but had a
different water supply. At the time of the outbreak the
supply was chiefly from the river Witham, which had for
some weeks been frozen. The water was turbid, and had
an offensive smell when heated, and contained a large excess
of organic matter."
At Sedgley Park School in 1874 the contamination of
the water supply by ordinary sewage was followed by an
outbreak of diarrhoea and sickness, associated with great
langour and prostration. The defective drain was repaired
and the attacks ceased.
In a large factory in Schenectady, New York, employing
2000 hands, much inconvenience was felt, independent of
season, from prevalence of diarrhoeal diseases amongst work-
men, sometimes 10 per cent of the employes being affected.
The company substituted distilled water for that from the
river Mohawk, allowing no other in tlie works. The improve-
ment in the health of the hands was so marked that arrange-
ments are being made to supply the families of the operatives
as well, and another firm is about to adopt the same practice.
(Thirteenth Report^ State Board of Health of New York,
p. 514.)
Diarrhoea of a dysenteric character, or possibly true
dysentery, may also result from the use of impure water.
IMPURE WATER, ITS EFFECT UPON HEALTH 125
Many outbreaks have been described by medical officers on
service in tropical countries, some traced to suspended
matters brought down by floods, others to the fouling of the
water by cesspit oozings and faecal soakage, others to water
collected from near where a large number of bodies had been in-
terred, and still others to the use of water which appeared only
to be brackish. In many cases, when a purer supply of water
was obtained, the epidemic ceased. Thus in 1870 a severe
epidemic of dysentery occurred amongst certain of the troops
at Metz who used water from wells which were found to be
polluted with faecal soakage. These wells were closed and
the epidemic came to an end. In 1881 the wells were
again used for supplying drinking water to the garrison,
whereupon the disease once more broke out, but disappeared
directly when the wells were again closed. At Prague, in
1862, an outbreak of dysenteric diarrhoea followed the
pollution of the shallow wells by an overflow from the
sewers. In 1840 and 1845 Dr. Hall observed that dysentery
became epidemic in Tasmania amongst the population drink-
ing stagnant water, whilst the convicts and others who used
pure well waters entirely escaped. Many instances are also
recorded in which the water from running streams was
drunk with impunity, whilst that from the standing pools
caused diarrhoea.
Outbreaks of dysentery occurred at Millbank Prison
(London) in 1823 and 1824, which Dr. Latham, after a most
exhaustive inquiry, attributed chiefly to the use of a polluted
water supply. 1 Quite recently (June 1894) Dr. Geo. Turner
has investigated the cause of similar outbreaks at the Suffolk
County Asylum at Melton. He says : " The various forms of
dysentery usually arise from the use of polluted water or
decomposed food, the deleterious action of these two causes
being frequently assisted and intensified by bad hygienic con-
ditions, such as insufficient nourishment, defective drainage,
want of proper ventilation, etc. ... In fact the use of bad water
1 New Sydeiiham Society Works of Dr. P. M. Latham, vol. ii.
126 WATER SUPPLIES
is by far the most common origin of dysentery, and I have no
doubt whatever, occasioned the late outbreak. Probably
former epidemics were due to a similar cause." This interest-
ing report will be again referred to. The water was derived
from two deep bored wells which had been most carefully
constructed, and which yielded a water believed to be of the
highest degree of purity. Yet Dr. Turner was able to prove
that the water in the bores was polluted by leakage, and
to this pollution by subsoil water the periodical epidemics
were to be attributed. As all the sanitary arrangements,
including the drainage, were in a very satisfactory condition,
the subsoil water could not be fouled by soakage from cess-
pools or defective drains, but that it was specifically infected
seems proved by the report. One form of dysentery, at
least, is due to the action of an animal known as the "amoeba
coli," and it is interesting to note that Dr. Turner found an
amoeba both in the drinking water and in the water of the
subsoil through which the bore-tubes passed.
Diseases caused by the Mineral Constituents.
Goitre. That glandular enlargement of the neck may be
caused by drinking certain waters is a well-known fact, and
there is little doubt that this effect is produced by some one
or more of the minerals dissolved in it ; but unfortunately we
do not know the nature of the goitre - producing substance,
and it is impossible therefore to ascertain beforehand
whether a given water will cause the disease or not. In
England goitre is or was most prevalent in parts of Derby-
shire and Nottinghamshire, and also in the valleys of
Sussex and Hampshire. In nearly all countries there are
localised areas in which the affection appears to be endemic,
and it has usually been noted that the waters of such
districts contained much lime and magnesia salts. Thus at
Kamaon, in the province of Oude (N.W. India), Dr. M'Clellan
found that of the population drinking water collected from
granite, gneiss, and green sandstone, not one was affected
IMPURE WATER, ITS EFFECT UPON HEALTH 127
with goitre ; of those obtaining water from clay, slate,
mica, and hornblende, under half per cent were affected,
whilst one-third of the whole population deriving their water
supply from the limestone rocks suffered from a more or
less severe form of the disease. Dr. Wilson, on the other
hand, found that at Bhagsoo goitre was very prevalent, yet
the waters here are very soft, and almost free from lime and
magnesia compounds. Other constituents, such as sulphide
of iron, copper, etc., have been suspected to be the cause of
goitre, because in certain districts where the disease prevailed
such impurities were present ; but observers have not been
slow to point out that such explanations are not generally
applicable. That the disease is really attributable to the
water and not merely to the influence of soil, site, etc.,
appears to be fully established. A French Commission
sitting in 1873 reported that at Bozel in 1848 there was a
population of 1472, of whom 900 were goitrous, whilst at
St. Bon, a village some 2600 feet higher, there was not a
single case. When the water supply of St. Bon was laid on
to Bozel, the disease decreased so rapidly that in 1864 there
were only 39 people in the latter village found to be suffering
therefrom. In the French military journals there are many
cases quoted, proving that certain waters will produce goitre
in a few days, and that persons were in the habit of resorting
to the use of these waters to escape conscription. On the
other hand it has been pointed out that in certain villages
supplied with water from the same source, some were afflicted
with goitre, whilst others were not. Hirsch, in summing up
all the evidence as to the cause and distribution of the
disease, says : " As to the nature of this goitrous virus and its
means of conveyance, it is impossible to form a well-grounded
opinion. Its existence and development would appear to
depend upon certain definite kinds of soil, such as a soil con-
taining dolomitic rock, and it would appear to occur princi-
pally in water. Whether its nature is organic or inorganic
is a question that evades our answering."
128 WATER SUPPLIES
Plumbism. Natural waters rarely contain lead, and prob-
ably never in sufficient quantity to produce any evil effects ;
but certain waters, both hard and soft, containing very little
or no alkaline carbonates, dissolve traces of the metal if con-
veyed through leaden service pipes. The amount of lead
dissolved depends upon the character of the water, the length
of time which it is in contact with the pipe, the temperature,
pressure, and possibly upon other factors of which we as yet
know but little. The effects produced by the small amount
of lead dissolved are rarely so serious as to cause death, or
even the severe colic or paralysis characteristic of lead
poisoning, and for this reason the injurious results of the
long-continued use of waters so polluted are only gradually
receiving recognition. Amongst the effects produced are a
state of listlessness, leading to melancholia, depression, and
actual insanity, pallor and debility, constipation and in-
digestion, paralysis, colic, gout, kidney disease, blindness,
etc. Still-births increase, and the children of lead -poisoned
parents are rickety and ill-developed. That the effects are
much more serious and widespread than is generally sup-
posed, is being rendered evident by the reports of the medical
officers of districts in which such waters are used. Thus
Dr. Hunter, the Medical Officer of Health for Pudsey (York-
shire) says in his report for 1891 : "Lead poisoning has been
common in the town during the year. This is a matter
that, from its importance, claims your serious attention. As
lead poisoning is not often registered as a primary cause of
death, it does not make a show in the death-list, but there
is no doubt that the death-rate is greatly increased by its
prevalence in the town, the deaths being registered as
caused by diseases of the various organs of the body that
have been affected by the lead. But if even no death could
be put down to lead poisoning, the amount of pain, suffering,
and misery caused is widespread, and can only be appreci-
ated by the sufferers. There is a mistaken feeling amongst
those who are lucky enough to escape, that the risks of this
IMPURE WATER, ITS EFFECT UPON HEALTH 129
kind of poisoning are exaggerated." Dr. Hunter found in
the water first drawn from the taps in the morning from
2 to 1'3 grains of lead per gallon. Dr. Barry, of the Local
Government Board, estimates that in the West Riding of
Yorkshire alone 600,000 persons are liable to lead poisoning
by the drinking waters with which they are supplied. 1
Water which has stood in the pipes all night naturally
becomes most 'seriously contaminated, and probably, w r ere the
users careful to allow this to run to waste before drawing
any for drinking purposes, cases of lead poisoning would be
less common. The water which afterwards passes through
the pipes will contain an exceedingly slight trace, unless a
great length has to be traversed. Such waters will of course
take up the metal if stored in lead cisterns, or if drawn from
a well through a leaden pipe. The quantity of lead necessary
to produce any ill effect varies in different individuals. The
great majority appear to be able to eliminate the poison as
fast as it is introduced, but in others it tends to accumulate
until the amount stored in the system is sufficient to affect
the function of some organ or even to induce a diseased
condition. The actual amount of lead consumed by any
individual in the districts above referred to cannot be esti-
mated, since the quantity present in the water may have
varied almost with every time of using. It is possible that
there are individuals so susceptible that the most minute
quantities will in time produce an appreciable effect. The
only safe course is to prevent waters with a plumbo-solvent
action coming in contact with the metal, by the use of tin,
iron, or copper for the pipes and of slate for the cisterns.
The so-called tin-lined lead pipe is not to be commended,
since, during the process of lining, the tin dissolves a small
amount of lead, forming an alloy which appears to be almost
as easily acted upon by water as lead itself. Some time ago
I found a large trace of lead in a water which was supposed
never to have been in contact with that metal. It was stored
1 Vide, Appendix.
K
130 WATER SUPPLIES
in tinned copper and passed through block tin pipes. The
lead was traced to the tin lining of the copper vessel, and the
makers denied the possibility of there being any lead therein,
and asked me to visit their works and see the process of
" tinning." I availed myself of the opportunity, and found
the tin melted ready for the work to be commenced. I was
informed that this was "pure" tin, but upon further in-
terrogating the workmen I ascertained that it was technically
called " pure " tin for tinning purposes, and contained, if I
remember aright, about 15 per cent of lead, the latter being
added to cause the tin to adhere to the copper. My corre-
spondent, one of the partners in the firm, was himself ignorant
of this fact. Tin-lined iron pipe, known in commerce as the
"Health" pipe, is absolutely safe, and the best form of
service pipe for all drinking waters. An interesting sample
of water was recently submitted to me for examination. It
was found that the leaden pipes from the hot -water cistern
regularly split at the bends after being in use for about a
couple of years. The pipes from the cold-water cistern were
unaffected. The water proved to contain only about 1
grain of carbonate of lime per gallon, though it had several
degrees of hardness. When cold it had not the slightest
action upon lead, but after being boiled it attacked the
metal so energetically that I have no doubt of its being able
to erode the pipes in the manner described. Doubtless, at
the angles slight fissures would be found in the lead, and by
the prolonged action of the water these would ultimately
extend right through the thickness of the pipe.
The various ways in which lead can be removed from
water, and by which an " active " water can be rendered "in-
active " will be described in a later chapter.
Diseases due to Specific Organisms.
Whilst waters containing impurities both of vegetable and
animal origin are constantly being drunk with apparent im-
punity, yet in almost all cases it is found that sooner or later
IMPURE WATER, ITS EFFECT UPON HEALTH 131
outbreaks of disease occur pointing to some specific polluting
material having gained access to them. The danger naturally
is greatest where the filth which contaminates the water is
derived from human excrement, whether it be discharged from
sewers into our rivers, or oozes through a defective cesspit,
cesspool, or drain into wells or tanks, or whether it percolates
through the sewage-sodden ground around our habitations, and
in an imperfectly filtered and purified condition reaches the
subsoil water from which our supplies are derived. In such
cases our observations only require to be continued sufficiently
long to ensure an outbreak of some specific disease being
recorded. Of this many illustrations will be given when
typfioid fever and cholera are being considered. There are
other diseases, however, which are due to specific organisms
which apparently may occur in water free from pollution by
sewage. Of these the most important is malaria, or malarial
fever, a disease which in many countries is far more pre-
valent than any other.
Malaria. Malarial disease is at the present time almost
unknown in England. Even in the districts in which ague
was most prevalent, as in the fens of Lincolnshire and marshes
of Essex, it is now but rarely met with. Whether this be
due to better drainage or purer water supplies it is impossible
to decide, probably both are important factors. The organ-
isms which gain admittance into the blood of the infected
person have only recently been discovered, and their life
history has not been so completely studied as to throw much
light upon the way in which they enter the system. Swampy
districts are most frequently malarious, but they are not
necessarily so, and swamp water which is usually loaded with
vegetable matter is frequently drunk without causing malaria.
This is doubtless due to the fact that whilst the natural habitat
of the malarial parasite discovered by Laveran is in tropical
water-logged districts, yet it is not of universal occurrence
in such districts, and may, under certain conditions, of which
we are yet ignorant, thrive elsewhere. The disease, however,
132 WATER SUPPLIES
is only of interest here, inasmuch as there is evidence sufficient
to warrant us in believing that one of the modes in which the
malarial organism enters the system is with the drinking
water. Thus Dr. Parkes, during the Crimean War, questioned
the inhabitants of the highly-malarious plains of Troy, and
found that it was universally believed " that those who drank
marsh water had fever at all times of the year, while those
who drank pure water only got ague during the late summer
and autumnal months." Mr. Bettington, of the Madras Civil
Service, who carefully investigated this subject, obtained very
strong evidence of the production of malaria by drinking
water. In one village he found that fever was prevalent
amongst those who drank water from one source a tank fed
partly by marsh water but absent amongst those who obtained
water from other sources. In another village in which fever
was endemic, it entirely disappeared when a better water supply
was obtained. In the Wynaad district, where malaria is very
fatal, he says that it "is notorious that the water produces fever
and affections of the spleen." Boudin relates that " on board
a French ship-of-war bound from Bona to Marseilles, a malig-
nant epidemic of malarial fever broke out at sea, 13 men
dying out of a crew of 229, whilst 98 were more or less seriously
ill, and had to be sent into hospital at Marseilles ; it came
out, on inquiry, that the vessel had shipped at Bona several
casks of marshy water, which had given rise to lively dissatis-
faction among the crew on account of its disagreeable smell
and taste, and that not a single case of sickness had occurred
among those of the crew who had drunk pure water." Not-
withstanding such apparently conclusive evidence, many
observers doubt the production of malaria by drinking water.
Amongst the more recent ones may be cited Mr. North, who
spent much time in investigating the cause of this disease in
and around Rome. He observes that the healthiest parts of the
city of Rome are supplied with water from springs which
arise in a locality so unhealthy that there is great risk to
health, and even to life, in passing the nights there during
IMPURE WATER, ITS EFFECT UPON HEALTH 133
certain seasons of the year. He concludes that there is not
sufficient proof of the disease being conveyed by water, not-
withstanding that such a belief is universal in all districts in
which the disease prevails.
Enteric or Typhoid Fever. The production of typhoid
fever by the use of polluted drinking water is an indisputable
fact, and the instances which can be adduced in proof of this
statement are so numerous that it is difficult to make a
selection. The following examples are given not only as
illustrating such proof, but also on account of their being
typical of outbreaks produced by the pollution of the water
in most diverse manners. In some the source of the infected
material was almost self-evident, in others the discovery of the
mode by which the water became contaminated taxed the
ingenuity and patience of the investigator to the utmost,
whilst in others specific pollution could only be inferred.
At Lausen in Switzerland an outbreak of typhoid fever
occurred 1 amongst that portion of the population which derived
its drinking water from a certain spring. On the other side
of the hill was a brook which passed underground, and it was
suspected that this stream really fed the spring in question.
When flour was added to the brook water, however, none of it
made its appearance in the spring, but when salt was dissolved
in the stream, its presence was soon after discovered at Lausen.
Obviously the water in traversing the hill became filtered so
completely as to remove all the particles of the flour, yet such
filtration had failed to remove the typhoid poison, which it was
proved had been introduced into the brook by the stools of a
patient suffering from that disease. Shortly after the fouling
of the stream typhoid fever broke out amongst those who used
the spring water, 67 persons being attacked within 10 days..
In 1872 an epidemic occurred at Nunney (Somersetshire)
which Dr. Ballard investigated on behalf of the Local Govern-
ment Board. He found that the brook supplying the village
with water had been specifically polluted by the drainage of
1 Iu August 1872. Deutsch. Arch.f. klin. Med. Bd. xi., 1873, S. 237.
134 WATER SUPPLIES
a house into which typhoid fever had been introduced from
without. 76 cases occurred amongst a population of 832.
In 1874 a serious outbreak at Over Darwen (Lancashire),
was investigated for the Local Government Board by Dr.
Stevens. It was proved that a patient who had contracted
the disease elsewhere resided in a house the drain from which
was blocked and defective at a point where it crossed a leaking
water main. Dr. Stevens succeeded in demonstrating that
the sewage was sucked into the water main freely and regu-
larly. The disease spread rapidly, and no less than 2035
persons, or nearly one -tenth of the whole population, were
attacked within a very short period.
In 1882 a serious outbreak occurred at Bangor (N. Wales),
which ultimately affected 540 persons out of a population of
about 10,000. In May a case of enteric fever had occurred
in an isolated house which discharged its sewage into a small
stream which at a point lower down joined a larger stream,
the Afon Gaseg, from which Bangor derived its water supply.
During June two other cases occurred in the above house,
and specifically polluted sewage continued to find its way
into the Afon. The filter beds were said to be very imperfect,
and these were disturbed on 30th June by the bursting of a
water main. Within a fortnight of this accident the outbreak
commenced, attacking simultaneously various localities in the
town.
In 1879 an epidemic occurred at Caterham and Eedhill
in Surrey. Within a fortnight 179 persons were attacked.
Of the 143 houses first infected, 136 had their water supply
exclusively from the public mains, and in the other 7 houses
this water was occasionally used. Of the 2258 houses in
the two parishes, 1343 derived water from the mains; the
remainder were chiefly supplied from wells. Dr. Thome,
who investigated the outbreak, found that just prior to the
outbreak, the Water Company had been enlarging their re-
servoirs and had sunk a shaft down to the conduit. One
of the labourers employed in this conduit had contracted
IMPURE WATER, ITS EFFECT UPON HEALTH 135
typhoid fever at Croydon, but was able to continue his work.
Diarrhoea was profuse, and as he could not conveniently leave
the shaft his motions were passed at the bottom and were
afterwards washed into the conduit. "The outbreak took
place simultaneously in Caterham and Redhill exactly fourteen
days after the water supply had been befouled in this manner."
In 1880 a case of typhoid fever was introduced into the
town of Nabburg (pop. 1900) and spread among the inmates of
the infected house ; about a fortnight later other cases occurred
amongst the inhabitants of the row in which this house was
situated, and within the next fortnight about half (35 out
of 77) the inhabitants were suffering from typhoid fever.
Three out of the row of 17 houses and the poor's -house
remained free from the disease, and it was found that these
were supplied with water from a well, whilst all the others
derived their water supply from a tank fed by a pipe which
ran through a slop puddle. This slop puddle received the
drainage from a dung-heap upon which typhoid excreta had
been thrown, and the water pipe was perforated at the part
where it was covered by the filth. As soon as these pipes
were repaired the epidemic ceased.
The danger which may arise from the proximity of a sewage
farm to a water supply is well exemplified by the lleport of
Dr. Page to the Local Government Board on an outbreak of
typhoid fever at Beverley (Yorkshire) in 1884. The sewage
of the East Riding County Lunatic Asylum was disposed of
upon a field next the Water Company's well and works, and
the effluent water "following in the direction of the natural
line of drainage " percolated towards the Company's premises.
Certain defects were found in the well, and prior to the out-
break cases of typhoid fever had occurred in the Asylum.
The total number of households invaded was 125, and there
were 231 cases, 12 of which proved fatal.
In all the above instances the source of the specific pol-
lution was discovered. In the following there was proof
only of the contamination of the water by sewage. This
1 36 WA TER SUPPLIES
must have contained the specific organism of typhoid fever,
but the cases which introduced these into the sewage remain
undiscovered, though in some instances the possibility of such
specific contamination was proved.
In 1867 an outbreak of typhoid fever occurred at Slier-
borne in Dorset. Dr. Blaxall, who was instructed by the
Local Government Board to investigate it, attributed it to
the direct connection of the water supply pipes with the closet
pans. Some of the taps to these pipes were broken. When
the water was turned off at the mains, the foul air from the
closet pans, or if the pan happened to be full of excrement,
actual faecal matter could be drawn into the water pipes.
In 1873 Dr. Buchanan contributed a most important
report to the Local Government Board on an outbreak of
typhoid fever at Cains College, Cambridge. Twelve of the
fifteen cases which occurred were in Tree Court, and Dr.
Buchanan could find no condition capable of explaining the
outbreak but the pollution of the water in the branch main
which supplied this court alone. He found that the closets
in this court were the only ones in the College flushed directly
from the main, and that on account of defects in the valve
taps, when there was an intermission in the water supply a
reflux of air and water took place into the main. There had
been two intermissions during the term, one a fortnight before
the first case, and the other a fortnight before a more general
outbreak. Inside the pipes a dirty-looking layer was found,
which upon analysis proved to be derived from sewage ; hence
doubtless not only sewer gas but also actual liquid filth had
been sucked from the closet pans into the pipes.
In 1887 an interesting outbreak occurred in the Mountain
Ash, Urban Sanitary District (Glamorganshire), which com-
prises several mining villages. The cases ultimately numbered
over 500, and the localisation was such as to throw suspicion
upon one particular branch of the public water mains. The
only possible explanation appeared to be the fouling of the
water in this branch at a particular point. The ground was
IMPURE WATER, ITS EFFECT UPON HEALTH 137
accordingly opened there, and it was found that the water
main passed through some drains which had been " wantonly
smashed " for this purpose, and the main itself was defective
and leaking. Prior to the outbreak there had been inter-
missions in the supply, allowing the fluid filth by which the
pipe was surrounded to be sucked into it, and so contaminate
the water passing through that particular branch.
The following outbreak, due to polluted ground water, is
typical of a large number which have been reported from
time to time in districts deriving their water supplies from
wells sunk in a polluted subsoil. At Terling, in Essex, an
alarming epidemic of typhoid occurred in 1867. Out of a
population of about 900, no less than 260 were attacked
within two months. The wells supplying the cottages were in
close proximity to the privies, cesspits, bumbies, and manure
heaps. Towards the end of a period of drought a case of
typhoid fever occurred which probably was imported. Three
weeks later, and after a heavy rainfall, the disease broke out
with alarming violence. The well waters were proved at all
times to be seriously contaminated, but until the introduction
of the specific pollution the village had been free from the
disease. In the filth -sodden soil the typhoid bacillus had
probably found a suitable nidus for its rapid multiplication ;
thus the heavy rainfall would not only wash impurities into
the wells from the surface, but wash the organisms out of
the soil into the rising ground water which supplied the wells.
In 1889 an outbreak occurred at New Herrington, Durham,
278 cases being reported between the 1st April and 7th June
out of a population of 3600. Dr. Page discovered that a
deep well supplying the village was being contaminated by
the sewage of a farm three-quarters of a mile away. This
sewage discharged into a tank, and the overflow disappeared
down a fissure in the ground and ultimately found its way
into the well at a point 45 feet below the surface. Two tons
of salt were put down this fissure and soon after the amount
of chlorine in the well water began to rise, increasing ulti-
138 WATER SUPPLIES
mately from 4 grains to 24 grains per gallon. Specific pol-
lution, however, was not demonstrated, as no case of typhoid
fever was known to have occurred at the farm for years.
Dr. Maclean Wilson last year investigated for the Local
Government Board an outbreak of enteric fever at Chester-le-
Street, between Durham and Newcastle. Of the 1100 houses
in the village some 40 per cent were supplied by the Consett
Water Company, and some 60 per cent by the Chester-le-Street
Company. Of the 41 infected households, all but 2 derived
water from the latter source, and these 2 were amongst the
initial cases, "possibly not due to the cause producing the
general outbreak." The Chester-le-Street Company draws its
supply from the Stanley Burn, about two miles above the village.
Above the intake quite a large population drains directly or in-
directly into the stream. In a group of cottages at Southmoor
a series of cases of typhoid fever had occurred in October
1 892, and January and February 1 893, and the bowel discharges
of these patients passed into a stream which forms a tributary
of the Stanley Burn. The nitration of this water before being
supplied to the consumers does not appear to have been
satisfactory. The outbreak may be said to have commenced
on 14th November 1892, and came to an end in mid-March.
Dr. Wilson concluded that "there appeared nothing in the
inter-relations of the sufferers by fever, nothing in the milk
supplies used by them, and nothing in their sanitary surround-
ings in the least likely to afford a common source of infection.
On the other hand is the fact that so many persons using the
same polluted water suffered, while their neighbours who used
other water escaped. Furthermore, there occurred shortly
before each of two outbreaks of the fever, opportunity for the
bowel discharges of enteric-fever patients gaining access to
the particular stream which afforded the water supply of
invaded households in Chester-le-Street."
' The dissemination of typhoid fever by river waters is a
subject of the greatest importance, and has already been
referred to when rivers were being considered as a source of
IMPURE WATER, ITS EFFECT UPON HEALTH 139
water supply. As few rivers of any magnitude escape pollu-
tion by sewage, the great question is, whether such waters
can safely be used for supplying towns with drinking water.
That exceedingly polluted river water may be used for long
periods without producing an outbreak of typhoid fever is
undoubted, but can complete immunity be ensured ? If the
water used be drawn many miles below the lowest point of
contamination, if it be thoroughly filtered, and every possible
precaution be taken to avoid collecting water when the river
has been disturbed by heavy rains and floods, is all danger
removed ? The answer to this would depend upon the amount
of reliance to be placed upon the safeguards which depend
upon human agency. Can all accidents be guarded against ?
can perfect filtration be secured at all seasons and under all
circumstances ? To the temporary break-down of a filter bed,
Koch attributes the recent outbreak of cholera at Hamburg
(vide cholera). A similar accident might lead to an epidemic
of typhoid fever, assuming that the river water were speci-
fically polluted at the time. This coincidence of specific
pollution and defective action of the filters may be an
extremely improbable one, but the degree of probability
depends upon many as yet imperfectly known factors, such as
the length of time which the typhoid bacillus can live in
river water, or in the sedimentary matter on its bed, the
conditions under which mere filtration can be depended on
to remove the organism, etc.
In 1891 Mr. Hiram F. Mills, a member of the Board of
Health of Massachusetts, prepared for that board a report on
" Typhoid Fever in its Relation to Water Supplies." He found
that in Massachusetts the highest typhoid death-rates were
not in the cities but in the towns supplied with well water.
The introduction of purer water supplies had in all cases been
followed by a decrease in the typhoid mortality, but in two
cities, Lowell and Lawrence, with a population of 123,000,
there had been during the previous twelve months about one-
third more deaths than in the city of Boston with four times
140 WATER SUPPLIES
the population. The cause of this excessive prevalence of
typhoid fever was investigated, and it was found that prior
to the outbreaks the Lowell water supply had been con-
taminated by the feces of typhoid patients discharged into
Stony Brook, only three miles above the intake of the water-
works. This pollution was followed in about three weeks by
a very rapid increase in the number of deaths from typhoid
fever in Lowell, and about six weeks later by an alarming
increase in the number of deaths in Lawrence, whose water
supply is drawn from the Merrimac River, nine miles from
where the Lowell sewage enters the river. An examination
of the water from the service pipes of the city of
Lawrence led to the discovery of the typhoid bacillus
therein. These two cities are the only cities in the State
which draw their water for drinking from a river into which,
within twenty miles above, sewage is publicly discharged.
" The amount of sewage that has directly entered the river
(Merrimac) and its branches during the chemical examina-
tions of the past three years is estimated to be about
1 gallon in 600 gallons of the river water passing
Lawrence, and there has been no more impurity in the water,
that could be detected by chemical analysis, than in about
one-half of the drinking water supplies of the State obtained
from ponds and streams ; but the facts which have been pre-
sented, showing that these two cities have so much higher
death-rate from typhoid fever than any other cities of the
State, together with what is known of the relation of typhoid
fever to sewage-polluted drinking water, are the strongest
grounds for concluding that, even with the small amount of
organic impurity in the water, as shown by chemical analysis,
the germs of this disease are able to pass, and do pass, from
one city to the other in the water of this river." Experiments
were made to ascertain whether the typhoid bacillus could
withstand a temperature only a little above freezing-point
long enough to pass from the Lowell sewers to the water
mains of Lawrence. It was calculated that the Lowell
IMPURE WATER, ITS EFFECT UPON HEALTH 141
sewage would reach the intake of the Lawrence Waterworks
in eight hours, and would pass through the reservoirs into
the mains within ten days. Typhoid germs kept in ice-cold
water were found to be killed somewhat rapidly, but it was
not until the twenty-fifth day that all the bacilli had perished.
Evidently, therefore, the typhoid-fever germs from the Lowell
sewers may live in winter to enter the Lawrence mains in
great numbers. The fact that more cases of fever occurred
near the reservoirs than in the districts towards the ends of the
mains, is explained by the bacteriological examination of the
water, which proved that the number of bacteria in the water
gradually diminishes with the distance from the reservoirs.
The Merrimac is a large, swift river, and Dr. Edwards
denied that the ejecta of a few persons could possibly
contain a sufficient number of germs to lay low some hundreds
of people in Lowell. He elaborately computed the dilution
which the ejecta had undergone, and came to the conclusion
that the water theory involved a physical impossibility, and
consequent reductio ad absurdum. A somewhat similar con-
clusion was arrived at by the Metropolitan Water Supply
Commission after considering the evidence adduced for, and
against, the theory of the Tees River water being the cause of
the typhoid epidemic in the towns in that river valley. As
we know nothing of the number of bacilli which a typhoid
patient may discharge, nor of the number which are necessary
to produce an attack of the disease, arguments and speculations
of this character can have but little weight.
It is interesting to note that in 1892-93 another outbreak
of typhoid fever occurred in the Merrimac valley, involving
Lowell, Lawrence, and Newburyport. Dr. Sedgwick, who
again conducted the investigation, found that in December
1892 there was a marked increase in the number of cases
of typhoid fever in Lowell. It was predicted that Lawrence
would soon suffer, and before long fever began to increase
there ; and at the same time a very unusual, and at first
apparently unaccountable outbreak occurred at Newburyport,
142 WATER SUPPLIES
lying below these cities at the mouth of the Merrimac.
Contrary to the advice of the State Board of Health, it was
discovered that, owing to a scarcity of water, the company at
Newburyport had for some time been drawing water from
the river. " The occurrence of this epidemic in Newburyport,"
says Dr. Sedgwick, "and its apparent connection with the
outbreaks in Lowell and Lawrence, must be accounted one of
the most interesting phenomena in our whole series of
investigations, and may serve to confirm the truth of the
saying that ' no river is long enough to purify itself.' "
In the same year (1892), an outbreak of typhoid fever
occurred at Chicopee Falls. Cases of fever had occurred
above the intake of the Water Company from the Chicopee
River ; and everything pointed to this infection of the public
water supply as the cause.
Tees Valley Epidemic.
The continued prevalence of typhoid fever in the Tees
valley and the occasional occurrence of more or less extensive
epidemics, caused the Local Government Board to instruct
their inspector, Dr. Barry, to visit the district and fully
investigate all the circumstances, and, if possible, discover
the cause.
Two epidemic outbursts occurred here, one in September
and October 1890, and the other in January and February
1891. Each outbreak was most marked during a six-week
period. Out of 1463 cases, 91 per cent occurred in three
out of the ten registration districts embraced by the Tees
valley. These three districts comprised the towns of
Darlington, Stockton, Middlesborough, South Stockton,
Ormesby, Normanby, Eston, and Kirkheaton, and the two
rural districts of Darlington and Stockton. The possibility
of these epidemic outbreaks being due to infected milk
supplies, to defective systems of sewerage and drainage, or
of faulty excrement and refuse disposal, was fully considered.
Many insanitary conditions, of course, were found, but their
IMPURE WATER, ITS EFFECT UPON HEALTH 143
distribution was not such as could afford, in Dr. Barry's
opinion, a probable cause for the outburst of disease. Milk
as a factor was easily excluded. When the water supply
was examined, Dr. Barry found that nearly half the popula-
tion in the above districts obtained their water from the
river Tees through the works of the Darlington Corporation
and the Stockton and Middlesborough Water Board.
During the first epidemic period 33 persons per 10,000
of those using Tees water were attacked with enteric fever,
and only 3 amongst persons supplied with water from other
sources. In the second epidemic the attack -rates were
28 and 1 respectively. The Tees water was therefore
gravely incriminated, and its source was fully examined.
It was found that, " either directly or indirectly, the drain-
age of some twenty villages and hamlets, as well as that of
the town of Barnard Castle," is poured into the river
above the intake of the water companies. Photo-lithographs,
showing rubbish tips on the banks of the river, and the
outlets of numerous drains and sewers, accompany the
Report. The river, in fact, appears to be utilised as a
common sewer. The introduction of the specific organism
of typhoid fever, and the failure of filter beds, it is argued,
would necessarily lead to outbreaks of this disease amongst
the users of the polluted water, and this is what Dr. Barry
believes did occur just prior to both epidemics. Heavy
floods, due to an abnormal rainfall, and to the melting of
snow, washed down accumulations of filth, and shortly
afterwards enteric fever became excessively prevalent.
" Seldom, if ever," says Dr. Thome Thorne, the Medical
Officer to the Local Government Board, " has a case of the
fouling of water intended for human consumption, so gross or
so persistently maintained, come within the cognisance of the
Medical Department, and seldom, if ever, has the proof of
the relation of the use of water so befouled to wholesale
occurrence of typhoid fever been more obvious and patent."
Notwithstanding this strongly expressed opinion on the
144 WATER SUPPLIES
part of the Chief Medical Adviser of the Local Government
Board, the members of the Royal Commission on the
Metropolitan Water Supply, whilst acknowledging that
Dr. Barry's Report constituted "a formidable indictment
against the water supply," were evidently deeply impressed
with the way in which Dr. Barry's conclusions were traversed
by Mr. Wilson, the representative of the Stockton and
Middlesborough Water Board. Mr. Wilson asserted that
the notification of diseases being compulsory over practically
the whole area supplied with Tees water, and only over
one-third of the other districts, renders the returns of the
number of cases of typhoid fever unreliable for comparative
purposes. He also pointed out that many villages and
hamlets supplied with Tees water altogether escaped, and
that the distribution generally coincided with differences in
sewerage arrangements, the most cases occurring where the
system of sewerage was so faulty that previous outbreaks of
fever had been attributed to them by official inspectors, and
the probability of further outbreaks asserted. With reference
to the effects of the floods and the introduction of the
specific poison of typhoid fever, he replied, the floods of
13th August could only have washed down the filth which
had accumulated since the next preceding flood on 1st July,
and that in this interval there had been no traceable case of
enteric fever above the intake. The suggestion that, there
may have been unrecognised cases is a "perfectly unsup-
ported hypothesis." Mr. Wilson's evidence caused the
Commissioners to refrain from expressing any opinion as to
the origin of the disease ; but the concluding paragraph of
that portion of their Report dealing with this question is
very significant. " That the pollution on a given day of a
river like the Tees, with a flow of at least 1000 million
gallons in the twenty-four hours, by what must at most have
been a very small amount of active enteric poison, at a point
seventeen miles above the intake, should so seriously affect
the water that the admission of a certain limited amount of it
-IMPURE WATER, ITS EFFECT UPON HEALTH 145
into the reservoirs should produce, notwithstanding filtration,
an extensive outbreak lasting for some six weeks, is a hypo-
thesis so startling, and so entirely unsupported by previous
experience in other places, that it is fair to demand the
most conclusive evidence before accepting it as proven ; and
though we attach great importance to the opinion of such an
experienced inspector as Dr. Barry, we cannot say that such
conclusive evidence has, in our opinion, been brought before us."
Here, at present, the matter rests, and is likely to rest,
unfortunately. When a Royal Commission regards evidence
as non- conclusive, which the Medical Officer of the Local
Government Board asserts is so conclusive that " seldom, if
ever, has the proof of the relation of the use of water so
befouled to wholesale occurrence of typhoid fever been more
obvious and patent," it behoves those of more limited
experience, and less accustomed to balance conflicting
evidence, to guardedly express their opinions.
Dr. Bruce Low's more recent Report on the occurrence of
enteric fever amongst the population of the Trent valley, in
Lincolnshire and part of Nottinghamshire, is a much less
voluminous production than Dr. Barry's. The Trent and its
numerous tributaries are shown to be excessively polluted by
the sewage of towns and villages, by surface water from highly
manured land, and by a somewhat large population living in
tugs, canal boats, and barges. The analyses of various
samples of Trent water afford abundant evidence of this
pollution ; and prove also that the stream becomes defiled at
so many points that no opportunity is afforded for the natural
causes of purification to produce much effect. Night soil
from several large towns is freely used upon land bordering
on the stream, and much of the same filth is conveyed by
boats plying upon it and when these barges are unloaded
we hear of the fluid filth remaining in the hold being
pumped into the river. Notwithstanding this, throughout
nearly the whole of its course the river water is used for
domestic purposes, and regarded as "wholesome and harmless."
L
146 WATER SUPPLIES
In the Gainsborough Kural Sanitary District, the Infectious
Disease Notification Act has not been adopted, and the number
of cases of typhoid fever which has occurred during recent
years has had to be ascertained by inquiry from local prac-
titioners, some of whom could only give information from
memory. Based upon statistics so obtained, Dr. Low shows
that, during the last four and a half years, the enteric fever
attack-rate in the villages using well water only averaged
1 '92 per annum per 1000 population, whereas in the villages
using Trent water the attack-rate was 29 '3. From the
number of villages and aggregate population, it is evident
that the fewest cases occurred amongst the more scattered
population ; but whether the drainage and sewerage arrange-
ments were satisfactory in the larger villages where enteric
fever was more prevalent is not stated. Neither is the
number of deaths from typhoid fever in each group given to
confirm the deductions drawn from the estimated number of
cases. Apparently the results of Dr. Low's investigations
were communicated to the Parochial Committees of the
villages most concerned, and the unanimity with which each
declared that Trent water was not injurious, and that its
village was in a healthy state, is somewhat amusing. Where
money has to be expended, the arguments which will convince
a Parochial Committee that anything is wrong have to be
very conclusive and clinching.
In the town of Newark about half the population is
supplied from the Trent, and the other half from polluted
shallow wells. During the last three and a half years, 78 '5
per cent of the notified cases of enteric fever occurred among
that half of the population using river water. By the advice
of the Medical Officer of Health, a fresh supply of pure
water has just been obtained from the new red sandstone at
Edingley. 1
In the Thorne Rural Sanitary District only a portion of
the population derives water from the Trent or its tributaries ;
1 Vide page 224.
IMPURE WATER, ITS EFFECT UPON HEALTH 147
and it is admitted that, although this water is excessively
polluted, there is no excessive prevalence of typhoid fever
amongst those drinking it.
During recent years quite a number of limited outbreaks
of typhoid fever have been traced to the use of milk which
had been stored in vessels rinsed with sewage-polluted water ;
and in some instances this water was proved to be specifically
infected.
The evidence given is sufficient to prove that specifically
polluted water, whether derived from a well, spring, or river,
can provoke an epidemic amongst the consumers of such
water ; and it is exceedingly probable that in those outbreaks
due to water in which specific contamination was not proved,
that such pollution had actually taken place, though the investi-
gator failed to discover it. This is not to be wondered at when
we consider the exceedingly mild character of some typhoid
attacks. It is not at all uncommon for labourers suffering
from such slight attacks to continue their usual occupations ;
and the discharges from such a person may poison a water
supply without its ever being discovered either by the sufferer or
by skilled investigators that such specific pollution has taken
place. Apart from these more extensive outbreaks, numerous
cases of typhoid fever constantly occur which appear to be
due to sewage-contaminated water, and in which there is
apparently conclusive evidence that such sewage had not been
infected by typhoid ejecta. To account for these cases it has
been assumed that the bacillus coli communis, found in all
faecal matter, and which bears some resemblance to the
typhoid bacillus, is really a degenerate or attenuated form of
the latter; and that under favourable circumstances it can
again acquire its original properties, and provoke a typical
attack of typhoid fever, when introduced into the system.
Whether this be the case or not, the danger from drinking
sewage-polluted water is sufficiently great to render such
water unfitted for a public supply unless and until it can be
demonstrated that, by filtration or some other process, all
148 WATER SUPPLIES
disease-producing organisms can be infallibly removed. This
conclusion, derived from the consideration only of the danger
from typhoid fever, is strengthened greatly by the fact
that this disease is only one of the many which may be
disseminated by drinking polluted water.
Cholera. The evidence upon which cholera is classed
amongst the water-borne diseases resembles closely in its
nature that which has been adduced to prove that typhoid
fever is disseminated by polluted drinking water. On
account of the more general prevalence of the latter disease,
the danger is almost constant; whilst with cholera the danger
is only intermittent, and usually at long intervals. The
terrible destructiveness of cholera, however, when once
introduced, makes the study of the modes by which it is
spread of the highest importance. Until the middle of the
present century, the possibility of the cholera poison entering
the system with the drinking water had scarcely been
suggested. In 1849 Dr. Snow was led to strongly suspect
that the specific pollution of the drinking water was the
cause of certain localised outbreaks of the disease which he
investigated in the neighbourhood of London. In 1854
occurred the noted outbreak around Golden Square, West-
minster, which was investigated by Dr. Snow and others,
and also by a special committee appointed by the General
Board of Health. During August, 26 cases had occurred in
this neighbourhood, but on the 1st September a large number
of the inhabitants were simultaneously attacked ; on the 2nd
an even larger number of cases occurred, then the epidemic
declined rapidly. Over 600 deaths occurred during the
month. Every house in the district was examined, and every
case as far as possible investigated. The very centre of the
outbreak was the western half of Broad Street, near the
public pump. An examination of the cesspool and drainage
of the house No. 40, adjoining the pump, proved conclusively
that the contents of the former had direct access to the well
supplying the latter. About 78 hours before the general
IMPURE WATER, ITS EFFECT UPON HEALTH 149
outbreak, the ejections from a child suffering from an attack
of diarrhoea, which proved fatal, were poured into the drain.
Out of 73 persons who died during the first two days of the
outbreak, 61 were in the habit of drinking the pump water.
In a number of cases it was found that the drinking of the
water was followed by cholera ; and a lady and her niece,
living quite away from the district, who had the water sent
to them, both died of the disease after drinking it. In one
particular street of 14 houses the only 4 which escaped
without a death were those in which this water was never
drunk. In a factory employing 200 people, where the water
was used, 18 persons died; whereas in the adjoining brewery,
where the men never drank the water, no case occurred.
Adjacent to these was a block of lodging-houses, amongst
which the water was used, and here there were 7 fatal cases.
Certain exceptional cases occurred, of immunity amongst
those drinking the water, and of attack amongst those not
using it, which rendered the evidence not quite conclusive.
The Rivers Pollution Commissioners in their Sixth Eeport
describe a number of outbreaks in London and elsewhere, in
which grave suspicion rested upon the water supply as the
cause. In London, during the 1849 epidemic, it was proved
that amongst the consumers of Thames water the mortality
increased with the increased pollution of the river at the
various points from which the water was abstracted. Thus,
amongst those using water taken from the river above Kew,
the mortality was *8 per 1000, whilst amongst those drinking
water drawn between Battersea and Waterloo Bridge it was
16 '3 per 1000. In 1854 a similar coincidence was observed.
In 1866 the area chiefly affected by cholera was almost
exactly that of the district supplied by the East London
Water Company, which distributed water described as being
"unfiltered and excessively polluted with sewage," and which
there were grave reasons for suspecting had been specifically
contaminated with the excrement of two patients who had
died of cholera. They also show that the introduction of
WATER SUPPLIES
pure water supplies had reduced the cholera mortality in the
towns which had been attacked by successive epidemics. In
the following table the total numbers of deaths given show
the decrease in the mortality after the introduction of pure
water supplies, although in each case the population had
increased rapidly.
Year of Cholera Epidemic.
1832
1849
1854
1866
Total deaths in Manchester and
Salford ....
890
1115
50*
88*
Total do. in Glasgow
2842
3772
3886
68*
Total do. in Paisley and Charles-
ton .....
Not known
182
173
7*
Total do. in Hamilton
63
251
44
2*
* Indicates that prior to this outbreak the town had substituted a
pure water supply for an impure one.
The most interesting of the localised outbreaks recorded
is one which occurred at Theydon Bois, in Essex, in 1865.
A gentleman and his wife who had been visiting at Wey-
mouth returned home vid Southampton, cholera having
appeared in the latter town eight days before. The gentle-
man had had an attack of diarrhoea thirty-six hours before
leaving Weymouth, and had not quite recovered on his
return home. The day after their return the wife was
attacked with diarrhoea, and both used the water-closet, the
soil pipe of which was afterwards found to be defective.
The matters which escaped from the soil pipe penetrated
downwards along the outer wall of the house, passed beneath
the foundations, and saturated the earth in the immediate
vicinity of the well. Water poured down the closet was seen
to commence dripping into the well within ten minutes. This
water was used by the family, and within twelve days of the
specific pollution, out of the twelve persons who drank the
IMPURE WATER, ITS EFFECT UPON HEALTH 151
water, nine were attacked with cholera of so malignant a
character that all the cases proved fatal.
A number of instances have been reported from India
and elsewhere, in which polluted water appears to have been
the cause of localised outbreaks. At a jail near Poonah
twenty-four cases of cholera occurred. Twenty-two of the
sufferers belonged to a road-gang who alone drank water
from the Mootla River. The rest of the prisoners used water
laid on from a lake, and only two of these were attacked.
Of these two, one had attended the cholera patients and the
other slept near one of the earliest cases during the night
when he was attacked with vomiting. At Vadakencoulam,
an outbreak of cholera was confined to the higher castes who
drank of a polluted well water, whilst the lower castes who
used water from other wells escaped. Many other accounts
of a similar character are to be found in the Indian Medical
Gazette and in the reports of Indian medical officers.
The recent epidemic of cholera at Hamburg (1892) is in-
teresting in many respects. Just prior to the outbreak a
large number of destitute Russian Jews from cholera-stricken
districts in Russia had been encamped for a time in wooden
huts on the quays of the Elbe, the sewage from which
passed into the dock and would be carried up the Elbe by
the rise of the tide, above the intake of the waterworks.
In eighty -eight days over 18,000 persons were attacked with
cholera in the city, and over 8000 cases terminated fatally.
Professor A. Koch investigated this outbreak, and in a paper on
Water Filtration and Cholera, he gives the reasons which led
him to conclude that the epidemic was chiefly due to the use
of imperfectly-filtered polluted water. " The cholera epidemic
in the three towns of Hamburg, Altona, and Wandsbeck,"
he says, " has been in this respect instructive in the highest
degree. These three towns, which are contiguous to each
other, and really form a single community, do not differ
except in so far as each has a separate and a different kind
of water supply. Wandsbeck obtains filtered water from a
152 WATER SUPPLIES
lake which is hardly at all exposed to contamination with
faecal matter ; Hamburg obtains its water in an unfiltered
condition from the Elbe above the town, and Altona obtains
filtered water from the Elbe below the town. Whereas
Hamburg was notoriously badly visited by cholera, Wands-
beck and Altona if one excepts the cases brought thither
from Hamburg were almost quite free from the disease.
Most surprising were the conditions of the cholera epidemic
along the boundary between Hamburg and Altona. On
both sides of the boundary the conditions of soil, cultivation,
sewerage, population, all things, in short, of importance in
this respect, were the same, and yet the cholera in Hamburg
went right up to the boundary of Altona and there stopped.
In one street which for a long way forms the boundary there
was cholera on the Hamburg side, whereas the Altona side
was free from it. Indeed, in the case of a group of houses
on the so-called Hamburger Platz, the cholera marked out
the boundary better than any one having the map of the
frontier between Hamburg and Altona before him could
have done. The cholera not only marked the political
boundary, but even the boundary of the water distribution
between the two towns. 1 The group of houses referred to,
which is thickly populated by families of the working class,
belongs to Hamburg, but is supplied with water from
Altona, and remained completely free from cholera ; whereas
all around on the Hamburg territory there were numerous
cases of disease and death. Here we have to do with a kind
of experiment which was performed on a population of over
100,000, but which, in spite of its immense proportions,
complied with all the conditions which one requires from an
exact and perfect experiment in a laboratory. In two great
populations nearly all the factors are the same, one only is
different, and that the water supply. The population sup-
plied with unfiltered water from the Elbe is seriously visited
1 Many of these statements have since been disputed. Vide Lancet,
25th May 1894.
IMPURE WATER, ITS EFFECT UPON HEALTH 153
by cholera the population supplied with filtered water is
only visited by the disease to a very small extent. This
difference is all the more important as the water of Hamburg
is taken from a place where the Elbe is relatively but little
contaminated ; but Altona resorts to the water of the Elbe
after it has received all the liquid and faecal refuse of 800,000
people. Under these conditions there is no other explana-
tion for the scientific thinker but that the difference in the
incidence of the cholera on these two populations was
governed by the differences in the water supply, and that
Altona was protected against the cholera by the filtration of
the water of the Elbe."
At a later date, however, a small outbreak of cholera did
occur in Altona ; but Koch was able to prove that at this
time the Altona filters were defective and allowed the in-
fectious matter contained in the Elbe water to pass through.
The " Comma " bacillus had been found in the Elbe water ;
it was not discovered in the imperfectly-filtered water, but
Koch attributed this to the small quantity of water submitted
to examination.
Since the discovery by Koch of the "Comma" bacillus,
which he and most other observers consider to be the specific
cause of cholera, great attention has been given in India and
elsewhere to the detection of this organism in drinking waters
suspected of producing the disease. The search so far has
been very rarely successful, and at the present time the proof
that cholera can be disseminated by drinking water rests upon
the accumulation of evidence of cases, such as the above, each
failing in some point as an absolute demonstration, but, taken
collectively, furnishing proof of a most convincing character.
Yellow Fever. There is little or no evidence of this disease
being disseminated by polluted water. Epidemics which have
occurred on board ship have been attributed to the decom-
position of the organic matters in the bilge water, and it has
been pointed out that when yellow fever was epidemic in
Gibraltar, the drinking water was very impure; but the
154 WATER SUPPLIES
relationship between the contaminated water and the fever is
merely conjectural.
Oriental Boils. In Syria and other countries, where this
disease is prevalent, there is a general opinion that it is caused
by drinking certain waters. Various mineral substances have
been suspected, but there appears to be very little ground for
the suspicion. Many Anglo-Indian authorities think that some
parasite may be present in such waters and enter the skin
when the water is used for purposes of ablution. Other forms
of boils, ulcers, and the elephantiasis of the Arabs, have been
attributed to impure waters, but the evidence is too slight to
render it worthy of consideration.
Diseases due to Animal Parasites.
The study of the life history of many entozoa has proved
that certain stages of their existence are passed in water; hence
it at least seems probable that such species as infect man and
animals may be introduced with the drinking water, or may
gain entrance through the skin when water infested with these
organisms is used for washing purposes or for bathing. There
is a constantly increasing amount of evidence in support of these
theories, which, if correct, furnish additional proof of the risk
incurred in drinking impure water, especially in an unfiltered
condition. The danger of introducing the ova or larvae of
these parasites into the system is one which can be more
easily guarded against than the introduction of the infinitely
more minute micro-organisms producing cholera and typhoid
fever, since the simplest filtration will remove the former,
whilst the most careful filtration can scarcely be trusted to re-
move the latter.
Bacteria also may multiply indefinitely within the body,
however few the number originally introduced ; but the
number of immature or mature forms of an entozoon which
develop will depend upon the number of parasites which have
gained access to the system. In the first case the effect upon
the individual will be practically uninfluenced by the number
IMPURE WATER, ITS EFFECT UPON HEALTH 155
of organisms swallowed, whilst in the second the effect will
entirely depend upon and be in direct relation to the number
introduced.
The entozoa most likely to infect man through the medium
of drinking water are : Bilharzia hcematoHa, Filaria sanguinis
hominisj Dracunculus mediensis, and Rhabdonema intestinale,
but it is quite possible that Filaria loa and many others also
gain access to the system in this way.
Bilharzia hwmatobia. This entozoon is the cause of the
endemic hcematuria so common in Egypt, Abyssinia, and the
Cape of Good Hope. The ova are passed with the urine, find
their way into water, and hatch into ciliated embryos. These
probably pass through a farther stage of development in
some mollusc or arthropod, again enter the water, and are
once more ready to complete the cycle of their life history if
received into the body of the human host. Dr. Sonsino, from
his experience in Egypt, believes that, were a rule made of
filtering all drinking water, no person would become infested
with this parasite. He found the disease almost entirely
limited to the more ignorant portion of the population who
use unfiltered water. A closely-allied organism, believed to
be the cause of a peculiar form of haemoptysis in Japan and
the East, may also, judging from analogy, gain access to the
system through the same medium impure water.
Filaria sanguinis hominis. Mosquitoes derive the embryos
of this entozoon from the blood of infected persons (Manson),
and the larvae develop in the body of that insect. These are
transferred to water, and thence again into the human body,
either, as Manson conjectures, by piercing the skin, or, as is
more generally believed, by being swallowed either with the
drinking water or accidentally whilst bathing. This organism,
which produces endemic hcematuria and chyluria, occurs
almost exclusively within the tropics, but affects all races and
nationalities.
Dracunculus mediensis, or Filaria dracunculus. The em-
bryo of this species is aquatic in habit, and according to Fed-
156 WATER SUPPLIES
sclienko it undergoes a further development in the body of a
cyclops. In some parts of India and Africa it is said, at times,
to infect nearly half the population. The abscesses to which the
fully-developed worm gives rise being most commonly found
in the feet and legs, and especially about the heel, it has been
generally assumed that the parasite enters through the skin, to
which it may become attached when bathing, paddling, or
walking barefooted over moist ground. Hirsch, however, has
collected a mass of evidence proving that infection takes place
through the medium of the drinking water. For example, he
records an outbreak of dracontiasis in 1849 amongst the
members of two trading caravans travelling from Bahia to
Janeiro. They encamped near a stream and made use of the
water for drinking, although expressly warned of the conse-
quences by the natives. They did not bathe in it. A few
months later all the members were affected with guinea worm,
except a negro, who was the only one of the party who had
not drunk the water.
Itliabdonema intestinale. Sonsino states that this parasite
is not quite so innocuous as is generally supposed. He has
seen cases of intense anaemia and of enteritis caused by it,
and he is certain that it is taken in with foul drinking water.
Ascarides lumbricoides, or common round worm. Experi-
ments made to infect man with the eggs of this worm have
invariably given negative results, yet it seems probable that
one of the ways in which persons become infected is by the
introduction of the parasite at some stage of its development
with the drinking water. Both in England and elsewhere
the excessive prevalence of lumbrici has been noted over
localised areas where the inhabitants resorted to polluted
ponds or shallow wells for drinking water.
Trichocephalus dispar, or whip worm. Half the inhabit-
ants of Paris are said to be infected with this parasite, which,
however, is far more common in the tropics than in temperate
climes. Leuckart has proved that the eggs passed with the
faeces must reach water or some very damp medium before
IMPURE WATER, ITS EFFECT UPON HEALTH 157
the embryo can develop. If it be now introduced into the
stomach with the drinking water, the shell of the egg is
dissolved and the embryo liberated.
Anchylostoma duodenale. This parasite induces extreme
anaemia, disorders of the intestinal canal, haemorrhages, etc.,
and causes great mortality in Brazil, West Indies, and Egypt.
During the construction of the St. Gothard Tunnel a severe
outbreak of disease occurred amongst the labourers, who had
become infected by this worm. Isolated cases have also
been recorded in many parts of Italy, and possibly in other Jx
European countries. Part of its life cycle is passed in damp
earth, and it has been frequently observed that the disease Q*
induced by it is confined almost entirely to the lower classes, CQ
and more especially to those who drink water from shallow
pools and watercourses.
Tcvnia echinococcus. The hydatid stage of this tape- worm ^
occurs in man. The tape-worm itself develops in the intes- 25
tines of the dog, and the ova passed may easily find their way ffi
into water, and by this means be introduced into the human CL
stomach. Hydatid tumors are common in Iceland, parts of
Australia, Switzerland, and Southern Germany.
Many other parasites which affect domestic animals are 21
taken in by these animals when drinking excrement-polluted *$
water. Thus Distoma echinatum is common in the duck, the
Schlerostoma armatum or palisade worm causes aneurism in
the horse, species of Uncinaria cause a form of anaemia in
dogs, etc., and all appear to require water or some very moist
medium in which to pass through a certain stage in the cycle
of their life history.
The Effect upon Animals of drinking Polluted Water. This
has been but little studied, but evidence is accumulating tend-
ing to prove that drainage from farmyards is not quite so in-
nocuous as is generally supposed, and that water polluted with
such excrement may be a carrier of disease. It would be
strange indeed if man alone were injuriously affected by
imbibing such impurities. As the relation of the diseases of
158 WATER SUPPLIES
animals to those of man become better understood, it will
probably be found that many specific diseases are common to
both, and that the one can, in various ways, infect the other.
Dr. Vaughan (Michigan) believes . that animals may suffer
from true typhoid fever, and that he has succeeded in in-
ducing the disease in dogs and cats. If such be the case, it
will explain the outbreaks of this fever amongst travellers in
uninhabited regions, who have been compelled to drink water
fouled by wild cattle, and may also account for many of the
localised outbreaks which from time to time occur, where
the most diligent inquiry fails to discover any specific pollu-
tion of the suspected water by human agency. In 1878,
Dr. Hicks attributed an outbreak of typhoid fever at Hendon
to the milk of certain cows who drank sewage -contaminated
water (Lancet, 1878, vol. ii. p. 830), and since that time
other observers have recorded outbreaks which they attri-
buted to the same cause ; but whether* the milk itself was
originally infected or merely became infected by the admix-
ture with specifically polluted water is still open to question.
In 1889 Dr. Gooch attributed an outbreak of diphtheritic
tonsillitis at Eton College to the use of milk from cows sup-
plied with filthy drinking water (Brit. Med. Journ. 1890,
vol. i. p. 474). In other similar cases, however, the milk is
believed to have been specifically infected from sores upon
the teats, but even here, the possibility of the disease, of
which the sores on the teats are a symptom, being caused by
drinking polluted water must be admitted.
In America, where a considerable amount of attention has
been paid to the dissemination of disease amongst cattle by
impure drinking water, many outbreaks of anthrax, hog
cholera, glanders, and other diseases have been recorded which
competent observers attributed to this cause. On one station
the carcase of an animal which had died of anthrax was cast
into a tank or pond from which about 1000 head of cattle
were supplied with water. Within a very short time 10 per
cent of these died of anthrax. Some years ago, when wooll
IMPURE WATER, ITS EFFECT UPON HEALTH 159
sorters' disease appeared amongst the operatives at a woollen
factory in Yorkshire, a number of cattle grazing in a meadow
through which flowed a stream receiving the waste water
from the mill, were also attacked. In 1893, many cattle
on a farm in South Russia died of anthrax, and the bacilli were
found in the water used, derived from a well. Professor
P. Frankland has shown that under certain conditions the
anthrax bacillus forms spores in water, and that these spores
retain their vitality for a considerable period. Texan fever,
by some pathologists regarded as a' form of anthrax, is
believed to be spread by the use of water contaminated with
the excreta of infected cattle.
Hog cholera, a dysenteric affection, is almost certainly a
water-borne disease. The specific organism can live for a
considerable time in water and even multiply in it, if sewage-
polluted, hence American observers are of opinion that
specifically-contaminated streams are the most potent agents
in its distribution. Upon a farm, in Iowa, where chicken
cholera and hog cholera had been prevalent, the dead animals
were thrown into a stream. Shortly after a number of cattle,
horses, and sheep drinking from the stream were affected with
a disease which invariably proved fatal after an illness of
about two days' duration.
Glanders, a specific infectious disease, may be transmitted
from animal to animal by the use of a common drinking
trough, much as diphtheria is believed to be spread amongst
children by the use of common drinking vessels.
That many entozoal diseases, amongst cattle, are propagated
by polluted waters can scarcely be doubted, and it is quite
possible that actinomycosis may be so caused.
At the present time no one would contend that water
fouled by cattle was fit to be used by man for drinking pur-
poses, and probably ere long proofs will be forthcoming that
the use of such water by cattle is not only inimical to their
health, but also a source of danger to the public generally
who consume their milk and flesh.
CHAPTEE X
THE INTERPRETATION OF WATER ANALYSES
BY a chemical analysis the saline constituents of a drinking
water may be ascertained and their quantities determined,
and the same applies also to any sedimentary matter which
the sample contains. Chemical analysis also may tell us of
the presence of organic impurity, but, as will be seen in the
sequel, it can afford us very little information with regard to
its quality, and cannot even accurately measure the quantity.
By aid of the microscope the minute forms of animal and
vegetable life can be detected and identified, but the most
minute forms, the bacteria, require a special search to be
made to determine their presence and character.
In the preceding chapters on "The Quality of Potable
Waters," and on " Diseases caused by Impure Waters," it has
been rendered evident that of the many impurities which
drinking water may contain, the organic matter only is a
serious source of danger, and that by far the greatest risk is
incurred in using waters liable to contain certain living
organisms which, when introduced into the system, are capable
of producing specific disease. Of the presence or absence of
such organisms chemical analysis can give us no information.
The presence of dead organic matter may be chemically
demonstrated, but inasmuch as the nature of this organic
matter, whether poisonous or innocuous, is beyond the power
of the analyst to reveal, it is obvious that the results of a
mere chemical analysis may often be worthless or even mis-
THE INTERPRETATION OF WATER ANALYSES 161
leading. This point cannot be too strongly emphasised, since
the popular impression, shared alike by the ignorant and the
learned, that a chemist, by performing a few mysterious
experiments with a water in his laboratory, can pronounce
at once whether it be pure or impure, safe or dangerous,
must be dispelled. This opinion has been fostered by analysts
who rarely hesitate to pass judgment upon a water from the
results of their chemical examination, from the determination
of the chlorides, nitrates, phosphates, and ammonia, of the
organic carbon and nitrogen, and of the oxygen consumed, or
of the ammonia derivable from the organic matter. All these
factors are of more or less importance as an index of the
degree of pollution, but their real value can in very few cases
be assessed without some previous knowledge of the source of
the water. The inorganic constituents can easily be determined,
and whether, either in quantity or quality, these are objection-
able, the chemist can safely express an opinion. Those only
therefore need further be considered which by their presence
tend to throw some light upon the source of the organic
matter, contained in greater or less quantity in all waters.
These are the chlorides, nitrites, nitrates, ammonia, and
phosphates ; and inasmuch as their determination is often of
importance, the value of each may be discussed.
Chlorides. In the great majority of instances the only
chloride present is chloride of sodium or common salt ;
occasionally other chlorides, as of magnesium and calcium, may
be found in drinking waters, but as these are of trifling signi-
ficance they can usually be disregarded. Rain water,
especially in districts near the sea, always contains a trace of
salt. Certain geological formations are rich in salt, and waters
obtained therefrom may contain considerable quantities. Urine
also contains nearly 1 per cent ; hence pollution with sewage
will add salt to the water. The effluents from many manu-
factories, alkali works, mines, etc., are also rich in chlorine.
From these various sources, therefore, the chlorides found in
waters are derived. Where the geological strata contain
M
1 62 WATER SUPPLIES
little or no salt, and there are no manufacturing or mining
effluents to pollute the water, the amount of chlorides present
may serve roughly as an index of the extent to which it
has been contaminated by sewage. In Massachusetts it has
been found that the amount of chlorine in the surface waters
and streams decreases in amount from the seaboard westward
or inland. By the examination of waters from sources
removed from all risk of contamination, the normal chlorine
for such districts has been determined. " By placing on the
map of the State the amount of chlorine l normally present in
its unpolluted waters, and then connecting the points of
equal amounts, lines of like chlorine contents are obtained,
which are called isochlors" From the map thus prepared
the normal chlorine is found to vary from "45 grain per
gallon near the coast to less than '06 in the western part of
the State (Board of Health Report, 1892). Over any given
area, the amount of chlorine in excess of the normal, as
above ascertained, can only be due to the influence of the
population discharging its sewage thereupon. Assuming
that 100 persons per square mile add on an average '03
grain of chlorine per gallon to the water flowing from the area
considered, the extent of the contamination can be approxi-
mately calculated. It must be remembered, however, that
the amount of chlorine present does not necessarily signify
present pollution. The organic matter which originally
accompanied the salt, and which alone is deleterious, may
have undergone complete oxidation and destruction, so that
organically the water may be very pure although the amount
of chlorine present indicates that at one time it was excessively
polluted. This fact detracts very considerably from the
importance of the chlorine determination. It affords some
evidence of the previous history of the water, and that is all.
In insular countries the estimation of the chlorine is of even
less value, since they cannot be mapped out into isochlors.
Over limited areas, however, the normal chlorine may some-
1 1 part of chloride of sodium equals *61 part of chlorine.
THE INTERPRETATION OF WATER ANALYSES 163
times be ascertained, and any excess found in samples from
that district will be in a measure proportionate to the present
or past pollution of the water. For example, in the parish
of Writtle (Table III., p. 52), the normal chlorine did not
exceed 2 '5 grains per gallon, yet in that parish subsoil waters
were found containing as much as 14*0 grains per gallon, and
that this was due to past and present pollution with sewage
was substantiated by the excess of other substances, especially
nitrates, which, as we shall see, are also in most cases derived
from the same source. Unless this normal chlorine be known,
the determination of the chlorides has no value whatever.
The variation in the amount of chlorine in pure surface
waters from various geological formations is given in Table I.
and any excess over the amounts given there would probably
point to past or present pollution, and in any case would
indicate that further investigation of the source was desirable
or necessary. In shallow -well waters, even when pure
(Tables III. and IV.), the chlorine varies so greatly in amount
that it is only in rare cases, as in the one referred to above,
that the determination affords any information of value. In
spring waters also it is difficult to decide upon the normal
chlorine of any particular formation (Table V.), but if in any
case the amount found greatly exceeds the average, past or
present pollution is indicated. The same remark applies to
deep-well waters (Table VI.). If the source of the water
be not known, reliance upon the chlorine estimation may lead
to serious error. I have known an analyst of repute, after
examining one of our Essex deep-well waters, certify that the
large amount of chlorine indicated serious contamination with
sewage, whereas the water was almost absolutely pure,
hygienically, containing no organic matter, and no excess of
chlorine over that natural to waters from that particular
source. In several instances, when examining water from
these deep wells, I have found the amount of chlorine below
the normal and have sometimes been able to prove that this
was due to surface water (usually impure) having gained
1 64 WATER SUPPLIES
access to the well. In other cases a large excess of chlorides
has been traced to the influx of sea water. The possibility
of the excess of chlorine being derived from manufactories
or mines must also be considered before concluding that
the water contains contaminating matter of animal origin, and
the fact that wells sunk near the sea shore, and near tidal
rivers, may contain an excess of chlorides derived from the
infiltration of sea water must not be forgotten.
Nitrates and Nitrites. The combined nitrogen found in
drinking waters is contained in the organic matter, ammonia
(NH 3 ), nitrites (M'NO 2 ), and nitrates (M'NO 3 ). Traces of all
three are found in most samples of rain water (vide page
27). Nitrogenous organic matter undergoing putrefaction
invariably produces ammonia, and by oxidation this ammonia
is converted, by micro-organisms found in all soils, into water
and nitric acid, the latter decomposing the carbonates present,
and forming nitrates of soda, potash, or lime. The ammonia,
however, is not apparently converted directly into nitric acid,
but passes through an intermediate stage, a lower oxide of
nitrogen, nitrous acid being first formed. This process
will be described in greater detail when the purification
of water is being discussed. The Rivers Pollution Com-
missioners found that whilst the organic matters contained in
sewage, and therefore of animal origin, yielded abundance of
nitrates and nitrites by oxidation, no less than 97 per cent of
the combined nitrogen of London sewage being converted into
nitrates by slow percolation through 5 feet of gravelly soil,
vegetable matters yielded mere traces of these compounds.
Upland surface waters " in contact only with mineral matters,
or with the vegetable matter of uncultivated soil, contain, if
any, mere traces of nitrogen in the form of nitrates and
nitrites ; but ... as soon as the water comes in contact with
cultivated land, or is polluted by the drainage from farmyards
or human habitations, nitrates in abundance make their
appearance." Subsoil waters derive their nitrates in part
from the oxidised ammonia of rain water, in part from the
THE INTERPRETATION OF WATER ANALYSES 16$
slow decay of vegetable matter, and in part from sewage
matters. The amount derived from the two former is almost
invariably small. Vegetable matter is not highly nitrogenous,
and as a rule decomposes but slowly. Animal matter, on the
contrary, decomposes rapidly and yields much ammonia.
Nitrates serve for the food of plants, and the active growth
of vegetation may remove nearly the whole of these salts from
a water. In reservoirs the nitrates decrease gradually as the
vegetable organisms increase. The total combined nitrogen
therefore in a water may at one time exist in decaying animal
and vegetable matter, or in the form of ammonia ; at another
in the form of nitrites and nitrates, and yet again as a con-
stituent of the protoplasm of living vegetable organisms, in
which latter case it is not in solution, but merely suspended
in the water. Whenever organic matter undergoes putrefac-
tion in the absence of air or free oxygen, not only are nitrates
not formed, but any nitrates present are decomposed, their
oxygen being required for the formation of water and carbonic
acid by combination with the carbon and hydrogen of the
decomposing substances. The nitrogen appears to be set free,
possibly accounting for the excessive amount of that element
found in such deep-spring waters as those of Bath, Buxton,
and Wildbad. In this way the small amount of nitrates
found in most deep-well waters is accounted for. Such being
the case, it is evident that even concentrated sewage may
undergo such changes as would totally obscure its origin so
far as the combined nitrogen is concerned. At first this would
be contained chiefly in the dissolved animal impurities ; after
passing through the surface soil, it would exist chiefly in the
nitrates formed by the oxidation of the organic matter, later
the nitrates may be decomposed, and the nitrogen liberated,
when the water would be almost or entirely free from com-
bined nitrogen. On the other hand, certain deep- well waters,
especially in the chalk, contain very considerable amounts of
nitrates, which it is difficult to believe are derived from the
oxidation of sewage matters. It has been suggested that
1 66
WATER SUPPLIES
these nitrates are derived from fossil remains, or from natural
deposits of nitrates, or from vegetable matter ; but as no proof
of these statements is forthcoming, they must be received
with reserve. In the eastern counties the chalk wells yield
waters which in some districts are absolutely free from nitrates
(S.E. Essex), whilst in other districts (Norfolk) they may
contain possibly as much as 1 grain of nitric nitrogen per
gallon. The following may be quoted as examples.
Nitric N.
per gallon.
Depth of
Well.
Authorities.
Stratford : Phoenix Works .
oo
feet
200
J. C. Thresh.
Wimbledon ....
03
200
Chatham Public Supply
48
490
t j
Southend , ,
05
900
? >
Witham ,,
45
600
R.P.C.
Mistley : Tendring Hundred
W. W. Co. ...
05
160
J. C. Thresh.
Braintree Public Supply
Colchester(Donyland Brewery)
'02
oo
430
305
T. A. Pooley.
J. C. Thresh.
Saffron Walden Public Supply
95
46
? 5
Norwich ....
80
About 400
In none of the above examples is there any possibility of
recent sewage contamination.
Notwithstanding these facts the Rivers Pollution Com-
missioners considered the total combined nitrogen to be an
index of previous sewage contamination. They assumed
that 100,000 parts of average London sewage contains 10
parts of combined nitrogen in solution. The mean amount
of such nitrogen found in a large number of samples of rain
waters examined was '032 per 100,000. After deducting
this latter amount from the amount of nitrogen, in the form
of nitrates, nitrites, and ammonia found in 100,000 parts of
a potable water, the remainder, if any, they say, " represents
the nitrogen derived from oxidised animal matters, with
which the water has been in contact. Thus, a sample of
water which contains, in the forms of nitrates, nitrites, and
THE INTERPRETATION OF WATER ANALYSES 167
ammonia, '326 parts of nitrogen in 100,000 parts, has obtained
326 - '032 = -294 part of that nitrogen from animal
matters. Now, this last amount of combined nitrogen is
assumed to be contained in 2940 parts of average London
sewage, and hence such a sample of water is said to exhibit
2940 parts of previous sewage or animal contamination in
100,000 parts." The Rivers Pollution Commissioners, how-
ever, point out that, on the one hand, the nitrates may not
indicate the full extent of the previous sewage pollution,
since the roots of growing crops take up much of the
ammonia, nitrites, and nitrates contained in polluted water,
and animal matter which decomposes without access of air
destroys nitrates ; and, on the other hand, that the nitrates
present may indicate 10 per cent of previous sewage con-
tamination in deep wells and springs, and the risk of using
such waters be regarded as nil, providing surface pollution
be rigidly excluded. This 10 per cent of previous sewage
contamination corresponds to 1 grain of nitric nitrogen per
gallon.
Mr. F. Wallis Stoddart, in an excellent paper on " The
Interpretation of the Results of Water Analysis," 1 describes a
series of experiments in which he passed sewage containing
cholera bacilli through a nitrifying bed of coarsely-powdered
chalk, and found that although the organic matter in solution
was completely nitrified, yet the cholera bacilli or spirilla
could be detected in the effluent. From the result of his
own observations and experiments, he concludes that natural
waters " can at most obtain from one-tenth to two-tenths of a
grain of nitrogen as nitrates per gallon from sources other
than animal matter," and " that practically the whole of the
nitrogen of sewage may be oxidised into nitric acid without
materially diminishing the risk involved in drinking it." He
urges that whenever the nitrogen as nitrates exceeds half a
grain per gallon, it indicates "either dangerous proximity
of the well to a source of pollution, or such easy communica-
1 Practitioner, 1893.
1 68 WATER SUPPLIES
tion with it that the distance separating the two points is no
guarantee of purification." In the various tables of analyses
given in previous chapters will be found instances of many
waters, the source of which I carefully examined, and which
were collected and analysed by myself, containing more than
this amount of nitric nitrogen ; and I am perfectly convinced
that these waters are hygienically of the highest class, and
can be used without the slightest risk or danger. On the
other hand, in Table VII. there will be found analyses of
many waters, containing very much less nitrogen as nitrates,
which have almost certainly (in most cases the proof was
very conclusive) given rise to outbreaks of typhoid fever.
If Mr. Stoddart's maximum of '5 be accepted as proof that
a water is dangerous, then the public and private water
supplies of many of our healthiest districts districts remark-
ably free from outbreaks of typhoid fever must all be con-
sidered dangerous. As a matter of fact, the amount of
nitrates which would condemn a water from one source may
be absolutely without significance in water from another, all of
which goes to demonstrate, as will be shown in the sequel, that
mere chemical analysis is absolutely powerless to prove that
any water is of such a quality as to be incapable of producing
disease amongst those who drink it.
Nitrites may result from the oxidation of ammonia, or
from the reduction of nitrates, and, as it is an easily oxidisable
compound, its presence indicates a condition of instability, of
matter undergoing change. Usually this matter is of animal
origin and derived from manure or sewage, the ammonia
produced by their decomposition being in process of oxidation
to nitrates. Where the soil is not sufficient in quantity,
or is defective in quality, the oxidation may be incomplete,
and incompletely purified and probably incompletely filtered
water is the result. Usually in such cases an excessive
amount of ammonia is also present. But, though usually,
this is not invariably the source of the nitrites and ammonia.
Where nitrates are present the nitric acid may be reduced by
THE INTERPRETATION OF WATER ANALYSES 169
contact with rnetals, such as iron or lead, forming the pipes
in which the water is conveyed, or lining the upper portion
of the well. Where such is the case, a trace of the metal
can always be detected in the water. Unless this fact be
borne in mind and it often appears to be overlooked a good
and wholesome water may be classed as dangerous or polluted.
Certain organisms also found in water are capable of reducing
nitrates to nitrites. Still the presence of nitrites always renders
a water suspicious, and their origin should be carefully in-
vestigated.
Ammonia. All rain water contains this compound, as
does also melted snow. The first portions of a shower, and
the rain collected in the neighbourhood of towns, are richest
in ammonia. As an average, *02 grain per gallon, taken
by the Rivers Pollution Commissioners, is probably fairly
approximate, but the variation is very wide ('2 to '01). In
passing over or through the ground the ammonia is rapidly
oxidised, and by the time the water reaches a stream or the
general body of subsoil water, most .of it has disappeared.
Rain water stored in covered cisterns, however, usually
retains its ammonia for a considerable period. In such
waters, therefore, the ammonia, unless excessive, is devoid of
significance. Many deep -well waters also contain much
ammonia, the origin of which has given rise to a good deal
of surmise. The generally accepted theory is that it is due
to the reducing action of ferruginous sands on the nitrates
present. This may be so in some cases, but my observations
lead me to believe that it is often due to the reduction of the
nitrates by the metal of the bore tube, pump pipe, and lining
of the well. I was led to this conclusion from the fact that
I found the water from one and the same well, at one time
quite free from ammonia, and at another containing as much
as one part of ammonia per million parts of water. In the
water containing ammonia I also found a very faint turbidity,
which cleared up on the addition of a little acid, and gave
the reactions for iron. The clear, ammonia-free water also,
170 WATER SUPPLIES
when stored for a time in an iron tube became turbid, and
nitrites, ammonia, and iron could be detected in it. Generally,
however, the ammonia found in river, spring, and well
waters is derived from putrescent animal matter that is, from
manure and sewage ; but before this conclusion can be safely
drawn, the other possible sources must be excluded. Dr.
Brown, in his Report to the Massachusetts State Board of
Health, 1892, whilst agreeing that imperfect oxidation of
sewage matter is generally the source of the ammonia, calls
attention to the fact that several waters in the State free from
such pollution contain a considerable amount of free ammonia.
"They are all associated with iron oxide and the fungus
Crenothrix" Such waters are found also in many swampy
regions, and in wells sunk in ferruginous river silt, and
usually become turbid from the formation and deposition of
oxide of iron when exposed to the air. The odour of these
waters is said to be "often disagreeable from dissolved
sulphuretted and carburetted hydrogen."
Phosphates. Phosphatic minerals are widely distributed in
nature, and traces may be dissolved by waters rich in carbonic
acid. Albuminous matters, whether of vegetable or animal
origin, give rise to phosphates by their decay, hence their
presence, especially in what the analyst may conceive to be
an excessive amount, has been held to indicate contamination.
The difficulty of detecting phosphates, when silica is also
present, as is usually the case, the still greater difficulty of
estimating the quantity, and the very doubtful value of the
information when obtained, has caused most chemists to ignore
their presence. Traces may be found in wholesome waters,
and their absence affords no proof that a water is free from
pollution, hence the determination is useless.
Organic Matter. By no known process can either the
quantity or quality of the organic matter in water be deter-
mined. When a known volume of water is evaporated to
dryness, the weight of the residue is that of the inorganic and
organic substances contained therein. When this residue is
THE 1NTERPRETA7UON OF WATER ANALYSES 171
ignited the organic matter is destroyed and volatilised, and
the " loss on ignition " has been regarded as approximately
expressing the weight of the organic constituents. Such,
however, is rarely the case, since carbonic acid may be driven
off from the carbonates present, and any nitrates present will
be more or less completely reduced. Moreover, some salts
retain water so tenaciously that the whole is not driven off at
the temperature used for drying, and this moisture is given
off when the residue is ignited. For these reasons, chiefly,
the " loss on ignition " cannot be depended upon as an index
of the amount of organic matter present. But although the
total amount of the animal and vegetable substances cannot
be determined, the carbon and nitrogen therein can be ascer-
tained by careful chemical analysis. Not only so, but the
authors of the original process believed that, with certain
reservations, the proportion of the nitrogen to carbon indicated
whether the organic material was derived from the animal or
vegetable kingdom. In fresh peaty water the Kivers Pollu-
tion Commissioners found that N: = 1: 11 '93, whilst in
similar waters, which had been stored for weeks or months in
lakes, N:C = 1 : 5'92. After such water had been filtered
through porous strata, N :C = 1 :3'26. In fresh sewage the
average of a large number of samples gave N :C = 1 : 2*1.
Highly polluted well waters, soakage from cesspools, etc.,
gave N : C = 1 : 3 '126. In sewage after filtration through soil
the proportion of N to C rose from 1 : 1'8 to from 1 : 4'9 to
1 : 7'7. Evidently therefore the ratios of N to C "in soluble,
vegetable, and animal organic matters vary in opposite
directions during oxidation, a fact which renders more
difficult the decision as to whether the organic matter
present in any given sample of water is of animal or
vegetable origin."
All nitrogenous organic matter, whether of vegetable or
animal origin, yields more or less ammonia when boiled with
a strongly alkaline solution of permanganate of potash, and
the ammonia so yielded by potable waters is called "albu-
172 WATER SUPPLIES
rnenoid," or " organic " ammonia. The proportion of nitrogen
in the ammonia so yielded to the total nitrogen in the organic
matter is unfortunately not constant ; but the chemists to the
Massachusetts Board of Health believe that when the process
is performed as in their practice, about one -half of the
nitrogen is converted into ammonia. Albumenoid substances
of animal origin contain about 16 per cent of nitrogen, but
vegetable matters contain very much less ; hence the amount
of "albumenoid" ammonia is no index to the amount of
organic matter present in the water. Professor Wanklyn, who
devised this process, considers that undeniably contaminated
waters always yield an excessive amount of albumenoid
ammonia (over *10 part per million) ; usually with much
free ammonia (over *OS part per million). If the albumenoid
ammonia distils over very slowly and is in excess, but the
water contains little free ammonia and very small quantities of
chlorides, Professor Wanklyn considers this an indication that
the contaminating matter is of vegetable origin. He adds :
" The analytical characters, as brought out by the ammonia
process, are very distinctive of good and bad waters, and are
quite unmistakable." The generally accepted opinion, how-
ever, is that no reliance can be placed upon these determinations
taken alone, and in the Massachusetts State Board of Health
Iteport for 1890 there is quoted as an example the results of
the analyses of certain of the Boston water supplies. Reservoir
No. 4 is known to contain the purest water, but the average
" albumenoid ammonia " during two years was '26 per million.
The water of the Mystic Lake is the worst of the Boston
waters, since it contains both sewage and manufacturing
refuse ; yet during the same period the average albumenoid
ammonia was exactly the same as in the purer water. In
the table given below many other examples will be found of
the erroneous conclusions which may be drawn from a too
implicit reliance upon the determination of the ammonia
yielded by distillation with alkaline permanganate.
Forschammer devised a process for the estimation of the
THE INTERPRETATION OF WATER ANALYSES 173
amount of oxygen required to oxidise the organic matter in
water. This method, as improved by the late Dr, Tidy, has
become very popular, and many attempts have been made to
render the results comparable with those obtained by Frank-
land's process, in which the amount of organic carbon and
nitrogen is ascertained by combustion, but with only partial
success. The results, when compared with those obtained by
the "albumenoid ammonia" process, prove that there is no
relation between the amount of ammonia yielded by a water
when distilled with an alkaline solution of permanganate of
potash, and the amount of oxygen absorbed when the same
water is digested with an acid solution of the same salt.
This process tells us little or nothing of the nature of the
polluting material ; it does not even distinguish between
organic matter of vegetable and animal origin, and it affords
us no evidence of the amount of such substances present.
The presence of certain bodies of mineral origin (sulphuretted
hydrogen, nitrites, the lower oxides of iron, etc.) also absorb
oxygen, and unless great care is taken to ascertain the absence
of these, or to ascertain the exact amount of oxygen consumed
by them if present, serious errors may be introduced. When
these corrections are made the oxygen process is still open to
all the objections which have been urged against the albu-
menoid ammonia process. It may condemn a perfectly harm-
less water as polluted, and pass as of good quality a water of
most dangerous character. The following table was devised
by Drs. Tidy and Frankland.
AMOUNT of OXYGEN absorbed by 1,000,000 parts of WATER.
Upland Surface
Water.
Water other than
Upland Surface
Water.
Water of great organic purity
medium purity
,v , doubtful purity
Impure water
Not more tli an I'O
3-0
4-0
More than 4'0
Not more than '5
1-5
2-0
More than 2 '0
174 WATER SUPPLIES
When the quality of a water is considered from the bio-
logical side instead of the chemical, the absurdity of dividing
waters into classes of pure, medium, doubtful purity, and
impure, is obvious. A water containing a poisonous quantity
of typhoid bacilli might upon analysis be brought within
any of these classes, according to the quantity and quality of
the accompanying impurities. In the analyses given below
there are instances of waters coming within Tidy's limit of
" great organic purity," yet which proved to be capable of
causing disease. I have examined many such waters myself,
and have also passed many waters as perfectly safe for
domestic purposes which a mere reference to the above
standards would have condemned as doubtful or impure.
Many other special processes for determining whether a
water be safe or dangerous have been devised, but inasmuch
as they are rarely used, it may safely be inferred that they
possess no advantage over those to which we have already
referred.
Whilst no single determination will enable the analyst to
certify that a water is free from danger, or that it is so
polluted as to be dangerous to health, the determination of
several constituents may enable him to pronounce it to be
polluted and dangerous, but will never justify him in certify-
ing that it can be used absolutely without risk. As the
freedom from all dangerous polluting material is the informa-
tion usually sought from the analyst, it follows that if this
cannot be ascertained by analysis, a chemical examination is
in most cases quite useless. Where a water is known to be
contaminated with sewage, or known to be liable to such
pollution, an analysis is superfluous. When we also consider
that many sources of supply are only subject to intermittent
pollution, and that waters from the same reservoir or from
the same well (vide Analyses Nos. 24, 25, and 26, 27) may
vary considerably in composition, according to the depth from
which the samples are taken, the character of the season,
etc., it is obvious that the chemical examination of a water
THE INTERPRETATION OF WATER ANALYSES 175
is a matter of comparatively trifling importance compared
with the thorough examination of its source and an accurate
knowledge of its history. Frequently waters are sent for
analysis, and the analyst is wilfully kept in ignorance of
their origin lest the information should prejudice his
report, yet without this knowledge he is not justified in
expressing an opinion whether any water can be used with
safety. In commenting upon a recent paper in which I
expressed these views, a writer in the Chemist and Druggist
says : "It would seem, therefore, that we are face to
face with the question, 'Is water analysis a failure.' It
has been so exclusively the province of chemical analysts
to pronounce judgment upon domestic waters, and they
generally have given so little attention to the large issues
attached to analysis, and so very much to sets of standard
figures for chlorine, nitrogen, hardness, and so on, that the
attack from the medical health side is not unexpected.
There has been more wrangling over water analyses than
over anything else in chemistry and for what ? Some
figure in the second or third place of decimals, probably, and
in regard to what this ammonia or that ammonia implies,
when a visit to the source of the water and an inspection of
the sewage trickling into it might settle everything. That
is what Sir George Buchanan and Dr. Thresh advocate."
The Royal Commission on Metropolitan Water Supply
received evidence proving that waters containing very large
amounts of organic matter were drunk continuously by a popula-
tion with perfect impunity, whilst other waters containing so
little organic matter as almost to defy chemical detection
had proved, time after time, to be of the most poisonous
character. For these reasons they conclude that the water
question has passed from the domain of chemistry into that
of biology. This, however, is not strictly correct. The
biological problems involved in the investigation of water
supplies are numerous and complex, and as yet but im-
perfectly understood. At the present time it is doubtful
1 76 WATER SUPPLIES
whether a biological examination really tells us more than a
chemical analysis, and very often it cannot tell us as much.
The reason will be explained shortly.
Although a mere analysis cannot guarantee us purity and
safety, yet it very frequently can reveal to us impurity and
risk. When the source of a water, upon most careful examin-
ation by an expert, is found to be free from all danger of
pollution, and the chemical examination proves that the in-
organic constituents are unobjectionable both in quantity
and quality, and that organic matter is absent or present in
barely appreciable amount, then safety, so far as human
foresight can be trusted, may be guaranteed. If organic
matter be present in appreciable quantity that is, if the
water yield such a quantity of organic nitrogen and carbon,
or albumenoid ammonia, or requires such an amount of
permanganate for oxidation as to render it of suspicious or
of doubtful purity a study of the history of the water and
of its geological source may, and generally does, enable an
opinion to be formed as to the nature of the organic matter,
and as to whether it is of an innocuous or dangerous charac-
ter. Chemical analysis, therefore, has its use ; it is only
when it is made the sole arbiter between safety and risk
that it is abused, and is liable to lead to errors fraught with
most disastrous consequences. Let the analysis be as careful
and complete as possible, but let the results always be inter-
preted in the light afforded by a searching examination of
the source of the sample. Let all so-called standards be
abandoned as absurd, and let the opinion as to whether a
water is dangerous or safe be based upon a full consideration
of other and more important factors.
In the following table the erroneous conclusions which
may be deduced from a too great dependence upon analytical
data are fully exemplified.
THE INTERPRETATION OF WATER ANALYSES 177
Remarks.
1. Analysis of water from the river Ouse below where it
receives the sewage of Buckingham. Examined for
the Town Council, 29th February 1888, by W. W.
Fisher, Public Analyst. Report " Does not
appear from the analysis to contain sewage matters."
Quoted by Dr. Parsons in his report to Local
Government Board on an outbreak of enteric fever
in 1888, as a "further illustration of the inability
of a chemist to prove the quality of organic matter
in water when its quantity is small."
2. Analysis of the Buckingham public water supply by
Mr. Fisher. Certified by him to be a first-class
water, yet believed by Dr. Parsons to have been
the cause of the above outbreak.
3. Analysis of the Beverley water supply from borings in
the chalk, by Mr. Baynes, 18th July 1884. In
1884 an outbreak of typhoid fever occurred here,
and was investigated for the Local Government
Board by Dr. Page. The evidence led him to
conclude that the specific contamination of the
water supply was the immediate cause of the out-
break. The water had been repeatedly analysed,
and the analysis given was made " on the very
border of the period when the water was acting
as the epidemic agent." It was certified to be "of
a very high degree of purity, and eminently suitable
for drinking and domestic purposes." Specifically
infected sewage from an asylum had been spread
upon land near the well and reservoir.
4. 5. Analyses of water from the much polluted Trent at
(4) Torksey, and (5) Knaith, by Dr. Tidy, 20th
December 1890. The analyst reported that "there
is no evidence of the product of sewage contamina-
tion." From Dr. Bruce Low's Report to the Local
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THE INTERPRETATION OF WATER ANALYSES 179
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Government Board, on the occurrence of enteric
fever amongst the population using the Trent
water, 1893.
6. Analysis of the well water supplying Houghton-le-
Spring, 24th April 1889. Early in the month a
sudden outbreak of typhoid fever occurred here,
and a sample of the water was at once sent for
analysis. The analyst reported : " This water is
very free from indication of organic impurity. . . .
It is a good water for drinking purposes." Dr.
Page, who investigated this outbreak for the Local
Government Board, found that sewage from a farm
three-quarters of a mile away was discharging into
the well at a point 45 feet from the surface.
7-14 form a very interesting series of analyses by chemists
of the highest repute, of the Tees water as supplied
to the towns in the Tees valley. Two outbreaks of
enteric fever occurred in these towns, the first
between 7th September and 18th October 1890;
and the second between 28th December 1890 and
7th February 1891. Dr. Barry reported upon them
to the Local Government Board. He found the
river above the intake of the Water Companies
excessively polluted by sewage, cesspool drainage,
etc. It is with reference to the relation of this
water to the typhoid epidemics that Dr. Thorne
says : " Seldom, if ever, has the proof of the relation
of the use of the water so befouled to wholesale
occurrence of typhoid fever been more obvious or
patent." The analyses now quoted were made
before, during, and after the epidemic periods, yet,
as will be seen, in not a single instance did the
chemical examination indicate either pollution or
danger.
7. Analysis of the Middlesborough water supply by Dr.
Frankland, F.R.S., 23rd August 1890. Report
THE INTERPRETATION OF WATER ANALYSES 181
" Peaty . . . but in all other respects the water is of
excellent quality for domestic use, and it is free
from any trace of sewage contamination"
8. Ditto., 23rd October 1890. Report " With the
exception of a peaty taste, it is in all respects of
excellent quality for dietetic and all other domestic
purposes."
9. Analysis of the Middlesborough water supply by A. H.
Allen, F.I.C., 27th October 1890. Report The
results " negative any suspicion of contamination
by sewage or cesspool drainage. . . . No suspicious
results were obtained on bacteriological and other
microscopical examination."
10. Analysis of the Middlesborough water supply by
Messrs. Pattinson and Stead, 29th October 1890.
Report " Perfectly wholesome and free from any
sewage contamination. . . . The microscope reveals
nothing of an objectionable character."
11. Analysis of the Darlington water supply by F. K.
Stock, County Analyst, 2nd December 1890.
Report -" I have no hesitation in saying that the
Tees water, as at present being supplied to consumers,
is of good and wholesome quality."
12. Analysis of the Middlesborough water supply by Dr.
Frankland, F.R.S., 1st January 1891. Report
" Of excellent quality for dietetic and all domestic
purposes."
13. Analysis of Darlington water supply by W. F. K.
Stock, County Analyst, 9th February 1891. "I
am of opinion that Tees water, as supplied to the
town on 29th January 1891 (the date when the
sample was taken), was good and wholesome drink-
ing water."
14. Analysis of the Stockton water supply by A. C.
Wilson, Borough Analyst, August 1891. Report
" Heavily charged with organic matter of vegetable
1 82 WATER SUPPLIES
origin ; there is, however, no appearance of animal
pollution."
That the river Tees some miles above the Company's
intake is grossly polluted with sewage, no one has
denied, yet these waters, upon analysis, were said to
be pure and wholesome, and free from any trace of
sewage contamination. As they are stated by the
most competent authorities to have been the cause
of the extensive epidemics of typhoid fever, most
of them must have been absolutely poisonous at the
time they were examined.
15, 16. In 1887, when an inquiry was being held to investi-
gate the pollution of the river Tees, the late Professor
Tidy examined a number of samples of water there-
from. No. 15 is the mean of several analyses of
samples taken above where the river receives the
sewage of Barnard Castle, and No. 14 is the mean
of several analyses of samples taken at Darlington,
15 miles below Barnard Castle. Notwithstanding
the sewage poured in at this town, and at points
nearer Darlington, Dr. Tidy reported that the water
at the latter place was rather better than at the
former, and was good and wholesome. He adds :
" I am of opinion that if the quantity of sewage
discharged into the river at Barnard Castle was
enormously greater than at present, the self-purify-
ing action of the water would be amply sufficient
to oxidise every trace of sewage impurity within a
short distance of the outfall. Further, I am of
opinion that Darlington would not be prejudiced
(although the river is the source of the water
supply) even if an outbreak of fever or cholera were
to occur at Barnard Castle."
17. Mean of four analyses of the Mountain Ash water
supply (spring and surface water) by Dr. Dupre,
November 1887. A serious outbreak of typhoid
THE INTERPRETATION OF WATER ANALYSES 183
fever occurred here, commencing in July 1887, and
continuing until October. Mr. John Spear investi-
gated it for the Local Government Board, and
attributed the epidemic to insuction of filth into
one of the water mains during intermission of the
service. Dr. Dupre found the samples almost
identical from a chemical point of view, and very
pure and free from any indication of sewage pollu-
tion. The two samples, however, which were taken
from the taps, after six hours' intermission, were
found, when examined microscopically, to contain
fungoid growths and large animalculse, which were
absent from the two other samples.
18-23 are analyses quoted from the Reports of the
Massachusetts State Board of Health, 1890-92.
18. A sample of unpolluted surface water containing less
nitrates and yielding more albumenoid ammonia
than (19) a sample of surface water known to be
polluted by sewage.
20. The average of a series of monthly examinations of
the water of the Merrimac Kiver, supplying the
town of Lowell during 1891, when typhoid fever
was epidemic, and attributed to the water being
specifically infected nine miles above the intake.
2 1 . Analysis of water from the Chicopee River, supplying
the city of Chicopee. Specific pollution is believed
to have taken place seven miles above the intake,
and to have caused an outbreak of typhoid fever in
the city.
22. Analysis of the water from No. 4 reservoir, the purest
of the four water supplies to the city of Boston,
and (23) of the water from Mystic Lake, the
most impure supply, showing that the albumenoid
ammonia yielded by the latter does not exceed that
yielded by the former.
24, 25 are waters from a deep well in Essex ; (24)
1 84 WATER SUPPLIES
collected during dry weather; (25) collected eighteen
hours after very heavy rain. This well water is
liable to most serious pollution, yet a report based
merely upon the results of the first analysis would
most certainly have been favourable.
26, 27 are waters taken by me from the same well ; 26
from near the surface, and 27 from near the
bottom.
28, 29, 30. Analyses of waters from bored wells in the
chalk supplying the Suffolk County Asylum. From
a Keport by Dr. Geo. Turner on art outbreak of
dysentery.
28, 29. These samples were taken from the same well
(350 feet deep), the first on llth October 1893 and
the other ten days later. The difference in the
amount of chlorine is most marked, and led Dr.
Turner to conclude that the lining of the bore was
defective, admitting subsoil water. Sample 28
corresponds closely with No. 30, which was taken
from a second bored well, 305 feet deep, and only
16 feet from the first well. Waters 28 and 30 are
probably free from admixture with subsoil water.
That such water gained access to the well from
which Nos. 28 and 29 were taken was proved by
digging a hole near the bore and pouring into it a
quantity of solution of chloride of lithium. Two
days later, lithia could be detected in the water
pumped from the bore tube. No. 29 is an example
of an impure disease-producing water, containing
less chlorides and absorbing less oxygen than an
unpolluted water from the same source.
With the discovery of the fact that such diseases as typhoid
fever and cholera are due to the introduction into the system,
not of dead organic matter, but of actual living organisms,
faith in the chemical analysis of waters began to be shaken.
THE INTERPRETATION OF WATER ANALYSES 185
When still more recently the actual microbes causing these
diseases had been identified, and processes had been devised
for isolating them from the multitude of other organisms
found in water, it seemed as though the examination of water
for sanitary purposes had passed from the domain of the
chemist to that of the bacteriologist. The study of the
number and character of the bacteria, it was hoped, would
enable the biologist to definitely pronounce whether a certain
water was capable of causing disease, or whether it was
perfectly harmless in character. Up to the present time such
hopes have not been realised, and the results of an ordinary
bacteriological examination are as likely to be misleading as
those of a chemical analysis. The reason for this is not
difficult to explain, when the significance of certain of the
discoveries made by bacteriologists is thoroughly understood.
An enormous number of species of bacteria have already been
discovered, although the science is in its infancy. They are
almost ubiquitous, abounding in the air, water, and nearly all
articles of food and drink. Of this immense variety very
few appear to be capable of causing disease ; the remainder
are perfectly harmless to human beings, whilst many are
already known to discharge most important functions in the
economy of nature. Upon their presence the fertility of soil
in a great measure depends; they break down the dead
organic matter into the simpler forms which can be assimi-
lated by the roots of plants. By their action the foul organic
constituents of polluted water are converted into carbonic and
nitric acid, which, in combination with the mineral bases, form
innocuous carbonates and nitrates. They are, in fact, nature's
scavengers, consuming the foul and effete, and producing there-
from matters of a harmless character.
The microbes found in water are chiefly bacilli. Micrococci
are comparatively rare, whilst spirilla are not uncommon,
especially in polluted waters. Already over 200 distinct
species of microbe have been discovered in potable waters,
and amongst these are several which are pathogenic or disease
1 86 WATER SUPPLIES
producing. According to Professor Percy Frankland, 1 these
are
Typhoid bacillus
Cholera spirillum, or "comma bacillus"
Tetanus bacillus
Anthrax , ,
Tubercle
Bacillus brevis
capsulatus
proteus fluorescens
coli communis
hydrophilus fuscus
pyocyaneus
Staphylococcus pyogenes aureus, and the organisms causing
septicaemia in mice and rabbits.
Up to the present, however, the only diseases which are
certainly caused by drinking specifically-infected water, and
the micro-organisms of which have been with certainty
discovered in such waters, are cholera and typhoid fever.
Doubtless further research will add to this short list, but as
yet the organisms causing malaria, dysentery, and other
diseases, believed to be produced by specific microbes entering
the system with the drinking water, have not been with
certainty identified therein. The utmost, therefore, that can
be expected of the bacteriologist is that he should discover
and identify the cholera or typhoid bacillus, should either
of these organisms be present in a sample of water. submitted
to him for examination. The multitude of other bacilli
present, however, renders this a difficult and often impossible
task ; the search has been likened to the finding of a needle
in a stack of hay. Whilst, therefore, the absolute identifica-
tion of the specific cause of cholera or typhoid fever
establishes its presence, the failure to isolate it is no proof
of its absence. As a matter of fact, numerous samples of
water, credited with the production of one or other of these
1 Journal of State Medicine, January 1894. "The Bacteriological
Examination of Water."
THE INTERPRETATION OF WATER ANALYSES 187
diseases have been examined with negative results. As
examples may be quoted the examinations of the water
supplies to Hamburg and Altona during the cholera epidemic,
and the water supplies to Worthing, and to the towns in the
Tees valleys, during the outbreaks of typhoid fever, which
recently occurred there. Although the Elbe was known to
be polluted with cholera excreta, the comma bacillus was
never discovered in the imperfectly-filtered river water, to the
use of which Koch and others, who investigated the outbreaks,
attributed their occurrence. At the commencement of the
second serious epidemic of typhoid fever at Worthing, two
samples of the water were submitted to bacteriological exami-
nation by Professor Crookshank. He found that they contained
far fewer bacteria than the water supplied to King's College,
and that there was a marked absence of liquefying colonies.
" There was no colony of typhoid fever bacilli, and no bacillus
to which suspicion could be attached of producing typhoid
fever." He concluded, from the results of his bacteriological
examination, " that both samples of the Worthing water rank
as very pure water." Considering that during the construc-
tion of additional works in the spring, a fissure was opened
which discharged into the wells a large volume of water,
polluted by surface drainage, and leakage from defective
sewers, and that this mixture of well and surface water
thereafter was supplied to the town, and was the water
examined by Dr. Crookshank, it is not surprising that the
results of these and other examinations were considered by
the public as "most remarkable." Chemical examinations
made from time to time also failed to detect any pollution.
The following statements, made by the Deputy Mayor of
Worthing 1 at a meeting of the Town Council, held 18th July
1893, are particularly interesting, not only as showing how
little reliance can be placed upon either the bacteriological or
1 From Report in the Sussex Coast Mercury, 22nd July 1893. Worthing
has a population of about 17,000, and during the year 1893 nearly 1500
cases of typhoid fever occurred.
1 88 WATER SUPPLIES
chemical examination of drinking waters, but also as showing
the disastrous results which may follow misplaced confidence
in these results. The Deputy Mayor, at the above meeting,
after speaking of the finding, about two months ago, of the
fissure which gave to the town an enormous additional yield
of water, said : " We congratulated ourselves upon that fissure,
but I think there is no doubt, and certainly no member of
the Sanitary Committee has any doubt, that it is to that very
fissure the whole of the difficulty we are sustaining, and have
sustained, is entirely due." He then referred to the various
chemical and bacteriological analyses which had been made,
resulting in the water being pronounced thoroughly good and
pure. Notwithstanding these results the Committee cautioned
the public that they should boil the water, and the boiling
went on until the first outbreak practically ceased. "We
were hoping," he said, " that the difficulty had ceased, and
that we were to have no more typhoid among us; but,
unfortunately, another analysis was made by Dr. Crookshank,
the water being taken from two or three different sources,
and each sample was declared to be good. Perfectly pure
were, I think, the doctor's words. Well now, to that, I am
afraid, to some extent, we may attribute the cause of the
second outbreak. It was stated publicly, with the best
intentions, to allay public excitement and the panic which
was prevailing, that the water was perfectly pure, because we
had the best evidence that it was so ; and I have no doubt
that the public, who do not like the trouble of boiling every
drop of water they drink, ceased the boiling, and thus the
second outbreak came upon us, and is still going on." It is
quite unnecessary to point the moral of this plain statement
of facts. As it has been found impossible to dam out the
water from the prolific but fatal fissure, the present source
of supply is being abandoned. A proposal to attempt the
purification of the water by filtration through sand has not
been acted upon, Dr. Thorne having brought under the notice
of the Sanitary Authority Professor Koch's experience, to
THE INTERPRETATION OF WATER ANALYSES 189
the effect that, " even under favourable circumstances, sand
nitration cannot give absolute protection against the danger of
infection." During the Tees valley epidemic, also, the water
was repeatedly examined bacteriologically. Although an
excessive number of micro-organisms was found, sufficient in
fact to qualify the opinion that the water was polluted, the
typhoid bacillus was not once discovered.
It has recently been asserted that the so-called typhoid
bacillus (Eberth's) is often absent from typhoid stools, and
that the bacillus coli communis, which is invariably found in
all stools, is capable under certain conditions (probably by
growth in cesspools and sewers) of acquiring pathogenic
properties in man. It is even, by many, believed that this is
either a degenerate form of Eberth's bacillus, or that it is
capable of taking on the same properties, and of causing the
same disease typhoid fever. Such being the case, all waters
faecally polluted may be capable of producing this disease
when all the circumstances are favourable, and therefore
must be looked upon with the gravest suspicion, whatever
the results of bacteriological or chemical analyses.
All surface waters contain large numbers of micro-organ-
isms, but freshly-drawn deep-well waters, and waters from
deep-seated springs, are almost sterile. When such pure
waters are kept for a few days, however, the number of
micro-organisms increases enormously. Professor P. Frank-
land says that such a water, containing only, say, 5 microbes
per cubic centimetre when freshly drawn, may, even if kept
in a sterile flask |nd protected from aerial contamination,
contain, after a few days, perhaps 500,000 in the same
volume, or, in other words, as many as are found in slightly-
diluted sewage. He points out, however, that whilst in
sewage the numbers only gradually diminish, in these
pure waters " after the rapid increase in numbers follows a
correspondingly rapid decline, so that the numbers again very
soon fall below those found in impurer surface waters." It
follows, therefore, that the purest water which has been
190 WATER SUPPLIES
kept a few days may be confounded with a water from the
filthiest source, and that even if the number of micro-organ-
isms found in a water is to be taken as a criterion of its
purity or otherwise, the bacteriological examination must be
made before such multiplication can have ensued. In freshly-
drawn deep-well and spring waters there should be few or
no bacteria ; in the purest mountain streams and lakes there
should not be more than a few hundreds in a cubic centi-
metre (15 drops). In ordinary river waters from 1000 to
100,000 may be found in the same volume, whilst in sewage
there may be several million. Rain, hail, snow, and ice are
not free from bacteria, though usually the number contained
therein is small.
In 1887 Professor W. R. Smith made a series of experi-
ments for the Local Government Board (vide Report of the
Medical Officer, 1887) on the differentiation and identification
of micro-organisms found in water supplies. The results
gave evidence of the multifarious character of the organisms
in question, and illustrated the need for caution against
drawing general conclusions from the results of cultivating
water organisms by any single method. In the same year
Dr. Dupre, F.R.S., reported to the Board on changes effected
in the aeration of certain waters by the life processes of
particular micro-organisms under different conditions of
temperature, light, and nutrient material, but the results
obtained seem of no practical value. " The process of oxygen
consumption was found, as might be expected, to be in-
fluenced by these circumstances, but it would not yet be
safe to formulate general inferences from the facts."
Koch, in an able article on Water Filtration and Cholera, 1
has endeavoured to set up a standard of purity based upon
the number of bacteria, capable of cultivation in certain
media, contained in a given quantity of the water. He
would regard even filtered river water containing over 100
1 Translated by J. A. Ball, Esq., and published by the Local Govern-
ment Board.
THE INTERPRETATION OF WATER ANALYSES 191
micro-organisms in a cubic centimetre as open to suspicion ;
but, as we have just seen, he does not regard such water, if
once polluted, as absolutely safe, however careful and thorough
the nitration ; but to this question we shall have shortly
to refer again. The Royal Commissioners on Metropolitan
Water Supply do not entirely concur with this conclusion.
They point out that the typhoid bacillus is, so far as is
known, only found in human excrement, and that it has
not yet been found to retain its vitality when in faecal matter
for more than 15 days; that in all ordinary waters there
exist organisms which "undoubtedly exert an influence
in diminishing the vitality of the typhoid bacillus ; that
exposure to direct sunlight destroys these bacteria ; that
they have a tendency to subside more or less rapidly in all
slowly -moving waters, and to be carried down with other
matters held in suspension ; and that there are strong grounds
for believing that small doses either of cholera or of typhoid
poison may be swallowed with impunity. Such being the
case, they fall back upon the " evidence of experience," and
whilst acknowledging that the various water supplies to
London are contaminated with sewage, which may, and often
does, contain the specific poison of typhoid fever, and may
contain the bacillus of Asiatic cholera, they " state without
hesitation, that, as regards the diseases in question, which
are the only ones known to be disseminated by water, there
is no evidence that the water supplied to the consumers
in London by the companies is not perfectly wholesome."
In other words, these polluted river waters, which have under-
gone a filtration far less perfect than that required by Koch
(since London water usually contains many hundreds of
micro-organisms in the cubic centimetre), are perfectly safe
and wholesome.
The attempt to set up a standard of purity based upon the
number of micro-organisms in a given quantity is as illogical
as the old chemical standards. Both depend upon quantity,
whilst the real point at issue is the quality. In reputedly
1 92 WATER SUPPLIES
good waters it has been observed that the micro-organisms
present capable of liquefying gelatine by their growth are
few in number, whilst in sewage-polluted waters they abound ;
but this fact is of little value, since it only enables somewhat
gross pollution to be detected, and most of these liquefying
organisms are perfectly harmless. Bacteriology, like chemistry,
may tell us something of hazard and impurity, but neither can
be depended upon to determine with certainty whether a water
is actually injurious to health. To condemn one water
because it yields a little more albumenoid ammonia than
another, or because it contains a few more organisms than
another, when we know nothing of the nature of the sub-
stance yielding the ammonia, and nothing of the character of
the organisms, is obviously so illogical as to be absurd, and
yet this is what is almost invariably done. Bacteriological,
microscopical, and chemical examinations must always be
associated with a thorough investigation of the source of the
water, to ascertain the possibility of contamination, continuous
or intermittent. Then, and then only, if everything be satis-
factory, we may be justified in speaking of safety and of
freedom from risk; but where either the bacteriological,
microscopical, or chemical examination is unsatisfactory, the
inquiry into the history of the water must be most careful
and complete, and a guardedly-expressed opinion given only
after a full consideration of the bearing of the one upon the
other. The possibility of accidental pollution is a point
too often overlooked ; yet it is to such accidental pollution
that outbreaks of disease are most frequently attributed, and
of this the examination of samples of water, prior to the
occurrence of the contamination, may tell us little or nothing.
The danger of such pollution does not, unfortunately, vary
with the amount of any constituent found in the water, and
a source yielding a water of great chemical and bacterial
purity may be more liable to occasional fouling than a source
yielding water containing excessive quantities of chlorides
and nitrates, or even of unoxidised organic matter.
CHAPTER XI
THE POLLUTION OF DRINKING WATER
IN the preceding chapters many illustrations will be found
of the ways in which water may become polluted; and in
the succeeding chapters frequent reference will have to be
made to the subject; yet it appears advisable to consider it here
somewhat systematically, since it forms a natural supplement
to the two preceding sections. From w r hat has been already
said it is evident that by far the most dangerous polluting
matters which can gain access to a drinking water are the
solid and liquid waste products cast out of the human system
and usually deposited in cesspits, cesspools, drains, and
sewers. There is a widespread and very erroneous impression
that in districts without water-closets the drainage, consisting
merely of slop water, is practically innocuous, and that it
may be disposed of in ways not admissible with ordinary
sewage. Chemically and bacteriologically, it is almost im-
possible to distinguish between the sewage of towns in which
water-closets are in general use, and of towns in which other
forms of excrement collection and disposal are adopted. In
the drainage from the former we have all the chamber slops,
the water in which soiled bed-linen, clothing, etc., have been
washed ; and both these are not only excessively foul, but
may also be specifically polluted. Both kinds of sewage,
therefore, must always be dangerous ; and every effort
should be made to prevent their gaining access to any
source of water supply.
o
194 WATER SUPPLIES
Pollution of Water at its Source.
(a) Rain and Rain Water. Rain water, if collected with
ordinary care, is never likely to be polluted with human
excrement. It frequently contains the ordure of birds, soot,
dust, and decaying vegetable matters, which have accumu-
lated during the dry weather on the collecting area, and
all of which are more or less objectionable ; but I know
of no instance in which the use of such rain water has
caused disease (vide Chapter II.). These constituents usu-
ally render the water so unsightly and unpalatable that no
one will use it until after it has been filtered or boiled ; and
this may account for the absence of any deleterious effects.
Such rain water, when kept, appears to undergo some
process of fermentation and self-purification, which renders it
again bright and fairly palatable. When collected by aid of a
"separator," so as to prevent the first washings of the roof or
other collecting surface passing into the reservoir or tank,
and when properly stored, the rain furnishes probably the
safest of all waters for drinking purposes.
(b) Surface and River Waters. Water collected from un-
inhabited moorland or mountainous districts may contain
vegetable matter, but will be free from animal pollution.
If from cultivated land, manurial matters, more or less
changed by oxidation, will gain access to the water. As
human excrement is constantly employed as manure, the
pollution may be of a dangerous character. In such districts
also there must be human habitations, farmyards, etc. ; and
unless special precautions are taken, the drainage from these
will contaminate the water. Cesspits and cesspools are
frequently so defectively constructed as to permit of the
contents being washed out by heavy rains; or they may
overflow into ditches, and the filth be carried into the
nearest watercourse. During dry seasons such streams may
receive but little polluting matter, whilst in seasons of flood
the accumulated filth of months may be carried into them.
THE POLLUTION OF DRINKING WATER 195
In too many instances the whole of the sewage of towns is
discharged bodily into rivers which are used a few miles
lower down as the water supply to other towns and villages.
No doubt in the course of transit from point to point much
of the solid matter is deposited on the sides and bottom of
the river, and some of the dissolved filth is oxidised or
otherwise destroyed ; but it is open to question whether any
river in this country is sufficiently long for this process of
self-purification to be complete, and for the water to become
absolutely free from danger. With every flood the deposited
filth is disturbed and carried downwards ; and unless due
provision has been made for tiding over these periods without
having to abstract the turbid water, seriously-polluted water
may have to be used, and if the filtration be not perfect,
serious consequences may ensue. Many outbreaks of typhoid
fever have been attributed to the use of such waters. For
long periods the consumption of the water may have produced
no injurious effects ; but an exceptional flood or the failure
of a filter bed at a critical period may result in a serious
outbreak of disease. Examples of epidemics so produced
have already been referred to. No doubt the danger arising
from the introduction of sewage into a stream supplying
drinking water varies with the proportion of sewage to the
volume of water into which it is discharged ; but, however
small this proportion, it cannot be said that the degree of
dilution is sufficient to render the water entirely safe. When
sewage has been purified by chemical treatment or by fil-
tration through land, doubtless the danger is reduced to a
minimum, but there is always the risk of imperfectly-
purified sewage being carried into the stream. That the
effluent from a sewage farm may pollute a drinking water
in such a way as to cause disease seems probable from the
report on the outbreak of typhoid fever at Beverley already
mentioned. It is true that in this case the water contaminated
was derived from a well ; but had the effluent found its way
into a stream used as a water supply, it is not improbable
196 WATER SUPPLIES
that the result would have been the same (vide Chapter XII.,
on the " Self-purification of Rivers ").
(c) Subsoil Water. In thinly-populated districts the sub-
soil water may be absolutely free from any trace of sewage
contamination. In populous districts, on the other hand, a
considerable amount of sewage must gain access to the subsoil.
Fortunately, however, the " living " earth possesses such puri-
fying properties that the filth may be rendered perfectly
powerless for evil. In fact, Koch has given it as his opinion
that " the subsoil water gives us absolute security with respect
to the danger of infection, and it should, therefore, if it can
only be obtained in sufficient quantity, and if it is not objected
to on account of chemical characteristics, e.g. too great
hardness, or too great an admixture of chloride, be preferred
under all circumstances to surface water. I indeed hold it
even to be desirable, and in some cases even necessary, that
works already constructed to filter river water should be so
changed as to be used for obtaining subsoil water." As most
subsoil waters have received an admixture of sewage, how is
it that such a careful observer as Koch can regard it as under
all circumstances preferable to surface water? The fertility
of soil depends upon the presence of organic matter, vegetable
or animal, undergoing decay. This decay is almost entirely
due to the action of micro-organisms, which produce nitric
and carbonic acids, without the former of which the soil
would be practically barren. The decomposition of organic
matter appears to take place in three stages. First, ammonia
is produced, and this probably by the action of several species
of bacteria ; next, the ammonia is converted into nitrous acid
by an organism discovered simultaneously in 1890 by Frank-
land and Winogradsky ; finally, another organism has been
proved by Warington and Winogradsky to be the cause of
the conversion of the nitrous into nitric acid. In rainless
districts nitrates accumulate upon the surface, immense
deposits being found in Chili, Peru, and various parts of
India. In other regions the nitrates so formed are dissolved
THE POLLUTION OF DRINKING WATER 197
by the rain and carried to the roots of plants, and serve for
their nourishment. The proportion not so utilised by plants
as food passes into the subsoil water. All the organisms
above referred to are found most abundantly in the first few
inches of soil, the numbers decreasing rapidly with the depth,
until at a few feet from the surface they are no longer to be
detected. Where the surface is covered with vegetation, the
decomposition of dead organic matters is so complete, and
the amount of nitrate extracted so large, that no undecomposed
organic matter and little of the products of its decay reaches
the subsoil water. Moreover the undisturbed soil constitutes
one of the most perfect of filters; hence subsoil water, if properly
collected, is one of the purest of waters, providing the mineral
ingredients of the subsoil are not too soluble, or are not of
an otherwise objectionable character. In towns and villages
where there are aggregations of houses, or even in the prox-
imity to single cottages, the surface soil may be so denuded
of vegetation that this process of decomposition may not be
complete, and unchanged or only partially changed filth may
be washed through into the ground water. Where the filth
escapes from defective drains, cesspools, and cesspits, this is
still more likely to be the case ; hence water obtained from
wells in proximity to such defective sanitary arrangements
must be polluted. In towns and villages, especially where
such defects are common, the whole of the subsoil water over
a large area may be contaminated. Doubtless, even here
the filtering powers of the earth are most marked, otherwise
outbreaks of disease would be much more frequent amongst
communities using such water; but the "records of every
medical officer of health prove that this filtration cannot
always be depended upon to remove the germs of disease.
A heavy rainfall, either by carrying the filth through with
unusual rapidity, or by causing the ground water to rise into
the more polluted soil above, may carry these organisms into
the wells, and so produce an epidemic. Where wells are
improperly constructed and allow of water entering at or near
198 WATER SUPPLIES
the surface, the danger is greatly accentuated. Where they
are open at the ground surface, or where the covering is
defective, heavy rains may wash the filth directly into the
water. The great difficulty experienced in constructing wells
so as to exclude impure surface water leads Koch to conclude
that "Wells, constructed no matter how, should not be
tolerated in future " (vide Chapter IV.). Koch's remarks,
therefore, do not apply to ground water as derived from wells
of any kind. It must also be remembered that where the
subsoil is full of fissures, impurities may be carried along
such channels for considerable distances and contaminate the
drinking water at a point far from where the polluting matter
enters the ground. Thus the epidemic of typhoid fever at
New Herrington was proved to be due to the drainage from
a farm three-quarters of a mile away from the well, the
channel of intercommunication being undoubtedly the fissures
in the rock forming the subsoil.
The natural level of water in a shallow well is that of the
plane of saturation of the subsoil, A, C. When the level of the
water in the well is lowered by pumping, an area of ground
around is drained, the extent of this area depending upon
the porosity of the soil and the depth to which the water is
abstracted. The ground drained has the form of an inverted
cone, with a rapidly-increasing gradient towards the well, E
(Fig. 13). The drainage area has been found by experi-
ment to have a radius ranging from 15 to 160 times that
of the depression due to pumping ; hence polluting matters
gaining access to the subsoil within this area will flow into
the well. The extent of the drainage area varies with the
porosity of the soil ; where the soil is dense and but slightly
pervious the area may not exceed 15 times the depth of the
Avater in the well when at its highest level, whereas where
the subsoil is exceedingly porous the area may be 160 times
this depth. As in most cases the subsoil water is travelling in
a definite direction, if the point of pollution, B, be where the
plane of saturation is higher than that around the well, and
THE POLLUTION OF DRINKING WATER
199
the latter is in the line of flow of the subsoil water from
where the pollution enters, it is tolerably certain to gain
access to the well, either continuously or occasionally, when
the level of the ground water rises above a certain height.
If the sewage or other polluting matters enter the subsoil at
the other side of the well, the risk of contamination is greatly
FIG. 13.
diminished. Hence in districts where the ground water is
polluted locally the position of the well is of considerable
importance.
The prevalence of malarial diseases, enteric fever, and
cholera is believed by many sanitarians to be influenced
largely by the rise and fall of the ground water. Frequently,
in India, outbreaks of malaria have followed a rapid rise in
the ground water, due to heavy rainfalls, and the epidemics
may have been due to the contamination of the wells by the
filth carried down by the rain. Pettenkofer, at Munich,
200 WATER SUPPLIES
found that enteric fever was most fatal when the subsoil
water was lowest, and especially when the fall had been rapid
and from an unusual height. Fodor, at Buda-Pesth, found
exactly the opposite condition to obtain, the enteric fever
mortality rising and falling with the ground water ; and this
connection between the height of the subsoil water and the
prevalence of enteric fever has been observed from time to
time in this country. Where this has occurred, the explana-
tion which suggests itself is, that the water became more
and more polluted with the rise in level, and this is the
generally -accepted opinion in this country; but there are
many eminent observers both here and on the continent who
do not accept this explanation. Pettenkofer also regards
cholera as a disease, the spread of which is largely influenced
by the movements of the subsoil water. Even if such is the
case, which is by no means generally admitted, it may be
that the effect is due rather to the varying extent to which
the water becomes polluted, rather than to the fouling of the
ground air by the decomposition of the organic matter and
the active growth of specific organisms in the damp soil left
by the falling ground-water.
Springs fed by subsoil water will be affected in quality in
the same way as the water in wells, but only rarely to the
same extent. Such springs usually drain considerable areas,
and therefore, unless the pollution arises near the source of
the spring, the dilution will be great, and during the period
which must elapse between the impurity entering the ground
and its reaching the outlet, time will have been allowed for a
more or less complete oxidation of the organic matter in the
pores of the soil, and for a more or less complete filtration to
have occurred. Baldwin Latham found that at Croydon,
which is supplied with water from springs in the chalk, measles,
whooping-cough, and diphtheria were more prevalent during
wet seasons, when the ground-water level was high, and that
typhoid fever and small-pox were liable to become epidemic
when heavy rains followed a prolonged drought. In rural
THE POLLUTION OF DRINKING WATER 201
districts springs are frequently fouled by cattle, and by the
rainfall, if heavy, washing filth into the dipping places, since
the springs are not properly protected. Land springs, fed by
thin beds of sand, or gravel, or light porous soil of any kind,
are especially liable to be seriously affected by manure spread
upon the surface of the ground, and if this manure contain
human excrement the danger is greatly enhanced. In a
recent outbreak of typhoid fever which I investigated, and
which affected a small group of cottages, I found that the
excreta from a mild case of this fever had been discharged
into a defective privy cesspit sunk in the porous soil within
a few feet of the land spring which supplied the cottages.
When slop water, the contents of earth closets, etc., are
properly disposed of by spreading upon a sufficiently large area
of garden or other cultivated ground, the danger of specific
pollution of the ground water is reduced to a minimum.
Where the sewage escapes from defective drains at some
depth from the surface, and excremental filth oozes through
the sides of cesspools and cesspits sunk in the ground, the
danger of pollution is considerable, and increases with the
proximity of these defects to the point from which the sub-
soil water is abstracted. The model bye-laws of the Local
Government Board require not only that the drains, cesspits,
and cesspools shall be so constructed as to prevent any such
leakage, but also that the two latter shall not be constructed
within a certain distance from "any well, spring, or stream
of water used, or likely to be used, by man for drinking or
domestic purposes, or for manufacturing drinks for the use
of man." Under ordinary circumstances the distance from
a privy should be not less than 40 to 50 feet. Cesspools
being still more dangerous, the minimum distance from a
well should not be less than 60 to 80 feet. Since dust and
debris, when being cast into ashpits, may be blown about, and
so gain access to a well or stream supplying drinking water,
no ashpit should be less than 30 to 40 feet from the
water supply. The proper paving of yards, of pig-styes,
202 WATER SUPPLIES
stables and cowsheds, of slaughter-houses, of business
premises, especially where offensive trades are carried on,
efficient drainage and sewerage, and a proper system of
sewage disposal, are all necessary, not only for preventing the
pollution of the ground water, but also of the ground air, the
condition of the latter being probably as important a factor
in determining the salubrity or otherwise of a locality as the
condition of the former. The burial of the carcasses of
animals near a well may cause pollution of the water, and it
is believed that anthrax may be spread amongst cattle by the
use of water contaminated by the decomposing bodies of
other animals which have died from that disease. The
proximity of a graveyard to a source of water supply is
certainly undeMrable; but if the direction of flow of the
ground water be from the well towards the graveyard,
danger will only arise when, by pumping, some of the graves
are brought within the drainage area. If the distance from
the graves to the well be sufficient to exclude the former
from the drainage area of the latter, however heavy and
continuous the pumping required for the supply of water,
there will be little or no danger of contamination from this
source. If, on the other hand, the flow of water be from
the graveyard towards the well, or the well be within
the drainage area above described, the supply will almost
certainly be contaminated. Such waters, and waters from
the neighbourhood of battlefields, have frequently given
rise to dysenteric diarrhoea amongst the populations con-
suming them.
It is well known that the earth around gas mains acquires
an offensive and peculiar odour. Where the mains are
defective this smell is most marked and perceptible at a
great distance from the pipes. It may even reach the
ground water and taint the wells. In 1884 the wells in the
Clarence Victualling Yard at Portsmouth had to be closed on
account of the impregnation of the water with coal gas which
had escaped from the leaky mains traversing the yard. "In
THE POLLUTION OF DRINKING WATER 203
Berlin in 1864, out of 940 public wells, 39 were contamin-
ated by admixture with coal gas" (Parkes).
(d) Deep- Well Water. The pollution of deep-well water
very frequently arises from defects in the construction of
the well. If the sides are perfectly impervious and the
top properly protected, the access of surface water will be
entirely prevented ; where these conditions do not obtain the
water may become contaminated. As will be seen, when
the construction of deep wells is being considered, it is often
exceedingly difficult to keep out water from the more super-
ficial water-bearing strata, which may have to be pierced in
order to reach the pure water in the rocks below. A striking
instance of this fact will be found in the account of the
fatal outbreak of dysenteric diarrhoea at the Melton Asylum
(Chapter IX.). The water tapped by the deep well may itself
be impure, especially if the water-bearing rock be fissured
and the outcrop be in an inhabited district. If the fissures
are open or only contain freely -permeable rocky debris,
polluting matters may travel considerable distances. Several
instances of such pollution have already been referred to. 1
Pollution of Water arising during Storage. Reservoirs
fed by springs and streams, if not provided with some
arrangement for excluding storm water, may be contaminated
by filth carried down by the floods. When rivers are in
flood, the impurities which had deposited on the bottom and
sides, and which may contain the specific organisms of
enteric fever, and possibly of cholera and other diseases, are
disturbed and become suspended in the water, and if allowed
to pass into the storage reservoirs may lead to an outbreak
of disease, especially if the filtering arrangements at the time
are not in perfect working order. Many extensive epidemics
of enteric fever have been attributed to the use of water so
polluted. At Ashton-in-Makerfield a recent outbreak of
typhoid fever was attributed by Dr. Wheatley, the Local
Government Board Inspector, to the pollution of the water in
1 Vide also note in Appendix.
204 WATER SUPPLIES
the reservoir by the manuring of the ground immediately
surrounding it with the contents of the privies and middens
of the town. Surface water from these fields actually drained
directly into the reservoir. The growth of certain vegetable
organisms in open reservoirs may result in the production of
odorous substances affecting the whole of the water. These
have been already referred to in a preceding chapter.
Covered service reservoirs may have an overflow connected
with a sewer by means of a trap. If for a lengthened period
the water level never rises sufficiently high to reach the
overflow, the evaporation of the water in the trap might
unseal the latter and allow of sewer air gaining access to
the water in the reservoir. Of course the overflow should
discharge in the open air and at some little distance from
a trapped gully communicating with the sewer. Overflow
pipes from house cisterns have frequently been the cause of
the contamination of the water stored therein, from being
directly connected with soil pipes or drains, and outbreaks
of disease have been attributed to the use of such water.
House cisterns also are often placed in situations which
render the water liable to pollution. Even at the present
day it is not uncommon to find such a cistern within a water-
closet. Usually they are placed in inaccessible corners and
left uncovered. In a large institution, recently, a series of cases
of erysipelas and diphtheria led to the examination of the
drainage, water supply, etc. The water drawn from the
taps within the buildings was found upon analysis to show
signs of pollution, whereas the water from the main before
entering the premises was free from suspicion. When the
cistern was examined, it was found to contain a considerable
amount of filthy - looking sediment and the decomposing
bodies of a rat and bird. When the cistern had been
thoroughly cleaned the \vater from the taps was as pure as
that from the main. Where the house cistern supplies
directly the water used for flushing the closets, there is
always a danger of air from the closet pan finding its way
THE POLLUTION OF DRINKING WATER 205
into the cistern. All these defects admit of simple remedies.
The overflow pipe should terminate in the open air ; the
water-closet should be flushed from a separate cistern ; the
house cistern, if it cannot be dispensed with, should be
tightly covered, placed in an easily accessible situation, and
kept perfectly clean.
The materials of which tanks and cisterns are composed
may contaminate the water. New bricks, cement, and
mortar give up certain substances to the water stored therein,
and if the cement and mortar contain road-scrapings, the
dissolved substances may not be of an entirely innocuous
character. In rural districts no new house can be inhabited
until the owner has obtained from the Sanitary Authority
a certificate to the effect that it has within a reasonable
distance a wholesome supply of water. In the discharge
of my duties I have frequently to examine water from
recently -constructed wells, which, from their position and
my knowledge of the character natural to the subsoil of the
locality, should have been of satisfactory quality. I usually
find that such waters are excessively hard, and give indica-
tions of the presence of organic impurity. The hardness, I
find, is due to the salts given up by brickwork, mortar,
and cement, whilst the organic matter is in part derived
from the wooden curb at the bottom of the well ; but I am
strongly inclined to believe that it is in greater part derived
from road-scrapings which have been mixed with the bonding
and lining material. The water in such wells gradually
improves in quality as the soluble matters are exhausted.
Tanks made for storing rain water, if lined with cement,
may cause the water to be very hard even for a prolonged
period. Underground tanks, if not properly constructed and
covered, may admit impure surface and subsoil water.
Waters of less than 1 of temporary hardness dissolve to a
slight extent both lead and zinc, and therefore will act more
or less freely upon cisterns lined with these metals. Waters
with a temporary hardness of 1 to 3 may at first attack
206 WATER SUPPLIES
a leaden cistern ; but the surface gradually becomes covered
with a thin white, opaque deposit, which protects the metal
from further action. If the surface be now scoured, the
lead is again attacked. Decomposing organic matters and
the presence of air are believed to increase the plumbo-solvent
action of a water ; hence, if stored in a dirty cistern, it may
dissolve lead more freely from the sides thereof than from
the surface of a clean leaden pipe. Roques, 1 in a paper
on "The Perforation of Zinc Cisterns and the Corrosion of
Lead Pipes by Water," states that zinc and galvanised iron
cisterns are not corroded uniformly but in well-defined
places, which fact he attributes to the galvanic action set
up between purer and more alloyed portions of the metal.
The presence of nitrogenous matters and ammonia he found
to accelerate the action, especially in the case of zinc. The
action was also most marked in the presence of oxygen, and
at the surface where the metal is alternately in contact with
water and air. Waters of over 3 of temporary hardness
may with safety be stored in either galvanised iron or leaden
cisterns. Wooden water-butts are an abomination. Under
all circumstances wood is a most unsuitable material of
which to construct receptacles for storing water; it gradu-
ally rots and gives up organic matter to the water, and
encourages the growth of worms and other low forms of life.
Pollution of Water arising during Distribution. Water,
whilst in the mains and service pipes, may be affected in
quality either by its action upon the materials of which the
pipes are constructed, or by the insuction of gaseous and
liquid impurities.
Cast iron is powerfully acted upon by soft waters. Hence,
if such waters are distributed through mains of this material,
the surface of the pipe becomes corroded, and the water, carry-
ing with it a little of the rust in suspension, becomes more or
less turbid and unsightly. The rust which forms being much
more voluminous than the iron from which it is produced,
1 Bulletin de la Societe Chimique de Paris, 5th June 1880.
THE POLLUTION OF DRINKING WATER 207
forms concretions on the sides of the pipes, gradually decreas-
ing the calibre, until they are no longer capable of conveying
a sufficient quantity of water, or until the metal is so de-
creased in thickness as to be easily perforated or fractured.
By using pipes which have been coated inside and out with
Angus Smith's varnish (of pitch and coal-tar oil), this
corrosive action is almost entirely prevented. The common
method of "jointing" water mains has frequently led to
deterioration of the quality of the water. Tow or gaskin is
used for calking the joint, to prevent the molten lead running
into the interior of the pipe, and at each joint therefore more
or less tow is exposed to the action of the water. In a long
main this may impart a peculiar odour and taste to the water,
due to the organic matter which it has dissolved. The Rivers
Pollution Commissioners in their 6th Report, page 222, state
that these hemp-stuffed joints afford a nidus for the breeding,
development, and decay of animalcule; so that the deteriora-
tion of the water is for a year or two very great, and
continues to be perceptible even after the lapse of many
years. As an example of the fouling of water from this
cause, the case is quoted of the inquiry held by the Board of
Trade in 1869 on account of the complaint of the inhabitants
of Putney and Wandsworth, that the water supplied by the
Southwark and Vauxhall Company was bad and unfit for
domestic purposes. It was found that the water was derived
from a recently-laid main, 9J miles in length, with over 4000
tow-calked joints. The result of the inquiry showed that
"the evil complained of was due chiefly, if not entirely, to
the deleterious influence of the tow used in packing the joints
of the main." Analysis proved that a marked quantity of
organic matter was taken up by the water from the tow.
The small service pipes are usually of lead or galvanised
wrought iron, both of which may affect the water if, as we
have previously observed, the temporary hardness be very
low. Unfortunately, the water which acts upon lead also
acts upon zinc; hence one cannot be substituted for the other.
208 WATER SUPPLIES
As zinc, unlike lead, is apparently not a cumulative poison,
galvanised iron may be used instead of lead, as possibly the
lesser of two evils. In many cases the lead pipe becomes
tarnished and encrusted, and then is so slightly, if at all,
affected by the water passing through it, that it may be used
without appreciable risk. Glasgow is supplied with Loch
Katrine water, which has a hardness of less than 1, and
lead service pipes are in general use ; yet lead poisoning is
unknown in that city. The Manchester water supply is
very similar in character, but few cases of lead poisoning
have been observed, and they were probably confined to
persons who had drunk water conveyed through new
service pipes. Both the Manchester and Glasgow waters
act powerfully on both tarnished and untarnished lead.
Professor W. A. Miller, F.R.S., in his evidence before the
River Commissioners on Water Supply, gave it as his opinion
that such waters as that from Loch Katrine, when passed
through a pipe continuously, paint, as it were, the inside with
a deposit of vegetable matter, which combines with the oxide
of lead, and so forms a closely adherent film, which prevents
all change. The experience of Glasgow and Manchester has
been very different to that of the majority of towns using
soft moorland water. As an example of the more usual
results following the use of these waters, the experience
of Pudsey may be cited. The Medical Officer of Health, Dr.
Lovell Hunter, in his report for 1892, says, "The Local
Board in 1892 bought the plant of the Calverley District
Water Company. The moorland water supplied is soft and
organically pure, but often unsightly, from the presence of
peat. It has, however, two serious defects : it is too dear a
fact that interferes with the quantity used, and it takes up
lead from the service pipes." To remedy the latter evil, 3
grains of chalk were mixed with each gallon of water, com-
mencing in July. The water, which prior to this date had
contained, when delivered through the service pipes, from
"2 to '9 grain of lead per gallon, was afterwards found to
THE POLLUTION OF DRINKING WATER 209
yield only from '07 to '35 grain, according to the length of
the service pipe. The use of this water soon produced a
serious effect upon the health of the inhabitants. In a letter
received from Dr. Hunter, he says, "Anaemia and debility
were the most common symptoms. The debility was
peculiar ; the patients nearly always complained that they
felt as if they would sink down from weakness, and that the
least exertion made them sweat freely. When the poisoning
was at its worst, I think I may safely say that the majority
of the people had the blue gum line (so characteristic of lead
poisoning) without any other sign of poisoning. Colic was
also a common symptom. Paralysis was not common, but
we had five or six cases of what may almost be called general
paralysis, so helpless were the patients ; and in these cases
drop-wrist was included, but I only heard of one case of
drop-wrist by itself. Lead poisoning is a complaint which
may imitate almost any other complaint, and it is a practical
point to know that we had it rampant in this district, and
doing immense damage to health, without recognising what
we were dealing with." Well waters also may be affected
by the lead piping attached to the pump. This is especially
the case with waters from the Bagshot sands, which appear
to contain very little carbonate of lime. In several parts of
my districts, where the water is derived from these beds, a
trace of lead can be found in all the supplies drawn through
a leaden suction pipe. The River Pollution Commissioners
mention that some polluted shallow- well waters not only act
upon lead violently, but continuously, and that several
instances of poisoning from the use of leaden pump pipes
had come to their knowledge. The one analysis given of
such a water shows that it was far purer than the average of
shallow-well waters, but that the temporary hardness was
under 1. When a galvanised iron pipe was substituted for
the leaden one, the water, as might have been expected from
its composition, became charged with zinc, and zinc poisoning
followed the lead poisoning. The so-called tin-lined lead
p
210 WATER SUPPLIES
pipes also yield lead to the water, inasmuch as the tin in the
process of lining becomes alloyed with the lead.
As previously stated, water which acts upon lead will also
attack the zinc coating of galvanised iron. A case of poison-
ing from this cause recently came under my notice. The
water supply to a newly-erected country house was derived
from a spring arising at the edge of a patch of Bagshot
sand. The water was piped from this spring to the house,
a distance of half a mile, through galvanised iron pipes.
The only child, who, prior to the removal into the new house,
had been perfectly healthy, became a sufferer from obstinate
constipation. At length suspicion rested upon the water
supply, probably because an iridescent film always formed on
its surface when exposed in open vessels, or when heated in
an open pan. (This film is very characteristic of the presence
of zinc, and is often put down to a trace of oil or grease.)
Upon analysis I found that the water contained about 3
grains of carbonate of zinc per gallon. When the water
supply was changed, the constipation ceased. Many months
after I again examined the water, which had been allowed
to flow freely through the pipe, in the hope that it would
speedily dissolve off the whole of the zinc ; but it still con-
tained too large a quantity to be considered safe for domestic
use. Dr. Heaton, in the Chemical News (22nd Feb. 1884),
gives an analysis of a water from near Llanelly, which is
carried for half-a-mile through galvanised iron pipe. It was
found to contain over 6 grains of carbonate of zinc to the
gallon. Unfortunately the degree of temporary hardness is
not stated, nor the reason why the Medical Officer sent it for
analysis. Dr. Venables, in the Journal of the American Chemi-
cal Society, 1 gives the analysis of a spring water which, after
passing through 200 yards of galvanised iron pipe, and after
being in use a year, contained over 4 grains of zinc carbonate
per gallon. The temporary hardness in this case was under
1. He concludes that, "when the dangerous nature of zinc
1 Reprinted in Chemical News, 5th January 1885.
THE POLLUTION OF DRINKING IV ATE R 211
as a poison is taken into consideration, the use of zinc-
coated vessels in connection with water or any food liquid
should be avoided." Wooden pipes, which were formerly
used for conveying water, are quite unsuited for the purpose,
chiefly on account of the defective joints. They are also
said to rot and contaminate the water, but specimens of such
pipes, now in the Hornsey Museum, and which had been in
use in London for probably two centuries, show no signs of
rotting.
The insuction of polluting matters into water mains, and
the danger arising therefrom, does not seem to have received
the attention it deserves. When the water supply is shut
off, as is done periodically where the supply is intermittent,
and occasionally, for various reasons, where the supply is
constant, it is obvious that little or no water can be drawn
from the mains at any point without air or water being
drawn in at other points, as at unturned taps, ball hydrants,
defects in joints, perforations through pipes, etc. Where
water-closets are flushed directly by a tap from the service
pipe, should this tap be defective or not turned off, air, and
possibly filth, may be drawn into the pipe from the closet
pan. To an accident of this kind Dr. Buchanan attributed
the outbreak of typhoid fever at Caius College, Cambridge.
The same medical officer, when investigating the cause of the
prevalence of typhoid fever at Croydon in 1875, made a
series of experiments of a very interesting character. He
was partly led thereto from the recorded incident of bloody
water being drawn from a tap at a house next door to a
slaughter-house. He put into a closet pan sufficient burnt
sugar to colour some thousand gallons of water. This pan
was flushed with a stool tap. During the intermission of
the water supply the whole of the burnt sugar solution was
drawn into the mains, and, strange to say, only from one
house was a complaint received of the discoloration of the
water. Most of the colouring matter must therefore have
travelled a considerable distance along the mains, and have
212 WATER SUPPLIES
become very largely diluted before reaching the consumers.
The balls in ball hydrants fall when the water pressure is
reduced in the mains by drawing water after the supply has
been turned off at the works. The boxes are usually placed
below the ground level as a protection from frost, and are
generally found filled with dirt w T hich has washed in from
the roads. Dr. Kelly, who investigated an outbreak of
typhoid fever which occurred at West Worthing in 1893,
attributed it to the pollution of the water in a certain main
by the insuction of filth from these hydrant boxes. 1 He
examined many of these hydrants before the morning pump-
ing had begun, and found most of the balls down, and most
of the boxes half full of mud. "It is obvious," he says,
" that any surface or road filth may thus enter the mains in
wet weather, and a person may drink impure water which
has been fouled at a distant point." Where the water mains
are defective, the insuction may take place through the
apertures in the pipes or joints. Gas, emanations from
sewers, foul ground air, and the water which had previously
escaped from the main when under pressure, may be drawn
into the pipe during the intermission in the supply. Sewage
from leaky drains and sewers has in this way gained access
to the water mains, and several serious outbreaks of typhoid
fever have been attributed to this cause. The serious and
continued epidemic of typhoid fever at Mountain Ash
(Glamorganshire) in 1887 was attributed by Mr. John Spear,
who investigated it, to the pollution of the water in a certain
branch main, and the distribution of the disease led him to
predict almost the exact spot where the contamination took
place. When the main at this point was laid bare it was
found to be laid alongside and even through old rubble
drains, and the main itself was here defective. He had
1 Hydrants of this character cannot be too strongly condemned. It
was subsequently found that water from the specifically polluted mains
supplying Worthing proper had been used for watering the streets in
West Worthing.
THE POLL UTION OF DRINKING WA TER 2 1 3
" opportunities of observing how considerable was the suction
of air into the pipes at certain points after intermission of
supply, and, on its renewal, how much air, coming with much
noise and force, had to be expelled," proving that during
intermissions of the service large contamination of the water
of the special main must have occurred.
Where water mains are directly connected with the sewers
in order to supply water for flushing purposes, there is
always a danger of sewer air gaining access to the mains ;
hence such a mode of flushing should be discontinued.
Not only is polluting matter drawn into service pipes and
mains during intermissions in the supply, but even when the
pipes are running full such insuction is possible. Our
knowledge of this subject is entirely due to Dr. Buchanan's
investigations, made in connection with the Croydon epidemic,
previously referred to. He found " (1) The lateral in-current
is freely produced when the water pipe is descending, and
when the pipe beyond the hole is unobstructed ; (2) If the
force of water-flow in a descending pipe be moderate, a
moderate degree of obstruction beyond the hole does not
prevent the in-current ; (3) In horizontal pipes of uniform
calibre, when the flow is strong, or the pipe beyond the hole
is long, or when the end of the pipe is at all turned upwards,
the in-current does not take place ; but (4) Momentary inter-
ference with flow a tergo, or momentary reduction of obstruc-
tion a fronte, allows a momentary in-current through the
hole ; (5) In-current through a lateral hole takes place with
incomparably greater ease when the hole is made at a point
of constriction of the water pipe."
Potable water may also be contaminated by the barrels,
skins, etc., in which it is conveyed, when distributed by these
means. Where the supply is not laid on to the houses it is
often stored in buckets, open jars, tubs, and other vessels, which
may be unsuitable from the difficulty of keeping them clean,
or on account of the material of which they are composed. The
water in them may also be exposed to foul emanations from
214 WATER SUPPLIES
drains, closets, accumulations of filth, or to dust from the
proximity to ash-places, and so become polluted. In eastern
countries many holy wells and pools from which pilgrims
drink are defiled by the water being poured over the people
and being allowed to run back into the well or pool, or by
the pilgrims actually bathing in the water. In these coun-
tries also the tanks which contain the drinking water are
often used for rinsing clothes and for bathing purposes.
Such modes of pollution rarely occur in this country, but
people have been known to bathe in reservoirs used for
supplying drinking water, and dogs are sometimes drowned
therein.
From the multitude of ways in which water may be
polluted at its source, during storage, during its passage
through the mains, and within the premises which it supplies
it follows that not only must the utmost care be exercised
in the construction of works, and in the distribution of the
water, but that this must be supplemented by a vigilant and
continuous supervision over every detail, if the purity of the
supply is to be kept above suspicion.
THE SELF-PURIFICATION OF RIVERS
IN previous chapters frequent reference has been made to
this subject ; but it is one of such far-reaching importance as
to merit special and separate consideration. For all practical
purposes the materials polluting our streams may be divided
into two groups the waste products of manufacturing pro-
cesses, and the contents of drains and sewers, the latter
being by far the more dangerous. When the contaminating
matters from factories become so diluted by the water into
which they are discharged, or the water, after receiving it,
undergoes such a process of self-purification that it presents no
evidence of pollution to the senses, and chemical analysis
reveals nothing objectionable, there is no risk incurred in using
it for drinking purposes. Where the material which fouls the
river contains the waste products of human life, of the body
in disease and health, in other words, when sewage is the
polluting matter, this condition no longer obtains. Ample
proof has been already adduced of the fact that dilution and
purification may have taken place to such a degree that the
most careful analysis can detect no element of danger, yet
that the water may be practically poisonous and capable of
causing most serious epidemics of disease. The question in
which we are interested therefore is, not whether a fouled
river- water may regain its pristine appearance of purity, but
whether it can ever again become absolutely safe for drinking
purposes. Ordinary observation enables us to answer the
216 WATER SUPPLIES
first question in the affirmative; all the researches of chemists
and bacteriologists since the days when the Rivers Pollution
Commissioners first experimentally studied this subject, have
failed to answer the second. On the one hand, we have
the Commissioners of Metropolitan Water Supply so satisfied
that sewage-polluted river water can be rendered safe for
human consumption that they recommend the metropolis to
draw still further from this source, and on the other we
have the Massachusetts State Board of Health about the
same time reporting that the results of their investigation of
repeated outbreaks of typhoid fever in cities using such
waters served to confirm the truth of the saying that " no
river is long enough to purify itself." It will be remembered
that the Rivers Pollution Commissioners came to the con-
clusion, from the results of their experiments, that " there is
no river in the United Kingdom long enough to effect the
destruction of sewage by oxidation." The experiments and
observations upon which this opinion was based are recorded
in their 6th Report, and have now become historical. Ex-
perimenting first with the Irwell and Mersey, rivers so
notoriously polluted by sewage and other refuse organic
matters that " ordinary aquatic life is entirely banished from
their waters," they found, after making all possible correc-
tions for dilution, etc., that in the Irwell a flow of 11 miles
reduced the organic carbon by to 2 9 '6 per cent, and the
organic nitrogen by to 11 '8 per cent. In the Mersey, a
flow of 13 miles reduced the former by to 20'8 per cent,
and the latter by 1 3 -2 to 17 '9 per cent. Selecting the Thames
as a much less polluted river, samples were taken about a
quarter of a mile below where it is joined by the Kennet, and
again just above the Shiplake Paper Mills. These points
were selected because in the four intervening miles the river
does not receive any other affluent or pollution of im-
portance. The analytical results showed that even under
very favourable circumstances the reduction in the proportion
of organic matter was very small, " so minute indeed that,
THE SELF-PURIFICATION OF RIVERS 217
even assuming it to go on at the same rate by night and
day, in sunshine and gloom, it would require a flow of 70
miles to destroy the organic matter." To exclude certain
elements of uncertainty, diluted London sewage was next
experimented with. It was agitated with air and then
allowed to syphon in a slender stream from one vessel
to another, exposed to light, and falling each time
through 3 feet of air. The results indicated approximately
the effect of oxidation which would be produced by the flow
of a stream containing 10 per cent of sewage for 96 and 192
miles respectively, at the rate of 1 mile per hour. By the
flow of 96 miles the organic carbon was reduced by 6 '4 per
cent, and the organic nitrogen by 2 8 '4 per cent, whilst the
flow of 192 miles reduced the former 25 - 1 per cent, and the
latter 33 '5 per cent. Fresh urine and deep chalk- well water
were next mixed together and submitted to similar treatment.
Still less effect was produced ; the carbon was but slightly
reduced, whilst the nitrogen showed an actual increase.
Finally, the results were checked by the examination of the
gases dissolved in dilute sewage (5 per cent) after standing
for different periods in accurately-stoppered bottles exposed
to diffused daylight at a temperature of about 17 C. The
dissolved oxygen gradually disappeared, but so slowly that
" so far from sewage mixed with twenty times its volume being
oxidised during a flow of 10 or 12 miles, scarcely two-thirds
of it would be so destroyed in a flow of 168 miles, at the
rate of 1 mile per hour, or after the lapse of a week."
WeigM of dissolved Oxygen in
100,000 parts of Water.
946 Immediately after Mixture
803 After 24 hours
616 48
315 ,, 96
201 ,, 120
080 ,, 144
036 168
The Commissioners believed that it was the clarification
2i 8 WATER SUPPLIES
by subsidence which takes place in nearly all rivers, which
had led to the belief, so general, but erroneous, in the rapid,
self-purifying power of running water. Their conclusions,
however, were disputed by the late Dr. Tidy and others ; but
inasmuch as, at this period, the part played by the minute
forms of animal and vegetable life in the process of purifica-
tion was unknown, many of the experiments which they
recorded have now little or no interest. One set of observers
held, with the Commissioners, that purification where it took
place was chiefly due to the deposition of suspended im-
purities, others contended that much of the dissolved organic
matter also disappeared. This latter view was strongly
supported by the report of Drs. Brunner and Emmerick
(1875) on the river Isar as it flows through Munich. They
took every precaution to render the results trustworthy,
estimating the quantity and strength of the sewage and
other refuse matters entering the river from the city sewers,
and making due allowance for the effect of dilution by its
tributaries. The results of analyses, inspection, and calcula-
tion proved that the river water two hours' flow below Munich
was practically as pure as the water above the city, or, in
other words, that all the dissolved and suspended impurities
cast into it at Munich had disappeared. The former view
viz. that subsidence and dilution are the main factors in
producing the so-called self-purification is still upheld by,
amongst others, Professor Percy Frankland. He undertook
a series of experiments to test this point in connection with
the Thames, taking samples of the water flowing in the
river from different points on the same day. One day at
Oxford, Reading, Windsor, and Hampton ; on another day at
Chertsey and Hampton, etc. His analyses of these waters
are given in a paper contributed to the International Congress
of Hygiene, entitled " The Present State of our Knowledge
concerning the Self-Purification of Rivers," and he concludes,
" From the analytical table it will be seen that the idea of
any striking destruction of organic matter during the river's
THE SELF-PURIFICATION OF RIVERS 219
flow receives no sort of support from my experiments ; the
evidence is in fact wholly opposed to any such supposition."
At first sight it appears strange that such skilled observers
should arrive at conclusions so diametrically opposed ; but
the investigation is beset with difficulties, some practically
insurmountable. The water at different points is not the
same ; even if time be allowed for the water first sampled to
reach the subsequent sampling stages, it will be more or less
diluted by ground water or by tributary streams, and receive
additional polluting matter along its course. The insoluble
matter in suspension, or on the bed and sides of the river,
may by its decomposition be rendered soluble ; hence, unless
the rate at which the soluble matters are oxidised and
destroyed is greater than that at which the insoluble organic
material is rendered soluble, the analysis of the water will
show no improvement, or in fact may, as in Professor Frank-
land's experiments, show even a deterioration. Such de-
terioration is therefore no proof that a process of oxidation
is not taking place ; its true interpretation is probably the
one just given. This is confirmed by the experiments of
Sir F. Abel, Dr. Odling, Dr. Dupre, and Mr. Dibdin, on the
oxygenation of the Thames water. They found that each
1000 million gallons of water between Blackwall and Purfleet
lost from 25 to 35 tons of oxygen, and retained oxygen to
the extent of from 5 to 15 tons. The quantity of water
passing Erith upwards in the upward flow of the tide was
estimated by the engineers to be 40,000 million gallons.
This should contain 1600 tons of oxygen; it was found
to contain only 400 tons ; thus 1200 tons must have
destroyed thousands of tons of dry organic matter, altogether
disregarding the oxygen the river was absorbing from the
atmosphere during the w r hole time the oxidation was going
on. The experiments of M. Geradin confirm these observa-
tions ; they are published in Le Rapport sur V Alteration la
Corruption et Vassouvissement cles Rivieres, and refer to the
river Seine. This river before it reaches Paris contains its
220 WATER SUPPLIES
full amount of oxygen ; when it gets to Paris the greater
proportion of the oxygen is at once removed, and this
removal can only take place by its use in the oxidation of
organic matter; a few kilometres farther on the river is
found to again contain its normal quantity of oxygen, which
fact is accounted for by the organic matter being disposed
of. Professor W. R. Smith, "River Water as a Source of
Domestic Water Supply." Journal of State Medicine, April
1894.
The balance of evidence is decidedly on the side of those
who uphold the theory of self-purification, and the diverse
conclusions arrived at by different observers can be accounted
for by the varied and often imperfect character of the experi-
ments, and by the diverse conditions which obtain in different
streams. That river water, grossly befouled by sewage in its
higher reaches, becomes a few miles lower down so pure, from
a chemical point of view, as to be certified by the most
eminent analysts to be fitted for all domestic purposes, and
is actually so used by millions of our population, is a fact
which cannot be gainsaid. Whether this process of purifica-
tion be merely due to sedimentation and dilution, or to
these factors, assisted by oxidation, is, however, a matter of
trifling importance, since it is now fully recognised that the
disease-producing material is not the dead organic matter in
solution, but the living organisms in suspension. The problem
is not a chemical one, but a biological one. If the specific
disease-producing bacteria can be carried long distances by
streams, it matters very little whether they are accompanied
by an increased or decreased amount of the soluble impurities
which were introduced therewith. Unfortunately, biologists
differ as widely as chemists in their views, some contending
that a biologically impure water may, by a few miles' flow,
supplemented by some process of sand filtration, be rendered
biologically pure, whilst others consider that the water of a
river specifically infected at any point cannot afterwards be
rendered safe for domestic purposes by any such means. The
THE SELF-PURIFICATION OF RIVERS 221
opinion of the biologists who hold the latter view is supported
by a large mass of evidence proving that many epidemics of
typhoid fever and cholera in this country, in the United
States, and elsewhere, were due to the use of river water
which had been polluted many miles above the intake of the
water supplied to the populations amongst which the outbreaks
occurred (vide Chapter IX.). As an example of the evidence
adduced in support of the former view, may be cited the
Report made by the Imperial Board of Health in Mecklenburg
on the water supply to the town of Rostock. This town
takes its water from the river Warnow, which, 80 kilometres
above, is polluted by the sewage of the city of Giistrow.
According to Herr Kiimmel, 1 "The Imperial Board of Health
sent a committee to investigate this matter, including an
eminent biologist, and these gentlemen made a trip up the
Nebel and Warnow from Rostock to Giistrow. . . . They
tested the water at various places, from above the town of
Gtistrow down to the Rostock Waterworks. They found that,
though the town of Giistrow deteriorated the water very much,
and that the water 2 kilometres below r was polluted much
more by a large sugar manufactory, the number of microbes
above the town of Giistrow, and that 25 kilometres below the
town and below the sugar manufactory, was nearly the same ;
that whilst in the interval the number of microbes had in-
creased to 48,000 in a cubic centimetre, the number was
again reduced to about 200 ; and at last, just above Rostock,
where the river was said to have been deteriorated by the
sewage of the town above, the number of microbes was less
than it was above the town of Giistrow, and no town at all
was situated above the point where the first test of the water
was taken. This experiment was made twice once during the
summer, and the second time in October last (1890). The
result of the inquiry had been that the Imperial Board had
declared the town of Giistrow might send its sewage water
into the river."
1 Proceedings of International Congress of Hygiene, vol. vii. p. 183.
222 WATER SUPPLIES
On the opposite side we may adduce the Report of the
Massachusetts State Board of Health on the Outbreaks of
Typhoid Fever at Lawrence, Lowell, and Newburyport,
referred to in Chapter IX. In the Newburyport epidemic the
typhoid bacilli must have travelled from Lawrence, a distance
of over twenty miles. The Royal Commission on Metropolitan
Water Supply, notwithstanding the amount of evidence given
by bacteriological experts, felt bound to fall back upon the
" evidence from experience " in order to enable them to decide
whether the Thames could safely continue to be used as the
source of water supply to the city ; but from their report it is
quite evident that even on theoretical grounds they regarded
the danger of disseminating typhoid fever in London by the
use of water from the Thames and Lea as being exceedingly
remote. Selecting the year of highest mortality from typhoid
fever which has been recorded in recent years, allowing seven
attacks for each fatal case, and assuming that the whole of
the discharges from all the cases in the two valleys passed
directly into the rivers at the period of smallest now, there
would be one typhoid case in the Thames valley to a mass of
water 5 miles in length, 100 yards in width, and 6 feet
in depth, and in the Lea valley to a similar body of water
3 miles in length. But as only a very small proportion
of such discharges ever reach the rivers, the degree of dilution
must be much more considerable. This is an attempt at a
reductio ad absurdum argument, such as Dr. Edwards applied
to the Merrimac River (p. 141). The danger arising from
the flooding of ditches and pools and the washing down of
the contents by heavy rains, is said to be scarcely appreciable,
since the quantity of typhoid matter which would in this
manner reach the streams must be excessively small, and a
still smaller amount w r ill have retained its power of setting
up disease. Typhoid dejecta lose their virulence after a few
days, fifteen being probably the maximum, and as the typhoid
bacillus does not form spores, it is only from typhoid dejecta
of very recent deposit from which danger is to be apprehended,
THE SELF-PURIFICATION OF RIVERS 223
and this clearly reduces very greatly the supposed risk of
specific pollution of the water in times of floods. At such
times also the volume of river water is vastly augmented,
and floods occur chiefly at a time when the temperature of
the water is too low to favour the development of the bacilli,
and when typhoid fever is least prevalent. The Commissioners
also regard typhoid fever as being an exclusively human
affection, and that consequently the pollution of water by
animal manure, however objectionable it may be on other
grounds, cannot be regarded as a possible source of such
disease. Pathogenic bacteria in water are in an unnatural
medium, and whilst the natural water bacteria increase
rapidly, the former undergo rapid attenuation and loss of
virulence, and, being worsted in the struggle for existence,
they speedily succumb. Direct sunlight also destroys these
bacteria, and even diffused light reduces their vitality.
During the process of sedimentation also a large proportion
of the bacteria are deposited. Dr. P. Frankland has shown
that in the process of softening water by the addition of lime,
98 per cent of these organisms are removed in the precipitate.
In the river water as supplied to London no pathogenic
bacteria have ever been discovered. It is admitted by most
bacteriologists also "that small doses of cholera and typhoid
poison may be swallowed with impunity, and some even
believe that these small doses act as a vaccine and render the
imbiber immune. Theoretically, therefore, the danger of an
epidemic of typhoid fever, or even of cholera, from the use of
Thames and Lea water would seem to be remote, especially
when the additional safeguard of careful sand filtration is
introduced. Bacteriology, however, is in its infancy, and our
views on many of the above points may have to be consider-
ably modified ; and whilst the " evidence of experience " in
London has so far justified the conclusion at which the
Commissioners have arrived, the same kind of evidence,
according to most trustworthy observers in other towns using
polluted river water, leads to a very different conclusion.
22 4
WATER SUPPLIES
The general acceptation of the Commissioners' views with
reference to the use of sewage-contaminated streams would
be a great national misfortune, and would, it is to be feared,
impede the action of sanitary authorities in their efforts
to secure the freedom of our rivers from pollution by sewage.
The Commissioners, doubtless, never intended that their con-
clusions should apply to any other rivers than the Thames
and the Lea, and this fact should be carefully borne in mind,
since the acceptance as a general principle of a view which is
applicable only to a particular case is illogical and may bring
about disastrous results.
In connection with this subject the recent experience of
Newark is interesting. In August 1893 this town finally
abandoned the use of the filtered Trent water, and the Table
below, kindly prepared for me by Dr. Wills, the Medical
Officer of Health, shows in a striking manner the beneficial
effect of the new deep-well supply.
TABLE SHOWING NUMBER OF CASES OF TYPHOID FEVER NOTIFIED
IN NEWARK-ON-TRENT, FROM 1890 TO NOVEMBER 1895.
Population 14,500.
January.
I
cS
I
t
I
^
1
1
I
October.
November.
December.
H
1890
1
4
1
2
3
3
3
]
1
6
20
8
53
1891
25
17
8
5
5
12
7
14
12
15
5
125
1892
I
1
5
1
3
5
12
12
7
12
10
69
1893
16
16
4
5
4
5
5
*8
5
4
4
2
78
1894
1
2
1
2
3
1
10
1895
1
1
1
1
3
New water supply.
CHAPTEE XIII
THE PURIFICATION OF WATEK ON THE LAK(JE SCALE
THE water derived from deep wells, springs, and the sub-
soil rarely, if ever, requires filtration or any other form of
purification. Surface water, if collected in sufficiently large
lakes or reservoirs, usually, by sedimentation, becomes so
clarified as to require no further treatment. As examples
may be mentioned the water supplies to Glasgow and
Liverpool, derived from Loch Katrine and Vyrnwy Lake
respectively, neither of which are subjected to any form of
filtration, the mere subsidence of the suspended matters
which enter the lakes with the surface drainage effecting all
the purification which is necessary. River water, even if
collected in reservoirs sufficiently large to hold several days'
supply, is rarely sufficiently purified by sedimentation to be
adapted for use without filtration or some other process of
purification. The collection of water in large reservoirs not
only permits the suspended matters, living and dead, to
subside, but the detention of the water in such receptacles
affords time for the pathogenic organisms which may be
present to lose their vitality, by the action of light, or " by
the deleterious action exerted upon them by the harmless
water-bacteria " (P. Frankland). On the other hand, the
storage of water in large open reservoirs has its disadvantages,
as will be pointed out when the storage of water is being
considered. All other processes of purification, such as
boiling, distillation, and precipitation, are only applicable in
Q
226 WATER SUPPLIES
special cases or on the small scale ; and even after the water
has been submitted to these processes, it usually requires
filtering, either to clarify it or render it palatable. Hence
filtration is by far the most important method of purification,
and an accurate appreciation of the factors necessary to
ensure that this is, under all circumstances, as complete as
possible, is absolutely necessary if our polluted rivers are to
continue to furnish the water supplied to our large centres of
population. Until quite recently, the effect of filtration had
been considered exclusively from the chemical point of view,
and that modification which decreased most materially the
proportion of organic carbon or organic nitrogen or albu-
menoid ammonia was regarded as being the most satisfactory.
Inasmuch as this decrease was never very large, the process
was not looked upon with much favour or regarded as of very
great importance, and hence was often performed in a very
careless and haphazard manner. Bacteriological research,
however, having demonstrated that certain specific diseases
were caused by living organisms, some of which might enter
the system with the drinking water, greater attention was
paid to the subject, and efforts were made to secure greater
clarification and transparency, the results being judged by the
examination of samples of the water in long, glass cylinders.
By this means some of the more important conditions necessary
to ensure the removal of the suspended matters were dis-
covered. Further bacteriological progress, however, succeeded
in demonstrating that water which appeared by such a test to
be perfectly clarified might still contain very large numbers
of those excessively minute organisms, bacteria, certain of
which are capable of causing disease ; and quite recently Mr.
Stodard has proved that a filter which is capable of effecting
almost perfect oxidation of the dead organic matter in a
water, rendering it pure from the chemist's point of view,
may yet permit of cholera bacilli passing through in large
numbers. Evidently, therefore, neither chemistry nor the
physical test of transparency can determine whether any
PURIFICATION OF WATER ON LARGE SCALE 227
process of filtration is efficient. We are, therefore, compelled
to resort to the bacteriological test, by which we can obtain
some approximate idea of the quantity and character of the
organisms which have succeeded in passing through the filter
beds. Much remains yet to be discovered in this science
before the results of bacteriologists can be implicitly relied
upon. The confidence of the Worthing authorities in the
bacteriological examination of their water supply proved to
be misplaced. We have, however, at present nothing else so
trustworthy, and as the study of the process of filtration from
the bacteriological point of view has led to most important
discoveries, we must accept it as our safest guide.
Professor P. Frankland in 1885 commenced a series of
bacteriological experiments bearing on the filtration of water
at the London Waterworks, which led him to conclude
that to obtain satisfactory results (1) The storage of the
unfiltered water should be considerable, to allow of sedimenta-
tion ; . (2) The filtration should not exceed a certain rate ;
(3) The depth of fine sand should be considerable ; and (4)
The filtering materials should be renewed frequently. The
effect of subsidence in diminishing the number of bacteria in
water, and, therefore, in diminishing the risk of disseminat-
ing disease, is well shown in the following table, taken from
a paper by Professor Frankland, read at the Edinburgh.
Congress of Hygiene (1893).
TABLE SHOWING THE BACTERIAL EFFECT OF SUBSIDENCE IN
THE RESERVOIRS OF THE WEST MIDDLESEX NEW RIVER
COMPANIES :
No. of Micro-organisms
in 1 c.c. of Water.
New River Company at Stoke Newington
Cutting above reservoir .... 677
After passing through first reservoir . . 560
After passing through second reservoir . 183
West Middlesex Company at Barnes
Thames water as abstracted at Hampton . 1437
After passing through first reservoir . . 318
After passing through second reservoir . 177
228
WATER SUPPLIES
By far the most important and extended series of obser-
vations on the purification of water by sand filtration has
been conducted by the Massachusetts State Board of Health,
and published in their Annual Reports (1890-93). In 1891,
investigations at the experiment station having confirmed the
belief that the typhoid bacillus was sometimes present in
sewage-polluted waters, and was able to live therein for at
least three weeks, and further investigations by the Board
having proved that high death-rates from typhoid fever result
from the drinking of such water, a special study was made
" of filtering materials coarse enough to purify a municipal
water supply economically, while removing these disease-
producing germs." It was proved by these experiments that
water could be filtered at the rate of 2,000,000 gallons per
acre daily, " with the removal of substantially all the disease-
producing germs which may be present in the un filtered
water." The experiments were made Avith water to which
approximately known numbers of the E. prodigiosus or JJ.
typhi abdominalis had been added. The former bacillus was
usually selected on account of the similarity of its life history
to that of the typhoid bacillus, and because the results
obtained with it were more reliable. The number of bacilli
added varied from a small number to several hundred thou-
sands per cubic centimetre. The following table, from the
Report for 1892, "shows the average percentages removed of
single species of bacteria under favourable conditions, and by
filters which can be constructed on a large scale."
No. of
Filter.
Rate Gallons per
Acre daily.
Kind of Bacteria.
Per Cent
removed.
36 A
1,500,000
B. typhi abdominalis
99-93
36 A
3,000,000
B. prodigiosus
99-95
33 A
2,000,000
do.
99-96
34 A
2,000,000
do.
99-98
37
2,000.000
do.
99-89
PURIFICATION OF WATER ON LARGE SCALE 229
Filter 36 A consisted of 58 inches of sand of an effect-
ive size of *20 millimetre, with a loam layer 1 inch deep
placed 1 foot below the surface.
Filter 33 A consisted of 60 inches of sand of an effective
size of '14 millimetre.
Filter 34 A consisted of 60 inches of sand of an effective
size of '09 millimetre.
Filter 37 consisted of 61 inches of sand of an effective size
of -20 millimetre.
Such a high degree of efficiency had not before been
obtained, and if such results are obtainable on a large scale,
the danger to be apprehended from the use of sewage-polluted
waters which have been so carefully filtered would seem to
have been reduced to a minimum. The filtration at the
Altona Waterworks, which Koch believes practically saved
the city from an outbreak of cholera, was certainly not nearly
so thorough, and the same applies to the filtration of the
Thames water as supplied to London, which for so long has
secured the inhabitants immunity from typhoid epidemics.
The filtering materials experimented with were placed in
galvanised iron tanks about 6 feet deep and 20 inches in
diameter, and the rapidity of filtration was regulated by a
tap at the bottom. Beneath the effective sand was a layer, 1-J-
inches thick, of coarse sand, and below this successive layers
of gravel, increasing in size, the whole having only a depth of
3^ inches. It was found best to pack the sand dry, as, when
introduced with water, stratification took place. The polluted
water was supplied continuously from a small reservoir, the
excess passing off through an overflow, so that the depth of
water upon the filter bed remained constant throughout the
experiments. When the accumulation of suspended matter
on the surface of the filter bed impeded the filtration to such
an extent that the tap at the bottom when wide open did not
pass the water at the prescribed rate, the upper surface of
the sand was removed. The sand used was carefully sifted,
and its " effective size " determined by further sifting a
230 WATER SUPPLIES
sample. This size is such that 10 per cent of the sand is
of smaller grains, as ascertained by sifting, whilst the re-
mainder is of larger grains. The results of the Massachusetts
experiments may be briefly summarised as follows :
(a) Increased rapidity of nitration with deep layers of
sand caused a slightly larger proportion of the bacteria to
pass through the filter. With thinner layers still more
bacteria were able to pass.
(6) With both continuous and intermittent filtration the
finer sands are slightly more effective than the coarser ones.
(c) The depth of sand within certain limits exerted but little
influence except when the water was being filtered rapidly ;
with moderate rapidity of filtration (2,000,000 gallons per acre
daily) 1 foot of sand appeared to be as effective as 5 feet.
(d) In filters made of coarse sand, the addition of a loam
layer increased the efficiency. When the effective size did
not exceed *20 millimetre and the filtration was not too rapid,
the loam had little or no influence.
(e) The effect of scraping the sand to remove the clogged
surface was to cause an increased number of organisms to
pass through the filter. The filters required three days' use after
scraping usually to reach their maximum degree of efficiency.
The effect of scraping was more marked in shallow than in deep
filters, and with high rates than with low rates of filtration.
( /') Over 80 per cent of the bacteria removed were found
in the upper inch of sand, and 55 per cent in the upper
quarter- inch. The B. prodigiosus, which is very like the
typhoid bacillus in its mode of life in water, was not found
below the upper inch.
(g) The average depth . of sand necessary to be scraped
from the surface of the filter was a quarter of an inch, but
was found to vary with the size of the sand, decreasing as
the fineness of the sand increased.
(k) Much less water will pass a filter at 32 F. than at
70 F., owing to the increased viscosity of the water.
(i) Within certain limits and under equal conditions the
PURIFICATION OF WATER ON LARGE SCALE 231
quantity of water passed between successive scrapings is not
influenced by the rate of filtration.
(j) Finer sands require more frequent scraping than coarser
sands, whether the filtration be continuous or intermittent.
(k) Shallow filters require more frequent scraping than the
deeper ones. This appears to be entirely due to the greater
head available in the deeper filters for overcoming friction.
(I) Filters used continuously require less frequent scraping
than when used intermittently.
The bacteriological examination of the effluents from all
the filters in July and August showed that a larger number of
organisms were then present than at any other time. From
the results of the experiments which were instituted to ascer-
tain the cause, the reporters infer :
1. That during the summer months the temperature or
other conditions for continuation of life of bacteria at the
surface of filters are more favourable than at any other time.
2. That certain species of bacteria are even able to multi-
ply there at times during this period, although most species
rapidly decline.
3. That this is far less noticeable in the case of inter-
mittent than of continuous filters.
4. That typhoid-fever germs fail to grow under these
conditions, so that the hygienic value of filtration is not
affected by the growth during warm weather of a very few
species of the more hardy water-bacteria.
The above results have been confirmed in important par-
ticulars by Dr. Koch, but he has also shown that some of their
conclusions must be received with caution. The conclusions
at which he has arrived from the study of the outbreak of
cholera at Altona, and of other epidemics due to imperfectly-
filtered water, are (1) That the real effective agent in re-
moving micro-organisms from the water being filtered is the
layer of slimy organic matter which forms upon the surface
of the sand. (2) That if this surface be removed by scraping,
or its continuity affected in any way, as by the freezing of
232 WATER SUPPLIES
the surface, the number of bacteria which pass through the
filtering material increases considerably ; in fact, both cholera
and typhoid germs may pass in sufficient numbers to cause
an epidemic amongst those who use the imperfectly-filtered
water. (3) That water should not pass through the filters at a
rate exceeding 100 mm. per hour (about 2,000,000 gallons
per acre daily). (4) That after a filter bed has been scraped,
water should be allowed to stand upon it for at least twenty-
four hours, to allow of the slime depositing before filtration is
commenced, and that the water which first passes through
should not be allowed to reach the pure-water reservoir.
At the Altona Waterworks the filtered water has been
regularly examined bacteriologically since the summer of
1890. By keeping the pace of filtration below 2,000,000
gallons per acre daily, the bacteria in each c.c. of the filtered
water practically always remained below 100 ; usually they
were much below 20 to 30 being the average. In January
1892 the number of micro-organisms suddenly increased to
from 1000 to 2000 per c.c., and in February an outbreak of
typhoid fever occurred. Suspicion was expressed that
filtration might have been disturbed by ice formation, or by
the superficial layers of sand becoming frozen during the
process of cleansing in the keen frosty weather ; but absolute
proof was not forthcoming. In January and February 1893
the epidemic of cholera occurred in the town, and this had
been preceded by an increase in the number of bacteria in
the filtered water. On the 30th December 1892 the number
of germs began to increase, and reached on the 12th January
1893 the number of 1516, and remained high until early in
February. Up to this time the water from each filter bed,
of which there were ten, had not been examined separately ;
when so examined, from the 1st of February Filter No. 8 was
found to be acting worst. On the 3rd this filter was ex-
amined, and when the water was drawn off it was found that
the sand layer was frozen at the top. The freezing had
taken place during the period of cleansing.
PURIFICATION OF WATER ON LARGE SCALE 233
Koch also points out that winter with its period of frost
is not the only enemy of nitration. Occasionally in summer,
river and stored surface-water is so rich in vegetable growths
that these rapidly form an almost impervious layer upon the
surface of the sand, and to keep up the supply of filtered water,
greater pressure and more frequent cleansing are necessary,
both tending to give a filtered water which is imperfectly
purified. These disturbances, however, are only dangerous
to the public health when the natural water contains specific
bacteria, and as the whole filters are never affected at the
same time only a portion of the disease germs could ever pass.
Yet that even this part can cause epidemic outbreaks is proved
by the experience of Altona, Berlin, and other places. To
secure efficient filtration Koch lays down the following rules:
1. The pace of filtration must not exceed 100 mm. in the
hour. To make sure of this each separate filter must be
provided with a contrivance by which the movement of the
water in the filter can be restricted to a certain pace, and
continually regulated so as to keep that pace.
2. Each separate filtering basin must, when in use, be
bacteriologically investigated once each day. There should,
therefore, be a contrivance enabling samples of water to be
taken immediately after they have passed the filter.
3. Filtered water containing more than 100 germs,
capable of development, in a cubic centimetre should not
be allowed to reach the pure-water reservoir. The filter
should, therefore, be so constructed that insufficiently pure
water can be removed without its mixing with the good
filtered water.
4. The filter beds should be of small area, far smaller
than those used in London, 1 or recently constructed at
Hamburg.
At the same time Koch admits that in waterworks of
good construction and intelligent management, Rule 2 need
only be strictly observed in times of danger. He is also
1 The average size of these is one acre.
234 WATER SUPPLIES
bound to admit that the standard of 100 germs per c.c. is
arbitrary, and is only "intended to give a basis obtained
from experience to form a proper judgment." There are
strong grounds for suspecting that at Altona a number of
cases of cholera occurred, though not an epidemic outbreak,
during the period when the filtration was up to Koch's
standard, and that these were due to the water being
specifically infected. As the typhoid bacillus is much
smaller than the cholera germ, it would seem probable that
the danger of disseminating typhoid fever by the distribution
of imperfectly-filtered water is greater than in the case of
cholera.
Prior to the investigations of the Massachusetts State
Board of Health, the small amount of chemical purification
produced by sand filtration was attributed to the oxidation
of the organic matter by the oxygen held in the pores of
the sand. By the experiments above referred to the
oxidation was proved to be due to the action of nitrifying
organisms, which adhere to the sand. When nitrification
has been well established in a filter, the rate of filtration
within certain limits was found to exert but little influence
upon the removal of the organic matter. Also, within certain
limits, the effect varied little with the degree of coarseness of
the sand, but deeper filters were more efficient in removing
the organic matter than shallower ones. In some experiments
with filters in which the nitrifying action had become well
marked, the albumenoid ammonia yielded by the effluent was
80 per cent less than that yielded by the water before
filtration. The importance of removing as much as possible
of the organic matter is due to the fact that the food supply
available for the bacteria which are present is reduced thereby,
and their growth and multiplication in the water subsequently
is retarded.
Experiments which were made with the coloured water of
the Merrimac River proved that new sand removed the colour
more efficiently than sand which had been in use some time.
PURIFICATION OF WATER ON LARGE SCALE 235
One filter of sand and loam continued to remove all the
colour for over two years ; after the end of the third year
the water which passed through was very slightly but
uniformly coloured.
The oxidising effects produced by sand filtration are, how-
ever, in the light of recent bacteriological research, of very
secondary importance in the purification of water. Any
considerable chemical purification cannot be constantly relied
upon when water is treated on a large scale. New sand
filters have but little action. It is only when they have, so
to speak, become charged with the nitrifying organisms that
any appreciable effect is produced, and it takes some time
for this action to become well established. Moreover, the
nitrification, after proceeding satisfactorily for a time, may
suddenly cease, to commence again after a more or less
lengthy interval. The cause of this intermittent action is
difficult to explain. The Massachusetts investigators think
that the action probably only commences when a certain
quantity of nitrogenous matter has become stored up in the
pores of the sand. It then proceeds rapidly until this is
consumed, and again ceases until a further quantity has
accumulated, and this may require months. Another singular
fact is that the total nitrogen in the unfiltered water almost
invariably exceeds that found in the filtrate, which appears
to indicate that some of the nitrogen is liberated in the
gaseous state and escapes into the air.
The filter beds of the eight London Water Companies
exceed 100 acres in area. The depth of sand used by the
various Companies varies from 2 feet to 4 feet 6 inches, and
the depth of the filter beds from 2 feet 9 inches to 8 feet.
The following description of the Leeds Waterworks may be
cited as an example of the most modern system of sand
filtration. The water from the Washburn valley and moor-
lands is collected in a reservoir 195 acres in extent, and
capable of holding a year's supply. From this it passes to a
settling pond, having an area of 3 acres, and capable of hold-
236 WATER SUPPLIES
ing 10,000,000 gallons. A certain amount of water, however,
is collected, which flows directly into this settling reservoir.
From here it flows on to the filter beds, seven in number,
each having an area of nearly an acre. The filter beds
consist of 2 feet of fine sand, 3 inches of pea-gravel, 3 inches
of ^-inch gravel, 4 inches of 1-inch gravel, and 9 inches of
rough stones. The water, after passing through the beds,
enters a series of perforated pipes 3 and 4 inches in diameter,
all of which discharge into a main culvert along the centre,
terminating in a small circular, covered tank, where observa-
tions can be made as to the rate at which the water is
passing through the bed. The filtered water is then con-
ducted into a service reservoir. In the middle of each bed is
a rectangular iron box, used for washing the sand scraped
from the surface of the filter during the process of cleansing.
The filters are cleaned in order, one each week on an average,
from J to | of an inch of the surface being removed.
This is wheeled along planks to the washing box, and after
being washed is again replaced. When the tanks are emptied
for cleansing, the water is only drawn off to near the bottom
of the sand, and in refilling the water is backed up from
below, and not discharged on to the surface, as this would
disturb it and impair the efficiency of the filtration. The air
in the sand escapes not only from the surface, but also from
escape pipes, which pass through the walls of the tanks. If
this precaution be not taken the air may cause fissures to
form in the sand. When the water has risen above the
surface of the sand it is then turned on from above, and
flows over the side of a trough, so as to be uniformly supplied
to the filter with the minimum amount of disturbance.
Eight men are constantly employed in keeping the filters in
thorough working order. On an average each square yard
of filter passes 412 gallons of water per twenty-four hours.
The head of water, or rather the difference in level between
the surface of the water on the filter and in the circular tank
into which the filtered water is discharged, is 4 to 4J feet.
PURIFICATION OF WATER ON LARGE SCALE 237
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238 WATER SUPPLIES
Table VIII. gives the area in acres, rapidity of filtration, etc.,
of the filter beds of several large public supplies, compiled from
a report of a sub-committee of the Dumfries Town Council,
which considered the subject with the view of improving their
filtering arrangements. The River Commissioners on Metro-
politan Water Supply reported that, as a general rule, the
filtration of water by the London Companies was carried out
efficiently, from 98 to 99 per cent of the organisms being
removed from the water. The occasional failures, they
thought, could be remedied by increasing the number of filter
beds or by having recourse to double filtration ; " and assuming
the water to be invariably as efficiently treated as it is usually
by the most careful of the Companies, the raw waters of the
Thames and Lea can be transformed, in the judgment of Dr.
E. Frankland, who, as is well known, has been no sparing
critic of the London water into a beverage quite as good,
from the point of view of health, as deep- well water." This
opinion, it must be remembered, is not shared by many other
sanitarians of equal eminence. In any case it is obvious
that only the efficiency of the filtration can safeguard the
metropolis from outbreaks of typhoid fever and possibly of
cholera. Doubtless, however, the Water Companies will not
be slow to adopt the recommendation of the Commissioners,
and will take every precaution suggested by the breakdown
of the filtering arrangements at Altona.
The area of filtering surface required is given by the
formula A = =^ where Q is the maximum daily demand in
cubic feet, F the filtering rate in feet, and A the required
area in square feet. This area must always be available ;
hence an additional area must be provided for use whilst
other portions are being cleansed. According to Hennel the
number of filter beds required for different populations is as
under :
PURIFICATION OF WATER ON LARGE SCALE 239
Population.
2,000
10,000
60,000
200,000
400,000
600,000
1,000,000
These include filter beds out of use for cleansing.
In all cases a sufficient number of filter beds should be
provided, to allow of the cleansing and renovating of one set
without overworking the remainder. The filtration must not
be too rapid, not over 2,000,000 gallons per acre daily. To
accomplish this the head of water must be reduced after
cleansing, and gradually increased as the pores of the sand
become closed by the slimy matter which settles on its
surface. By " filtering head " is meant the difference between
the level of the water on the bed and in the well which
receives the filtered water. After cleansing a few inches of
head may be sufficient ; when it exceeds 3 feet the surface
again requires renewal. Each bed should have an arrange-
ment for regulating the flow, and the water should be
admitted into the filter beds in such a manner as not to
disturb the surface. The surface sand when removed for
cleansing may be washed in hoppers admitting the \vater
from below, or in troughs through which water is constantly
flowing. Deep filter beds keep the water cooler in summer
and retard freezing in winter, the latter being the more
important, since freezing not only interferes with the efficiency
of the filtration, but may damage the walls of the filter
beds, by the expansion of the surface water in the act of
freezing.
In many places water is obtained from galleries or
trenches sunk along the edge of lakes or running streams, the
general impression being that the water so obtained is
derived from the lake or stream, and that it undergoes a
process of natural purification and filtration in its passage
240 WATER SUPPLIES
through the intervening soil. In many cases, however, this is
really ground water which is intercepted on its way to its
natural outlet. Such water is usually very free from organic
matter, and contains but few bacteria. Where the ground
water falls below the level of the water in the stream or lake,
doubtless a certain quantity of the water which passes into
the galleries is derived from the latter sources, and is not so
likely to be of good quality, since it only passes through soil
which is constantly saturated with water, and therefore never
aerated, and destitute of any oxidising powers. In such cases
also the filtration is liable to be inefficient, and to allow
of bacteria and other particulate matters passing into the
collecting channels.
Many attempts have been made to filter water on the
large scale without employing filter beds, which are expensive
not only on account of the space required, but of the con-
stant labour and attention required to keep them in a state
of efficiency. One of the best-known processes is that of the
Atkins Filter and Engineering Company, which is in use
by the Henley -on -Thames Water Company, and has been
adopted by many large institutions. The filtering apparatus,
technically known as the "Scrubber," consists of a perforated
metal cylinder to contain the sand or other filtering material,
fitted into a tank and so arranged as to revolve easily by
turning a handle. The cylinder is only partly filled with
the filtering material, and the collecting tubes, which convey
away the filtered water, lie as nearly as possible in the centre
of this as it lies in the cylinder. To clean the filter it is
only necessary to turn the handle, when the cylinder revolves,
agitating the filtering material with the water, and the latter,
together with the impurities washed out, are run off through
a by-pass. Several such "scrubbers" can be connected
together. By another arrangement the sand is put into a
number of discs fitted on a revolving centre collecting-tube.
The water filters through the flat surface of each disc, so that
the area of filtering surface is much increased. More perfect
PURIFICATION OF WATER ON LARGE SCALE 241
filtration can be secured by passing the water through two
"scrubbers" in succession, and affords, naturally, safer results
for drinking water. The Company claims that, with an area
of only 600 square feet, their machines will filter as much
water as an acre of filter bed (3,000,000 gallons per day).
Under the latter system the cost of cleansing is said to be
from 5s. to 10s. per million gallons, whereas it is only about
half the amount with the Atkin "scrubbers," with "the
great sanitary improvement of daily cleansing in addition."
Such machines for rapid filtration do not appear to be regarded
with much favour in this country, and there are no records of
the bacteriological examination of waters which have passed
through these filters. The conditions laid down by the
Massachusetts Board as being necessary for perfect filtration
not being observed, experimental evidence of efficiency is much
to be desired. Other machines of a similar character the
"Loomis," the "Duplex," the "Hyatt," the "Bowden," etc.
are, however, in use in the United States, chiefly for filter-
ing turbid river-water, and Dr. P. S. Wales, Medical Director,
United States Navy, states that, even with this rapid
filtration, 98 per cent of the micro-organisms can be
removed, but that "spores readily passed through the
filtering material." (The typhoid and cholera bacilli are
not known to form spores.) The four machines above
referred to have been used for experimental purposes at the
Museum of Hygiene, Washington, D.C., and gave very satis-
factory results. The system of rapid filtration is successfully
pursued, amongst other places, at
Oakland, Cal., capacity for 24 hours . 4,000,000 gallons.
Atlanta, Ga. ,, ,, . 3,000,000
Long Branch, N.Y. ,, ,, . 2,000,000
Ottnrawa, Iowa ,, ,, . 1,500,000 ,,
Athol, Mass. ,, ,, . 1,000,000 ,,
The city of Alleghany, Pa., was contemplating erecting a
plant for filtering 30,000,000 gallons per day, when Dr.
242 WATER SUPPLIES
Wales's paper was published. 1 These filters appear to be
especially applicable for the waters of muddy, rapid rivers,
which speedily clog the ordinary sand filter, and arrest the
flow of water. To expedite the process of sedimentation so
as to remove more of the suspended matter before passing the
water into the filters, alum is largely used. The addition of
about half a grain per gallon, on the average, is sufficient.
At the Atlanta Waterworks, during 1890, 253 Ibs. of alum
were used per day, corresponding to 617 grains per 1000
gallons. Some waters, such as that of the Potomac, cannot
be clarified without a coagulant. In this country the water
supply to the village of Ingatestone (Essex), previously referred
to, derived from a fine sandy clay, for years resisted all
our efforts to clarify it. Alum, or rather Spence's Alumino-
ferric, was used as a coagulant, and the water then filtered
through vertical sheets of flannel. This not proving satis-
factory, various recently-introduced filtering and purifying
materials were experimented with. Finally, at my recom-
mendation, a filter bed was made of sand and polarite mixed
in equal proportions, and with a few inches of fine sand on
the top. This filter has now been in use for nearly two
years, and has answered admirably. The use of the alum
was discontinued, as it was found quite unnecessary. Two
beds were prepared, so that one could be used whilst the
other was cleansed and allowed to rest for re-aeration.
At the Antwerp Waterworks, "spongy iron," together with
gravel, was used as filtering material, but the beds choked up
gradually and the iron became almost inactive. For three
years, however, the results were satisfactory, so far as regards
the purification of the water. To meet the difficulties just
referred to, Dr. W. Anderson, F.R.S., invented the " Revolving
Purifier," which has been in use at Antwerp since 1885, and
has also been adopted at Boulogne-sur-Seine, Agra, Monte
Video, and other places. The apparatus is described by the
1 Transactions of International Congress oj Hygiene, London, 1891.
vol. vii.
PURIFICATION OF WATER ON LARGE SCALE 243
inventor as a " cylinder supported horizontally on two hollow
trunnions, of which one serves for the entrance and the other
for the exit of the water. The cylinder contains a certain
quantity of metallic iron, in the form either of cast-iron
borings, or, preferably, of scrap iron, such as punchings from
boiler plates. The cylinder is kept in continuous but slow
rotation by any suitable means, the iron being continually
lifted up and showered down through the passing water by a
series of shelves or scoops fixed inside the shell of the cylinder.
By this means the water, as it flows through, is brought
thoroughly into contact with the charge of iron, which, in
addition, by its constant motion and rubbing against itself
and the sides of the cylinder, is kept always clean and active."
During its passage through the apparatus the water takes up
from ~j to i of a grain of iron per gallon, which is got
rid of either by blowing in air or by allowing it to flow
along shallow open troughs. The oxide thus, formed may
settle in subsidence reservoirs, or may be filtered out by rapid
passage through a thin layer of sand. At Boulogne the
average amount of organic matter removed by this process
from the Seine water was 63 per cent, and the microbes,
which in the unfiltered water ranged from 800 to over 7000
per cubic centimetre, were reduced to an average of about 40.
The bacteriological results are admittedly only approximate,
and on one occasion, at least, a large number of bacteria were
found in the filtrate. It seems probable that, compared with
sand filtration as usually conducted, the revolving purifiers
may destroy a larger proportion of the dissolved organic
matter ; but unless supplemented by careful sand filtration it
would be unsafe to assume that a specifically-polluted water
could be rendered safe for drinking purposes by passing
through one of these cylinders.
Whilst sand is almost universally employed for the filtra-
tion of water on the large scale, and usually is the sole
effective filtering medium, in a few instances other materials
have been used, together with the sand, either mixed there-
244 WATER SUPPLIES
with, or in layers. A carbide of iron (Spence's Magnetic Car-
bide) was in use for a large number of years for filtering the
excessively-polluted Calder water for the domestic supply to
Wakefield. This water was not only fouled by sewage, but
also deeply discoloured by the refuse from dye-works ; yet the
filters converted it into a colourless, palatable water. The
layer of carbide was in use for nearly thirty years, and was
never renewed ; all that was found to be required was the
cleansing of the surface sand. The filtration was intermittent,
to allow of the aeration of the filter. The magnetic carbide
is also in use at Calcutta for filtering the turbid and polluted
waters of the Hooghly, and at Cape Town, Demerara, and
other places. Its use was discontinued at Wakefield because
a purer supply has been obtained from another source.
Spongy iron, polarite, and other insoluble iron compounds are
used for similar purposes, and are useful in special cases, as
in the examples given. Now that the removal of dissolved
organic matter is considered to be of much less practical
importance than the removal of the living organisms, less
importance is being attached to the use of such materials, and
it can only be under exceptional conditions that these aids to
sand filtration are necessary. It is upon the proper use of
sand that the real efficiency of filtration must depend, though
where desirable this may be supplemented by the use of other
filters, or the introduction of a layer or layers of other
materials ; and the substances above enumerated, yielding
nothing to the water, yet exerting an oxidising action upon
the organic matter, are probably the best which have yet been
discovered.
At Reading Waterworks polarite is now largely used for
filtering the water of the Kennet, a polluted, navigable stream.
The following description of the filters is taken from an
excellent paper read by Mr. Walter, the Waterworks Engineer,
at a recent meeting of the County Association of Municipal
Engineers held in Reading :
"The process of purifying the river Kennet water is by
PURIFICATION OF WATER ON LARGE SCALE 245
natural percolation, through a series of filters or chambers,
the first chamber containing coke, and the second and third
chambers * polarite,' granulated in two sizes ; there are also
intermediate or regulating water chambers for facilitating
cleaning out, the water passing from the last polarite chamber
into a distributing channel, and on to sand filters, as it has
been said, to make doubly sure of filtered water ; but sub-
sequent experience has proved that perfect purification can be
obtained by polarite chambers without the aid of sand. The
first two sets of these chambers were started in work in
November 1892. Each polarite chamber measures 40 feet by
9 feet, and has a depth of 2J feet of polarite, giving an area
of 40 j^ards super each chamber, or a total of 160 yards super
for the two sets. By adding the 2J feet of polarite in each
set it gives a depth or thickness of 5 feet to each set of
chambers, and an area of 80 yards super per set. From
December 1892 to August 1893 there had passed through
these two sets a total quantity of 409,880,000 gallons of
water, giving an average of 18,848 gallons per yard super per
day. Two additional sets were started in August last, 1893,
of the same dimensions as the above, giving a total area of
160 yards super, with a depth of 5 feet for each set of
chambers, which have passed on an average 12,500 gallons
per yard super per day. From 1st January of
the present year to the 31st of March last, 190,218,319
gallons of water have passed through these chambers, giving
an average of 13,215 gallons per yard super per day, or at
the rate of 550'6 gallons per yard super per hour. The water
has been such that no complaints (which previously were an
everyday occurrence) have been made since purification by
polarite came into full working order. It has had a most
severe test during the past and previous autumn and winter
seasons, but like many a good engineer it has often been
overworked, but has stood it well. From experience gained
in connection with the treatment of the river Kennet water,
there is no hesitation in stating the opinion that 'polarite,'
246 WATER SUPPLIES
as applied here, is capable of effectually purifying a river water-
supply for all purposes, and the system can be carried out at
less cost of construction and maintenance than filtration by
large areas of sand beds."
The effluent from the polarite filters is afterwards passed
through four sand filters, each having an area of 10,000
square feet. As these filters pass about 2,000,000 gallons
per day, this is at the rate of over 8 gallons per square
foot per hour, or four times the average of the London Water
Companies.
In connection with these works also there is an improved
system of sand-washing, which was invented by Mr. Walker.
Cone-shaped hoppers, mounted on trunnions, and connected at
the bottom of the inverted cone with the water supply under
pressure, are filled with the sand scrapings to be washed.
The water is then turned on, and the upward rush keeps it
in a continuous state of agitation, and the impurities are
carried off by an outlet at the rim of the hopper. By this
process sand -washing is not only less laborious, but less
expensive than by the older methods. One man can wheel,
tip, and wash 9 to 10 cubic yards of sand per day at a cost of
3|d. to 5d. per cubic yard. By the older processes the cost
was from Is. 6d. to 3s. per cubic yard.
Water, when softened by the addition of lime, also under-
goes an improvement in quality, the precipitate of carbonate
of lime carrying down with it a very large proportion of the
microbes previously suspended in the water. The filtration
through sand which follows, to remove the last trace of
carbonate, still further purifies the water, so that the soften-
ing process has a double advantage. As this process is
primarily conducted for removing the carbonate of lime, and
not for the removal of organic matter, and is of very
considerable importance, it will be fully considered in a
later chapter.
CHAPTER XIV
DOMESTIC PURIFICATION
THE water supplied by a public company can scarcely be
considered wholesome if it requires filtration by the consumer,
yet in many towns unfiltered surface water is distributed,
and as this often contains visible suspended impurities, some
form of filtration must be resorted to if the water is to have
a bright and pleasing appearance. The forms of filter
generally employed for purifying all the water consumed in a
dwelling may be classed under two heads (a) low-pressure
filters, (6) high-pressure filters. The latter are directly in
communication with the service pipe, and the water is
filtered through under the pressure in the main ; whilst the
former are indirectly connected by means of a ball-cock, the
only pressure being the column of water in the filter above
the filtering material.
The high-pressure filters may contain any of the materials
ordinarily used for clarifying water, either in a granular
condition and tightly packed or in one porous mass. (Animal
charcoal, polarite, magnetic carbide, carferal, silicated carbon,
etc.) No doubt for a time such filters remove a considerable
portion of the suspended matter, but they can never be
trusted to remove more than a small portion of the bacteria,
the most dangerous of the constituents. The separated filth
accumulates, and to remove it there is usually an arrangement
permitting of water being forced through in the opposite
direction, whereby much of the dirt is washed away. All of
248 WATER SUPPLIES
it cannot be thus removed; hence the efficiency of the filter is
more or less rapidly impaired, and the filtering material
requires constant renewal. Unfortunately, purchasers of such
filters are rarely aware of this fact, or, if they are, the trouble
and expense causes such renewals to take place at very long
intervals. The whole system is wrong, and should not be
FIG. 14.
encouraged. Even if carefully attended to such filters cannot
be depended upon for any length of time, and as they possess
few advantages over low-pressure filters their use should be
abandoned. The best filters of this class are Major Crease's,
the Berkefeld and Pasteur filters. The former consists of a
stout cylindrical vessel filled with carferal, a compound of
iron, alumina, and carbon. The water passes in from the
DOMESTIC PURIFICATION 249
main at one end, and out to supply the house from the
opposite extremity. The filtering material within the
cylinder is packed between two perforated plates, one of
which can be screwed down upon the other so as to obtain
any required degree of compression. It can also be readily
unpacked for cleansing or for renewal of the carferal. The
"Berkefeld" is, strictly speaking, a bacteriological filter, its
object being, not the oxidation of dissolved organic matter,
but the removal of the whole of the suspended matter,
including the most minute organisms. The filtering cylinder
is composed of compressed fossil earth (Kieselguhr), and the
water is purified by filtration through the side. The
suspended matters removed from the water remain upon the
surface, and can easily be washed or brushed away, and the
cylinders can be resterilised by being placed in warm water
and boiled for an hour. Fig. 14 is a section of a cistern
filter working with a pressure of 20 Ibs. upwards. A 3-tube
filter of this kind will supply 50 gallons of water per hour.
A smaller, single-tube filter is shown in Fig. 15. It is
intended for attachment to the water supply either from a
constant main service, with a pressure of, say, 30 Ibs. upwards,
or from a cistern not less than 20 feet above where the filter
is fixed.
The Pasteur or Chamberland-Pasteur filter is very similar
to the Berkefeld, but is made of china clay, is somewhat harder,
and therefore not so readily fractured. Both are efficacious
at first, but the latter is said to yield a more palatable filtrate.
To the use of the Pasteur filter by the French army during
recent years is attributed the great decrease in the mortality
from typhoid fever amongst the soldiers (50 per cent). In
other instances, when used for manufacturing purposes, their
use has been discontinued on account of the slowness of the
filtration, and because after prolonged use the filtered water
was no longer bacteriological ly satisfactory. In a series of
experiments made by Dr. Johnston, bacteria were found in
the water passing through a Berkefeld filter within from 3 to
250 WATER SUPPLIES
10 days of continuous use. The Pasteur filtrate remained
sterile for six weeks. Recent experiments made by Dr. Sims
Woodhead (Brit. Med. Journal} confirm the superiority of
the Pasteur filter.
u
FIG. 15.
S. Water-inlet.
T. Outlet for filtered water.
U. Outlet for water used for washing cylinder.
A number of forms of these high-pressure filters are made
for fixing to taps, pumps, etc. They yield a water which
at first is absolutely free from micro-organisms, and as they
are extremely simple in construction and admit of being
very easily cleansed, no other filter can be compared with
them for high-pressure work.
Bailey Denton's self -supplying filter may be taken as
typical of the low-pressure service filter.
The upper compartment contains the filtering material,
which may be sand, charcoal, or any other of the substances
used for such a purpose, and is fed from the house cistern at
a higher level. When the filtered water in the tank below
DOMESTIC PURIFICATION 251
reaches a certain level the supply to the filter is cut off, and
the remaining water as it drains from the filtering material
is replaced by air, so that the filter is frequently aerated. If
fixed in an easily accessible situation, the material can be
examined and removed for cleansing as often as may be
required. The capacity of the lower compartment is made
suitable for the actual requirements of the household.
Kain water may be effectually filtered by some such
arrangement as the above, and if for any reason the reservoir
for the filtered water is below the level of the ground, the
water may be raised by a pump. Even with this system of
treatment the rain water should be collected by means of a
"separator," in order to prevent an unnecessary amount of
filth being passed into the storage cistern, which not only
fouls the water but causes the filter to require much more
frequent cleansing.
The number of domestic filters in the market is enormous,
and it may truthfully be asserted that the majority of
them are worthless. Some are intended merely to remove
a portion of the dissolved organic matter, and fail entirely to
remove any bacteria which may be present. Others, which
claim to remove the micro-organisms, only do this imperfectly
and for a short time, and after being in use for a period
the filtered water may actually contain more bacteria than
were present in the unfiltered water. The use of such filters
engenders a false feeling of security, and the users may fall
victims to their misplaced confidence. I have had occasion
to examine several much-vaunted filters, and found them
absolutely useless ; they were coarse strainers and nothing more.
The so-called " table filters " are usually the least reliable, since
the amount of filtering material is too small to purify the
water for any length of time, if at all ; and if the material be
made sufficiently compact to prevent the passage of micro-
organisms, the rate of filtration is excessively slow, and the
pores of the filter become rapidly choked. The Berkefeld and
Pasteur filters are probably the most reliable, but are very
2 5 2
WATER SUPPLIES
slow in action. The tubes must be frequently removed,
washed, first with water, then with a dilute solution of
permanganate of potash, and finally sterilised by boiling or by
heating over a charcoal stove or Bunsen burner.
For ordinary domestic purposes an inexpensive sand filter,
which can be made by any person, is as good, or better, than
many of the high-priced filters in the market. The follow-
FILTER PAPER
FIG. 16.
ing is a description of a cottage filter (Fig. 16) costing only a
few pence : Take a large-sized earthenware flower-pot, and
plug the hole at the bottom with a cork, through which passes
a short piece of glass tube. Upon the bottom place a few
fragments of a broken flower-pot (pieces \ to \ inch square).
Upon these place a layer of small, clean- washed gravel, and upon
this 6 to 1 2 inches of well- washed, fine, sharp sand. Cover the
smooth surface of the sand with a circular piece of coarse filter
DOMESTIC PURIFICATION 253
paper and sprinkle over this a few pieces of the small gravel.
Mount the pot on a tripod or other convenient stand, and it is
ready for use. The paper prevents the upper surface of the
sand being disturbed by pouring in the water, and can be
removed, together with most of the sediment which has
formed thereon, as often as necessary. Every few months,
or oftener if required, the sand can be thoroughly washed
and replaced. A layer of finely -granulated polarite and
sand, in equal quantities, may be substituted for the lower
half of the sand layer, and improves the character of the
filtered water in some instances, especially where the water
to be filtered contains much vegetable organic matter, as is
usually the case when taken from ponds. For the polarite,
magnetic carbide, spongy iron, or animal charcoal may be
substituted to suit particular circumstances. Animal char-
coal, from the remarkable power which it possesses of removing
certain colouring matters from water, and of absorbing or
oxidising organic matters generally, of a complex character,
used to be considered one of the best, if not the best, of all
filtering materials. Water, however, which has been in con-
tact with it forms a favourable medium for the growth of low
forms of life, and bacteria grow within its pores. Prof. P.
Frankland found that for some days animal charcoal removed
most of the bacteria, but that it gradually lost this power,
and before the end of a month the filtered water contained many
more germs than the unfiltered. It will remove traces of
lead, but this property it does not retain for any lengthened
period. Vegetable charcoal, ground coke, and other forms
of charcoal also are used as filtering media, but they do not
possess the decolorising and oxidising powers of animal char-
coal. They are equally efficacious in removing low forms of
life, and retain this property longer. Ground slag, pumice,
sandstone in slabs, etc., are occasionally employed in filters,
but possess no advantage over good sand. Sponge soon
becomes foul, and only acts as a coarse strainer ; its use is not
recommended.
254 WATER SUPPLIES
Whatever material be used, it must be remembered that
it can only retain its efficiency for a limited period, and no
filter should be purchased which does not permit of the
filtering media being easily removed for cleansing or re-
newal. The filter should also contain a sufficient amount of
the material to produce something more than a mere straining
action. If not of sufficient depth, it may remove all the
coarser suspended matters, and the water appear bright, yet
the micro-organisms may pass through with the utmost ease.
Earthenware vessels are the best for containing the filtering
medium. Galvanised iron is easily acted upon, and may
contaminate the water with zinc. Wooden casks may be
used if the inside has been previously well charred, and if
the charring be repeated occasionally.
When drinking water is of suspicious quality, and there is
the slightest doubt about the efficiency of the filtration, it
should be well boiled before use, say for ten minutes. This
kills everything save certain very resistant spores; but as
there are good grounds for believing that none of these spores
are disease producing, their presence is of little consequence.
It is better to use the water soon after cooling and before
the spores have had time to develop. Boiling also removes
most of the carbonates of lime and magnesia, rendering the
water softer; as the dissolved gases are also given off, its
taste is flat and insipid. It can easily be again aerated by
pouring through a cullender or sieve from some little height,
when the finely-divided streams of water again take up gases
from the air.
By distillation a pure water may be obtained from the
sea, and from other salt -laden or impure waters. The
saline matters remain behind in the boilers, and the steam,
when condensed, can only contain any traces of volatile im-
purities which may have been present. These volatile sub-
stances have been charged with causing diarrhoea, but it is
much more probable that the illness was due to defective
distillation allowing some of the impure water to gain access
DOMESTIC PURIFICATION 255
to the vessel in which the distilled water was being condensed
or collected. By aeration the insipid flavour of distilled
water may be improved.
When tea or coffee is made with boiling water, the astrin-
gent matter in the leaves or berries may tend to produce still
further purification. In many epidemics of typhoid fever,
it has been noticed that persons who drank the infected water
only when made into tea or coffee escaped entirely.
Turbid and polluted waters are sometimes clarified by the
addition of from 2 to 6 grains of alum to each gallon, a very
little lime also being added if precipitation is not sufficiently
rapid. The flocculent precipitate which forms carries down
with it most of the bacteria. Perchloride of iron is sometimes
used instead of alum, and for the same purpose.
Where only foul-smelling, impure water is obtainable, Dr.
Parkes recommended the use of permanganate of potassium,
which is the active ingredient in Condy's Fluid. The solu-
tion of permanganate should be added gradually and with
constant stirring, until a very faint but permanent pink tint
is perceptible. A little alum is then added, and the water
allowed to clear by subsidence. Such waters also are im-
proved in quality by being stored in well -charred casks.
Very foul waters, when kept, often undergo a kind of fermenta-
tion, and become clear, bright, and palatable.
CHAPTER XV
THE SOFTENING OF HARD WATER
As previously explained, the hardness of water is due to
the presence of compounds of lime and magnesia, chiefly
the former. The temporary hardness is due entirely to the
carbonates of these bases, whilst the permanent hardness is
caused by the sulphates, chlorides, and other salts. The
disadvantages attending the use of hard waters have already
been referred to, the chief being the waste of soap when the
water is used for certain domestic purposes. With very hard
waters this waste is so great that it is much more economical
to soften the whole of a public supply than for each con-
sumer to soften his quota by aid of soda or soap. From
the description of the various processes^ in use for softening
water, and their cost, the conditions which determine whether
it is advisable to adopt one or other of them will be
manifest.
Water may be softened (a) by boiling; (b) by distillation;
and (c) by the addition of lime, with or without carbonate of
soda, soda ash, or other chemicals.
(a) By boiling, the carbonic acid gas is driven off, and
the carbonates of lime and magnesia which had been held
in solution by this gas are deposited. The process is trouble-
some and expensive. The Rivers Pollution Commissioners
calculated that the fuel (coal) necessary to be used to soften
1000 gallons of water by boiling for half-an-hour would cost
about 7s. 6d. The same quantity of Thames water softened
THE SOFTENING OF HARD WATER . 257
by soap would cost 9s., so that boiling is not much less
expensive than softening by soap.
(6) Distillation naturally is much more expensive than
simple boiling, and would never be resorted to simply for
softening a water. Boiling merely removes the temporary
hardness ; distillation separates all the saline ingredients, so
that distilled water is the softest of all waters.
(c) By the addition of lime. Lime has a great affinity
for carbonic acid, combining therewith and forming carbonate
of lime or chalk. When lime, therefore, is added to a natural
water, the carbonic acid is absorbed, and the chalk previously
held in solution thereby is precipitated, together with any
carbonate of magnesia which may have been present. The
sulphates and chlorides are unaffected, so that the permanent
hardness is not reduced. Care has to be taken that an
excess of lime be not added, since it is somewhat soluble in
water, and any excess present will again increase the hard-
ness. As 1 cwt. of lime, costing Is., will soften as much
water as 2 cwts. of 60 per cent soda ash, costing 14s., or 1
ton of soap, costing over .30, there can be no question as
to the economy of using lime. Dr. Clark was the original
patentee of the lime process, and it is the one almost uni-
versally adopted. Since the lapse of his patent many
modifications have been devised for the purpose of dosing
the water automatically with the proper quantity of lime,
and for facilitating the removal of the carbonates precipi-
tated. Atkins', Gittens', the Porter-Clark, the Stanhope,
the Howatson, and Archbutt and Deeley's processes, are
those best known, but some of these are more especially
designed for softening water for manufacturing purposes and
for use in steam boilers, than for water for domestic use.
In Clark's original process lime water was added to the
water to be treated, and the mixture was allowed to clear
by subsidence in large tanks or reservoirs. To ensure com-
plete clarification required at least 24 hours. Large tanks
were necessary, and these had frequently to be cleansed.
s
258 WATER SUPPLIES
Modern inventors have devised means for dispensing with
the large settling tanks, and for ensuring much more rapid
and complete removal of the precipitated carbonates. In
Atkins' process lime is mixed with water in a cylinder called
the "lime cylinder," and the solution so formed passes
through special regulating valves into a "mixer," in which
it is mixed with the water to be treated in the proper pro-
portion. The mixture then flows into a " softening cistern,"
in which a portion of the precipitated matter is deposited,
and the partially clarified effluent is next conducted into
patent machine filters, which " are constructed with a series
of hollow metal discs, covered with cloth, so arranged as to
give the largest possible amount of surface in the smallest
space." Sets of revolving brushes are attached in such a
manner as to play over the whole surface of the discs when
set in motion, and by means of pulleys outside the tanks,
worked if necessary by steam, the brushes are made to
revolve, and the filters are rapidly cleansed. At Henley
(population 5000) such an apparatus, with three filters, has
been in use since 1882, and, according to Professor Attfield's
analysis, the water is reduced by the treatment from 19*5
to 4*2 of hardness. At Southampton (population 65,000)
about 2,000,000 gallons of water per day are softened, and
the plant is said to be the largest in the world. It includes
twelve filters, a softening tank 76 feet x 45 feet x 5| feet,
two "lime" cylinders, mixer, and lime -slacking mill, all
comprised in one building measuring about 134 feet by 48
feet. Without enlarging the building additional plant can
be added, so as to increase the supply of softened water to
3,000,000 gallons per day. 1 At Lambeth Workhouse, with
1500 inmates, there is an installation for softening 300,000
1 Much dissatisfaction has arisen lately at Southampton in consequence
of the water, after being softened, depositing calcareous matter in the
mains, and not always being delivered free from turbidity. Whilst, on
the one side, this is declared to be the fault of the process employed,
the patentees assert that is entirely due to the careless way in which the
system is worked.
THE SOFTENING OF HARD WATER 259
gallons of water per day. The plant occupies a space of
22 feet by 16 feet, and the only attention required is said
to be the labour of one man for an hour a day. The cost
of the plant was about 2000, and the total expense of
treating the water supply is said not to exceed 50 per
year, or, including interest on capital, about Jd. per 1000
gallons. The saving in soap, soda, fuel for boilers, repairs
to boilers, tea, etc., is believed to amount to over .1000 per
year. The Atkins Company, recognising the validity of
the objections to this system where comparatively small
quantities of water are required, have recently introduced a
plant dispensing with the costly machinery, and reducing
the expense and trouble of cleaning and renewing the filters.
The apparatus (Fig. 17) consists of three parts, viz. a "lime
cylinder," B; a mixer, A; and a " softening cistern," D, holding
two hours' supply. The mixture of lime and hard water is
delivered at the bottom of the cistern, and the softened and
clarified water flows over the top into troughs, which convey
it into the storage cistern. The action is continuous.
Mr. W. G. Atkins has also recently introduced a new form
of filter, which is stated to be " capable of dealing with un-
limited quantities of suspended matters, and in which the filter-
ing medium is constantly being cleaned, sterilised and aerated."
The Porter-Clark Company claim that their system is
the most economical, since the apparatus is of a very simple
character, requires very little labour and attention, and
works under pressure, so that the softened and filtered water
can be delivered into high-pressure cisterns without pumping.
It consists of two vertical cylinders and a filter press. In
the first cylinder there is a continuous preparation of lime
water. In the second the hard water and proper proportion
of lime water are mixed, and in the press, which is made up
of a series of plates, with cloths interposed, the precipitate
formed is filtered out. Where large quantities of water are
being treated, some motive power is required to keep the
contents of both cylinders in a state of agitation. The
A /
THE SOFTENING OF HARD WATER 261
approximate price of a plant softening, automatically, 1000
gallons an hour, is 200 ; for softening 2000 gallons, 280.
The London and North- Western Railway Company use this
system at various depots. At Liverpool, Camden, Willesden,
and Rugby, about 1,000,000 gallons, in all, are softened
daily for use in their locomotives. Modified forms of this
apparatus are made for special purposes. One form, which
dispenses with motive power, save that of a man for a few
minutes daily, will soften from 500 to 2000 gallons of water
per hour, and by the use of various other reagents besides lime,
such as caustic soda and carbonate of soda, the permanent as
well as the temporary hardness can be reduced where necessary.
The Porter-Clark process has been adopted in a large number
of public institutions, manufactories, mansions, etc.
The " Stanhope " water softener (Fig. 18) occupies but little
space, possesses no movable parts, and no filtering apparatus,
the water being clarified by subsidence in special tanks con-
taining numerous sloping shelves, upon which the carbonates
are deposited. It aims at reducing both the permanent and
temporary hardness, lime and soda being the chemicals used
for this purpose. The only attendance required is that of a
man to mix the lime-water and soda every few hours, and to
open the mud cocks occasionally to let out the accumulated
precipitate. The cost of softening by this process is stated
by the makers to average Id. per 1000 gallons, though this
will depend upon the character of the water treated. It
appears to be a favourite with manufacturers, especially wool-
washers and bleachers, and with large users of steam power
for boiler purposes. Quite recently the Stanhope water
.softeners and purifiers have been considerably improved. For
the sloping shelves in the clarifying tower a series of perforated
funnel-shaped cones (Fig. 19) have been substituted. These
cause the water to traverse the tower more slowly, and more
perfect sedimentation results, A continuous mechanical lime
mixer has also been added. For potable purposes some system
of filtration is necessary to secure absolute clearness. The
FIG. 18. The "Stanhope ' Water Softener.
THE SOFTENING OF HARD WATER 263
makers recommend filter presses, since the work left for the
cloths to do is almost nil, and they may be used for a length
of time without requiring cleaning. The natural head of
water from the clarifying tower supplies all the pressure
necessary. This simple mode of filtration may be sufficient
for certain very pure waters, but for contaminated waters
sand filtration would be far preferable.
The " Howatson " softener is somewhat similar in principle
to the above. The lower portion of the apparatus consists of
a tank divided into two compartments, each having a hopper
bottom. Into one the water and chemicals are introduced,
and after chemical action has taken place the mixture passes
at the bottom into the other, which acts as a "subsidence
filter." The lime and other chemicals are contained in two
smaller tanks placed above the larger, and which are used
alternately. By means of floats, cocks, and nozzles, the
proportions of the chemical solution and of the hard water to
be softened can be regulated. No agitator is required, and
the deposited carbonates are removed by occasionally turning
the sludge taps at the bottom of the hoppers.
At Stroud Waterworks the water is softened and clarified
by a very simple modification of Clark's original process, all
filtering machines being abandoned. By aid of a small water
wheel, driven by the water to be treated, two pumps are
worked, one raising lime water and the other the hard water.
By altering the length of the stroke the proportion of the two
can be adjusted, and as the rapidity with which the wheel
rotates depends upon the pressure of the water in the mains,
the relative quantities of lime water and hard water pumped
remain constant. The treated water is clarified by subsidence
in large settling tanks. The machine above referred to is the
patent of C. E. Gittens, Limited, and will soften 1,000,000
gallons of water per day. 1
Messrs. Archbutt and Deeley have recently devised an
apparatus which they regard as having many advantages
1 The amount actually softened is 300,000 gallons per day.
FIG. 19. The Stanhope Water Softener (Clarifying Tower).
THE SOFTENING OF HARD WATER 265
over others in the market, especially for treating waters
containing magnesia salts. The chemicals used (lime and
soda ash) are boiled with water and then mixed with the
hard water, contained in a tank, by means of a steam
" trajector." After thorough mixing, steam and air are forced
by a " blower " through perforations in a series of pipes laid
close to the bottom of the tank. This stirs up the mud and
diffuses it throughout the water, and when the liquid is
allowed to rest precipitation is very rapid. In from thirty
minutes to one hour the water is almost perfectly clear and
can be drawn off. By using duplicate tanks, one quantity of
water can be treated whilst that in the other is undergoing
clarification. Water which contains magnesia compounds,
after precipitation, still contains a little carbonate of magnesia,
which rapidly blocks up the boiler " injector." To obviate
this the water, when being drawn off from the settling tank
into the storage tank, is dosed with carbonic acid gas by aid
of a blower. The carbonic acid is derived from the combus-
tion of coke in a special stove. The water when sufficiently
carbonated no longer deposits in the tubes. By this process
the labour involved is as great for softening 2000 gallons as
20,000, but with large quantities the expense for labour is
said not to exceed ^d. per 1000 gallons. Some waters are
found to clarify much more rapidly if a little alum be added,
together with the other chemicals, and this the inventors
recommend in such cases.
The cost for chemicals required to soften waters of various
qualities is given in the following table by Messrs. Archbutt
and Deeley, and is quoted here, since the chemicals used in
this process are the same, both in quality and quantity, as
those used in other processes which are designed to soften
water containing both lime and magnesia. It will be observed
that the cost increases rapidly with the amount of sulphates
present, especially sulphate of magnesia, since such water can
only be softened by use of soda ash as well as lime. In each
case the hardness is reduced to from 3 to 5.
266
WATER SUPPLIES
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THE SOFTENING OF HARD WATER 267
The Maignen "Filtre Rapide" Co. are the makers of a
plant which softens and filters the water automatically.
By means of a small motor worked by the flow of the
water to be softened, the proper amount of " Anti-calcaire "
is added, and mixture takes place in a small tank. From
this the water flows to another tank, where most of the sedi-
ment is deposited. Finally it traverses one of their rapid
filters and reaches the storage tank in a completely clarified
condition.
Although certain of the processes described would appear
to require very little personal attention, according to the
statements of the inventors, yet, if uniformly satisfactory
results are to be obtained, there must be constant supervision.
The treated water must be repeatedly examined to ascertain
that neither too little nor too much of the lime or other
chemicals is being added. If too little, the water will not
be properly softened, and if too much, the water will be
rendered alkaline, and the magnesia will not be removed.
When the amount of lime added is a little less than the
theoretical quantity required to precipitate wholly the lime
and magnesia salts, the two carbonates separate in a form
which settles well, and the softened water filters readily.
When the full theoretical amount is used, or a slight excess,
the carbonates deposit slowly, and in a form which rapidly
clogs the filters. Even after passing the filter, more magnesia
continues to separate for from twelve to twenty-four hours.
When spring or deep -well waters are being softened, the
best proportions of lime water and spring or well water having
been once determined, it only remains to examine the water
occasionally to see that these proportions are being main-
tained, and that the lime water is uniform in strength. If
the lime water be not saturated with lime it will be too weak,
whereas, if by undue agitation it is not only saturated, but
contains lime in suspension, it will be too strong. With
river waters the case is often different. The composition
may vary considerably with the season, and, if a tidal river,
268 WATER SUPPLIES
with the state of the tide, and skilled examinations must be
frequently performed to ascertain the exact proportion of
chemicals to be added.
The Rivers Pollution Commissioners state that at Canter-
bury, Caterham, and Tring, the water is reduced 20 in
hardness by Clark's process, at a cost of only 27s. per
1,000,000 gallons for lime and labour. This may be taken
as a fair estimate of the cost for lime and labour of softening
an average sample of such hard waters as are being used for
town supplies. Assuming that the interest of capital ex-
pended in plant, buildings, land, etc., increases the cost to
Id. per 1000 gallons, or 4:3: 4 per 1,000,000, and that
the hardness to be reduced is only 16, the following may be
taken as a low estimate of the saving effected by the soften-
ing of a town water supply
Cost of softening 1,000,000 gallons . . .434
Suppose T V only is used for washing purposes
(domestic and laundry), and that half of
this is softened with the cheapest soda, and
the remainder with soap, the cost would be,
very approximately ..... 60
Suppose ^ be used in steam boilers, that steam
coal costs 13s. per ton, and that 25 per cent
more fuel be used on account of incrustation,
the cost of additional coal is 920
Total 69 2
This represents a saving of nearly 65 per 1,000,000
gallons, or of 23,000 a year to a town of 30,000 population.
A town of one-third the size would save 7,000. Even in
very small towns the saving would be enormous. This
estimate is very much below those usually given by makers
of softening apparatus, since in many cases the cost of
softening is less than that given above, and a larger propor-
tion of water may be used for washing purposes. They
forget, however, that all the water used for washing purposes
is not completely softened. When used for personal ablution
THE SOFTENING OF HARD WATER 269
only the very small quantity taken up on the hands is
completely softened, as the water after use is found to be
only 1 to 2 degrees softer than before. The saving in the
wear and tear of boilers, of culinary utensils, and the saving
in the consumption of tea, are also items which have not been
taken into account in the above estimate, yet which can be
made to show a very considerable pecuniary balance in favour
of softened water. Under the most adverse circumstances,
where the water contains both lime and magnesia salts, and
is "permanently" hard, requiring the use of soda as well
as lime for softening, and large tanks and filter beds for
ensuring complete clarification, the cost could not exceed
Is. per 1000 gallons, and the saving effected would be
actually greater than in the towns, where the cost was only
Id., since the waste of soda, soap, fuel, etc., which would be
prevented, would be so much greater in proportion.
As few people realise the enormous saving effected
by the substitution of a soft for a hard water supply,
probably the following report, which deals not only with the
actual economy in the use of soap, soda, and fuel, but also
with the saving of labour and other items, will be read with
interest.
METROPOLITAN ASYLUMS BOARD.
Report of the Committee for the Darenth Asylum ami Schools.
ink May 1887.
AT their meeting this day your Committee received from Mr.
Harper, the Steward, a report as to the economical results which
have attended the adoption at the Asylum and Schools of the Atkins
system for softening the water supply. These results have fully
justified the expectations of your Committee, inasmuch as, during the
past twelve months, the estimated reduction in expenditure in the
several departments of the Asylums and Schools, consequent upon
the adoption of the system, has amounted to between 800 and
900,! an amount that may be subdivided as follows :
1 There being about 1800 inmates, the saving is at the rate of nearly 10s. per
head per annum. A later report, dated 1892, confirms the above in every par-
ticular.
WA TER S UPPL IES
Saving in value of soap and soda issued . . 300
Value of material and labour saved in replacing
steam and hot- water pipes, circulating
boilers, etc. . . . . . 384
Reduced annual wear and tear of steam boilers,
circulating boilers . . . . 240
Saving of coal . . . . . . 5600
980
Deduct working expenses :
Coat of lime . . . 38 17
Cost of renewing filter clotbs . 2000
Proportion of engineer's wages 50
108 17
Total estimated amount saved during the year 871 3
Regarding the reduction of expenditure on the items of soap and
soda, the Steward points out that not only has an amount of 300
been saved during the past twelve months, but that the wear and tear
on the linen has been greatly reduced by being washed in softened water,
a fact which would indicate a considerable saving over and above the
actual cost of washing materials used in the laundries.
As to the reduction of expenditure on material and labour in re-
placing steam and hot- water pipes, circulating boilers, etc., the
Steward further points out that the steam boilers, which, before the
introduction of the soft- water system, were incrusted with chalk deposit,
are now in a most satisfactory condition, and give no trouble whatever.
These boilers have, moreover, been recently examined by the inspector
of the Engine Boiler Insurance Company, and from his report it would
appear that not only is there now no incrustation, but tliat the incrusta-
tion which had been left formerly and could not be removed, particularly
in some inaccessible places, has come aivay of its own accord, leaving
the boilers perfectly clean. This appears to your Committee to be an in-
teresting point, and one to which attention should be specially directed.
Regarding the condition of the circulating boilers, hot- water pipes,
etc., which before were caked and congested with chalk deposit, it is
satisfactory to be able to announce that this deposit has entirely
disappeared, and that the coils and pipes are in every instance
perfectly clean.
The removal of these deposits indicates several distinct economies,
inasmuch as (a) the circulating tanks, which it had before been
found necessary to replace every year or two, will now, it is anticipated,
last for several years ; (&) much less time, combined with a correspond-
ing reduction in the consumption of fuel, is required to heat the water ;
and (c) a higher temperature is maintained in the Wards and clscwlicrc
than ivas before found practicable.
(Signed) H. PRIVETT, Chairman,
THE SOFTENING OF HARD WATER 271
The particular method of softening best adapted in any
given case depends upon many circumstances, such as
the character of the water to be softened, the purpose for
which it is chiefly required, the amount of available space,
the available motive power, the amount of water required,
and whether for constant or occasional use. The cheapest
plant, which, with the use of the cheapest chemicals, and
the least expenditure in labour, will produce the desired
result, will naturally be selected, and this can only be
decided upon when all the above factors have been duly
considered. Under suitable conditions all are capable of
giving excellent results.
During the process of softening, the bacteria contained in
the water suffer a considerable decrease in number. Ap-
parently these organisms become entangled in the precipitate
formed, and settle therewith to the bottom of the tanks.
Professor P. Frankland found that by agitating water with
powdered chalk, the treated water after subsidence only
contained about 3 per cent of the organisms originally
present. A carefully-filtered softened water, therefore, ought
to be 'practically sterile. With waters of a high degree of
purity, the filtration necessary after softening would be
merely to remove suspended particles of carbonates ; but
where river water, known to be sewage contaminated, is
being treated, the filtration must aim at removing all the
micro-organisms which may have escaped precipitation, or
have passed through the rapid filters supplied with certain
of the machines that is, this rough filtration must be sup-
plemented by thorough filtration through properly-prepared
sand filters. A water which has been thus treated would
appear to be as safe for domestic purposes as our present
scientific knowledge enables us to make it,
CHAPTEE XVI
QUANTITY OF WATER REQUIRED FOR DOMESTIC AND
OTHER PURPOSES
THE amount of water necessary to supply all the wants of a
given population may be calculated upon the basis of the
theoretical requirements of each individual or household, plus
the estimated quantity which will be necessary for municipal
and manufacturing purposes, or it may be calculated upon
the basis of the amount actually supplied to other similar
communities. The results so obtained will often be found to
vary considerably, and the causes of such variation are very
difficult to explain. The amount used in households similarly
circumstanced with reference to their supply varies greatly,
according to the habits of the individual members ; but where
the supply is practically unlimited and readily available, the
quantity used is always greatly in excess of that consumed
where the supply is limited, or where it is more or less difficult
to obtain. In rural districts, where water has to be purchased
from the hawker or fetched from a considerable distance, the
amount used is astonishingly small, that which has been used
for the purposes of personal ablution having often to serve
afterwards for washing the crockery, and finally for washing
the floors, etc. In numbers of cases I have found that the
amount used in country cottages could not have greatly
exceeded 1 gallon per person per day. Of course neither
perfect cleanliness nor health is possible under such circum-
WATER REQUIRED FOR DOMESTIC PURPOSES 273
stances. On the other hand, where the supply is abundant
and easy of access, a very large proportion is often wasted,
and 100 gallons or more per person per day may pass from
the mains into the sewers.
The purposes for which water is required may be summarised
as follows (a) For drinking, either as water or made into
such beverages as tea, coffee, and cocoa, and for cooking
purposes ; (b) for personal ablution, including baths ; (c) for
household washing, including cleansing and swilling of floors,
yards, etc. ; (d) for use in water-closets ; (e) for the supply of
horses, cattle, and washing of carriages ; (/) for watering
plants and gardens in the dry season ; (g) for municipal
purposes, cleansing streets, flushing sewers, extinguishing fires,
etc. ; and (h) for manufacturing and trade purposes. Where,
for municipal and manufacturing purposes, water can be more
cheaply obtained from wells, streams, or other sources, obviously
the public supply of pure water needs not be nearly so large
as in towns where such sources are not available. Where
subsoil water can readily be obtained from shallow wells, it
may be utilised for many of the above purposes, especially
for the stable and garden, and the demand upon the public
supply be further curtailed. The amount of water required
for each of the above purposes has been variously estimated.
Professor Rankine, in his work on Civil Engineering, states as
his opinion that 10 gallons per head should be allowed for
domestic purposes, 10 gallons for municipal purposes, and
10 gallons for trade purposes in manufacturing towns. Most
engineers, however, consider the estimate for municipal
purposes to be too high, since in the majority of towns the
amount used does not exceed 3 gallons per head. For trade
purposes also Rankine's estimate is probably excessive, 7
gallons per head being a liberal allowance. Dr. Parkes 1
measured the water expended in several cases ; the following
was the amount used by a man in the middle class, who may
be taken as a fair type of a cleanly man belonging to a fairly
clean household :
1 Parkes' Practical Hygiene.
274 WATER SUPPLIES
Gallons daily per
one Person.
Cooking ........ '75
Fluid as drink (water, tea, coffee) .... '33
Ablution, including a daily sponge bath, which took
2 to 3 gallons ...... 5'0
Share of utensil and house washing . . . 3*0
Share of clothes (laundry) washing, estimated . 3*0
12-0
The above may be taken as a liberal estimate for domestic
requirements applicable for most communities. Where water-
closets are introduced, 2 to 6 gallons, according to the mode
of flushing, must be allowed ; for the supply of horses and
cattle and use in garden 2 to 5 gallons ; for municipal purposes
to 10 gallons; and for manufacturing purposes to 10
gallons. Where the water is not required for trade or muni-
cipal purposes, a supply of from 16 to 23 gallons per head
will suffice ; but where the water is also wanted for cleansing
streets, flushing sewers, supplying factories, etc., as much
as 40 gallons may have to be provided. Allowing 2 gallons
for unavoidable waste, we may take 18 gallons as the minimum
and 42 as the maximum supply required by any community.
These figures may be checked by the actual amounts used
in various towns. The River Pollution Commissioners, in
their Six.th Report, in discussing the question whether a
constant or intermittent supply be the more economical, give
two tables one of the amount of water supplied per house in
each of seventy-one towns with a constant supply, and the
other of twenty-four towns each having an intermittent supply.
The following is a brief summary of the tables referred to :
Constant Intermittent
Supply. Supply.
No. of towns using not more than 50 galls.
per house ...... 3 1
No. of towns using over 50 and not more
than 75 galls, per house ... 13 4
No. of towns using over 75 and not more
than 100 galls, per house ... 8 2
WATER REQUIRED FOR DOMESTIC PURPOSES 275
Constant Intermittent
Supply. Supply.
No. of towns using over 100 and not more
than 150 galls, per house ... 20 9
No. of towns using over 150 and not more
than 200 galls, per house *. 10 2
No. of towns using over 200 and not more
than 300 galls, per house . . . 12 4
No. of towns using over 300 and not more
than 400 galls, per house ... 2 2
No. of towns using over 400 galls, per house 3
The mean daily supply per house in the seventy-one towns
was 135 gallons, in the twenty-four towns 127 gallons.
Taking five as the average number of persons per house, the
mean daily supply under the constant system was 27 gallons,
and under the intermittent system 25*4 gallons. In London,
with an intermittent system of supply, the average per person
was 40 gallons (204 per house).
The amount of water supplied per house under both
systems varied enormously. With a constant supply Hey-
wood and Middlesborough furnished the two extremes. At
the former town, with 5200 houses and 30 factories, only 20
gallons per house per day were consumed ; at the latter, with
7000 houses and 80 factories, the amount was 700 gallons, or
thirty-five times as much. The quantity stated to be supplied
to Heywood is probably erroneous, since the Heywood and
Middleton Company is elsewhere mentioned as supplying
7000 houses and 150 manufactories with 100 gallons per
house daily. This latter amount is, however, only one-seventh
that of the Middlesborough supply, and the difference is the
more marked inasmuch as both places are supplied by private
companies, and the latter in each instance are reported to
have inspectors who examine the taps and fittings to prevent
waste. With an intermittent supply, Huddersfield, with its
8500 houses and 600 factories, only used 49 gallons per house
daily, whilst Berwick, with 1150 houses and 7 factories, used
330 gallons per house. That these enormous differences
276 WATER SUPPLIES
depend more upon the amount wasted than upon the amount
used for either domestic, municipal, or trade purposes is
almost certain. The consideration of a few more modern
statistics confirms this opinion.
In the following table the amount of water used daily per
unit of population in a number of representative towns is
given. Most of the figures are taken from recent reports of
Medical Officers of Health or Water Companies.
Population.
Saffron Walden . . . 6,108
Melrose . . . . 1,300
Bridlington .... 9,806
Halstead . . . . 6,100
Chepstow . . . .3,387
East Ham .... 33,000
Atherstone . . . .5,000
St. Austell . . . . 3,400
Chelmsford .... 11,079
Bristol. . '. . . 222,000
Bedford .... 28,023
Weston-super-Mare . . 15,869
Swansea .... 93,864
Barking . . . .15,115
Nottingham. . . . 211,984
Wolverliampton . . . 82,620
Grantham . . . 16,746
Yeovil 9,648
Walthamstow . . . 49,400
The variations here, though not nearly so great as in the
River Pollution Commissioners' table, are still very considerable.
Having recently to make an examination of the Halstead
supply, I verified the above figures. The supply there is
constant, and the water is used for flushing sewers, watering
the streets, etc., as well as for flushing water-closets, and other
domestic purposes. In this town a large proportion of the
women are engaged during the week at the crape factories,
and Saturday is the great washing-day. The amount used
on a Saturday was as under :
WATER REQUIRED FOR DOMESTIC PURPOSES 277
From 8 A.M. to 2 P.M. . . . 9800 gallons per hour.
,, 2 P.M. to 4 P.M. . . . 9500
,, i P.M. tO 5 P.M. . . . 6000 ,, ,,
The average amount used on a week-day was 104,000 gallons,
and on Sundays 84,000 gallons. Small as this amount
appears, there is no doubt that a considerable portion was
wasted, since many thousands of gallons passed from the
service reservoir during the night, when little or none was
being used.
At Wolverharnpton the careful records kept at the Cor-
poration Waterworks show that in 1868 "the domestic
consumption per head of consumers, deducting for trade
purposes, street watering, etc.," was 18 gallons. In 1892 it
had increased to about 23 gallons. In the latter year the
total amount supplied for all purposes was about 29 gallons
per head daily.
At Newcastle the consumption per head, for all purposes,
in 1863 was 28 gallons; in 1881 it had increased to 38^
gallons. " This," says Dr. Armstrong, the Medical Officer of
Health, "shows an increase of 37 per cent in the amount
consumed for each person, due, no doubt, largely to improved
habits of cleanliness among the people. Looking at the
fact that baths and water-closets, which even then were
considered as luxuries, are now regarded as necessities in
almost every house of any pretensions to comfort, . . . it is
not too much to assume that there will be a still further
increase in the consumption per head." No doubt this in a
measure is true, but it is at least probable that much of this
increased consumption is really increased waste, consequent
upon the increased age of the mains and fittings. In London,
by greater attention to the sources of waste, the net supply
per head of population has in many cases been very consider-
ably decreased. The following table l is interesting as show-
ing the actual amount of water supplied daily by the London
Companies and the wide difference in the supply per head.
1 Report of Royal Commission on Metropolitan Water Supply, 1893.
27 8
WATER SUPPLIES
Name of Company.
Net Supply
daily.
Population.
Net Supply
per Head.
New River ....
32,640,976
1,159,260
28-16
East London
39,704,601
1,158,500
34-27
Chelsea ....
9,557,388
287,362
33-25
West Middlesex .
15,419,907
577,235
26-71
Grand Junction
16,701,734
350,000
47-72
Lambeth ....
20,234,560
655,921
30-85
Sonthwark and Vauxhall
24,373,348
841,989
28-94
Kent .....
12,530,891
460,524
27-21
171,163,385
5,490,791
31-19
Of this quantity it is estimated that about 20 per cent,
or between 6 and 7 gallons per head, is used for trade and
municipal purposes. Whilst the West Middlesex Company
supply only 27 gallons per head, the Grand Junction Company
supply 48 gallons, and this the engineer of the latter company
explained to be chiefly due to waste, since they found it
cheaper to pump water than to supervise and control the
waste.
The following table is taken from a paper by Mr. T.
Duncanson, A.M.I.C.E., on "The Distribution of Water
Supplies," read before the Liverpool Engineering Society,
April 1894.
Name of Company
or Town.
Year.
Domestic
Supply in
Gallons
per Head.
Trade
and Public
Supplies.
Gallons
per Head.
Total
Gallons
per Head.
Percent-
age of
Supply.
Given
Constant.
Liverpool
Bradford
1893
1891
17-10
18 to 20
9-8
20-0
26-9
38 to 40
100
100
Manchester
1893
15-0
9-0
24-0
100'
Birmingham .
1893
17-0
875
25-75
100
Glasgow .
1893
36-0
16-0
52-0
100
St. Helens
1893
18 to 21
1 8 to 20
36 to 41
100
Swansea .
1893
23-4
4-2
27-6
32
All waste is included in the amount set clown for domestic
supply.
WATER REQUIRED FOR DOMESTIC PURPOSES 279
Waste of water arises from two distinct groups of causes
(a) those over which the consumer has no control, and (b)
those under the control of the consumer. As a rule the
latter causes are responsible for the larger portion of the
waste. Under (a) are included leakages from faulty mains
and service pipes, and all other hidden defects, where the
water escapes unperceived into drains and sewers or into the
subsoil ; under (b) the waste from defective house fittings,
leaving taps open, etc. Such waste is also supplemented by
an unnecessarily great consumption, due to the use of im-
perfect appliances, such as many forms of closet basin, and
flushing tanks, the automatic flushing of urinals, and to the
use of water for gardens, fountains, and similar purposes.
By the employment of a staff of inspectors the waste
arising under (b) may be in a great measure controlled, but
something more is required for the discovery and check of
that arising under (a). By the use of water-waste meters or
detectors the particular branch mains from which the water
is escaping can be discovered, and by the aid of an instru-
ment resembling a large stethoscope the faults can be local-
ised. The " Deacon," " Tyler," " Kennedy," and " Ginman "
waste detectors are those best known. These meters register
automatically and continuously the rate at which the water
is passing through the mains to which they are attached.
It can thus be ascertained whether the draught has been
excessive at any particular time, or whether this is constantly
high. The number of houses supplied through each meter
being known, it is easy to decide whether the amount of
water which has passed is in excess of their requirements.
If, after an examination of the fittings and rectification of
visible defects, waste still continues, the mains and service
pipes require attention. If the ear be applied to the service
pipes near where they emerge from the ground, any escape
of water from the pipe or main in the immediate neighbour-
hood can be heard, the more distinctly the nearer the defect.
The ear can also be applied to the uncovered main for a
280 WATER SUPPLIES
similar purpose, but it is often more convenient to apply it
indirectly, using a walking-stick or a special instrument.
Upon placing one end on the exposed main and the other to
the ear, the fault, if any, can be localised.
Mr. E. Collins, M.I.C.E., in a paper recently read before
the Institution of Civil Engineers, on " The Prevention and
Detection of Waste of Water," says that a 4-inch Deacon's
meter will control 400 to 500 houses, but that smaller
districts are preferable. The outlay involved is consider-
able, averaging 150 for each 1000 houses controlled. This
sum includes the cost of the meters and of fixing them on
a by-pass, and of the valves necessary for isolating the
divisions of the district. Where the meters are in use,
however, a much smaller staff of inspectors is necessary, since
a glance at the meters enables the inspector to discover the
locality in which waste is taking place. At Shoreditch, as
previously mentioned, Mr. Collins was able in three years to
so reduce the waste as to save annually 720,000,000 gallons
of water. This was effected by a capital outlay of .1800,
and an annual expenditure of 926 for staff and establish -
mental expenses. Each 1,000,000 gallons saved cost there-
fore about 1 : 9s. Small as this sum appears, it is probable
that it exceeds the cost of pumping, especially if the most
modern machinery be employed. The prevention of waste
can only be accomplished by the expenditure of money, and
whether it be more economical to allow the waste to continue
or to control it depends upon circumstances varying from
place to place, and it is only after a careful consideration
of these that it can be determined in any given district which
is the cheaper.
When inquiries are made to ascertain the cause of the
variation in the amount supplied in different towns, it is
found that only on the assumption that it is due to the
varying quantity wasted can an explanation be offered.
Some towns, with manufactories using large quantities of
water, use less in proportion to the population than others
WATER REQUIRED FOR DOMESTIC PURPOSES 281
in which there are few or no manufactories. Towns in which
there are very few water-closets often use more than towns
in which water-closets are universal. Where the closets
are chiefly flushed by hand more water may be used than
where all have got a supply laid on. Where no water
is used for sewer cleansing more is often used than where
flushing arrangements are fixed at the end of every sewer.
Where water from the mains is used for street cleansing and
road watering, less is often actually used than in towns
which obtain water for these purposes from other sources.
In every town, moreover, there is a great outcry about the
amount wasted, and we can only conclude therefore that
since no other factor or combination of factors will explain
the difference in the amount supplied per head daily, that
this must be attributed chiefly to waste. Such being the
case it is evident that the amount of water necessary for the
supply of a town is very much less than the estimates given.
Probably 20 gallons per head daily would be an abund-
ant supply for all purposes in the majority of cases, and
30 gallons only be required in exceptional instances. To
prevent waste and unnecessary consumption, however, so
that the above quantities may suffice, the whole of the
works in the first instance would have to be most carefully
constructed, means taken to quickly detect where waste is
occurring, constant supervision exercised over all house fit-
tings, and all undue consumption checked by byelaws, or
by insisting upon the use of water meters by large con-
sumers. 1
Few persons realise the immense amount of water which
is wasted in almost every town. Thus in Liverpool, where
the average amount supplied daily per head was 33'5 gallons,
Deacon's water-waste detectors were introduced, and these,
together with efficient inspection, reduced the supply to 23
gallons without any restrictions being placed upon the
consumers. At Shoreditch, with a population of 87,000,
1 A meter suitable for small consumers is a want yet to be supplied.
282 WATER SUPPLIES
the introduction of waste detectors effected in the course
of three years a diminution of waste and undue consumption
amounting to 720,000,000 gallons per annum, or 23 gallons
per head daily. Mr. Boulnois recommended the use of
Deacon's meters at Exeter, and their introduction reduced the
waste from 75 to 12 gallons per head per day.
In other parts of London, in Bradford and elsewhere,
where waste detectors have been introduced, the expenditure
of water has been reduced by from one-third to one-half.
A most instructive instance of what can be done by
checking waste was given by Mr. Hawksley in evidence
before the River Pollution Commission. He said that
when "the city of Norwich Waterworks \vere transferred
from a very old-fashioned company to a new one . . . the
delivery amounted to 40 gallons per head per diem, and
that amount of consumption exhausted all their pumping
power. They obtained a very good manager, and, under
my advice, they applied for an additional Act of Parliament
to enable them to correct the fittings. . . . The bill was
carried, and it was put into operation, and now and for
many years past, although the constant supply has "been
unfailingly in use, the water is never shut off, and the
consumption has descended to 15 gallons per head per diem,
as compared with 40 previously." In many cases a check
is placed upon waste by placing in the service pipe leading
to the house cistern a disc with a small hole in it, which
prevents more than a certain amount of water passing through
in a day. This, however, is a most objectionable arrange-
ment, and quite unnecessary, since better results are obtained
by adopting regulations as to the strength, proportion, and
quality of the fittings, and enforcing the regulations.
In tropical climates*, doubtless, the demand for water is
greater, and probably even 30 gallons per head per day
would be barely sufficient. In Bombay 40 gallons is sup-
plied, and in Calcutta 35 '4 gallons of filtered water and 8 '9
gallons of unfiltered, total 44'3 gallons ; but in many other
WATER REQUIRED FOR DOMESTIC PURPOSES 283
cities the amount used falls far short of this. In Madras,
for instance, only about 18 gallons is supplied; but this is
very probably far too little for all the requirements of the
population.
The amount of water required by various animals natur-
ally varies, chiefly with the size. Cavalry horses are allowed
8 gallons, and artillery horses 10 gallons per day. Elephants
require at least 25 gallons, camels 10 gallons, and oxen 6
gallons per head daily.
By a careful study of the requirements of any community
the amount of water which must be supplied daily may be
estimated with a fair approach to accuracy ; but whilst every
care is taken to avoid waste, it must be remembered that
this cannot be entirely prevented, and that it is far wiser to
provide a supply in excess of the requirements, so as to be
prepared for contingencies, and for a possible increase in the
demand, from growth of population and other causes.
The amount of water used per week throughout the year
does not vary greatly, but, as a rule, more water passes through
the mains in summer than in winter. In Liverpool, during
1893, 1 the maximum consumption took place in the week
ending 8th July, and was about 15 per cent above the
average, and the minimum during March, November, and
December, and was about 9 per cent below the average.
(Vide Chapter XX.)
In small towns and rural districts where a large number
of houses have, gardens attached, the summer consumption of
water is often greatly in excess of that used in winter. The
most stringently enforced regulations often fail to prevent
water being used in excess for gardening purposes during
seasons of drought, and such misuse of the water by persons
living in the lower portions of a district may deprive those
residing upon higher ground of the supply to which they
have an equal right.
1 Duncanson, loc. cit.
CHAPTEE XVII
SELECTION OF SOURCES OF WATER SUPPLY AND AMOUNT
AVAILABLE FROM DIFFERENT SOURCES
WHERE there is only one source of water available there is
no question of selection, since there is no choice. Such
instances, however, are comparatively rare : usually there
are more sources than one from which water can be obtained;
and in deciding upon one or another many points have to
be considered. A water seriously contaminated with sewage
or intermittently liable to such contamination, water con-
taining mineral matter in excessive quantity or of deleterious
quality, and water with any marked odour or colour, would
naturally be at once rejected. Cceteris paribus, the water
of greatest hygienic purity and best adapted for manu-
facturing purposes would be selected. Where the available
quantity or economy in utilisation, or both, are in favour of
a water from a certain source, the importance of these factors
must not be allowed to outweigh those of purity and freedom
from risk. As the characteristics of good drinking waters
and the dangers attendant upon the use of polluted waters
have already been discussed, it is not necessary to do more
than refer to them here, special attention being directed
to the sections dealing with river water, the self-purification
of rivers, and the discussion of the risks involved in the
utilisation of river waters admittedly polluted, even when
the intake is many miles below the source of pollution and
SOURCES OF WATER SUPPLY, ETC. 285
the filtration is conducted according to most modern methods.
Where towns of any magnitude are concerned the subject
is so important that the services of experts engineering,
medical, and chemical would naturally be enlisted; and
by these all the advantages and disadvantages of the different
available sources would be carefully considered, and the
decision arrived at would be based upon the facts recorded
and the opinions expressed in their reports. The nature
of much of this evidence may be inferred from the sections
treating of the quantity and quality of water obtainable
from various sources, since the information there given is
of general application. The estimates of cost of collecting,
storing, and distributing will vary in each individual case,
and certain points bearing upon these questions will now
be briefly considered.
In the first instance, however, it will be better to consider
the simplest case that of providing a supply of water for
a single house or small group of houses. In this, as in
undertakings of greater magnitude, some knowledge of the
geology of the district is in most cases absolutely necessary.
Without this the search for underground water is mere
groping in the dark, which may or may not be successful.
Where a spring, however, is available, doubtless this will be
at once selected, especially if it arises at such an elevation
as to be capable of supplying the house or houses by
gravitation. In examining any district for the discovery of
springs, the sides of all streams should be carefully examined,
and all tributary rivulets should be followed up to their
respective sources. If the flow of the stream appears to be
considerably augmented at any point, it is probably due to
the influx of water from a spring, which may permit of being
tapped above the point of discharge. In this case the con-
struction of a reservoir large enough to hold at least a day's
supply and the laying of a service main is all that is required.
One great mistake is, however, frequently made in this simple
arrangement. The pipe is rarely of sufficient size, and some-
286 WATER SUPPLIES
times is not of suitable material. Galvanised iron pipe of 1
inch or even less diameter is often employed to convey water
considerable distances. If the water contain little or no car-
bonate of lime, the zinc will almost certainly be dissolved
and contaminate the water. The pipe then becomes coated
with a deposit of iron oxide, which tends continually to
increase, and ultimately the calibre of the tube becomes
too small to convey the required quantity of water. I
have known many cases in which such pipes have had
to be taken up and larger ones substituted. Cast-iron
pipes coated inside with Angus Smith's protective varnish
should be used, and the diameter should never be less than
2 inches. Where water is required for fire -extinguishing
purposes also, the diameter of the pipe must be consider-
ably greater, and the reservoir must be much larger. The
size of main required under different circumstances will
be discussed when the "distribution of water" is being
considered.
The character of the water yielded by springs from
different geological formations has been discussed in Chapter
V., and the variable yield from certain springs was also re-
ferred to. Before attempting to utilise any spring as a source
of water supply evidence should be obtained proving that
even after periods of continued drought the yield is suffi-
cient for the purposes required. Many springs which flow
freely in the late winter, spring, and summer fail com-
pletely in the autumn, or at least yield a greatly diminished
supply. The evidence of people who may have used the
spring or observed the flow for many years will have some
weight, but must not be too implicitly relied upon. The
flow should be gauged from time to time and the effect of
the rainfall ascertained, bearing in mind that the flow
may not be affected by even long continued heavy rains
until after the lapse of some months, and that the effect of
a long continued drought may not be observed until long
after it has passed away. The less variable the flow, the
SOURCES OF WATER SUPPLY, ETC. 287
more likely it is to be constant ; the longer the interval
between a heavy rainfall or a drought and the production
of any effect upon the flow, the less likely is such an effect
to be serious. As a rule land springs flow most copiously
in February and March, and are lowest in October and
November. The gaugings therefore in the autumn and early
winter are the most important, since the minimum flow is
the information required. If the character of the previous
summer be also taken into account reliable inferences may
be drawn from the results. Small springs may be gauged
by ascertaining the number of seconds required to fill a
bucket of known capacity, or better still by employing
a large vessel, such as a tank or tub. Or the water may be
caused to flow along an open channel, or trough, when the
cross section and velocity of the water in the trough can be
ascertained, and an approximate estimate of the flow easily
calculated. Larger springs may be gauged by damming up
the water and allowing it to discharge over a board from
which a rectangular notch has been cut. The notch should
be two or more inches wide and the edges chamfered. The
principle involved is the same as that already described for
gauging streams, and the height of the horizontal surface of
the water behind the dam above the lip of the notch being
measured, the flow can be ascertained from the formula there
given. The following table gives the discharge in gallons per
minute and per day over a notch- board for each inch of width,
and for varying differences of level. The quantity given in
the table, multiplied by the width of the notch used, in
inches, will give the yield of the spring at the time of
gauging. With notches exceeding 3 inches in width the
results may be relied upon ; with narrower notches they
are not quite so reliable. Moreover, where the flow is so
small that a notch of less than 3 inches is required, the
simpler plan of actual measurement is much preferable.
288
WATER SUPPLIES
Depth.
Flow per
Minute.
Flow per Day.
Depth.
Flow per
Minute.
Flow per Day.
I
31
446
2i
9-8
14,112
88
1,267
3
12'9
18,576
^
1-62
2,333
3i
16-3
23,472
1
2-50
3,800
4
19-9
28,656
H
3-48
5,011
H
23-8
34,272
H
4-57
6,580
5
27'8
40,032
IS
576
8,294
5i
321
46,224
2
7-0
10,080
6
36-6
52,704
It is a noteworthy fact that although springs are not
abundant on the chalk formation, yet some of the largest
springs in the country arise in the chalk. The following are
quoted from Hughes's "Waterworks" :
" Chad well, near Hertford, yielding from 2,700,000 gallons
up to 4,500,000 gallons per day.
"Woolmer, in the valley of the Lea, yielding 2,700,000
gallons per day.
" Grays Thurrock Springs, now pumped up for the supply
of Brentwood, Romford, etc., capable of yielding 7,000,000
gallons per day.
"Nine Wells, near Cambridge, yielding 423,000 gallons
per day.
" Cherry Hinton, near Cambridge, yielding 700,000 gallons
per day."
Where a spring is not available attention will probably
be next directed to the subsoil as a convenient source of
supply, in which case a slight knowledge of the geology of
the district may be invaluable. The points to which atten-
tion must be directed have been referred to in the chapter
treating of "subsoil water." The character of the strata
within reach being known, and the directions in which they
dip and the depth and position of the nearest wells having
been ascertained, the presence or absence of water at any
particular spot may usually be predicted, as well as the depth
at which it will be reached. Where the subsoil is permeable
and the water held up by an impervious stratum beneath,
SOURCES OF WATER SUPPLY, ETC. 289
depressions in the ground, and spots upon which herbage is
most abundant or appears greenest, will often indicate where
the water most nearly approaches the surface. At sunrise
and sunset films of vapour (mist) usually arise first over the
damper portions of an area, and continue of greater density
there than elsewhere. " On a dry sandy plain, morning
mists or swarms of insects are said sometimes to mark
water below" (Parkes). Near streams and near the coast
water is generally found at a slight depth. This is the sub-
soil water flowing towards its natural outlet. Near the sea,
however, the wells may and often do yield brackish water.
Even when some considerable distance from the coast, the
continued maintenance of a low level in the well may result
in the water becoming saline. During a recent exceptionally ^
dry season, the water in a well supplying a town on the ^
coast was markedly affected, although the well was 1 J miles 03
from the shore. The chlorine, which is normally about 3 j
grains per gallon, gradually increased, until a maximum of *J
18 was reached. In hilly districts water is most likely _,
to be found in the lowest portions of the valleys. Where ->
the water-bearing stratum is covered with an impervious 2S
one, the search for water is much more difficult, but a jx;
careful study of the local geology, to ascertain the dip ^J
of the various strata and the thickness of those lying ^
above the water-bearing rock, will usually lead to reliable
inferences being drawn. This is not invariably the case,
however. Thus in Essex a considerable portion of the 3
London clay is capped with drifts of sand and gravel
and boulder clay. The sand and gravel lying between
the London and the Boulder clay varies in thickness, and in
some places is entirely absent, and it is often impossible
to predict whether, by sinking at any particular spot,
water will be found or not. This uncertainty has led to
"water-finders" being employed, and as there is a pretty
general belief in the powers of the hazel-twig in the
district, it would appear as if the finders were usually
u
29 o WA TER SUPPLIES
successful. I have paid some attention to this subject
lately, and find that from the manner in which the hazel-
twig is held, by imperceptible muscular movements it can
be made to rotate between the hands. I have seen the
water-finder walk over places where water existed in abund-
ance without the twig indicating its proximity. In localities
which have been traversed by the finder, I have usually
found that there was no difficulty in indicating where water
could be obtained without the use of a hazel -twig. In
one instance the hazel-twig gave strong indications of the
presence of water at a point at which I was certain there
could be no water within 300 feet, since the soil was of
clay; and in that particular district it was known to be
300 feet in thickness. The owner of the land, however,
had every confidence in the water-finder and proceeded to
dig a well. When he had penetrated the clay to a depth
of about 100 feet and found no indication of water, his
confidence vanished, and the work was abandoned. A
gentleman with whom I am acquainted contends that the
hazel -twig in his hands gives reliable information. He
believes that the presence of the water affects him person-
ally, and the twig through him. Twigs of other trees do
not answer, since they do not possess the necessary elasti-
city, and cannot be made to rotate nearly so readily as
the hazel. He has certainly, recently, been able to indicate
the presence of water in unsuspected places, and as in
his case there can be no suspicion of intentional decep-
tion, the result must either be due to accident plus
unconscious cerebration, or to some, at present, inexplicable
influence of water upon himself or the twig. His last
success is recounted in a letter which he addressed to
me on 19th May 1894. He says, "General - asked
me if I would give my opinion upon the practicability
of finding water in a field facing his house. I went over
and marked out two spots, and at each of these places
digging was commenced, and at less than 10 feet from
SOURCES OF WATER SUPPLY, ETC. 291
the surface water was found. ... I should add that
some time since an engineer made experiments upon the
same ground with boring apparatus, but gave it as his
opinion that within the area no water was available."
According to the geological drift map, the parish in
which General resides is partly on London clay,
partly on gravel, and partly on boulder clay capping
the gravel, and it would seem an easy matter to indicate
almost the exact limits of the area in which water could
be found. In justice to my friend, however, I must add
that he knew nothing of the geology of the district.
Certain points requiring attention in selecting the site for
a well are referred to in Chapter IV., and the possible effect of
the pollution of the drainage area of the well, and the dimen-
sions of this area, are discussed in Chapter XI. Before works of
any magnitude are undertaken for utilising subsoil water, the
area of the collecting surface should be ascertained, its con-
figuration, etc., considered, and the depth of the ground water
and the extent of its fluctuations determined. The less the
fluctuation the more likely is the supply to be permanent,
and the less the liability to contamination. Rapid fluctuations
usually indicate variation in quality, as well as quantity, of
the available water. Where limited amounts only are required,
and the possibility of finding water or of determining the
quantity available cannot be inferred, from the absence of
similar wells in the vicinity, trial borings or sinkings must be
made. The character of the strata penetrated must be
noticed, and the boring continued until water is found or an
impervious stratum reached. Into the latter it is unnecessary
to bore unless it is believed to be of but slight thickness, and
the water above it is not sufficiently abundant. Thin beds
of clay are sometimes found in thick gravel drifts, and they
hold up a certain amount of water, which is obtainable by
pumping. When the clay is penetrated, the gravel beneath
may not be fully charged with water, in which case that
found above will run through and be lost. This is the
292 WATER SUPPLIES
explanation of the mysterious disappearance of water from
certain wells which have been deepened to increase the
supply or the storage capacity. Instead of the supply being
increased, the limited amount previously obtainable has been
lost, and the work has either been abandoned or an attempt
made to reach the water, if any, held in the lower pervious layer.
Where no impervious stratum is penetrated, the water when
reached will not begin to rise in the bore hole, or only to a
very slight extent, since it is not under pressure. In deep
wells, which will be considered later, as soon as the water-
bearing rocks are reached, the water begins to rise, more or
less rapidly, and may even overflow at the surface. In
sinking shallow wells the trial bore must be continued until
the depth of water is judged sufficient. By pumping the
water out of the bore hole and noting the time required for
it to again ascend to its former level, the abundance or other-
wise of the supply may be judged, the more rapid the rise the
greater the available amount of water. The yield of a well
is often gauged by the length of time required for it to fill to
its normal level after being pumped dry. The depth of water
and the diameter of the well being also known, the yield is
easily calculated. The result so obtained is always too low,
since the rapidity with which the water enters varies with the
square root of the head, and the head varies with the difference
between the level of the subsoil water and the level of the
water surface in the well. A more accurate result therefore is
obtainable by starting with the water at a conveniently low
level (say at half the usual depth), and ascertaining the
amount which must be pumped in a given time in order to
maintain it at this level. Such experiments only indicate the
amount available at that particular time, but if made after a
long drought, the result will probably indicate the minimum
yield of the well. Where the limited space available ne-
cessitates the well being sunk near drains, sewers, cesspools,
or other similar possible sources of pollution, not only should
every care be taken in the construction of the well, drains,
SOURCES OF WATER SUPPLY, ETC. 293
sewers, etc., to avoid contamination of the water supply, but
the risk should be reduced to a minimum by sinking the
well in such position that the flow of the subsoil water shall
be from the well towards the drains, and not from the drains
towards the well. In villages and on farms the ground water
is usually so polluted as not to afford a safe supply, however
carefully constructed the well. In such cases, however, good
water can often be obtained at a little distance away in the
direction of the higher ground -water level. This distance
will vary in different places according to the porosity of the
subsoil, slope of the ground water, and amount of water to be
pumped. Where water is only pumped in small quantities
at a time, the influence of the pumping will extend but a
short distance from the well ; but where a supply tank or
water butt has to be filled from time to time, the level of the
water in the well may be considerably depressed and the
drainage area be greatly extended (vide Chap. XL). According
to the permeability of the subsoil, the area capable of being
drained by the well will vary in diameter from 15 to 160
times the normal depth of water in the well. In a loamy
soil a distance of 20 times this depth may be sufficient for
safety; in very coarse gravel the distance should be 150 times
the depth. Where the slope of the ground water is steep there
might be safety within these limits, as the influence of the
pumping would not nearly be so marked at the side of lower
water-level ; but as the plane of saturation is usually nearly
horizontal it is best to err on the side of safety and regard it
always as such. Whether the water should be obtained by
sinking an ordinary well or by driving a tube well, may be
decided after considering the advantages and disadvantages
and relative cost of the different kinds of well as described
in Chapter XVIII., on " Well Construction."
Where springs are not available, and water is not obtain-
able from the subsoil, the possibility of obtaining a supply
from a deep well may be considered. As this is a some-
what serious undertaking, probably attention had better be
294 WATER SUPPLIES
directed in the next place to the supply which can be
obtained directly from the rainfall. It is agreed that about
half the rain which falls upon the roof or similar impervious
surface during the whole year can be collected. The other
half is lost by evaporation and by waste from the separators
and filters. Why should not this rain water be stored and
utilised ? Even where water is obtainable for drinking
purposes from springs or wells, it may be so hard or so
limited in amount that it is desirable to collect the rain water
for use in the laundry and for personal ablution. A fair-
sized mansion has often a roof area sufficiently large to collect
enough rain water for drinking, cooking, and general domestic
purposes. Assuming the area covered by the roof to be \ of
an acre (1210 sq. yards), and the minimum rainfall 20 inches,
then 10 inches of this may be collected. As a fall of 1 inch
upon an acre represents 22,620 gallons, 10 inches upon \ of
an acre represents 56,550 gallons for the year, or 155 gallons
per day, a supply which would suffice for ten persons, allow-
ing 15 gallons per head, or for fifteen persons at 10 gallons
per head. In most parts of the country the minimum rainfall
reaches 25 inches, therefore admitting of a more abundant
supply. Where the roof surface is not sufficiently large it
has been proposed to prepare a plot of ground for the purpose.
The best method of collecting, storing, and utilising rain
water was discussed when treating of rain water as a source
of supply (Chap. II.), and that section must be consulted for
further details.
Where larger quantities of water are required, as for
villages and towns, it may be derived from the rainfall on
natural gathering grounds, from the subsoil, from springs,
from deep wells, or from streams. Water collected in hilly
districts from uncultivated surfaces, forms, as we have already
seen, one of the best and purest supplies obtainable. A large
number of towns in this country are supplied from such
sources. Unfortunately in several instances the amount of
water obtainable in the area of the watersheds has been over-
SOURCES OF WATER SUPPLY, ETC. 295
estimated, the result being that in exceptionally dry seasons
something like a water famine has occurred. The approxi-
mate determination of the amount of water which can be
collected from the surface over a given area is one of the
most difficult problems in water engineering, since it depends
upon so many factors, some of which (the meteorological
conditions) are so variable as almost to defy our efforts to
predicate their possibilities. Upon these meteorological con-
ditions, so variable in themselves, depends in a very great
measure two other factors the loss by evaporation and by
percolation. The only factors which are uninfluenced by the
weather are the area, configuration, and character of the col-
lecting surface. The 6-inch ordnance maps give the contour
lines or lines of equal altitude drawn at every 25 feet. The
ridge or watershed lines are also marked, and from these the
ground slopes downwards on both sides. These lines are
continuous, save on the side which forms the natural outlet
of the water collected in the enclosed area of gathering
ground, technically known as a "drainage area" or "catch-
ment basin." In one such catchment basin, branching ridge
lines may form two or more secondary drainage areas. The
area from which the water is to be collected may either be
ascertained by actual measurement or be calculated from
an ordnance map. The configuration, character of the
surface and of the subsoil, and nature and amount of vegeta-
tion, require careful examination, since they influence greatly
not only the amount of rainfall which percolates, but also
the amount of loss by evaporation. A portion of the water
which penetrates the ground in one part of the area may re-
appear in another part as springs, or it may be that the
springs fed by the ground water lie entirely outside the
boundary of the watershed, in which case a further portion
of the rainfall escapes collection.
Where the hills are steepest, the rocks hardest, barest,
and most impermeable, the loss both from evaporation and
percolation will be smallest. The more permeable the
.296 WATER SUPPLIES
subsoil, the more abundant the vegetation and the less steep
the slopes, the greater will be the loss by evaporation and
absorption. Where the soil is peaty, where moss abounds
and bogs are extensive, much water is retained ; it neither
runs off the surface nor percolates into the subsoil, but is
slowly lost again by evaporation. The loss by percolation
is greatest where the subsoil is very porous as when it con-
sists of sand and gravel and when the outlet for the ground
water is outside the collecting area. However, as a rule,
the localities selected as gathering grounds for water supplies
have but a small proportion of their areas covered with any
depth of permeable subsoil, since such ground is objectionable,
not only because of the amount of water which it permits
to percolate, but because, in this country at least, it would
be cultivated or used for pasturing cattle, and would there-
fore tend to pollute the water. The amount of water which
may be lost by percolation has been referred to in Chapter IV.
Both this and the loss by evaporation are affected greatly
by the character of the rainfall. If the rain descends in
frequent slight showers, the whole may be lost ; whereas if
the same amount falls in a few heavy downpours, a large
proportion will run off the surface and may be collected.
In the hilly districts selected as gathering grounds the rain-
fall is not only usually more abundant than in the plains,
but it descends in sharper, heavier showers. As the water
collected from any given area would otherwise have found
its way into some stream or formed the natural source of
such stream, the problem of ascertaining the amount of water
which can be collected is frequently the same as that of
determining the amount of water available from such stream.
These we have already considered in Chapter VII., under
the heads of (a) area of watershed, (b) the topography and
geological character of the ground, (c) the average rainfall
and the rainfall during a consecutive series of dry years,
(d) the seasonal distribution of the rainfall, (e) the amount
of water which must be supplied for "compensation"
SOURCES OF WATER SUPPLY, ETC. 297
purposes, and (/) the facilities for obtaining storage. Based
upon this knowledge engineers have devised formulae for
estimating the probable daily yield of a catchment area.
Dr. Pole's formula is
Q = 62A(f Rw-E).
In this equation Rm represents the average rainfall of a long
series of years, and i Rm the estimated average of the three
driest consecutive years. E = the loss of rainfall by evapora-
tion, percolation, and unavoidable waste; and A = the area
of the gathering ground in acres. As 1 inch of rainfall
upon 1 acre represents 22,620 gallons of water, the average
amount of water which can be collected yearly during the
three driest consecutive years would be
22620Ax(iRw-E).
Since 22,620 divided by 365 is approximately 62, Pole's
formula gives the mean daily yield of water from the
catchment area. The importance of the factor E is evident,
and it is to the fact that this has been occasionally under-
estimated that the scarcity of water in certain towns during
long-continued periods of low rainfall is chiefly attributable.
In some cases, however, the fault has been due to the
reservoirs not having been sufficiently capacious to allow
of the accumulation of an ample reserve to tide over such
periods of drought. Under any circumstances the most
capacious reservoirs may become filled, and rain continue
to descend and pass down the bye-wash and be wasted. This
unavoidable loss Mr. Hawksley estimates at one-sixth .of the
rainfall. The loss by evaporation and percolation which,
as we have seen, depends upon so many factors is variously
estimated by engineers who have studied this subject. Mr.
Hawksley found at Sheffield that it was nearly 15 inches,
"although the ground is very elevated, ascending to 1500
or 1600 feet; but it lies rather with a southern aspect, and
the ground is mossy, and a good deal of water is held
superficially, and of course is re-evaporated." In this
298 WATER SUPPLIES
country the loss by evaporation and percolation is given by
the following authorities as under :
Mr. T. Hawksley, 11 to 18 ins. Average 14 ins.
Dr. Pole, 12 to 18 ins.
Mr. Humber, 9 to 19 ins. Average 13 to 14 ins.
Mr. Bateman, 9 to 16 ins.
Over most favourable areas, therefore, the loss may not
exceed 9 inches, whereas over the most unfavourable ones
which are likely to be selected as gathering grounds it may
be as high as 19 inches. The value of E in Dr. Pole's
formula, therefore, will vary from (unavoidable waste) 4- 9
to Rw , T q
~6~ H
In an excellent report recently issued by Dr Porter, the
Medical Officer of Health for Stockport, on the water supply
to that borough, there is an admirable illustration of the
use of this formula. The Disley gathering ground from
which the town is supplied has an area of 1700 acres. The
average rainfall thereon during the last twenty-six years has
been 48-6 inches. The loss by evaporation and percolation
he takes as 14 inches, and the loss by unavoidable waste
one-sixth the average rainfall, or 8 inches. E therefore = 14
+ 8 = 22, and the equation becomes
Q = 62 x 1700 ( of 48-6 - 22)
= 1,779,152 gallons.
As the average daily consumption of water is 1,750,000
gallons, the assumption is that even with reservoirs of suffi-
cient magnitude the available water is only just enough to
meet the present requirements of the borough.
The amount of storage necessary to render the required
amount of water available during the longest drought varies
considerably in different places. Where the rainfall is
heaviest the storage necessary is least, and vice versd. Over
the western half of this county, and in the more mountainous
districts, 120 days' storage has been found sufficient, but in
SOURCES OF WATER SUPPLY, ETC. 299
the eastern counties a storage for 300 days might even be
required. In such districts, however, surface water is very
rarely used for town supplies. There are few suitable col-
lecting areas, and the rainfall is too low and too varied in its
seasonal distribution to justify any attempt to obtain water
from such sources. In those parts of England in which sur-
face water can be rendered available a drought extending over
120 days, or a succession of droughts corresponding to that
period, must be so rare as to be phenomenal. In works of
such vast importance all errors must be on the safe side ; it
is wisest, therefore, to make provision for 150 days' drought
even in districts with heavy rainfalls, and in less favoured
districts to provide for the storage of 200 days' supply. This
appears to be the general opinion of the most eminent
engineers. It is impossible to give any precise rules as to
the relation of the rainfall to the amount of storage. Mr.
Hawksley's well-known formula gives results which confirm
the opinion expressed by Dr. Pole, quoted below. Let D =
the number of days' storage necessary, and F = the mean
annual rainfall of a long series of years, then according to
Hawksley
With a rainfall of 25 inches this formula gives 200 as the
number of days' storage required ; with 49 inches 143 days
would suffice. Dr. Pole says " the general judgment of ex-
perienced practitioners appears to be that for large rainfalls
a storage of 150 days or even less will suffice, but in drier
districts it may be necessary to go as high as 200 days ;
. . . and this is a provision which may reasonably be borne."
The extent to which the character of rain water can be
affected by the surfaces from which it is collected was referred
to in Chapter III.
Subsoil water is not utilised nearly to the same extent for
supplying towns as surface and river water, whilst rural
communities still continue to be supplied chiefly from this
source. The factors upon which the amount of water avail-
300 WATER SUPPLIES
able in the subsoil can be estimated have already been con-
sidered (Chap. IV.). A single well may yield sufficient water
for a large village, or if the subsoil be chalk or sandstone
and admit of headings being driven in various directions
from the bottom of the well, one well may even supply a
town of moderate size. Usually, however, two or more wells
are required, necessitating a corresponding number of pumping
stations and a considerably increased expenditure. A village
may sometimes be supplied from a single well in a patch of
gravel, but usually such drifts are not sufficiently extensive
or thick to yield a constant supply of any magnitude. A
parish in one of my districts is supplied from a well sunk in
the sand. The well is only about 1 2 feet deep and is capable
of yielding 22,000 gallons of water daily in very dry seasons.
Upon the same gravel patch and within 100 yards of the
well is the parish churchyard, but beyond this, springs out-
crop, and the water level in the well is 1\ inches higher
than in the trial bores made near the graveyard. The infer-
ence, therefore, is that the direction of flow is from the well
towards the church. The effect of forced pumping was tried,
and as this did not in any way affect the quality of the water
it confirmed the above conclusion. Assuming also that the
water in the well was kept constantly at 8 feet below its
normal level, and that the drainage area of the well is thirty
times the depression, the churchyard would still lie beyond.
But as the character of the drift renders it probable that
the drainage area will be little more than twenty times the
depression, and as this low level is rarely reached and never
maintained for more than a few hours, the margin of safety
is ample. (The underground accumulating reservoir or well
holds 14,000 gallons. It is built of 9-inch brickwork in
cement, 16 feet deep, with strengthening piers, and covered
with 6-inch cement concrete laid on rolled iron joists. The
tower is of red-brick, 24 feet to bottom of tank. The tank
is of wrought iron, circular, 15 feet in diameter, and 12 feet
deep, and is encased in brickwork, the total height of the tower
SOURCES OF WATER SUPPLY, ETC. 301
being 42 feet. The lower portion of the tower is used as the
engine-room, in which is a 2J h.p. engine with vertical boiler,
capable of raising about 4000 gallons of water per hour.
The mains are ordinary cast iron of 4 and 3-inch diameter,
turned and bored and coated with Angus Smith's composition.
The well is about 1 mile from the centre of the village. The
total cost, exclusive of land, was ,1350.)
The chalk formation in most cases contains a large store
of excellent water, but a single well, even with headings, rarely
yields enough water for a large town. The drainage area of
chalk wells cannot be estimated, since the water exists chiefly
in and travels through the fissures, and but very slightly, if at
all, through the chalk itself. It is evident therefore that the
freedom with which water percolates through a chalk subsoil
will depend upon the abundance and size of these fissures.
If the fissures are numerous and large the drainage area may
be very considerable. The well referred to on page 289 as
being affected by the sea, IJ miles away, is sunk in the
chalk. Cases are also recorded in which impurities have been
found to enter a well after travelling a very considerable
distance through such fissures. As an example of the amount
of water obtainable from wells in the chalk, the case of
Croydon may be cited. The old waterworks are close to
the town, and comprise four wells sunk in the chalk within a
space of 100 feet square. The level of the water in the wells
is not more than 25 feet from the surface, and the fissures
yielding the chief portion of the supply are about 25 feet
lower. Over 3,000,000 gallons per day have been pumped from
them. To meet the increasing demands of the town a new
well was opened in 1888. This is sunk 200 feet, all in the
chalk, and is 10 feet in diameter. Water was first found at
87 feet. At 142 feet from the surface and below headings
have been driven. The yield from the well was 130,000
gallons a day, but the first fissure cut by a heading increased
the daily yield to 600,000 gallons, and when the yield reached
2,500,000 gallons a day the work in the well had to cease
302 WATER SUPPLIES
through the inability of the two 24-inch pumps to keep the
water down. The total length of the headings is 813 yards,
and they are generally 6 feet high and 4^ feet wide. The
storage capacity of these and the lower part of the well is
about half a million gallons (Borough Engineers Report,
1890). A well such as that just described is usually spoken
of as a " deep " well, although sunk entirely in one pervious
stratum. The chalk, new red sandstone, oolite, and green-
sand contain vast stores of water of excellent quality access-
ible over very large areas to the well-sinker or borer, but it
must not be forgotten that there is a little uncertainty in
searching for water at such depths. The most experienced
geologists are sometimes at fault. The variations in thickness
of the water-bearing stratum and of the strata resting upon
it, the possibility of hitherto unsuspected faults existing, must
all be borne in mind. The water, also, when found, may be
quite unsuitable for domestic purposes. Thus in Essex many of
the borings piercing the London clay yield a water containing
so much sulphate of magnesia as to be aperient in property,
whilst others have yielded a water so brackish as to be useless.
The presence of beds of gypsum and of rock salt in the new
red sandstone must not be forgotten, the former rendering the
water excessively hard and the latter salty. At Rugby a well
sunk 1200 feet yielded only brackish water, and at Middles-
borough a well which was sunk for obtaining a pure water
yielded so strong a brine that salt is extracted from it. At
Wickham Bishops, Essex, a boring was sunk to a depth of about
1000 feet without water being found, yet everything had
indicated that an abundance of water would be reached at a
depth of about 500 feet. The section showed that there
existed a previously unknown and unsuspected fault crump-
ling the London clay back upon itself, so that this stratum
had to be twice pierced. When the second layer had been
penetrated and no water discovered the work was abandoned.
In other places the fall in the water-level from the heavy
continued pumping indicates that a time may come when
SOURCES OF WATER SUPPLY, ETC. 303
such supplies will fail, and unless the site of the well has been
carefully chosen, others may be sunk in such positions as
seriously to affect the supply.
The amount of water obtainable from a deep well in any
particular locality is difficult to predict, but a consideration of
the conditions bearing thereupon, referred to in Chapter VI.,
will assist us in arriving at fairly safe conclusions. The
information contained in the next chapter, gathered from
experienced well -sinkers, engineers, geologists, and others,
showing the actual amounts of water which have been
obtained from various underground sources during recent
years, will also be a useful guide.
It is advisable in all cases to derive the whole supply
required from one and the same source. In many towns,
especially on the Continent, water is derived from a number
of different sources. This may have been due to the
original supply proving inadequate on account of the increase
in population and the increased consumption of water
required by a higher standard of cleanliness. In Paris a dual
system of supply has been adopted. The one furnishes
unfiltered river water, and is used for municipal purposes and
for supplying baths, fountains, etc. The other furnishes a
purer water, derived chiefly from springs in the valley of the
Vannes. The suggestion to adopt such a dual system else-
where has not been favourably received. Apart from the
enormous additional expense necessitated by a duplicate
system of mains, it has many other objectionable features.
At Berlin the water of the Spree, after filtration, supplies a
portion of the inhabitants, whilst others are supplied from the
Tegeler Lake. Vienna derives water from springs in the
Styrian Alps and from wells sunk in the subsoil on the banks
of the Schwarza. The water supply to Brussels is most un-
satisfactory, and is derived from the subsoil, from the Harre,
and from the drainage of the Forests of Soignes and Cambre.
The Leipzic water-works present several peculiarities. Water
from the Pleisse is run into reservoirs, and the water filters
304 WATER SUPPLIES
through the natural gravel bottom, and is collected in earthen-
ware pipes, with open joints, which are laid in the subsoil for
this purpose. This supply is supplemented by the yield
from five groups of Artesian wells. The water supplying
Stockholm is derived in part from a lake and in part from the
subsoil, almost exclusively from the latter during the winter
months. Interesting details of these arid other works are
given by Palmberg and Newsholme in their Treatise on Public
Health and its Applications in different European Countries.
CHAPTEE XVIII
WELLS, AND THEIR CONSTRUCTION
THE practice of obtaining water by means of wells sunk in
the subsoil is one which dates from the remotest antiquity,
and at the present time a very large proportion of the popula-
tion of the globe derives its supply of water from such sources.
In Great Britain it is estimated that over one-third of the
population is so supplied. Whilst in every other depart-
ment of engineering improvements have advanced with rapid
strides, especially in recent years, shallow wells continue to be
constructed in almost precisely the same way as they were
thousands of years ago. The well-sinker is the most conserva-
tive of men, and in most districts it is impossible to get a
well constructed so as to protect the water from pollution. To
the country well-sinker a well is merely a reservoir to contain
water, and whether this water enters from the bottom, side,
or top he considers a point unworthy of consideration, and
in fact he makes the well in such a manner that water can
freely enter it at all points. The result is, that as wells are,
for convenience, almost invariably sunk in close proximity to
inhabited houses, impurities from the soil, from defective
drains, cesspits, and cesspools readily gain access and foul the
purer water which enters at a greater depth. It is not
surprising therefore that the great majority of such wells
yield water which is always impure, and liable at any moment
to become specifically contaminated and produce an outbreak
of disease. The time-honoured custom of lining the well
x
306 WATER SUPPLIES
with bricks, set dry, and resting upon a wooden curb, still
almost universally prevails. The brickwork may be carried
right up to the surface and the well left open, or it may be
covered with a lid, in which case it is frequently so left that
the water spilt upon withdrawing the bucket runs back into
the well, carrying with it filth from the surface of the ground
around, and during a heavy rainfall the surface water runs
directly into the well. Where the well is covered up, the
cover is generally near the surface, and may consist of old
railway sleepers or logs of wood admitting water freely.
Even if no sewage matters enter such wells, the wooden curb
and the rotting wooden covering yield putrid organic matter
to the water. Draw wells and dipping wells are also liable
to be contaminated by the dirty vessels let down into them,
by frogs, rats, and other animals getting in, and by dead
leaves and other matters blown by the wind. The animal
and the vegetable substances by their death and decay foul
the water. In wells otherwise carefully constructed it is
often found that impure water can gain access along the
track of the pipe leading from the pump to the well.
In a properly-constructed well no water should be able to
enter except from near the bottom, so that before reaching
the well it must have passed through a considerable thickness
of subsoil, becoming in its course thoroughly filtered and
purified. Various methods of accomplishing this difficult
task have been suggested; but as there are other ways of
obtaining subsoil water, which are more simple and far more
satisfactory, we may reasonably hope that ere long the
ordinary form of shallow well will be abandoned. Before
describing these other methods, however, the best ways of
constructing wells may be briefly referred to. Where the
excavation is through solid rock, such as chalk, limestone, or
sandstone, the steining, or lining with a cylinder of brickwork
or of iron or other material will only be necessary to keep
out the water from the more pervious surface soil. If bricks
be employed they must be well bedded on the rock with
WELLS, AND THEIR CONSTRUCTION 307
cement, and the whole of the brickwork lined inside with
hydraulic cement, and the lining continued some distance
below the last layer of bricks on to the exposed surface of
the rock, so as to render the junction as impervious as possible.
The brickwork should also be well puddled behind. Where
the rock is not freely porous water may accumulate in the
loose subsoil, and unless the greatest care be taken it will
enter the well. In the most modern wells cast-iron or
wrought-iron cylinders are employed for lining the upper
portion in order to keep out the surface water and land
springs. Similar cylinders are also employed to keep out
water from fissures which may be met with in excavating the
well. Where the subsoil is clay and impervious these pre-
cautions are of course not necessary. In ordinary wells, sunk
throughout in a porous subsoil, the lining should consist of
two separate rings of 4J-inch brickwork laid in cement and
lined with cement to a depth of 10 or 12 feet from the
surface. As this class of work is somewhat expensive, and
the cement is liable to fracture, either by the inward pressure
of the sides of the well or other causes, earthenware tubes are
now being made by the Leeds Fireclay Company for lining
purposes. .These tubes have an internal diameter of 2 feet
6 inches, and cost 17s. 6d. each. The upper edge is bevelled
internally and the lower externally, so that the lower edge of
the upper tube fits like a wedge into the upper edge of the
tube below it, and there are no projecting surfaces outside to
retard the downward movements of the tubes. The ground
having been excavated as deep as can be done with safety, a
tube is dropped in and some well-puddled clay laid on the
bevelled edge and another tube lowered. If properly driven
the tubes fit well together. The tubes are lowered by aid of
ropes, blocks, and cross-bars. Having got in the tubes, a
collier can easily work inside and undermine the edge, when
the weight will cause them to descend. Clay is preferred
for the joints, because cement breaks when the tubes are being
lowered. Of course the joints can afterwards be "pointed"
308 WATER SUPPLIES
inside with cement so as to make them more secure, and it is
advisable to try all the tubes, fitting and marking them before
using. Mr. Tudor, who has introduced these tubes, informs
me that he has put down in this way as many as twelve 3-feet
tubes in silty land. Other well-sinkers use a wooden curb or
crib of 3J feet in diameter. This is suspended and lowered
in the usual manner, and supports the tubes placed upon
it. The space between the ground and the tubes is filled in
with well-puddled clay. Or the well may be constructed in
the ordinary manner, dry steined with 4j-inch brickwork if
necessary, and the tubes then lowered and fitted and puddled
behind with clay. Dry-steined wells at present in existence
might with advantage be converted into tube wells in this
manner. The well itself having been so constructed as to
prevent the possibility of water entering anywhere except at
the bottom, it remains still to cover it in and protect the
top. The best plan is to project the dome of the well 6 or
1 2 inches above the surface of the ground and securely cover
with a properly-fitting iron cover. By this means easy access
is at any time gained for cleansing or examining purposes.
The pump should be fixed some little distance from the well,
and the drain carrying away the waste water should not go
near it. Every care should be taken to render water-tight
the aperture through which the pump pipe passes, and it
should be bedded in clay or cement so as to prevent the
water or rats forming a track alongside the pipe through which
impurities can gain access to the water in the well. If the
sides of the well be covered up to a sufficient height above
the ground, the pump may be fixed inside, the handle and
spout only projecting outside. A hooded aperture at the top
can be left for ventilation.
Quite recently I have seen wells the upper portions of
which were constructed from the halves of old steam boilers,
the domed end of the boiler forming the top of the well and
a hole being drilled through the side for the pump pipe to
enter. To prevent the action of a soft water upon the iron,
WELLS, AND THEIR CONSTRUCTION 309
it is desirable that the whole of the interior should be lined
with cement.
Koch, in his work on Water Filtration and Cholera, whilst
condemning strongly the ordinary shallow well, recognises
the fact that it is impossible to arrange that those already
existing should be abandoned. He therefore recommends
that the construction should be so altered as to remove all
danger of contamination from above. " To achieve this, one
should proceed by filling up the well to the highest water
point with gravel, and over the gravel with sand up to the
very top." Of course an iron pipe should traverse the sand
and gravel and be connected with the pump. A well so
constructed "gives the same protection against the infection
of water as is given by the sand filtration of the great
waterworks. In fact it really gives a greater protection,
since it is not exposed to the many disturbances in the
process of filtration already referred to, and is also not
affected by frost." So much attention is now being given
to perfecting as much as possible the water supply of the
great waterworks, that it is important not to lose sight
of the domestic water supply by pumps and wells. By
improving the wells in the manner explained above, "the
spread of cholera, 1 in so far as it is due to water, can be
restricted to a great extent. It is just in this respect that
a great deal can yet be done." This suggestion of Koch's is
one worthy of all consideration, since the change can be
effected at a minimum of expense, and the result leaves little
to be desired. It is important, however, to remember that
the superficial layer of sand should be at least 6 feet in thick-
ness. Where the subsoil water is reached at a less depth
than 6 feet, probably this method will not afford complete
protection in many cases. Dr. R. Kempster, in his researches
on "The influence of different kinds of soil on the cholera
and typhoid organisms," arrived at the following conclusions :
" White crystal sand, yellow sand, and garden earth have no
1 And of typhoid fever and other diseases disseminated by water.
310 WATER SUPPLIES
marked favourable or injurious action on the life of the
organisms. The length of life of the organisms in the soil
depends chiefly on the amount of moisture present. Peat, on
the contrary, is very deadly to both the comma and typhoid
bacillus. The soil acts as a good filter, holding back most of
the organisms, but it is possible for these organisms to be
carried through 2 J feet of porous soil by a current of water."
Where the ground water-level, therefore, is within 5 or less
feet from the surface, the side of the well should be rendered
impervious to a depth of 10 or 12 feet, or, better still, the
water should be obtained by aid of an Abyssinian tube well,
next to be described, driven to at least this depth.
In a great many instances subsoil water can be obtained
without the trouble and expense of well-digging, merely by
driving iron tubes through the ground until the subsoil water
is reached, and fixing a pump to the upper end of the tube.
Such tube wells were first used systematically during the
Abyssinian campaign, hence they are now popularly known
as "Abyssinian" tube wells. They are most suitable for
gravel, coarse sand, chalk, and similar porous water-bearing
strata, and for depths not exceeding 40 to 50 feet, though
under exceptional circumstances tubes have been driven
successfully to a depth of 150 feet. Naturally they cannot
be driven through hard rock, neither are they suitable for
obtaining water from marl, fine sand, or clay formations,
sirce the apertures in the perforated terminal tube are liable
to become blocked by the fine particles of which such strata
are composed. A pointed perforated tube is driven into the
ground by aid of a "monkey." (The tubes vary from 1-J to
4 inches in diameter, according to the amount of water which
it is desired to raise.) When this tube has been well driven,
a second tube is screwed on to the first and the driving
resumed. By lowering a plummet down the tubes from time
to time, it can be ascertained whether water has been reached
or whether sand or earth is filling up the end of the perforated
tube. When water is reached a pump can be attached and
WELLS, AND THEIR CONSTRUCTION
a sample drawn for examination, and
the quantity available ascertained.
If either the quantity or quality be
unsatisfactory, the tubes can be
driven deeper or they can be with-
drawn and redriven in another spot.
A well of this character is shown in
Fig. 20. Very often, where the
supply from an ordinary sunk well
is limited, it can be increased by
driving one or more of the "Abys-
sinian " tubes from the bottom of the
well. Special pointed and perforated
tubes are employed where the soil is
ferruginous or likely to corrode the
metal of the ordinary tube. Tubes
designed to prevent plugging with
sand are useful under certain circum-
stances, as when the water-bearing
strata contains together with the
sand a fair proportion of grit. In
fine sandy soils, however, it is
better to withdraw the tubes, ram
down a lot of fine gravel, and redrive.
In the " Abyssinian " tube well
the water is drawn directly from the
water-bearing stratum, there being
no reservoir. At first the water
invariably contains fine sand or
chalk, according to the nature of the
subsoil, but after a time a clear water
is yielded. This is probably due to
the removal of all the fine particles
and debris from around the terminal
tube and the formation of a natural
cavity in which the water accumu-
Fio. 20. Abyssinian Tube Well.
312
WATER SUPPLIES
lates. In suitable localities these tube wells answer
admirably, and not only are cheaper to sink, but yield a safer
supply of water than a sunk well. One man, usually, can
drive the smallest -sized tubes, but three or four men are
required for the largest tubes. In very light soil a 30-feet
well may be driven in less than one day ; in a firmer soil three
days may be required. Whatever the depth of the tube well
an ordinary pump will raise the water, provided the water
level in the tube is within 25 feet of the surface. If the
water stand at a lower level, a deep well pump must be pro-
vided.
The capacity of these tube wells varies with the depth,
yield of spring, and power of pump applied.
The following are the estimates of two of the best-known
firms of well-sinkers.
Size of Well.
Yield in Gallons per Hour.
Authority.
1| in.
150 to 600
Le Grand and Sutcliff
2
300 to 1200
J5 ) J
3
600 to 2400
4
1200 to 4400 -
5 > 5
1* -
150 to 900
C. Isler and Co.
2
300 to 1500
3
450 to 3000
33 J3
Messrs. Le Grand and Sutcliff have kindly furnished me
with the following table (see page 313), giving the depth of
well, size of tube, yield of water per hour of a series of typical
wells driven by them, which bear out the above statements.
Not only are these tube wells preferable to sunk wells on
account of the greater freedom from risk of contamination,
but they are much less expensive. The probable cost of a
well can easily be calculated from the following estimates
(see page 314).
WELLS, AND THEIR CONSTRUCTION
313
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WATER SUPPLIES
Twelve-Feet Tube
with Hire of Plant
and Man to Superin-
tend Driving.
Add for each
additional
Foot.
Pump, Column, and
Foundation.
IJ-inch tube
2 ,,
3
4
240
3 10
7 10
9 15
3s.
4s. 6d.
10s.
13s.
2 10 to 3 10
3 10 to 4"lO
5 J > 5
To the above must be added the man's time in travelling,
railway fares, carriage of materials, etc. A well driven recently
in one of my districts to a depth of 17 feet, a 2-inch tube
being used, cost 8:12 : 4, the items being as under.
17-feet 2-inch tube well . . . . 2 14 6
4-inch column, pump, and foundation . 380
Hire of man and plant . . . . 1 10
Man's time travelling . . . . 076
Railway fare and carriage . . . 0124
Total
8 12 4
The wages of the agricultural labourer who assisted in
driving the tube is not included, but would not exceed 5s.
These prices may be compared with the following schedule
of prices taken from Sir E. Rawlinson's Suggestions as to the
Preparations of Plans for Drainage and Water Supply (Local
Government Board, 1878).
Schedule of prices for sinking wells in Clay, lined with
9-inch brickwork in Portland Cement, Wooden curves,
cylinders, and pumping extra.
4 feet diameter to depth of 200 feet, 50s. per foot run.
5 200 65s.
6 200 85s.
7 200 105s.
Rough estimate of well-sinking, through Clay, Chalk, and
Gravel, entirely exclusive of brickwork or fittings.
Diameter of Well.
Depth.
Price per Foot of Depth.
Total Cost.
4 feet
5 ,,
50 feet
50 ,,
3s.
4s. 6d.
7 10
11 5
WELLS, AND THEIR CONSTRUCTION 315
Where hard rock has to be pierced or where the water-
bearing stratum lies at a considerable depth below the ground
surface, the well must either be excavated or bored. The
cost of sinking as compared with boring is so excessive that
nearly all deep wells are now bored. Not only is the cost
much less, but as the bore -hole is lined with metal tubes
(which should be of wrought iron, lap -welded and steel-
socketed), surface springs are excluded, and the possibility of
contamination reduced to a minimum. Various methods are
employed and many different kinds of tools, according to the
nature of the strata to be penetrated, and the depth and
the manner of the borings, which vary from 3 to 12 inches
in diameter ; but in soft rock, like chalk, this diameter may
be greatly exceeded. In the majority of cases the borings
are made from the bottom of a dug well, the object usually
being twofold : (a) to form a storage reservoir for the water ;
and (b) to provide a receptacle for the pumps. It is, how-
ever, found that in many cases the dug well can, with advant-
age, be dispensed with. It is only really necessary where the
spring is weak and the demand for water intermittent. Such
dug wells, unless very carefully constructed, also increase
greatly the liability to contamination by surface water.
During the process of boring a number of springs may be
tapped, and the quality of the water yielded by each can be
ascertained by analysis. If it be ultimately found that one
of the upper springs yields the most suitable water, the tubes
can be withdrawn and the hole plugged at such a depth that
only water from that particular spring is supplied. In the
older wells the tubes lining the bore are usually not con-
tinuous, and water from divers sources has free access to
the wells. In the more modern borings larger tubes are
used for convenience in boring, and a smaller tube with tight
joints is then inserted, reaching from the surface to the bottom
of the well. The outer tubes may be afterwards withdrawn
or the space between the two filled in with cement. With
such a continuous tube the pump can be so attached that
316 WATER SUPPLIES
the water is drawn directly from the bottom of the well.
The conditions which influence the yield of water from
bored wells are so lucidly expressed by Mr. K. Sutcliff,
in a paper read before the Brewers' Congress in 1886,
that no apology is required for reproducing them here.
" The continuous tube," says Mr. Sutcliff, " has an important
bearing on the yield from the spring; the weight of the
atmosphere being removed by the pump from the surface of
the water in the tube well. This, as regards the velocity of
the flow of the spring, is equivalent to drawing the water
from some 34 or 35 feet lower than is possible when the
weight of atmosphere presses on the surface of the water.
The increase in supply under these conditions is equal to
about 40 per cent, which acts as an important compensation
for absence of storage. It may be interesting to give an
example of this. A dug well, 25 feet deep and of 5 feet
diameter, will hold 3050 gallons of water. Suppose that
such a well is supplied by a spring which, when the head of
25 feet is removed from it, will flow at the rate of 950 gallons
per hour. As the maximum flow is only obtainable after the
storage is completely exhausted, the average yield must be
taken until that exhaustion occurs. Let the pumps be started
to draw 1500 gallons per hour, the quantity obtained by
storage will be exhausted in two hours. But as in that time
the spring would have been yielding an average flow of, say,
700 gallons per hour, the well would not be emptied until
the pumps had been going about four hours. When that time
had expired, the spring would be yielding its maximum of
950 gallons per hour, and the speed of the pumps would have to
be slackened proportionately. Under these conditions, a total
of 11,500 gallons would be drawn from the well in ten hours.
" Let a tube well be placed under exactly similar circum-
stances as regards supply and water level. The pumps draw-
ing from a tube well could get 950 gallons per hour plus 40
per cent; that is to say, 1330 gallons per hour. Therefore,
the tube well would in ten hours yield 13,300 gallons a gain,
WELLS, AND THEIR CONSTRUCTION 317
in that time, in spite of absence of storage, of 1800 gallons ;
and the pumping from the tube well could be continued uni-
formly at the same speed for an indefinite period, so long as
the spring maintained its flow.
" When the normal level of the spring is not sufficiently
near the surface, or the flow is not rapid enough to enable
an ordinary lift pump to draw the water, the tube well must
be made of such size as will enable a deep well pump to be
placed in it, as far below the surface of the water as may be
necessary to obtain the required supply. A deep well pump
can be placed 150 or even 200 feet below the surface ; but
when it becomes necessary to place it at that depth below
the water level, the supply required is one that is very great
compared with the spring that yields it. Because, although
all springs increase until the base of them is reached, that
augmentation is a constantly decreasing one. The reason for
this decrease is obvious. The water flows through channels
of fixed area. When the head of water is removed, the
pressure is increased proportionately with the depth that the
water is lowered ; but the friction of passing through the
channels also increases. So that to double the supply that
flows at 150 feet below the head of the spring, it would be
necessary to place the pump 600 feet under the water. These
facts are of the highest importance in deciding whether a
given spring can meet the requirement of the consumer.
Let it be supposed that two borings are made, and that
springs are tapped by these borings, which both overflow the
surface of the ground at the rate of 10 gallons per minute.
To the casual observer both of these springs might be con-
sidered as equal. But one might be ten times stronger than
the other. Let us call these springs A and B. The spring
A, when we lower it by pumping, gives no appreciable increase ;
whereas the spring B, when we lower it only 3 feet, yields
double the quantity of water. Why is this? If it were
possible to carry the pipes up from which spring A flows,
we should find that it would reach 100 feet before it came
318 WATER SUPPLIES
to rest ; whereas with spring B, if we only piped it 1 foot
higher, it would cease to flow. This would prove that spring
A is a high-pressure one, the source of which is 99 feet above
the ground level ; but spring B has its source only about 1
foot above the ground level. The channels of communication
in spring A are small, and the friction is depriving us of the
advantage of the great head of water. The channels of com-
munication from spring B are free and large. One may,
however, be deceived unless the test of pumping is a pro-
longed one. What is known as a ' pocket of water' may
appear from temporary pumping to be a spring of the B class ;
but sustained pumping will demonstrate the impostor, as the
water level will not recover itself without a more or less pro-
longed period of rest. This proves that while the channels
of communication are large, the area which is being drawn
from is small. Under such circumstances a multiplication
of wells would be of no advantage ; but in many instances
the friction of drawing water through the earth may be largely
diminished by sinking a number of tubes and coupling them
together, so that one pump draws from them. What is known
as the 'cone of depression' is reduced by this method of
drawing the water. Tubes placed, say, 20 feet apart, may
each only yield a small supply ; but the aggregate obtained
from a number of these tubes becomes very large.
"At the Burton Breweries, some forty or fifty 3-inch
'Abyssinian' tube wells yield 2,000,000 gallons daily; yet
no one of the 3-inch tubes delivers more than 2000 gallons
per hour. The area from which they draw is so extended
that at no one point is the water level materially depressed.
"At the Town Waterworks of Watford, a dug well of 10
feet diameter, supplied by a 12-inch boring at the bottom of
it, proved inadequate when drawn from night and day to
meet the requirements of the town. A single tube well of
8J inches in diameter, placed some 30 feet from the dug
well, doubled the supply of water obtainable, and thus
enabled the hours of pumping to be materially reduced.
WELLS, AND THEIR CONSTRUCTION 319
Somewhat similar experiences were obtained at the Town
Waterworks of Aldershot, Hertford, St. Albans, and Abbots
Langley, all of which towns now derive their water supply
from tube wells."
The -imperfect construction of many of our older wells to
some extent brought boring into disrepute. Thin sheet-iron
was in many districts used for lining the bore. The imper-
fect joints very frequently admitted the entrance of subsoil
water, hence the water yielded was often polluted. In a
comparatively few years the sides of the tubes corroded and
collapsed, and the supply gradually, or, in some cases, suddenly
failed. By the use of proper casing, such as the " Russian
Brand" swelled and collar-joint casing, employed now so
extensively, all these defects are obviated. The difficulty,
however, of making these tubes absolutely water-tight is
greater than at first would be anticipated, arid where the
slightest defect exists the continued raising of water by
pumps fixed directly upon the bore tube is very likely to
accentuate it by the continued lateral insuction of air and
water. A most instructive example of such a defect is
contained in Dr. Geo. Turner's Report on the Water Supply
to the Suffolk County Lunatic Asylum, previously referred
to. Some years ago the prevalence of dysentery in this
Asylum was attributed to the impure water supply, and a
fresh supply was obtained from two bored wells, so con-
structed that contamination of the water appeared quite
impossible. Dr. Turner says, "The construction of these
bores is very similar in principle, but varies slightly in detail.
In both instances an 8-inch steel pipe with screw joints was
sunk into the chalk, the bore was then enlarged, filled with
cement, and the 8-inch tube sunk into the cement, which was
then allowed to set. After the cement had set, a 6-inch steel
tube, also with screw joints, was passed through the cement
to a distance of 200 feet, when the bore was again enlarged ;
the cavity was filled with cement, which was allowed to set,
and then the boring was continued another 100 feet. The
320 WATER SUPPLIES
total depth of the bores was 305 and 350 feet respectively.
The space between the 8-inch and 6-inch tubes was filled with
cement through a composition pipe passed to the bottom, and
the bore was fastened to the pump by an air-tight joint."
Notwithstanding these elaborate precautions, dysentery again
broke out in the Asylum, and was again traced to the water
supply. Dr. Turner found that after continued pumping
there was a marked difference in the quality of the water
drawn from the two wells, and upon excavating around the
tubes and pouring into the excavation a solution of chloride
of lithium, he afterwards found distinct traces of this salt in
the water drawn from the pumps. From the result of these
and other experiments he concluded that there was no reason-
able doubt that neither of the tubes were water-tight. The
danger of lateral insuction must be greater in wells in which
the pump is screwed directly on to the lining tube, than in
those in which the pump pipe or barrel is merely inserted
within the lining tube, since the removal of the atmospheric
pressure, in the former case, causes water or air to enter the
bore through the most minute apertures, and in course of
time such apertures enlarge, admitting impurities more and
more freely. This danger, in some degree, counterbalances
the advantages of the increased supply, and it would appear
to be safer not to directly connect the pump with the bore
tube where water can be obtained in sufficient quantity
without such attachment.
The cost of constructing bored wells varies with the nature
of the strata which have to be pierced. Fifty years ago,
local well-sinkers in Essex would pierce 300 feet of London
clay, line the well, and fix a pump for a total cost of less than
100. A't the present time similar wells cost about three times
that amount, and the local well-sinker has disappeared. The
only explanation appears to be that it has been found more
economical to employ professional well-borers, and pay treble
the price for a properly-constructed well, than to employ the
local men. Sir K. Rawlinson, in his Official Report to the
WELLS, AND THEIR CONSTRUCTION
321
Local Government Board on Water Supplies, etc., gives the
following schedule of prices for making bore-holes in red
sandstone. The prices for boring in chalk and in sand and
clay average Is. per foot less, but in sand and clay, where the
boring exceeds 200 feet in depth, the price is, on the contrary,
about 3s. per foot more than for boring in chalk or sandstone.
Per Foot Run
Cost of Cast or
Wrought-iron
Diameter.
First
Second
Third
Fourth
Pipes per Foot.
Inches.
100 Feet.
100 Feet.
100 Feet.
100 Feet.
3or4
5s. 6d.
7s. 6d.
11s. 6d.
14s. 6d.
4s. to 5s. 6d.
5
7s. 6d.
10s. 6d.
13s. 6d.
20s. 6d.
6s. 6d.
6
8s. 6d.
11s. 6d.
14s. 6d.
20s. 6d.
7s. 6d.
8
9s. 6d.
12s. 6d.
16s. 6d.
22s. 6d.
10s. 6d.
9
12s. 6d.
15s. 6d.
20s. 6d.
25s. 6d.
11s. 6d.
10
13s. 6d.
16s. 6d.
21s. 6d.
26s. 6d.
13s.
12
17s. 6d.
21s. 6d.
25s. 6d.
30s. 6d.
18s. 6d.
The following schedule of prices for borings from the
surface from 3 to 12 inches in diameter, are exclusive of
lining tubes but include all labour and necessary plant. The
prices quoted are per foot.
Messrs. Le Grand and
Sutcliff.
C. Isler and Co.
Boring in
alluvial and
other free-
boring Strata.
In blowing
Sand, Rock,
Stone, and
other hard
or difficult
Strata.
Gravel, Clay,
Sand, or other
soft Strata.
Rock or
Stone.
Not exceeding 100 ft.
200 ft.
300 ft.
400 ft.
500ft.
7s. to 14s.
12s. to 24s.
16s. to 30s.
20s. to 40s.
30s. to 50s.
15s. to 50s.
20s. to 70s.
25s. to 70s.
30s. to 80s.
35s. to 90s.
8s. to 20s.
13s. to 30s.
18s. to 40s.
23s. to 50s.
28s. to 60s.
20s. to 40s.
25s. to 50s.
30s. to 60s.
35s. to 70s.
40s. to 80s.
The wrought-iron, lap-welded, steel-socketed tubes vary in
price with the fluctuations of the market, but the following
are recent estimates :
Y
322 WATER SUPPLIES
3 -inch internal diameter, | inch thick, 4s. per foot.
4 5s.
6 ,, ,, yV 9s. to 10s.
7| ,, ,, ,, ,, 11s. to 13s.
8|-inch diameter and -^ inch thick, 15s. to 17s.
10 ,, ,, ,, ,, 18s. to 20s.
11| ,, ,, I 23s. to 25s.
The approximate depth at which water may be reasonably
expected to be found, and the nature of the strata to be pene-
trated, being known, the cost of constructing a bored well can
be ascertained from the above data. An estimate of the
amount of water which the well will yield can only be given
by those who have made a special study of the hydrology of
the district.
The table on p. 323 gives the details of a number of typical
wells bored during recent years by Messrs. Le Grand and
Sutcliff.
As the temperature of the earth's crust increases as we
descend, it follows that water taken from a great depth must
have a higher temperature than water from shallower wells-
The increase in temperature has been found to vary somewhat
considerably in different localities, but 1 F. for every 50 to
60 feet descended is a fair average. A well 1000 feet deep,
therefore, may be expected to yield a water having a tempera-
ture 16 to 20 higher than that of the subsoil water in the
same locality, so warm in fact as to be decidedly unpalat-
able. In some countries the water obtained is quite hot.
Thus, in Queensland, some of the recently sunk deep bores
yield waters having a temperature of from 162 to 175 F.,
the average of a number of wells being over 100 F.
In all cases, before deciding upon boring for water, an
expert hydro -geologist should be consulted, otherwise the
experiment may prove a costly failure. Even the most
experienced expert may at times be at fault. Neither the
quality nor the quantity of water obtainable can be invari-
ably predicted. The supply obtainable may be increased
in various ways. By driving two or more tubes, and con-
WELLS, AND THEIR CONSTRUCTION
323
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WATER SUPPLIES
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WELLS, AND THEIR CONSTRUCTION 325
necting the various wells to a main leading to the pump, the
area, drawn from is increased. This, however, seriously
augments the expense, and unfortunately is not always suc-
cessful. Thus, at Liverpool, where sixteen bores had been made
from the bottom of one well, Mr. Stephenson found that the
yield of the whole was 1,034,000 gallons per day, whilst from
a single bore-hole, the other fifteen being plugged, the yield
was 921,000 gallons. In this case, of course, the bores were
much too near together. By placing the pump barrel at a
greater depth in the well, more water may be obtained. In
London the long barrel -pumps are fixed at depths varying
from 200 to 300 feet. The usual plan is to place them about
50 feet below the water level, so that pumping may go on
continuously, if necessary, until the head of water has been
reduced by this amount. Recently most successful attempts
have been made to increase the flow through closely-jointed
rocks, by exploding a charge of dynamite or blasting gelatine
at the bottom of the well. The explosion shatters the sur-
rounding rock and opens out the fissures through which the
water pours. At Rochester a well had been sunk to a depth of
over 300 feet without finding water. Messrs. Isler and Com-
pany placed a charge of gelatine, weighing 18 Ibs., at a depth
of 307 feet, and exploded it. The result was an abundant
supply of water, the well yielding afterwards some 20,000
gallons 'per hour. The proportion of unsuccessful borings in
England is probably very inconsiderable, but no data are
available upon which to base a reliable estimate. In several
of our colonies, where well-sinking is being undertaken by the
respective governments, some interesting information on this
and other points is given in the engineers' reports. The
following brief account of the results of boring operations in
our colonies is compiled from various blue-books issued during
the past and present year by the respective governments.
Queensland. During the last few years sixteen wells have
been bored by the Government under the supervision of the
official hydraulic engineer. Of these, six were abandoned:
326
WATER SUPPLIES
two by the contractors for reasons not stated ; two because
the water found (at a depth of 1781 feet and 2512 feet
respectively) was not fit for domestic purposes ; one because
the pump was lost in the bore, and one because at a depth
of 2000 feet no water was obtained. Nine of the borings
yielded satisfactory results. The principal wells are
District.
Depth.
Yield per Day.
Temp, of
Water.
Cost.
Barcaldine .
691 ft.
175,000 galls.
102 F.
1340
Blackall
1663
300,000
119 F.
5074
Charleville .
1571
3,000,000
106 F.
3525
Cunnarnulla
1402
540,000
106 F.
2316
Muckadilla .
3262
23,000
124 F.
7382
"65-mile bore"
2362
104,000
3073
About 140 private wells have been sunk, varying in depth
from 86 to 2484 feet. The number of unsuccessful borings
is not stated. The water is derived from the lower cretaceous
formation, and most of the wells overflow. The largest yield
is from a private bore in the Warrego district. The well is
1502 feet deep, and yields 3,500,000 gallons of water daily
(112 F.), at a pressure of 200 Ibs. to the square inch. The
yield at the present time from all the wells is estimated at
105,000,000 gallons per day. The flow of 66,000,000 gallons
is uncontrolled, and most of it wasted. A bill was recently
introduced to regulate the flow from these bores and prevent
the lowering of the pressure (water level), but it was thrown
out by the Upper House. Regulating valves are used for all
the Government bores.
In South Australia it is estimated that the area of the
water-bearing chalk basin is nearly 100,000 square miles; but
the number of wells bored at present is inconsiderable. Water
has been obtained at depths varying from 237 to 1220 feet,
the temperature ranging from 81 F. to 90 F., and the yield
from 48,000 to 1,200,000 gallons daily. In some wells the
water rises considerably above the surface ; in others it does
not reach the outlet of the bore.
WELLS, AND THEIR CONSTRUCTION 327
In the Colony of Victoria the Government has expended
some 50,000 in making experimental bores, but apparently
with little success. In some cases the rocks were pierced to
a depth of over 2000 feet without water being discovered ;
in others the water obtained was unfit for domestic purposes,
whilst in the few successful bores the water level was far
below the ground surface and the supply limited. One
instance is recorded in which the saline constituents of the
water acted so powerfully upon the iron lining of the bore as
to destroy its continuity within eighteen months.
New South Wales. In 1892 Mr. Boultbee, the Officer-in-
Charge for Water Conservation, issued a report on Artesian
boring, containing sections and descriptions of all the Govern-
ment bores. The bores when decided upon are let by tender,
the work being done under official supervision. Mr. Boultbee
gives a list of twelve completed borings, and refers to forty
other bores in progress. Particulars are also given of forty-
five private bores. The wells vary in depth from 53 to 2000
feet. Two borings appear to have been unsuccessful; the
remainder yield from 24,000 to 2,000,000 gallons of water
per day. Most of the private wells are from 700 to 1000
feet deep, and the flow varies from nil to 1,728,000 gallons
daily. The tenders for the Government bores varied from
24s. to 27s. per foot for the first 1000 feet ; from 27s. 6d. to
32s. 6d. for the next 500 feet, and from 30s. to 40s. for an
additional 500 feet, exclusive of casing. The contractor finds
all plant, tools, labour, etc., but the Government does all the
carting and supplies the casing. The average cost of the
bores per foot, including casing, is said to be 37s. All the
Government bores, and some of the private bores, have valve
arrangements for regulating the flow, but Mr. Boultbee
believes that some 16,000,000 gallons of Artesian well water
runs daily to waste, and he recommends legislation to prevent
this. Imperfect casing is also probably the cause of serious
waste, and this he thinks should be dealt with by legisla-
tion, as is already done in some of the North American States.
328 WATER SUPPLIES
The chalk basin yielding water is estimated to have an area
of 40,000 square miles. Over the catchment area supplying
this basin the average rainfall is 22 inches, and only about
\\ per cent of this finds its way into the rivers. It is
assumed therefore that 50 per cent of the total rainfall
percolates and is recoverable by means of wells and bores.
As the catchment area is only about 13,000 square miles in
extent, the water from the bores should not be sufficient to
irrigate more than about one-sixth the area of the chalk basin.
Mr. Boultbee believes that if further operations are equally
successful, it will be " difficult to estimate the progress and
prosperity that must naturally ensue." The few analyses
given show that some of the wells yield strongly saline water,
and others, water which is strongly alkaline, such as is
derived from the chalk in certain portions of Essex. The
Government Veterinarian, reporting on saline waters, says,
"It is easy to understand that starving, or even thirsty,
travelling stock may suffer disastrously from drinking at
once a large quantity of water containing a high percentage
of saline material. Horses and cattle will drink from 5 to 12
gallons a day, sheep from 1 to 2 gallons a day. Drovers
should be cautioned at saline drinking-places of the danger of
permitting stock to drink too freely, until they have become
accustomed to the medicinal properties of the water."
Cape of Good Hope. The Government Inspector of Water
Drills, in his report for 1893, says that the work undertaken
by the Government has been an unqualified success, but the
geological formation in many parts of the colony is such as
not to be "conducive to the existence of Artesian areas of
any great extent. A great portion of the colony, known as
the Karoo, however, contains many such areas, and here
prospecting for water has been most successful. This district
is composed of a series of areas formed by a network of
intrusive igneous dykes, chiefly of a dolerite nature, cutting
through the sandstone and shales and acting as intercepting
barriers to the underground water. Since the commencement
WELLS, AND THEIR CONSTRUCTION 329
of operations in May 1891, out of a total of 341 holes bored,
water was tapped in 289 and overflowed from 128. The
average depth was only 43 feet per hole, and the deepest bore
was only 227 feet. The flow from the 128 bore -holes is
estimated at 2,332,000 gallons daily, or an average of about
18,000 gallons per well. In several cases the flow has
decreased ; in others it has increased. The Inspector thinks
that there is little fear of exhausting the underground
reservoirs, since moderate -sized towns, such as Colsburg,
Victoria West, Hanover, Veuterstad, and Bristown, "boast of
perennial streams, issuing from one or two bore-holes in each
case, sufficient to supply their domestic wants as well as to
irrigate numerous erven." The Inspector recommends that
where the water does not overflow, 4-inch bores should be
made instead of 2-inch as at present, and to such a depth
as will ensure a 50-feet head of water from which to pump.
With a deep-well pump and windmill, practically inexhaustible
supplies could be obtained from such wells at a nominal cost.
A few very deep wells have been bored (up to 1200 feet),
but the results are not encouraging. In Bushmanland and
Bechuanaland, where the general geological formation is gneiss
and granite, the rock can only be pierced by the diamond
drill, and the wear and tear of the diamonds is severe. As
the water lies in the rock fissures at but a slight depth, the
rock is better penetrated by means of blasting.
In the United States a special department at Washington
collects information with reference to all wells bored, and in
several states Acts have been passed to encourage the sinking
of Artesian wells, and for preventing waste of the water
flowing therefrom. The number of such wells is simply
enormous. In the Utah Territory there are nearly 2000 ; in
the San Joaquin Valley, California, about 3000 ; in the San
Louis Valley, 2000 ; in Deseret, 2000, etc. In Kern County,
California, within an area of 18 by 14 miles, there is a group
of wells yielding 61,000,000 gallons of water daily. To the
development of well-boring the reclamation of the Great
330 WATER SUPPLIES
American Desert is in great part due. Enormous tracts of
land, over which the annual rainfall is only from 2 to 6 inches,
are now irrigated by the water overflowing from Artesian
wells.
In Algeria and Sahara the French engineers have during
recent years been engaged in reclaiming the deserts by means
of water derived from deep bores, and it is stated that
the flow from the wells already sunk is about 100,000,000
gallons daily, and that the effect produced upon the sandhills
by irrigation is amazing.
In Argentina and Uruguay a drilling company has
recently sunk a number of wells, and last year the Buenos
Ayres and Rosario Railway Company drove an Abyssinian
tube well to a depth of 200 feet, and obtained an abundant
supply of water.
In arid regions, and where the rainfall is fitful, water can
often be obtained for irrigation purposes by boring, and it
is probable, now that increased attention is being drawn
to this method of obtaining water, many districts at present
uninhabitable will become both populous and prosperous. In
certain of our Colonies it may safely be asserted that the
discovery of these subterranean sources of water will ulti-
mately conduce to far greater prosperity than the discovery
of gold.
In all attempts to obtain water by sinking wells, the
following facts should be borne in mind. Sand or gravel
resting on chalk will yield no water, unless the chalk also
is penetrated to below the plane of saturation ; that chalk
contains immense volumes of water, but almost exclusively
in the fissures. Wells or borings sunk in very solid chalk
may yield no water, the more fissured the stratum and the
greater the yield that may be anticipated. The tertiary
sands between the London clay and the chalk yield only a
moderate quantity of water. The impermeable beds of Pur-
beck and Portland stone often contain a considerable amount
of water in their fissures, but under the latter rock water
WELLS, AND THEIR CONSTRUCTION 331
may be found in the porous stratum between it and the clay
beneath. Limestone is only slightly porous, and the water
contained therein is probably chiefly found in the fissures.
The lower oolite contains large quantities of water held up
by the impervious beds of the lias. In the magnesian lime-
stone water is only found where fissures are struck, but in
this and the mountain limestone the water may be very
abundant. In fissures of the metamorphic rocks, water also
may be met with in the fissures if the sinking or boring is
fortunate enough to strike such ; but as the stratification is
usually very irregular, the result of a boring can never be
with safety predicted.
CHAPTEE XIX
PUMPS AND PUMPING MACHINERY
NUMEROUS varieties of pumps are now manufactured for
raising water, and each probably possesses some advantages
over the others under certain conditions. A pump which under
one set of circumstances will work effectively and economically,
may under other circumstances be ineffective or extravagant.
Where large quantities of water have to be raised, the
selection of a pump is of the highest importance, and it is
only when the duty which it will have to perform and the
exact conditions under which it must work are fully known
that the selection can be satisfactorily made. All the
varieties in ordinary use can be classified under the three
following types (a) Lifting pumps, (b) Plunger or force
pumps, and (c) Centrifugal pumps.
(a) The commonest form of pump, the atmospheric, is the
simplest form of this type. The essential part is the barrel,
which is truly cylindrical and carefully bored and closed at
the bottom by a valve opening upwards. Within the barrel
works a piston or bucket, fitting the cylinder accurately, which
is also provided with a valve opening upwards. When the
piston ascends, the atmospheric pressure is removed from the
surface of the lower valve, and water ascends through the so-
called suction pipe, ultimately entering the pump barrel.
When the piston descends the lower valve closes, and the water
is forced through the valve in the piston, and at the next
up stroke is discharged from the pump. The height at which
PUMPS AND PUMPING MACHINERY 333
the pump barrel may be fixed above the surface of the water
to be raised obviously depends chiefly upon the atmospheric
pressure. At sea-level this corresponds to a column of water
about 34 feet high. As the valves and piston, even with
best workmanship, are not perfect, such a pump cannot be
depended upon to raise the water more than 27 feet. The
vertical distance between the level of the water to be raised
and the highest point reached by the piston must not, there-
fore, exceed this distance. Where the water-level fluctuates
care must be taken to measure from the lowest level reached
during these fluctuations, otherwise the water may at times
fall so low that the pump will cease to act. This form of
pump is only suitable for hand power and for use where it is
not inconvenient to raise the water as required. For shallow
wells it is almost universally employed, the water discharged
from the pump barrel passing directly or through a very
small reservoir to the outlet. In another form the upper
portion of the body of the pump is elongated, or a pipe is con-
nected therewith, into which the water rises with every
stroke of the piston. As each stroke not only has to over-
come the atmospheric pressure, but has also to raise this
column of water, it is evident that the height to which water
can be so raised by hand power is limited. About 30 feet is
the highest to which water can be conveniently raised by one
man. When other motive power is employed it may be
raised by such a pump to about 100 feet above its source.
This limit, in actual practice, is probably due to several
causes, of which the principal is the uncertain action of the
piston valve under such great pressure. In deep wells, where
the water-level is more than 24 or 25 feet from the surface
of the ground, the pump must be fixed within the well,
the piston rod being lengthened so as to be connected with
a lever or handle, or to a fly-wheel. In such cases it is
usual to fix a double-barrel pump, since it is easier to raise
a given volume of water with such a pump than with a
single-barrel of capacity equal to the two together. With
334 WATER SUPPLIES
the double-barrel the work is distributed, each half turn
raising one piston, whereas, with the single-barrel the whole
lift is on one half turn. With a treble pump the work is
still more equally distributed; but as complications are
introduced the double-barrel is generally preferred.
The pump need not be fixed over or even near the well ;
but if at any considerable distance, it must be remembered
that a certain amount of friction is introduced, and must be
allowed for. The suction pipe must fall all the way from the
pump to the well, otherwise air may lodge in the bends
and impair the action of the pump. In long suction pipes it
is desirable to have a foot valve to retain the water when the
pump is not in use, and to prevent the concussion caused by
the sudden arrest of the motion of the long column of water
at each down-stroke of the piston ; a vacuum vessel also
should be connected with the pipe just before it enters the
pump.
In another form of lift pump a solid piston plays in a
barrel placed alongside a second barrel, which is closed at each
end by a valve opening upwards. The upper end of this
second cylinder is continuous with the rising main, whilst the
lower end is continued into the suction pipe. The upper end
of the pump barrel is connected by a wide tube with the
valve cylinder. When the pump is in action depression of
the piston causes a vacuum in the barrel within which it
works, into which water rises through the valve at the
upper end of the suction pipe. When the piston is raised
this water is forced through the upper valve into the rising
main. A pump of this character can raise water a height of
700 feet and upwards.
(6) In the plunger or force pump a solid plunger takes
the place of the ordinary piston or bucket, but the suction
pipe, valves, and rising main resemble in arrangement the
pump just described. The cylinder, however, in which the
plunger works is connected with the valve box by an opening
near its base, and the plunger does not accurately fit the
PUMPS AND PUMPING MACHINERY 335
cylinder in which it works. When pumping is in operation
the water rises in the suction pipe to fill the vacuum pro-
duced by the rising plunger, and when this falls it forces into
the rising main an amount of water equal to the volume of
the plunger which enters the cylinder. This single-acting
plunger pump is largly employed for raising water to con-
siderable heights. It is obvious that in this form of pump
also the vertical length of the suction pipe must not exceed
27 feet. As a matter of practice the pump barrel is usually
only a few feet above the surface of the water to be raised.
Two or three such pumps may be combined, and so arranged
that the discharge, instead of being intermittent, as in the
single-barrel pump, becomes practically continuous. For
high lifts and heavy pressures air chambers must be connected
with these pumps. The water being forced into these
instead of directly into the main, the compressed air
acts as a cushion, and tends greatly to equalise the flow
of water and relieve the valves from undue shock. The
force pump is less troublesome to keep in repair than the lift
pump, since it dispenses with the bucket, the clack valve of
which can only be reached for repairs by taking the pump to
pieces. Whilst the pump barrels are usually fixed vertically,
they are occasionally placed in a horizontal position. In
waterworks where water has to be raised from a well, and
then forced to a considerable elevation, usually two sets of
pumps are employed, one raising the water from the well to a
reservoir at or near the ground-level, and the other forcing
the water from this reservoir to the highest point at which
the water is required.
(a and b) The so-called bucket and plunger pump, which is
probably most extensively used for high lifts, combines in its
construction both principles a and 6, acting both as a lift
and plunger pump. The piston rod working within the pump
barrel has a cross section half that of the bucket or cylinder,
otherwise in construction it resembles the ordinary lift pump.
When in action the down-stroke of the piston forces the water
336
WATER SUPPLIES
through the bucket valve; but as half the volume of the
cylinder is occupied by the piston, half the water is forced
into the rising main. With the up-stroke the other half
passes into the main, whilst the barrel under the piston is
again filling from the suction pipe. It is practically, therefore,
a double-action pump, performing with one set of valves the
work of two smaller pumps.
Other combinations of these two classes of pump are
made, each manufacturer claiming some advantage for his
special construction.
(c) Centrifugal Pumps. These pumps differ entirely from
either of the types just described, inasmuch as they contain no
valves or pistons. A series of fans or blades are attached to
a spindle, passing through the centre of a
cast-iron case in which they are contained.
By the revolution of these fans a partial
vacuum is produced behind, into which
the water is drawn, or rather forced by
the pressure of the atmosphere, whilst the
water in front of the blades is forced into
the rising main. The efficiency of such
pumps depends chiefly upon the degree
to which fluid friction and shock, from
impact of the blades upon the water,
can be reduced, and these again depend
upon the mode in which the water enters
the pump, and upon the curvature and
arrangement of the blades. These pumps are not suitable for
raising water to any considerable height. Up to about 25
feet they are probably more effective than any other form of
pump, but above 30 feet a good plunger pump will give better
results. Centrifugal pumps are made capable of raising water
over 100 feet, and as they are more simple and compact than
other types, these advantages may, under certain circum-
stances, more than compensate for the larger amount of fuel
consumed when water has to be raised more than 30 feet.
FIG. 21. Centrifugal
Pump. A, rising
main ; B, suction
pipe.
PUMPS AND PUMPING MACHINERY
337
The advantages of this type as compared with either of the
preceding may be summarised as under :
1. There being no vibration or oscillation, a lighter and
less expensive foundation is required.
2. They are more easily and readily fixed and repaired.
3. Greater simplicity of construction, and greater dura-
bility from the absence of valves, eccentrics, air-
vessels, etc.
4. Less affected by sand or grit.
5. Moderate cost, and up to a certain point the greater
efficiency measured by (a) the power employed, (b)
the quantity of water raised, (c) the height to which
it is raised, and (d) the time required to raise it.
Theoretically the amount of water raised by a lift pump
in a given time depends upon the diameter of the pump
cylinder, the length of the stroke of the piston, and the
number of strokes, whilst in the plunger type the diameter of
the plunger must be substituted for that of the cylinder. For
convenience of calculation the following table gives the
amount of water in gallons delivered per inch of stroke in
pumps with cylinders or plungers of various diameters :
Diameter of Cylinder
or Plunger.
Gallons of Water delivered per
each Inch of Stroke of Pump.
2^ inches.
0176
2f
3
0212
0254
34
34
4
0298
0398
0454
5
0708
6
1020
8
1816
12
4080
To find the theoretical quantity of water raised per
minute by a given pump, multiply the quantity delivered
per inch stroke corresponding with the diameter of the cylinder
338 WATER SUPPLIES
or plunger by the length of the stroke and the number of
strokes per minute. For example, a pump with 4-inch
cylinder, 10-inch stroke, and working at 30 strokes per minute,
should deliver
0454 x 10 x 30 = 13-62 gallons per minute.
If such a pump actually delivered this amount of water its
action would be perfect, and its modulus of efficiency would
be considered as 100. In actual practice such an efficiency
is never reached. The common lift pump has usually only an
efficiency of about 50 ; ordinary plunger pumps of from 60 to
70, whilst the highest class of waterwork pump often does
not exceed 80. The efficiency of centrifugal pumps varies
widely with the conditions under which they are used, and
under favourable circumstances may not exceed 50 per cent
of the theoretical amount.
The degree of efficiency attained is an index of the quality
of the machine turned out by the maker ; but it varies with
the construction of the pump, and one form may show a
higher efficiency when working at a certain speed and doing
a certain duty, whilst another may excel it at a different speed
and duty. Unnecessary friction is introduced and efficiency
impaired if the suction and delivery pipes be too small, or
have sharp bends along their course. The delivery pipe
should have a diameter at least half that of the pump barrel,
and the suction pipe should be still wider. In the latter the
atmospheric pressure alone has to raise the water against the
force of gravity and has to overcome the friction, whereas in
the former these are effected by the power used to work the
pump.
Water may be raised by means of pumps by manual labour,
by labour of some animal, horse, pony, ox, mule or ass, by aid
of the wind or falling water, or by steam, hot-air, gas, or oil
engines.
For small and intermittent supplies, where the water has
only to be raised to an inconsiderable height, human labour
PUMPS AND PUMPING MACHINERY 339
must often be depended upon ; but both human and animal
labour is often used when wind or water power could be pro-
fitably utilised, and even where some form of gas or oil engine
would be more economical.
Hand labour may be employed in pumping, either in work-
ing a pump handle or in the continuous turning of a crank
and handle. In the ordinary pump the leverage is usually
about 6 to 1, i.e. the distance from the fulcrum to the
free end of the handle is about six times that of the fulcrum to
the point of attachment of the handle to the piston rod.
With a crank and handle the leverage varies from 3 to 1 to 4
to 1, according to the length of the stroke and the diameter
of the circle described by the handle. Whilst the latter is
pleasanter to work, it is evident that a man exercises more
power with the former. With the pump, the whole or nearly
the whole of the force is exerted in depressing the handle,
whereas with a crank and fly-wheel the work is more equalised.
With a single-barrel purnp the pump handle or the fly-wheel
can be so weighted as to render the work in the up-stroke and
down-stroke more nearly equal. If the well frame be provided
with a wheel and pinion the power required to raise water a
given distance can be diminished in any ratio ; but the amount
of water raised by each revolution of the handle is diminished
in the same proportion, or, in other words, what is gained in
power is lost in time. It is easier to raise a given quantity
of water with a double -barrel pump than with a single-
barrel pump of a capacity equal to the two barrels, since
with the former half the water is raised with each half
turn, whereas, with the latter the whole is raised at one half
turn.
The resistance to be overcome in raising water any given
height will be the weight of a column of water of that height
and of cross section equal to that of the pump piston, plus
the resistance due to friction and the weight of the pump
rods. The following table admits of the water pressure being
readily calculated :
340
WATER SUPPLIES
Diameter of Pump Cylinder.
Weight of corresponding Column
of Water 10 feet high.
2 inches
13-6 Ibs.
2i
21-2
3
30-6
8*
41-6
4
54-4
5
85-0
6
122-4
Example. Kequired the water pressure upon a piston of
3 inches diameter raising water to a height of 80 feet.
Since from the table a column of water 3 inches in diameter
and 10 feet long weighs 30'6 Ibs., the pressure of a column
80 feet long will be 244 '8 Ibs. The above weight includes
that of the column of water raised by the atmospheric pressure,
since the piston is raised against this pressure. With an
ordinary pump, having a handle with leverage of 6 to 1, a force
of g - = 40'8 Ibs. would have to be applied to raise the water
alone without allowing for friction, etc. By the use of a wheel
and pinion this power could be reduced so as to enable one man
to raise the water, the power which an ordinary labourer is able
continuously to employ for such a purpose being only 25 Ibs.
From the above table the height to which one or more men
can raise water by means of a pump -worked either by a
handle or crank can be determined approximately, if the
effect due to friction be not excessive.
The following table, by Molesworth, gives the theoretical
power required to raise water from deep wells, or to raise
water a given height. In using it an allowance must be
made for friction in the gearing and pipes, for it should be
remembered that the fluid friction of water traversing a pipe
varies directly as the length of the pipe and as the square of
the velocity. Doubling the length of a pipe therefore will
double the friction, whereas, diminishing the internal area by
half will increase it four-fold.
PUMPS AND PUMPING MACHINERY
341
Maximum Height to which Water can be raised.
Quantity of
Water
raised per
Hour.
By one Man
turning a
Crank.
By one
Donkey
working
a Gin.
Bv one
Horse
working a
Gin.
By one
Horse-power
Engine.
Gallons.
Feet.
Feet.
Feet.
Feet.
225 80
160
560
880
360 50
100
350
550
520
35
70
245
385
700
25
50
175
275
900
20
40
140
220
It is assumed that a good class double or treble-barrel pump
is used.
Wind as a motive power for driving pumps is again receiv-
ing considerable attention in consequence of the introduction
of improvements rendering the wind engine more reliable,
more uniform in action, less liable to damage by storms, etc.
For pumping water to supply farms, groups of cottages, and
mansions, the wind can often be utilised. Beyond the first cost
of the engine there is practically no expense, and in the most
modern mills self-regulating gearing reduces the personal
attention required to a minimum. Naturally they are most
efficient in exposed situations, but they can be utilised any-
where if placed at such an elevation as to receive the full
force of any wind which blows. The mill will work from 30
to 35 per cent of the possible time, but to provide for the
periods of calm it is necessary to have the mill amply large
and a storage reservoir capable of holding from four to seven
days' supply of water. Unless these precautions are taken in
the first instance, occasional failures in the supply are certain
to occur, necessitating the provision of a steam or other engine,
or gearing for animal power, to work the pumps during the
intervals of calm.
The wind engine may be fitted with a crank, to which
the piston rod of the pump is directly attached. This form,
however, is only adapted for raising very limited supplies of
342 WATER SUPPLIES
water ; for larger quantities, or where the water has to be
drawn from a considerable depth or forced to a height, it is
better to connect with gearing from which a double or treble-
barrel pump can be worked. Mills with annular sails are
now almost exclusively employed for pumping purposes, and
the sails may be either "solid" or "sectional." In the
" solid " form each sail is pivoted at both ends, and coupled
together with rods, and so adjusted as to develop the
maximum of power when working. An automatic regulator
causes the sails to furl when the wind pressure becomes too
high, and so ensures the safety of the mill. The head also
revolves, and is kept facing the wind either by a large tail
vane or a tail-steering wheel. By aid of levers the engine can
be started or stopped and its speed regulated. In the
" sectional " wheel the individual sails are not pivoted into
any framework, but are fixed at a definite angle and connected
together into a series of sections which vary in number with
the size of the wheel. Each section carries a weight or
counterpoise so hung that when the wind is very high the
wheel opens and assumes a tubular form, allowing the wind
to pass through. When the wind falls the sails resume their
normal position and the mill is again in action. It is claimed
that this form is safer in a storm, is more easily regulated to
work at a uniform speed, and is more sensitive to light breezes.
Either form can be fitted with an automatic appliance for
keeping the water in the supply tank or reservoir at a definite
height. Where water has only to be raised a few feet, the
wind engine may work an Archimedean screw, or a dash
wheel, or a "Noria" pump (an endless chain carrying a series
of small buckets), instead of the ordinary force or lift pump.
Such contrivances, however, are only adapted for raising water
for irrigation and similar purposes.
The amount of power developed by these engines varies
with the diameter of the wheel, its construction, and the
velocity of the wind. If built on correct principles the
wind will produce the same effect upon the wheel of one
PUMPS AND PUMPING MACHINERY
343
maker as upon another, but a difference may arise from loss
of power by friction, leverage, gearage, etc. Where the mill
has to be fixed at some distance from the pumps, the trans-
mission of the power causes further loss. Whilst some
makers claim that, with a wind of 18 miles an hour, their
machines, with wheel of 13 feet diameter, have 2 horse-power,
other makers, more modest, claim only to give 1 horse-power
with such a wheel. Roughly stated, the power of a wind
engine varies directly as the square of the diameter of the
wheel, that is, a 20-foot wheel will do twice the work of one
15 feet, and four times that of one 10 feet in diameter. As an
approximate guide to the amount of water which a wind engine
of modern construction will raise, the following estimates may
be useful. The water raised is given in gallons per hour, and
the wind is assumed to be blowing at a rate of from 14 to 18
miles an hour. It must also be remembered that the average
day's work corresponds to about eight hours.
Diameter
of Sail.
Gallons raised
per Hour.
Height raised.
Daily Supply.
Feet.
Feet.
Gallons.
Maker A.
10
200
100
1600
j j
12
250
150
2000
Maker B.
10
250
100
2000
> J
12
250
150
2000
j j
12
400
100
3200
Maker C.
10
240
50
1920
j j
12
240
100
1920
Maker D.
10
210 to 300
100
1680 to 2400
10
300 to 450
50 to 60
2400 to 3600
i i
12
300 to 500
100
2400 to 4000
30
7000?
150
Expressed in terms of h.p., a 10-foot mill will give |-1 h.p., a 12-
foot mill 1-li h.p., a 14-foot mill 1^-2 h.p., a 16-foot mill 2-2 h.p.,
an 18-foot mill 2^-3 h.p., and a 20-foot mill 3-4 h.p.
Estimates by different makers for pumping engines of
various kinds can readily be obtained, but in consider-
ing those for wind engines it must be remembered that the
storage capacity required is much larger than with any other
344 WATER SUPPLIES
form of engine, and therefore increases the initial expense.
Where a larger supply than 20,000 gallons per day is required,
a steam or gas engine is probably in all cases preferable, but
for raising smaller supplies the possibility of utilising the wind
as the motive power is always worthy of serious consideration.
Water Power. Running water, when available in sufficient
quantity, is one of the cheapest and most manageable sources
of power for pumping purposes. It may be utilised by means
of water-wheels, turbines, or rams, the choice often depending
on the fall which can be utilised, the amount of water to be
supplied, and the height to which it has to be raised ; but in
some cases, where any form is applicable, the selection will be
influenced by minor considerations. Whilst water-wheels
and turbines are occasionally used for pumping large
quantities of water, rams are rarely used when more than
10,000 gallons a day have to be raised. As the hydraulic
ram, where it can be utilised, is probably the simplest and
cheapest, it may be considered first.
Its construction will be rendered intelligible by the follow-
ing section and description (Fig. 22).
In this ram it is obvious that the water working the ram
is the same as that which enters the rising main, and as the
proportion of water raised to that wasted is invariably
small, its utility is somewhat limited. Recently, however, a
double-acting ram has been devised, whereby an impure water
by its fall is caused to pump water from a purer source. As
yet these are not in general use.
These self-acting pumps work day and night, and if by a
good maker, and properly adapted for the work they have to
perform, the amount of attention and repair required during
the year is remarkably little, as there are no parts requiring
packing or lubricating. With a reservoir holding sufficient to
meet one or two days' demand, repairs, when necessary, can
be effected without interfering with the supply. Where
large quantities of water are being pumped, a duplicate ram is
desirable.
PUMPS AND PUMPING MACHINERY
345
The smallest fall which can be utilised is about 18 inches ;
the greater the fall the larger the proportion of water, and
the greater the height to which it can be raised. Although
falls of 40 feet are sometimes used, the wear and tear conse-
quent upon the friction and shock necessitates the use of
specially-constructed rams. Special rams are also made
which will lift water a height of 800 feet, and the water so
FIG. 22. A is the feed pipe -communicating with the reservoir supplying the
water, B the escape valve, C the valve leading to the air-vessel, D, E is the rising main.
When water is admitted to A, it at first escapes through the valve B, which opens
downwards, but as the maximum velocity is reached the force is sufficient to close
the valve. The flow being suddenly stopped, the pressure rises, and lifts the
valve C, which opens upwards, a certain amount of water entering the air-vessel
D. The pressure being relieved by the recoil, both valves fall. The water again
escapes at B, and the action described is repeated. The intermittent flow into C is
converted by the compressed air into a constant flow through the rising main E.
raised may be caused to act upon a second ram and raise a
portion of the water to a height of 1500 feet. Rams,
however, are rarely used to lift water to more than 150 to
200 feet, as the amount of water wasted compared to that
supplied increases with the elevation, but more rapidly than
the elevation on account of the increased friction. A ram of
best construction will raise water thirty times the height of
346
WATER SUPPLIES
the fall, but it is not safe to depend upon delivering it at
more than twenty-five times the height. Where the water
supply is not sufficient to work a ram continuously, it may
often be dammed up and discharged at intervals by a
syphon arrangement, the ram then working intermittently.
Theoretically, disregarding friction, the product of the
amount of water falling in a given time into the fall should
be equal to the product of the amount raised into the height.
Thus 100 gallons falling 10 feet would raise 10 gallons 100
feet, 20 gallons 50 feet, or 100 gallons 10 feet, etc. Friction
and imperfections in construction, however, render such a
degree of efficiency unattainable'; but some of the best of
most modern rams have reached over 80 per cent of
efficiency, even with a rising main of considerable length
and when the water was being lifted over 100 feet. The
smaller the fraction expressed by the ratio of the fall to the
height raised, the less the efficiency. Tables giving the
efficiency for different ratios have been published, but they
are quite useless. Thus in a table recently issued the
efficiency of a ram with a ratio of fall to height of T \r is given
as 37 per cent, whilst more than one English maker will
guarantee at least 50 per cent, and 69 per cent has been
attained. Allowing for the friction in a moderate length of
rising main, a good ram properly fixed should supply not less
than the following percentages of the theoretical amount :
Fall.
Deree
EfficiBiicy citt'ciincd. by
Height
of Efficiency.
Blake's Rams.
raised.
i
*
86 per cent.
76
78 per cent.
\
70
83
66
72
I
63
\
60
75
\
58 ;
56
T\F
54
TV
52
69
PUMPS AND PUMPING MACHINERY 347
Example. It is required to know what amount of water
can be raised to a height of 100 feet, by a ram working
with a fall of 10 feet, the amount of water available being
20,000 gallons per day.
Here the ratio -^ should give an efficiency of at least
54 per cent. With perfect efficiency the amount raised
would be 2000, since
2000x100 = 20,000x10
and 2000x^^ = 1080, which is the number of gallons per
day the ram should be guaranteed to raise to the required
height.
The efficiency decreases very rapidly when the ratio of
the fall to the height raised exceeds J^, so that when -^ is
reached the proportion of water pumped to that wasted
becomes a very small fraction indeed. In such cases other
forms of water motors are preferable ; moreover, with a fall of
over 10 feet the wear and tear becomes so very considerable
that it is not desirable to attempt to utilise much greater
falls with a ram. These conditions, therefore, limit the general
usefulness of the ram to situations where the fall of water
available is from 1J to 10 feet, and where the supply has not
to be raised more than 250 feet.
A turbine can often be used where a ram is inadmissible.
In the ram the pump is a part of the machine, whereas a
turbine is merely a machine for utilising a fall of water to
supply the power to work a pump or set of pumps. It
follows, therefore, that a turbine worked by a falling stream
may be used for pumping water from any source, as from a
deep well, and the pumps may be placed at any convenient
distance from the source of power, the connection being
made by suitable gearing. Any fall from 1 to 1000 feet can
be taken advantage of, and there is practically no limit to
the depth from which the supply can be raised, or to the height
to which it can be propelled. Moreover, they can be so
constructed as to work with fluctuating falls and a constant
348 WATER SUPPLIES
efficiency of 75 per cent attained. In experimental trials the
best turbines have yielded 87 per cent of the actual power
of the water, but even with the best makers it is not
safe to rely upon more than 75 per cent.
The numerous varieties of turbines may be divided into
two classes. In the first or " pressure " turbine the falling
water is conducted through one or more pipes and allowed to
impinge upon the vanes of a wheel, which revolves upon a
pivot and is included in a metal case. The impact of the
water causes the wheel to revolve with a velocity depending
chiefly upon the fall. After expending its energy, the water
escapes around the centre of the case. The turbine may be
fixed horizontally or vertically, and the vanes may be fixed
or movable, the latter only being necessary where the power
required or the water available is variable. In the second
class of turbines or "impulse" turbines, the falling water
(conducted by suitable guides) impinges against a series of
"buckets," arranged around the periphery of the wheel.
This turbine, therefore, need not be acted upon by the water
all round, neither need the wheel be submerged. It must
always be fixed at the bottom of the fall, whereas the
" pressure " turbine may be placed as much as 20 feet above,
the water escaping from the centre passing down a suction
pipe and so contributing to the available power. The first
form is most generally applicable for low and medium falls,
and the latter for high falls. When the supply of water is
abundant and a high degree of efficiency is not necessary,
cheap forms of the turbine may be employed ; but where it is
required to fully utilise the power a machine should be
obtained, the high efficiency of which is guaranteed. As
large turbines are more efficient than small ones, it is often
advisable to store the water during the night and give the
whole out during the day to a large turbine, rather than
work a smaller machine with the constant flow.
On the Continent turbines are much more used than in
this country, the largest installation probably being at St.
350 WATER SUPPLIES
Maur, where four sets of turbines, each with a diameter of 40
feet, raise over 8,000,000 gallons of water per day to an
elevation of 250 feet for the supply of the city of Paris.
The fall of water utilised is only 3 feet. The turbines are
fixed with the axes horizontal, and are of the "impulse"
class. The turbines pumping water for the city of Geneva
are of the same description, but work with a fall of 165
feet.
Probably the greatest height to which water is raised by
any machine is by the turbines pumping water to supply the
town of La Chaux de Fonds (population 30,000). These
turbines, made by Mons. Escher of Zurich, work with a fall
of about 100 feet of water, derived from the Gorges de
1'Areuse, and throw that supplying the town to a height of
over 1600 feet.
As an example of a village supply the works recently
executed at West Lulworth (Dorset) may be cited. The
water from a spring on the hillside is piped to a tank placed
on a tower immediately over the turbine. The vortex
(pressure) horizontal turbine is fixed in a pit 20 feet below
the level of the water in the tank. The water falls to the
turbine by means of a vertical pipe, the waste water being
conveyed away from the bottom by a 12-inch drain and
discharged into the sea. From the turbine, which runs
about 600 revolutions a minute, the power is communicated
by a 10-inch pulley to a larger pulley on the overhead
shafting, and thence the power is transferred to a set of
three-throw plunger pumps. The machine is estimated to
be of 5 h.p., and will lift continuously 1200 gallons per
hour into the service reservoir, which is on the hillside, 300
feet above the source of the water. The reservoir has a
capacity of 60,000 gallons, and as the population to be
supplied is only about 400, it is obvious that the reserve is
ample to admit of the pumping being intermittent, and to
give time for repairs, etc., to the turbine when such are
needed.
PUMPS AND PUMPING MACHINERY
The efficiency of turbines decreases with the size; hence for
small supplies (of from 1000 to 4000 gallons per 24 hours) a
small water-wheel, which can be used without gearing, is often
more economical, both in first cost and in amount of water
used. Water-wheels are too well known to need any descrip-
tion. Recently, however, the substitution of light iron wheels
for the cumbersome wooden ones previously used has greatly
increased the utility of this machine. An " overshot " water-
wheel receives the water near the top and has a higher degree
of efficiency than either the " high breast," which receives the
water above the centre, or the undershot wheel, which receives
the water below the centre. Where sufficient fall is available,
therefore, the overshot wheel should always be selected. A
fall of 1 foot may be utilised for driving an undershot
wheel, but not less than 3 feet is required for the over-
shot. They are quite as reliable as rams, and as the wheels
revolve at a slow speed the shaft can be directly connected
with the piston rods of the pumps. Where the water avail-
able for working the wheel is variable, an adjustable disc
crank can and should be provided, so as to enable the stroke
of the pump to be correspondingly varied. The following
table gives approximately the amount of water which can be
raised per day to a height of 100 feet, with wheels of different
diameter and with different supplies of water :
Diameter of Wheel.
Water Supply
per Minute.
Quantity raised 100 Feet
in 24 Hours.
4 feet.
60 galls.
1,000 galls.
4
100
1,850
4
500
9,250
5
50
1,000
5
100
2,000
5
250
5,000
6
100
2,750
6
500
13,750
These figures refer to an "overshot" wheel. A "high-
breast " wheel would raise about 5 per cent less, and an
352 WATER SUPPLIES
"undershot " about 15 per cent less, assuming the fall utilised
to be the same. As these wheels run night and day, rarely
require any attention, are very inexpensive both to purchase
and fix, and can be worked by impure water, w r hilst raising a
pure water from a well, spring, or other source, it is obvious
that under many circumstances they are preferable to a ram,
whilst under others they can be used when the ordinary ram
is inadmissible.
Fuel Engines. Where neither wind nor water are avail-
able an engine, deriving its energy from the combustion
of fuel (coal, wood, charcoal, petroleum, or gas), must be
employed. Such engines differ from those previously
described in being a constant expense for fuel and attention ;
but the great improvements which have been effected in recent
years, especially in the construction of small motors, has prob-
ably reduced this expenditure to a minimum. The simplest
machines are those which dispense with the use of steam.
These are the hot-air, gas, and oil engines. The competition
between the makers of these various types of motors, not only
amongst themselves, but with the makers of steam engines, has
resulted in all being brought to such perfection that it is often
a difficult matter to decide which form is the most desirable.
The hot-air engine is very compact and economical, requiring
but little fuel and skilled attention, but it is only adapted for
small works, where the h.p. required is from J to 1. Its
only competitor under such conditions is the gas engine, and
as this is quite as economical in cost of fuel where gas is
reasonably cheap, and requires even less attention, it would
probably be selected where gas is available. The gas engine
is rapidly supplanting the steam engine in all but the largest
pumping stations, since they are not only more compact than
steam engines, but, with gas at a reasonable price, more eco-
nomical, when the great saving in repairs and in attendance is
taken into consideration. When once started they will run for
hours without any attention, and there is no risk of explosion
from neglect. " Oil " engines are of more recent introduction
PUMPS AND PUMPING MACHINERY 353
and, owing to the cheapness of petroleum, are claimed to be
more economical than gas engines should the cost of gas be over
2s. per 1000 feet. It is also asserted that the cost of the oil
used does not exceed that of the corresponding amount of
coal required in driving a steam engine, when such coal can
be obtained at 10s. a ton. Where coal is more expensive
there is a saving in the cost of fuel, but in all cases there is
saved the wages of stoker and driver and the cost of water.
As the oil used has a high flashing point there is no risk of
explosion, and the danger from fire is reduced to a minimum.
In the best machines the vapouriser is heated by a small lamp,
taking about 5 to 7 minutes. As soon as the temperature is
sufficiently high the engine will start when the jly-wheel is
turned. The lamp is then extinguished, since the heat of
the vapouriser is afterwards maintained by the continuous
explosions. When once started the only attention required is
periodical lubrication and the occasional replenishing of the
oil reservoir. In fact, after being set in motion it requires
no more attention than the gas engine.
These engines are now made to work up to 25 h.p.,
and where gas is not obtainable there is no doubt that they
will be extensively employed.
In order to enable gas engines to compete with oil engines
where there is no public gas supply, plants are now made for
converting petroleum oils, fat and grease of all kinds, into gas,
and it is claimed that the gas so produced is cheaper than
coal-gas. Water-gas may also be manufactured and used for
this purpose. As the " oil " engines convert the petroleum
into gas in the vapouriser drop by drop as it is required, there
does not seem to be any advantage in or any necessity
for constructing a gasworks, unless gas. is required for other
purposes besides that of supplying the motive power to the
engine.
Steam engines, except for large waterworks, are not likely
to be seriously considered as a source of power on account of
the comparatively large expense entailed in labour. For large
2 A
354 WATER SUPPLIES
works, however, they continue to be the only practical and
efficient motors. In such cases, also, the compound condensing
engine will be used. For engines under 10 h.p. the saving
effected by the use of a condensing arrangement will not
compensate for the additional cost of the engine. The
pumps may be driven by a steam engine either directly or
through the intervention of a crankshaft and fly-wheel. In
the former case the pistons of the cylinder and of the pump are
continuous, in the latter the piston of the cylinder acts upon
the fly-wheel and the pump piston is attached to the crank.
The crankshaft engine requires more space and stronger
foundations than the " direct " form, and as the latter are
now being made " compounding " and with high duty gear,
and are more compact, they will be generally preferred.
In calculating the horse power required for pumping a
supply of water, the chief factors are : (a) the quantity of
water to be raised, and (b) the height to which it has to be
lifted or forced. Besides this, an approximate estimate must
be made of the power which will be required to overcome the
friction due to gearing, and the passage of the water through
the pipes. The loss from friction in the pipes will depend
upon the nature of the surface of the pipe, degree of smooth-
ness or roughness, but more upon the diameter and velocity
with which the water is traversing it. It is of the highest
importance to have all the mains of sufficient diameter,
since the friction increases with the square of the velocity.
Thus the friction in a pipe discharging a certain number of
gallons per minute will be increased fourfold if the discharge
be only doubled. The friction also increases directly as the
length of the main. The main should always be of such
diameter that the vebcity shall not exceed 2 feet per second
(Rawlinson). With this velocity the discharge from pipes
of different diameters is given in the following table. It will
be observed that the volume for any pipe can be calculated by
multiplying the square of the diameter in inches by the volume
discharged from a 1-inch pipe.
PUMPS AND PUMPING MACHINERY
355
Diameter of Pipe.
Volume of Water discharged per Minute
with a Velocity of 2 Feet per Second.
1 inch
4'1 gallons.
11
9'2
2.
16-4
3
37-0
4
65-0
6
148-0
8
260-0
10
410-0
12
590-0
j
With pipes of such ample diameter the loss from friction is
very small and practically negligible.
An engine of one 1 actual horse power will raise 3300 gallons
1 foot high per minute, and any smaller quantity to a propor-
tionately greater height. From the following simple formula
the h.p. required to pump any given quantity of water can
easily be calculated :
GxH
3300
= H.R,
where G = the number of gallons to be pumped per minute
and H = the height to which it has to be raised.
The allowance for overcoming the friction of the bucket or
plunger in the pumps, and of the movement of the water in
the pipes, and for raising the piston rods (when pumping
from a deep well), cannot be exactly calculated. It is better
to err on the safe side and allow 80 per cent for small engines
and 40 per cent for larger powers.
In all waterworks it is necessary to provide more pumping
engines than are actually at any one time required, in order
to provide for such contingencies as a break-down or laying-
1 By actual horse power is meant the actual power of an engine given
from the shaft or fly-wheel. The term "indicated" horse power, which
is frequently used,- is the power given off in the cylinder, and is, of course,
higher than the actual or available power. Another term often employed
by makers of engines is "nominal" horse power. It is a variable
quantity, and so misleading that it should be abandoned.
356 WATER SUPPLIES
off for repairs. " In the case of small waterworks it is common
to have double the quantity of power needed, in the form of
two pumping engines, either of which is capable of doing all
the work. The reason for this is that the first cost would
probably be rather increased than otherwise, by subdividing
the work more, when the engines are very small, even although
the total horse power might be less. Then suppose the total
horse power needed were six i.h.p. 1 Two engines of six i.h.p.
each would probably not cost more than three of three i.h.p.
each ; moreover, in work, the efficiency of the one pumping
engine of six i.h.p. would be greater than that of the two of
three i.h.p. each. Of course there is no hard-and-fast line
between small and large works, but it may be very roughly said
that it is not advisable to subdivide the pumping power into
more than two engines if, by so doing, separate engines of less
than ten i.h.p. each have to be provided. In the case of large
waterworks, the stand-by power need only equal one- third,
one -fourth, or, in the case of very large works, perhaps
one-fifth of the whole, there being, in such cases, three, four,
or five pumping engines " (Burton, The Water Supply of
Toivns). Where engines are employed requiring the use of
fuel and attendance, it is desirable to have the machinery of
such power that the whole of the water required during
twenty-four hours can be pumped in a much shorter time. For
mansions, farms, etc., the engines may be sufficiently power-
ful to raise in eight or twelve hours as much water as will
serve for three or four days, thus necessitating pumping only
twice a week. For village water supplies pumping for from
four to six hours daily should suffice. For towns up to 20,000
inhabitants the pumps should raise in ten hours the whole
day's supply. For larger towns the pumping would probably
be continuous. Naturally the h.p. required will have to be
regulated by the quantity of water which has to be raised in
the given time.
1 Indicated horse power.
CHAPTEE XX
THE STORAGE OF WATKR
WHERE a water supply is derived from the rainfall upon
any catchment area, it is obvious that, whether it is to meet
the demand of a single house, or of a whole town, sufficient
storage must be provided to tide over the longest periods of
drought ever likely to occur, and to equalise the supply
during a succession of dry seasons. The various ways in
which the amount of storage necessary is calculated, and the
opinions of various engineers and hydrologists thereon, have
already been recorded in Chapter XVII., where the amount of
water available from different sources has been considered.
The reservoirs used for the above purposes are called " im-
pounding" reservoirs, and when of large size they are
usually situated in a valley, or at the junction of two valleys,
where, by excavation and the construction of a dam, a sufficient
quantity of water can be collected.
The ground must be first surveyed to ascertain the
character of the impervious stratum and its distance from
the ground surface. If of rock, its freedom from fissures
(common in certain formations), through which the water
could escape, must, if possible, be determined. The presence
of an undiscovered fissure may result in the reservoir, after
construction, having to be abandoned, or in the expenditure
of large sums of money in detecting and attempting to remedy
the defect. The dam may be of masonry or of earthwork,
but the former is only applicable where there is a rocky
358 WATER SUPPLIES
foundation. The latter can be constructed on rock, clay, or
other impervious strata, and is less costly than masonry. If,
however, the water is once able to penetrate it, the channel
will continuously increase in size and the dam will be
destroyed, whereas defects in masonry dams have not this
tendency to continuous increase and admit of being more
easily discovered and remedied. All vegetable matter should
be removed from the sides and bottom of new reservoirs,
otherwise these, by their decomposition, will give up organic
matter to the water, favourable to the growth of low forms of
life. To draw off the water a valve tower is provided, which
admits of valves being opened at various depths, so as to
avoid drawing either from too near the surface or too near
the bottom. A meter house may be required, in which to fix
the apparatus for recording the amount of water which is
passing into the mains, or the amount of compensation water
being supplied, or both, and a by-pass to allow of flood water
being diverted from the reservoir, and to prevent the water
rising above a certain level.
According to Rawlinson, the outer portion of the embank-
ment must be effectively drained, and if there are springs of
water in the puddle trench (as there usually are), these must
be collected and brought away. No form of culvert or other
works for drawing off water should be constructed within or
beneath or through the deepest made portion of the bank,
but the outlet tunnel, valve chamber, and works connected
with the drawing off of the water must be in the solid ground,
on the side of the valley. At the centre of the bank the
valve chamber should be formed. All pipes and valves should
be so placed as to be easily reached for repairs or renewals,
and it should be so arranged that no valve in the tier of
valves in the valve well need be worked under a greater head
than 10 or 15 feet.
In cases also where the water is derived from springs and
streams of variable flow, the supply sometimes falling below
that of the average demand, impounding reservoirs are
THE STORAGE OF WATER 359
necessary to equalise the supply. The size will depend upon
many circumstances, but will be chiefly influenced by the
length of time during which the yield is below the average,
and by the extent of the fluctuations. Where river water is
impounded it must also be remembered that at certain periods,
following heavy rains, the water will be more or less turbid
or impure, and may have to be allowed to run to waste.
Where the average supply of a stream is more than sufficient
to meet all requirements, more or less storage is still required
to enable pure water to be supplied whilst the river is in
flood and its waters turbid and possibly polluted. Wherever
the water collected requires to be filtered before being
delivered to the consumer, reservoirs for "settling" are an
almost indispensable adjunct to the filter beds.
Such " settling " reservoirs retard the clogging of the pores
of the sand in the filter beds, and therefore enable the filters
to work for longer periods without cleansing. They should
be so constructed as to allow of emptying and cleansing, but
should not be too shallow, otherwise the water may become
unpleasantly warm in summer. A water depth of 12 to 16
feet is usually recommended. As generally constructed, with
sloping sides, the growth of algae is favoured. Vertical sides
are preferable.
Smaller or " service " reservoirs are often also constructed
in or near the place to be supplied with water, in order to
enable a constant average flow to be maintained to meet the
very varying demand during the 24 hours. These are especially
necessary where the water has to undergo a process of filtra-
tion, in order that the process may be uniformly continuous.
Without such a service reservoir, during the period of
greatest demand imperfectly - filtered water would pass into
the mains, unless filter beds of an otherwise unnecessarily
large area had been provided. These reservoirs are also
commonly used when water is raised by pumping. Without
such storage it is evident that pumping would have to be
continuous, and that the rate would have to vary with the
360 WATER SUPPLIES
demand, whereas with a service reservoir the pumping
engines may work at a uniform speed, and for only a portion
of the 24 hours.
When the source from which water is derived is at a con-
siderable elevation, and long lengths of main convey the
water in different directions, as to villages and towns en
route to its ultimate destination, service reservoirs are often
constructed at elevated points, not only to break the pressure,
but to enable smaller mains to be used. Without these
reservoirs the mains would have to be capable of supplying
the maximum consumption, whereas with storage, the mains,
as far as the reservoirs, need only be capable of delivering the
average demand. As the maximum hourly consumption may
be twice the mean consumption, the difference in first cost,
where the mains are of any length, is very considerable.
Another very important advantage of such reservoirs is
that in case of fire there is a reserve of water instantly avail-
able. This is especially valuable in connection with the
supply of small towns, villages, mansions, and farms, since
the amount of water likely to be used in case of an outbreak
of fire would be a large faction of, or might even exceed that
of the whole capacity of the mains, whereas in large towns
the increased demand would only be a small fraction of
the average supply.
The amount of storage necessary and its character depends
upon the mode of supply, and whether by gravitation or by
pumping. Writing of these two classes of waterworks,
Burton, in his work on The Water Supply of Toivns,
says :
Gravitation works to be complete must consist of
1. Either a high-level impounding reservoir, or a high-
level intake with a settling reservoir.
2. Filter beds.
3. A service reservoir near the impounding or settling
reservoir, or, if there is high land conveniently
situated, a reservoir as near as possible to the town
THE STORAGE OF WATER 361
or within it, or one or more high-level tanks within
the town.
4. A distributing system.
" A pumping system may consist of JNIVERSITY
A. 1. A comparatively low-level intake. \ Q
2. One or more settling reservoirs.
3. A set of filter beds.
4. A pumping station, with
5. A high-level reservoir or tank near or within the
town, holding enough to compensate for the inequality
of the consumption during 24 hours.
6. A distributing system.
B. Where there is no land for a high-level reservoir, and a
high-level tank on an artificial support to hold enough
water to compensate for the variation in consumption
during 24 hours is considered impracticable.
1. A comparatively low-level intake.
2. One or more settling reservoirs.
3. A set of filter beds.
4. A low-level service reservoir.
5. A pumping station with engines pumping directly
into
6. A distributing system.
C. When the intake is so low that the water will not
gravitate to any convenient place for settling
reservoirs and filtering beds, and there is room for
these only on low ground.
1. A low-level intake.
2. An intake pumping station with engines pumping
into
3. One or more settling reservoirs.
4. A set of filter beds.
5. Main pumping station with engines pumping into
6. A high-level reservoir on a high artificial support, and
7. A distributing system.
D. The same as before, C, up to 5, but
362 WATER SUPPLIES
5. A low-level service reservoir.
6. Pumping station, with engines pumping into
7. A distributing system.
The last case, as that of B, occurs where there is no
natural site for a high-level reservoir, and where a high-level
tank of sufficient size on an artificial support would be too
expensive, or is, for any other reason, impracticable.
Under peculiar circumstances modifications of these
systems may be and are adopted, and, of course, when the
low-level intake is a well or spring yielding water invariably
pellucid, the settling reservoirs and filter beds are dispensed
with, and the system is much simplified, the water being
forced directly into a high-service reservoir or even into the
distributing mains.
Impounding reservoirs must be of ample size, not only to
meet present demands, but also such increased demand as
may arise in the more immediate future. Where large works
are being constructed 50 years is not an unreasonable length
of time to look forward to, and as a minimum the probable
increase in 30 years should be provided for. Many towns
have been recently subject to immense inconvenience and
anxiety on account of this neglect, or from underestimating
the growth of the population and the consequent increased
demand for water.
The conditions which affect the decision as to the size of
settling and service reservoirs are of a different character, but
probably the most important is the effect of storage. This
varies somewhat with the character of the water ; speaking
generally, the purer the water the less the liability to change.
In natural reservoirs, or lakes, water is less prone to be
infested by organisms, which affect the odour and taste, than
in artificially -constructed reservoirs. Pure surface water
contains too little organic matter to favour the growth of
these algae and fungi, and the effect of storage is beneficial
rather than otherwise ; yet cases are recorded where very pure
waters have developed an objectionable odour and taste.
THE STORAGE OF WATER 363
These growths are usually found to occur in reservoirs storing
water collected from gathering grounds which are in part
cultivated. The small amount of manurial matter, or the
products of its oxidation taken up by the water, supplies
constituents necessary to the growth and multiplication of
these low forms of life. Peaty water tends to lose its
colour if long stored, probably from the action of light, but
the observers for the Massachusetts Board of Health, who
have very fully studied the effect of storage, found that 12
months' exposure was necessary to completely bleach such
water. They found that surface waters, by storing, suffered
no change in the amount of ammonia and nitrates present, but
in other waters the nitrates were slightly reduced. Investi-
gating waters taken from various depths from a deep but
small lake, they concluded that vertical circulation took place
during the winter months, but that during the summer this
was in abeyance, and that the water at the bottom of the lake
remained stagnant. When the air is colder than the water,
the surface of the latter will cool, becoming at the same time
denser and tending to sink ; when the air is warmer than
the water, or the latter is exposed to the direct action of the
sun's rays, the surface will become heated, and, decreasing in
density, will retain its position. This, of course, applies to
water stored in large or small reservoirs, provided the water
is exposed to the air. The result of the stagnation is probably
very slight in waters of great hygienic purity, but in waters
containing organic matter the free oxygen disappears, the
water deteriorates, free ammonia increasing in amount,
especially at depths below 20 feet, and at such times samples
of water from near the top and near the bottom may yield
very different results upon analysis.
Ground water when stored in open reservoirs is said to
"deteriorate at all seasons of the year." The albumenoid
ammonia, or rather the organic matter yielding ammonia
upon distillation with alkaline permanganate, increases, and
in spring and summer the free ammonia becomes excessive,
364 WATER SUPPLIES
and at the same time nitrates are reduced. The micro-
organisms, which in the water at its source are few in number,
increase rapidly, so that they may even be in excess of those
found in much more impure waters. The same water when
kept in covered tanks is said to suffer but an inappreciable
change ; this is attributed to the absence of light and the
difficulty of access of air -conveyed microbes. I have fre-
quently observed, however, that the waters taken from a
whole series of wells over a definite area yielded much better
results both chemically and bacteriologically when examined
in winter than when collected in summer. In small open
tanks through which water is constantly passing, the water
undergoes, as a rule, but little change, but numerous instances
are recorded of the rapid and persistent growth of organisms
even in service tanks. This is almost certainly prevented by
thoroughly cleansing and covering the tanks. One organism,
however, grows better in the dark than in the light, the
" Oenothrix," and occasionally gives rise to trouble by im-
parting a nauseous odour and taste to the water. As this
fungus requires for its growth both protoxide of iron and
organic matter, a water in which it can nourish is not desirable
for a domestic supply.
The results of all the observations which have been made
on storage as affecting the size of service reservoirs lead to
the conclusion that it is desirable to reduce this storage to
the minimum compatible with safety. It is only necessary,
therefore, to consider what capacity is required for compen-
sating for the inequality of the hourly consumption, and for
a reserve in case of fire.
Inequality of Hourly Consumption. Whilst the maximum
consumption for a whole month rarely exceeds by 30 per cent
the mean for the year, the maximum hourly consumption
may exceed this by 100 per cent. Mr. J. Parry, M.Inst.C.E.,
found in Liverpool during 1893 that the maximum weekly
consumption took place in July, when it was 15 per cent
above the mean, and that the minimum occurred in November
THE STORAGE OF WATER 365
and December, and was 9 per cent below the mean. The
highest hourly rate at which water was delivered was between
10 and 11 A.M. on 6th July, when the delivery- was at the
rate of 50 gallons per head, or 85 per cent above the average
for the year. Mr. Parry says, " The weather at the time was
exceptionally warm, and it is not probable that the differ-
ence between the mean and maximum rate of discharge
could ever exceed this amount." Experiments which have
been conducted in Germany, however, have shown a greater
variation than this. Taking the mean of a number of records
from various waterworks, and taking the mean annual con-
sumption as 1 '0, the maximum daily discharge was 1 '4, and the
maximum hourly 2*1. The minimum flow is of trifling
importance ; in nearly all cases where waste is prevented as
much as possible, the flow during some portion of the night
approaches zero.
It is easily demonstrated that a service reservoir capable of
holding 7 hours' mean supply would be amply large to com-
pensate for all inequalities in the demand for ordinary purposes,
but in small towns this would be but a small reserve in case
of fire.
Reserve for Fire Extinction. In many cases little reserve
for this purpose is required, since by means of a by-pass or by
increased pumping all the necessary water may be rendered
available. Where such is not the case Burton gives a formula
for estimating roughly the amount of water which should be
stored for the special purpose of fire extinction :
Q = 200VP,
where Q = the quantity to be stored in cubic feet and P the
population of the town. This formula gives 125,000 gallons
as the storage for this purpose in a town of 10,000 population,
and 1,250,000 for a city of 1,000,000 inhabitants, or 10
hours' mean supply for the former and 1 hour for the latter.
To compensate for the inequalities in the demand for
domestic purposes and for use in case of fire, 1 7 hours' storage
366 WATER SUPPLIES
in the smaller town and 8 hours in the latter would suffice.
In any case 1 day's supply should be ample. This is a
reasonable mean between the estimates of those who recommend
6 or 7 hours' storage and those who would provide 2 or 3 days'
storage. Where such an amount cannot be kept in reserve the
pumping machinery must be sufficiently powerful to supply the
additional quantity, or if the water flows by gravitation from
impounding reservoirs the service mains must be large enough
to carry it.
In moderate-sized towns the service reservoir may be
placed upon an elevated tower of brick, stone, or ironwork.
The tank should be constructed of wrought or cast iron,
covered to exclude light, heat, and dust, and it should be
divided into two or more compartments for convenience in
cleansing. Where placed upon a natural elevation it may
be of brickwork rendered in cement. In larger towns, where
there is no elevated ground sufficiently near, and the erection
of tanks on towers would be too expensive, storage must be
dispensed with, and the mains, if a gravitation system,
must be sufficiently large to supply the maximum demand ;
or if a pumping system, the pumping engines must be so
constructed that the pumping corresponds exactly with the
consumption. A constant pressure may be obtained from a
stand pipe or by means of an air chamber. A float within
the stand pipe can be made to adjust the speed of the engine
or the stroke of the pumps, decreasing when the water rises
and increasing when the water falls, or the pressure in the air
chamber may be caused to automatically check or accelerate
the action of the pumps.
In Chapter II. reference was made to the storage of rain
water for the supply of cottages, farms, and mansions.
Denton recommends that the tanks used should be capable of
holding 120 days' supply, but few mansions or farms have
sufficient roof area to allow of anything like this quantity
being collected even in the wettest seasons, whilst the average
cottage could not collect more than half this amount. A
THE STORAGE OF WATER 367
tank capable of holding one-third of the rainfall is probably
as large as ever could be filled, and it is useless constructing
tanks to hold more water than can be collected, and absurd
to think of compensating for a too limited collecting
area by increasing the storage capacity. Only the excess of
rainfall over and above that used during the rainy season can
be stored, and the smaller the collecting areas, the smaller will
be the surplus and the smaller the tank which is necessary for
storing it.
Rain-water tanks are usually placed underground, where it
is almost impossible to ascertain if they are water-tight.
They are difficult of access and more difficult to cleanse.
Tanks fitted with rain-water separators and filters can be con-
structed above ground, and are in every respect preferable.
Underground tanks, if cut out of solid chalk or sandstone,
merely require lining with cement. Tanks constructed in
pervious soil must be made of brickwork in cement and be
rendered in cement, and arched over with the same materials.
Where water has to be pumped for single houses or small
groups of houses, in calculating the amount of storage
necessary it must be remembered that the inequalities in the
demand will vary to a much greater extent than when a whole
village or town is being supplied. For this reason the tank
must be larger in proportion, and also because provision must
be made for such contingencies as the breakdown of the pump-
ing machinery and an outbreak of fire. A comparatively small
quantity of water at the moment when a fire is discovered
may suffice to prevent a conflagration ; hence, if possible,
some provision should be made to render a supply readily
available. It has already been pointed out that water tends
to deteriorate in quality when stored in tanks ; therefore it
is better, if possible, to have a separate reservoir for storing
water for fire extinction. Where valuable property is con-
cerned, as in mansions and large farms, the additional expense
incurred may prove a valuable investment. The size of tank
required if the water is to be utilised for all purposes will
368 WATER SUPPLIES
depend upon (1) the amount desired to be stored in case of fire ;
(2) whether the pumping is constant, as by a ram, turbine, or
water-wheel, or (3) intermittent and at irregular intervals, as
when the ptiinps are worked by a wind engine, or (4) inter-
mijjftrii; but at regular intervals, as when manual labour or
sdme form, of gas, oil, hot-air or steam engine is used. Leaving
(1) out of consideration, with the second or fourth arrange-
ment a tank holding 2 to 4 days' domestic supply would be
ample. With the third system there should be storage provided
for from 7 to 1 2 days' supply. If the same tank is required to
store water for fire extinction, it must be larger, according to
the quantity considered necessary for use in such an emer-
gency. Where there is an ample amount of water at the
intake and a steam or similar engine is used for pumping, the
fire reserve needs not be large, since the engines can speedily
be set to work and the reserve supplemented.
The possibility of water being injuriously affected by the
materials of which small tanks are often made has been
mentioned in Chapter IX., and the advantages and disadvan-
tages of storing water in house cisterns, necessitated by an
" intermittent " public supply, will be referred to in the next
chapter on "The distribution of water."
Where the water supply is "constant," there should be no
necessity for storage cisterns in private houses. But where
the supply is only " constant " in theory, and not in actual
practice, as in many parts of London during seasons of drought,
these cisterns must be retained ; but in such cases draw-off taps
should be affixed to the rising main for the supply of water
for dietetic purposes. Of course this cistern should not
directly supply any water-closet or place of similar character.
Where the water supply is " intermittent," a storage cistern
capable of holding one day's supply is absolutely necessary.
CHAPTEE XXI
THE DISTRIBUTION OF WATER
IT is now generally admitted that no public supply is entirely
satisfactory unless the mains are constantly full and under
pressure that is, unless the supply be " constant." Under
the mistaken impression that the amount of water supplied
would be economised, most of the older waterworks only
admitted water to the mains for one or more hours daily,
during which time the house cisterns were filled, and the
amount used in each house was limited by the capacity of its
cistern. This " intermittent " system is now being gradually
abandoned, since, as we have already seen, a constant supply
when properly superintended is equally, if not actually more
economical. The risk of the water becoming polluted in
the mains (vide Chapter XL) is also reduced to a minimum
by keeping them constantly full and under pressure, and in
case of fire a supply of water is more readily available. As
the whole day's supply has not to be delivered in a very few
hours, the mains need not be so capacious, and house cisterns
are no longer necessary. The disadvantages of such cisterns
are numerous. Usually placed in inaccessible situations, un-
covered or imperfectly covered, and constructed of unsuitable
material, they are a frequent cause of the water becoming
fouled, or of its becoming unpalatable from the heat, and a
severe frost is more likely to cut off the supply. For these
reasons no engineer would now suggest the adoption of the
" intermittent " system, and it is to be hoped that where
2B
370 WATER SUPPLIES
adopted it will soon be abandoned, and that every house over
the areas supplied will have a constant service at high
pressure.
Whilst open conduits may convey water from the intake
to the filter beds, covered conduits or cast-iron pipes must
be used for carrying water from the filter beds to the service
reservoirs. Where the pressure is but slight earthenware pipes
may be used, or masonry, or brickwork, but iron will probably
be cheaper than the latter. For such aqueducts a fall of 5
feet per mile will suffice for pipes of 2 feet in diameter, and
a fall of 17 feet should not be exceeded. Earthenware pipes
are not desirable, but if used must be laid in a well-puddled
or concrete-lined, water-tight trench, and if valleys have to
be crossed the syphon portion must be of cast iron to with-
stand the pressure, and means should be provided to wash out
the syphon at its lowest point. In pumping mains the
velocity of the water should be about 2 feet per second, and
in no case exceed 2 \ feet. To allow for growth of population,
increased demand and corrosion of pipes, a velocity of 1 \ feet
in the first instance will probably be as large as can be
adopted with safety. (The power expended in pumping
varies directly as the cube of the velocity ; hence, what is
saved by using smaller pipes is more than lost in the cost of
power.) In gravitation mains a little higher velocity, 3 feet
per second, is permissible.
For calculating the velocity with which water will pass
through cast-iron mains when first laid, Eytelwein's formula
is fairly reliable :
V = ttV/" dh
where V = the velocity in feet per second ; d, the diameter
of the pipe ; h, the head of water ; and I, the length of the
pipe in feet. In new pipes ft = 50, but its value decreases
with the corrosion, and may sink as low as 32. The factor
50c? may be disregarded in pipes more than a few hundred
feet in length. Sharp bends should be avoided, since they
THE DISTRIBUTION OF WATER 371
increase the friction and retard the flow. Where the pipes
follow the contour of the ground, air-valves should be attached
to the highest points. All pipes used should have previously
been tested and proved to be capable of withstanding twice
the pressure to which it is calculated that they will be
subjected.
A "trunk" main conveys the water from the service
reservoir to the confines of the districts to be supplied. It
then breaks up into "distributing" mains, one for each dis-
trict. The "distributing" mains supply "service" mains,
and from these latter are taken the "house service " mains
or " communication pipes." No service main should be less
than 3 inches in diameter, and in towns it is never desirable
that they should be less than 4 inches. In many American
cities the minimum is 6 inches.
For the sake of economy mains of too small diameter are
frequently employed, and the mistake when discovered is a
costly one to remedy. A common error is to suppose that
the flow of water varies only with the sectional area of the
main, but a glance at Eytelwein's formula is sufficient to
disprove this. For example, with a head of 100 feet and
a main 10,000 feet long, what will be the flow from a 3-inch
and a 6-inch main respectively? In the first case
V = 50 V'25"x 100 = 2-5 feet per second,
10,000
and the flow = V x ^-'7854= '1227 cubic feet per second.
In the second case
V = 50 V'5 x 100 3'5 feet per second,
To, ooo
and the flow will be '687 cubic feet per second.
The loss of head on account of friction is a still more
serious matter when it is intended that the water shall be
available for fire-extinguishing. Thus, to quote an example
from Merry weather's Water Supply to Mansions : " The
passage of 300 gallons of water per minute through 500
372 WATER SUPPLIES
yards of 4-inch pipe will absorb in friction a head of 172
feet, whereas if 5-inch pipe be used, only 57 feet will be
absorbed ; that is, assuming the reservoir to be 200 feet
above the house, if you lay the 4-inch pipe 500 yards long,
when delivering 300 gallons per minute the head or pressure
on the jets will only be 28 feet, .and the height of the jets
about 20 feet, but with the 5-inch pipe the head will be 143
feet, and the height of the jet will be 100 feet ; in each case
the balance of the 200 feet is absorbed by the friction of the
water against the sides of the pipe."
In certain towns Liverpool, for instance special mains
are laid through the business parts for supplying water for
extinguishing fires. In the residential parts the same mains
act as fire mains as well as service mains.
Cast-iron pipes are practically universally used for distribut-
ing and service mains, and these should be properly varnished
within and without. This varnish generally imparts to the
water, for a time, a tarry flavour, which, although objection-
able, is not injurious. After long keeping the varnish imparts
less flavour to the water, but pipes so kept are not so durable
as those laid down soon after being coated. Turned and
bored joints are cheapest, but engineers are divided in
opinion as to whether these or joints made with lead are
the best. The latter are more flexible, and should alone be
used where the ground is not firm . or where there is danger
of subsidence. Where turned and bored joints are used, an
occasional lead joint should be introduced to allow for the
elongation and contraction caused by changes of temperature.
To prevent the undue influence of the variations of the
earth's temperature, Rawlinson says that the mains should
be laid at a minimum depth of not less than 3 feet. Other
engineers give 2 feet 6 inches as the minimum, but in
England the water in mains at the latter depth has become
frozen during very severe winters. The latter is the depth
of cover required in most large towns, but in Manchester 3
feet, and in Bradford 2 feet is adopted as the minimum.
THE DISTRIBUTION OF WATER 373
In all systems of distribution it is not only of the highest
importance to have all the mains of ample size, but that the
service mains be so arranged that there shall be few or no
"dead ends," and that, as far as possible, all valves and
connections should be placed so that in case of accident to
one main the supply may be kept up from another.
The "dead end" system had many apparent advantages
which caused it to be generally used. Parts of the system
could easily be cut off when necessary by a single valve, and
the sizes of the mains could be readily calculated. It was
soon found, however, that the stagnant water in the ends
became deteriorated in quality, and it has sometimes been
suspected that where disease germs had gained access to the
mains they had been able to multiply in the still water.
This can in part be prevented by placing flushing valves at
the ends of the mains, but these require constant attention,
and if regularly opened cause the waste of much water. On
the whole it seems preferable to adopt some form of inter-
lacing system, in which the ends of the mains are connected
together, wherever possible. By a proper arrangement of
sluices any small portion of the system can be cut off by
closing two valves, whenever such closure is necessary for
the repair of that portion. Formerly the supply to a district
had to be stopped every time the main was being tapped,
but ferrule machines have been constructed and are now
largely used, which enables the " house service " mains to be
attached to the service mains whilst the latter are full of
water under pressure. Where this machine is used the
occasions upon which it is necessary to cut off any part of
the system are very rare.
It is obvious that water- waste preventors, such as Deacon's,
cannot be used on any portion of the interlacing system.
They must be attached to near the ends of the distributing
mains, and each controlled by a valve beyond the meter, and
there should be a separate distributing main for each district
of from 2000 to 5000 people.
374 WATER SUPPLIES
House service pipes may be of lead, tin-lined lead, tin-lined
iron, cast iron or wrought iron, enamelled or galvanised.
Lead pipe is most generally applicable, but it should not
be used with waters which contain very little or no carbonates.
Such waters are usually very soft, but it is desirable to
remember that occasionally very soft waters contain car-
bonate of soda and have no action on lead, and that hard
waters sometimes are free from carbonates and then act upon
this metal. To prevent this action tin-lined lead pipe was
introduced, but has not answered the expectations of its
makers. It possesses little advantage over lead pipe, and has
many disadvantages, besides being much dearer. Still more
recently a tin-lined iron pipe has been placed in the market,
and so far as present experience enables its merits to be
appraised, it would appear to possess many advantages over
all other kinds of pipe. It consists of strong wrought-iron
tube with an internal lining of block tin, and the lengths are
joined up by screw joints, so that the tin lining is practically
continuous.
Wrought-iron pipes are cheaper than lead, and as easily or
more easily fitted, and admit of repairs and alterations being
made with equal facility, provided double screw joints are
used at convenient points. They are, however, very liable to
become choked by internal corrosion. A pipe 1 inch in
diameter may choke in from six to ten years. If galvanised
its durability is much increased. Certain soft waters, however,
possess the power of dissolving zinc, and of rapidly corroding
the iron. In such a case the tin-lined iron pipe becomes indis-
pensable, since the same waters invariably act upon lead.
Where water pipes have to be carried through made
ground containing ashes, spent lime, chemical refuse, etc.,
they should be protected by a clay puddle, concrete, or
asphalte covering, otherwise they will be injuriously affected.
To prevent the action of frost a minimum depth of 3 feet
is desirable, and within the house they should be placed in
positions in which the frost is least likely to affect them. No
THE DISTRIBUTION OF WA TER 375
pipe will withstand the action of frost, but lead pipes may
usually be frozen many times before actually bursting, on
account of the ductility of the metal. The split caused by
the expansion of the water in the act of freezing is in all
cases longitudinal. In lead pipe the metal bulges before
splitting. As it is of the highest importance for the pre-
vention of waste and pollution that all house connections
should be properly made, and the fittings be of a satisfactory
character, the regulations made under the " Metropolis Water
Act, 1871," as to house fittings, are given in an appendix, as
upon them are based the regulations of many other towns.
Mr. T. Duncanson, in his paper, already referred to, on
" The Distribution of Water Supplies," gives the following
brief summary of the objects to be aimed at in providing a
public supply of water :
"(1) That a sufficient supply of wholesome water for the
reasonable needs of a community should be provided.
"(2) That this water should be so supplied that at all
times there is sufficient pressure to reach the highest part of
every house.
" (3) That all piping and fittings should be of such a
character and so arranged as to reduce the probability of
failure to a minimum.
" (4) That there should be an effective system for the
prompt detection of waste when it does occur.
" (5) That all arrangements should be of such a character
as to reduce the inconvenience arising from necessity for repairs
to a minimum.
" (6) That all appliances for the consumption of water
should be so arranged as to use it in the most efficient way.
"The extent to which a public supply meets the above
requirements will be a fair index of its character."
APPENDIX TO CHAPTER XXI
REGULATIONS MADE UNDER THE METROPOLIS WATER
ACT, 1871
1. No " communication pipe " for the conveyance of water from the
waterworks of the Company into any premises shall hereafter be laid
until after the point or place at which such "communication pipe" is
proposed to be brought into such premises shall have had the approval
of the Company.
2. No lead pipe shall hereafter be laid or fixed in or about any
premises for the conveyance of, or in connection with the water
supplied by the Company (except when, and as otherwise authorised by
these regulations, or by the Company), unless the same shall be of
equal thickness throughout, and of at least the weight following, that
is to say :
Internal Diameter of Pipe in inches.
Weight of Pipe in pounds per lineal yard.
i in
4 >
i- ,
ch dian
>
icter
5 Ibs. pe
6
74
r linea
. yard
? ,
i
u ,
i
9 ,
12
16
3. Every pipe hereafter laid or fixed in the interior of any dwelling-
house for the conveyance of, or in connection with, the water of the
Company, must, unless with the consent of the Company, if in contact
with the ground, be of lead, but may otherwise be of lead, copper, or
wrought iron, at the option of the consumer.
4. No house shall, unless with the permission of the Company in
writing, be hereafter fitted with more than one "communication
pipe."
5. Every house supplied with water by the Company (except in
APPENDIX TO CHAPTER XXI 377
cases of stand pipes) shall have its own separate "communication pipe,"
provided that, as far as is consistent with the special Acts of the
Company, in the case of a group or block of houses, the water-rates of
which are paid by one owner, the said owner may, at his option, have
one sufficient "communication pipe" for such group or block.
6. No house supplied with water by the Company shall have any
connection with the pipes or other fittings of any other premises,
except in the case of groups or blocks of houses, referred to in the
preceding regulation.
7. The connection of every "communication pipe" with any pipe
of the Company shall hereafter be made by means of a sound and
suitable brass screwed ferrule or stop-cock with union, and such ferrule
or stop-cock shall be so made as to have a clear area of water-way equal
to that of a half-inch pipe. The connection of every "communica-
tion pipe " witli the pipes of the Company shall be made by the
Company's workmen, and the Company shall be paid in advance the
reasonable costs and charges of, and incident to, the making of such
connection.
8. Every "communication pipe" and every pipe external to the
house, and through the external walls thereof, hereafter respectively
laid or fixed in connection with the water of the Company, shall be of
lead, and every joint thereof shall be of the kind called "plumbing"
or "wiped " joint.
9. No pipe shall be used for the conveyance of, or in connection
with, water supplied by the Company, which is laid or fixed through,
in, or into any drain, ash-pit, sink, or manure-hole, or through, in, or
into any place where the Avater conveyed through such pipe may be
liable to become fouled, except where such drain, ash-pit, sink, or
manure-hole, or any such place, shall be in the unavoidable course of
such pipe, and then in every such case such pipe shall be passed
through an exterior cast-iron pipe or jacket of sufficient length and
strength, and of such construction as to afford due protection to the
water pipe.
10. Every pipe hereafter laid for the conveyance of, or in connection
with, water supplied by the Company, shall, when laid in open ground,
be laid at least 2 feet 6 inches below the surface, and shall in
every exposed situation be properly protected against the effects of
frost.
11. No pipe for the conveyance of, or in connection with, water
supplied by the Company, shall communicate with any cistern, butt,
or other receptacle used or intended to be used for rain water.
12. Every "communication pipe "for the conveyance of water to
be supplied by the Company into any premises shall have at or near
378 WATER SUPPLIES
its point of entrance into such premises, and if desired by the consumer
within such premises, a sound and suitable stop- valve of the screw-
down kind, with an area of water-way not less than that of a
half-inch pipe, and not greater than that of the "communication
pipe," the size of the valve within these limits being at the option of
the consumer. If placed in the ground such "stop- valve" shall be
protected by a proper cover and "guard-box."
13. Every cistern used in connection with the water supplied by the
Company shall be made and at all times maintained water-tight, and
be properly covered and placed in such a position that it may be
inspected and cleansed. Every such existing cistern, if not already
provided with an efficient "ball-tap," and every such future cistern,
shall be provided with a sound and suitable "ball-tap" of the valve
kind for the inlet of water.
14. No overflow or waste pipe other than a "warning pipe" shall
be attached to any cistern supplied with water by the Company, and
every such overflow or waste pipe existing at the time when these
regulations come into operation shall be removed, or at the option of
the consumer shall be converted into an efficient "warning pipe,"
within two calendar months next after the Company shall have given
to the occupier of, or left at the premises in which such cistern is
situated, a notice in writing requiring such alteration to be made.
15. Every " warning pipe " shall be placed in such a situation as
will admit of the discharge of the water from such "warning pipe"
being readily ascertained by the officers of the Company. And the
position of such "warning pipe" shall not be changed without
previous notice to and approval by the Company.
16. No cistern buried or excavated in the ground shall be used for
the storage or reception of water supplied by the Company, unless the
use of such cistern shall be allowed in writing by the Company.
17. No wooden receptacle without a proper metallic lining shall be
hereafter brought into use for the storage of any water supplied by the
Company.
18. No draw-tap shall in future be fixed unless the same shall be
sound and suitable and of the " screw-down " kind.
19. Every draw-tap in connection with any "stand pipe" or other
apparatus outside any dwelling-house in a court or other public place,
to supply any group or number of such dwelling-houses, shall be
sound and suitable and of the " waste - preventer " kind, and be
protected as far as possible from injury by frost, theft, or mischief.
20. Every boiler, urinal, and water-closet, in which water supplied
by the Company is used (other than water-closets in which hand
flushing is employed), shall, within three months after these rcgula-
APPENDIX TO CHAPTER XXI 379
tions come into operation, be served only through a cistern or
service-box and without a stool-cock, and there shall be no direct
communication from the pipes of the Company to any boiler, urinal,
or water-closet.
21. Every water-closet cistern or water-closet service-box hereafter
fitted or fixed, in which water supplied by the Company is to be used,
shall have an efficient waste-preventing apparatus, so constructed as
not to be capable of discharging more than two gallons of water at
each flush.
22. Every urinal-cistern in which water supplied by the Company
is used other than public urinal-cisterns, or cisterns having attached
to them a self- .-dosing apparatus, shall have an efficient "waste-
preventing" apparatus, so constructed as not to be capable of
discharging more than one gallon of water at each flush.
23. Every "down pipe" hereafter fixed for the discharge of water
into the pan or basin of any water-closet shall have an internal
diameter of not less than one inch and a quarter, and if of lead shall
weigh not less than nine pounds to every lineal yard.
24. No pipe by which water is supplied by the Company to any
water-closet shall communicate with any part of such water-closet, or
with any apparatus connected therewith, except the service-cistern
thereof.
25. No bath supplied with water by the Company shall have any
overflow waste pipe, except it be so arranged as to act as a " warning
pipe."
26. In every bath hereafter fitted or fixed the outlet shall be distinct
from, and unconnected with, the inlet or inlets ; and the inlet or
inlets must be placed so that the orifice or orifices shall be above the
highest water-level of the bath. The outlet of every such bath shall
be provided with a perfectly water-tight plug, valve, or cock.
27. No alteration shall be made in any fittings in connection with
the supply of water by the Company Avithout two days' previous notice
in writing to the Company.
28. Except with the written consent of the consumer, no cock,
ferrule, joint, union, valve, or other fitting, in the course of any
"communication pipe," shall have a water-way of less area than that
of the "communication pipe," so that the water-way from the water
in the district pipe or other supply pipe of the Company up to and
through the stop- valve prescribed by Regulation No. 12, shall not in
any part be of less area than that of the "communication pipe"
itself, which pipe shall not be of less than a half-inch bore in all its
courses.
29. All lead " warning pipes " and other lead pipes of which the
380 WATER SUPPLIES
ends are open, so that such pipes cannot remain charged with water,
may be of the following minimum weights, that is to say :
^ inch (internal diameter) . . 3 Ibs. per yard.
f ,, ,, 5 Ibs. ,.
1 ,, 7 Ibs. ,,
30. In these regulations the term "communication pipe" shall
mean the pipe which extends from the district pipe or other supply
pipe of the Company up to the "stop- valve" prescribed in the
Regulation No. 12.
31. Every person who shall wilfully violate, refuse, or neglect to
comply with, or shall wilfully do or cause to be done any act, matter,
or thing, in contravention of these regulations, or any part thereof,
shall, for every such offence, be liable to a penalty in a sum not
exceeding 5.
32. Where, under the foregoing regulations, any act is required or
authorised to be done by the Company, the same may be done on
behalf of the Company by an authorised officer or servant of the
Company, and where, under such regulations, any notice is required to
be given by the Company, the same shall be sufficiently authenticated
if it be signed by an authorised officer or servant of the Company.
33. All existing fittings, which shall be sound and efficient, and are
not required to be moved or altered under these regulations, shall be
deemed to be "prescribed fittings" under the "Metropolis Water
Act, 1871."
N.B. Water is wasted in several ways, as by defective works and
arrangements, by improper fittings, and by abuse and neglect ; proper
fittings and sound workmanship will give good works a fair commence-
ment, but subsequent inspection and repairs will be necessary so long
as they are in use. It will be found by experience that it is cheaper
to supervise and repair the mains and fittings, rather than to allow
water to flow to waste.
CHAPTEE XXII
THE LAW RELATING TO WATER SUPPLIES
IT generally happens that when a water supply is to be pro-
vided, land or water rights, or land and way leaves, have to
be acquired. This may be done either voluntarily or com-
pulsorily, the Public Health Act, 1875, section 175, providing
that any Local Authority may purchase, take on lease, sell, or
exchange any lands, whether situated within or without their
district, and may also buy up any water-mill, dam, or weir
which interferes with the proper drainage of, or the supply of
water to, their district. It is desirable, if possible, to purchase
voluntarily, as the expenses of acquiring land compulsorily
are considerable, and add much to the cost, especially in the
case of village water supplies. But it frequently happens
that the necessary land can only be acquired by compulsory
purchase, and to enable Local Authorities to purchase com-
pulsorily, the Lands Clauses Consolidation Acts are, by
section 176 of the Public Health Act, 1875, incorporated
with that Act ; and that section prescribes the course to be
taken by a Local Authority before putting in force the powers
of the Lands Clauses Acts as to purchasing and taking lands
otherwise than by agreement.
The Lands Clauses Act, 1845, contains valuable powers,
enabling tenants for life and other owners of limited estates
to carry out voluntarily sales of the lands in which they are
interested.
Many persons being incapacitated from selling their lands
382 WATER SUPPLIES
by reason of disabilities of various kinds, section 6 of that
Act enables all parties entitled to any such lands, or any
estate or interest therein, to sell and convey the same, and
particularly for all Corporations, tenants in tail or for life,
married women seised in their own right or entitled to dower,
Guardians, Committees of Lunatics and of Idiots, Trustees or
Feoffees in trust for charitable or other purposes, Executors
and Administrators, and all parties for the time being entitled
to the receipt of the rents and profits of any lands in possession,
to sell the same.
Similar powers, enabling tenants for life and other persons
having less than an absolute interest in lands to sell volun-
tarily, are conferred by the Settled Land Act, 1882, under
sections 3 and 58 of which a tenant for life, tenant in tail,
tenant by the courtesy, and other limited owners, may sell
the settled land or any part thereof, or any easement, right,
or privilege of any kind for or in relation to the land.
There is a prevalent idea that Local Authorities may use
roadside wastes for sinking wells and other water-supply pur-
poses ; but this is erroneous. Local Authorities, as such, have
no rights whatever in these wastes, and the law presumes, until
evidence is given to the contrary, that the soil of the roadway
to the middle of the road, and of the adjoining strip of waste,
belongs to the owner of the land adjoining to the highway or
to the strip of waste ; and the owner of the roadway and of
the strip of waste is entitled to use his property in every way
not inconsistent with the public right of passage, the right of
the public merely extending to pass along the surface of the
road, and for that purpose to keep it in repair.
This presumption as to the ownership of the soil of the
roadway has been said to rest on the supposition that
when the road was originally set out, the proprietors of the
adjoining land each contributed a portion of their land for
its formation, and the presumption that the soil of a strip
of land lying between the highway and the adjacent enclosure
belongs to the owner of that enclosure is founded on the
THE LAW RELATING TO WATER SUPPLIES 383
supposition that the proprietor of the adjoining land, at some
former period, gave up to the public free passage of the land
between his enclosure and the middle of the road, or, when
enclosing his land for the road, he left an open space at the
side of the road, over which the public might deviate if
necessary, to avoid the liability to repair which would other-
wise have fallen upon him. If the strip of land communicates
with or is contiguous to an open common or large portion of
land, the presumption is done away with or considerably
narrowed, for the evidence of ownership which applies to the
large portions applies also to the narrow strip which com-
municates with them.
Before proceeding to purchase lands, springs, or streams
for water-supply purposes, precautions should be taken
(a) To ascertain whether and to what extent neighbouring
landowners can prevent, by legal proceedings, the
water yielded therefrom being used for the pro-
posed water-supply purposes.
(b) Whether and to what extent such landowners can, by
digging wells, cutting trenches, or executing other
works on their own lands, abstract or divert the
water proposed to be utilised.
As to the first question As a general rule every land-
owner (including a Local Authority owning land) has the
right to dig wells and execute other works on his land, and
thus obtain or divert for his own purposes as much of the
water flowing under his land as he can, even though the
effect may be to abstract or divert the underground waters
which otherwise would flow to and become feeders of springs
and streams on other property. But the law is different with
regard to a watercourse, which has been defined by Lord
Tenterden as "water flowing in a channel between banks
more or less defined."
The riparian proprietors whose lands adjoin a watercourse
may take water from it, but in doing so must have due
384 WATER SUPPLIES
regard to the similar rights of others whose lands adjoin the
stream, and who have the right " to have the watercourse or
stream come to them in its natural state in flow, quality, and
quantity."
A spring and a stream have been thus defined by Jessel,
M.R. "A spring of water is, as I understand it, a natural
source of water, of a definite and well-marked extent. A
stream of water is water which runs in a defined course, so as
to be capable of diversion, and it has been held that the term
does not include the percolation of underground water."
What is a stream, and where does it begin 1 ? is a question
which was raised in the caseof Dudden v. Guardians of the
Glutton Union, reported in 11 Exchequer Reports, 627, and
26 Law Journal Reports, Exchequer, 146, where the plaintiff
was the owner of an ancient mill which was supplied with
water from a brook. Adjoining this brook was a spring, the
water from which flowed by a natural channel into the brook.
The guardians, for the purpose of supplying the workhouse
with water, placed tanks and pipes close to the spring-head,
and took the water before it flowed into the natural channel.
The judge directed the jury to find for the plaintiff (and they
did so) if they thought the water flowed in a defined regular
course from the spring-head to the brook.
Upon the application to the Court to set aside the verdict,
Baron Martin thus stated the law : " The right to flowing
water is a natural right, and all parties are entitled to the
use of it, but a party would not be entitled to divert it when
it is in the act of springing from the ground. He cannot
legally prevent its flowing into its natural channel." And Baron
Watson added, " If the diversion in this case had taken place
ten yards from the spring-head, there would be no doubt in
the case, and the rule is the same if the water is diverted at
the source."
The law respecting the right to water flowing in definite
visible channels is clearly enunciated by the judgment of the
Court of Exchequer in the case of Embrey v. Owen, reported
THE LAW RELATING TO WATER SUPPLIES 385
in 6 Exchequer Reports, 353, and 20 Law Journal Reports,
E. 212.
This case decided that water is publici juris in this sense
only, that all may reasonably use it who have the right of
access to it. No man can have any property in the water
itself, except in that particular portion which he may choose
to abstract from the stream and take into his own possession,
and that during the time of his possession only. Also that
the proprietor of the adjacent land has the right to the
usufruct of the streams that flow through it, not as an ab-
solute and exclusive right to the flow of all the water in its
natural state, but subject to the similar rights of all proprietors
of the banks on each side to a reasonable enjoyment thereof.
In the case of Milner v. Gilmour, Lord Kingsdown laid
down the law as to running streams as follows : "By the
general law applicable to a running stream, every riparian
proprietor has a right to what may be called the ordinary use
of the water flowing past his land, for instance to the reason-
able use of the water for his domestic purposes and for his
cattle, and this without regard to the effect which such use
may have in case of deficiency upon proprietors lower down
the stream ; but further he has a right to the use of it for any
purpose, or what may be termed the extraordinary use of it,
provided that he does not thereby interfere with the rights of
other proprietors either above or below him. Subject to this
condition he may dam it for the purposes of a mill, or divert
the water for the purpose of irrigation, but he has no right to
interrupt the regular flow of the stream if he thereby inter-
feres with the lawful use of the water by other proprietors,
and inflicts upon them a sensible injury." Such extraordinary
use, in order to be justifiable, must, however, be a reasonable
one, and one for which a riparian proprietor is entitled to take
the water from its natural course ; for where an unreasonable
use is made of the water by one riparian proprietor, the. others
are entitled to have it restrained, even though they prove no
actual damage, on the ground that it is an interference with
2c
386 WATER SUPPLIES
a right which, unless restrained, would in the course of twenty
years confer on the claimant a right of prescription in dero-
gation of the prior right. It would appear from the case of
the Swindon Water Co. v. Wilts and Berks Canal (Law
Reports, 9 Ch. 457), that an " extraordinary use," as well as
being reasonable, must be for the use of the riparian tenement.
But the law as laid down in these cases is inapplicable to
the case of subterranean w r ater not flowing in any separate
channel, or flowing indeed at all in the ordinary sense, but
percolating or oozing through the soil, more or less according
to the quantity of rain that may chance to fall.
The case of Broadbent v. Ramsbotham, reported in 11
Exchequer Reports, 611, and 26 Law Journal Reports, Ex.
115, decided that the right of a riparian owner to the lateral
tributaries or feeders of the main stream applies to waters
flowing in a defined and natural channel or watercourse, and
does not extend to water flowing over, or soaking through,
previous to its arrival at such watercourse.
In this case it was decided that the plaintiff", who was a
millowner, having the right to use the water of a natural
stream, called Longwood Brook, had no cause of action
against the owners of adjacent land for diverting water,
which, coming from a pond formed by landslips, escaped over
the surface of this land, and thence, by natural force of
gravity, found its way by land-drains or dykes to the brook ;
or for diverting the overflow from a well and a swamp on
that land, which ran in wet seasons to the brook ; or for
diverting the overflow from another well on that land used
as a watering-place for cattle, which overflow formed a stream,
and, after following the course of an artificial ditch, along a
hedge-side, and in other parts flowing down a small channel,
formed by the water, and over swampy places, where the
cattle had trodden in the soil, ran over a field, and thence
along a natural valley, and along hedge -sides and ditches,
and discharged itself into the brook ; and it was held that the
plaintiff, although he had a right to the use of the water of the
THE LAW RELATING TO WATER SUPPLIES 387
brook, had no cause of action against the owner of the adjacent
land for diverting either of the above three sources of supply
before the waters had arrived at a definite natural watercourse.
With regard to the second question, the law has been
defined and settled by two important decisions of the House
of Lords, the first of Chasemore v. Richards, decided in July
1859, and reported in 7 House of Lords Reports, 382, and 29
Law Journal Reports, Exchequer, 81, which decided that the
owner of land, containing underground water which percolates
by undefined channels, and flows to the land of a neighbour,
has the right to divert or appropriate the percolating water
within his own land, so as to deprive his neighbour of it.
In that case, much of the law relating to waters flowing
above or underground was dealt with by the various learned
judges who delivered judgments. The facts of the case
and the law relating to it were stated by Mr. Justice Wight-
man as follows :
"The plaintiff is an occupier of an ancient mill on the
river Wandle, and for more than sixty years he and his
predecessors had used and enjoyed, as of right, the flow
of the river for the purposes of working their mill; the
river had always been supplied above the plaintiff's mill, in
part, by the water produced by the rainfall on a district of
many thousand acres in extent, comprising the town of
Croydon and its vicinity. The water of the rainfall sinks
into the ground to various depths, and then flows and per-
colates through the strata to the river Wandle, part rising
to the surface, and part finding its way underground in
courses which continually vary.
" The Croydon Local Board sink a well in their own land
in the town of Croydon, and by means of the well and by
pumping from it large quantities of water for the supply of
the town of Croydon, the Board abstracted and interrupted
underground water (but underground water only) that other-
wise would have flowed and found its way into the river
Wandle, and so to the plaintiffs mill, and the quantity so
388 WATER SUPPLIES
diverted was sufficient to be of sensible value toward working
the mill."
The law as decided in Chasemore v. Richards has- been
followed and extended by the important recent case, decided
by the House of Lords in July 1895, of the Mayor, Aldermen,
and Burgesses of the Borough of Bradford v. Edward Pickles,
where it was decided that not only has the owner of land
containing underground water which percolates by undefined
channels and flows to the land of his neighbour the right to
divert or appropriate the percolating water within his own
land so as to deprive his neighbour of it, but his right to do
this is the same whatever his motive may be, whether to
improve his own land or maliciously to injure his neighbour
or to induce his neighbour to buy him out. In this case the
Corporation of Bradford were the owners of Trooper Farm
and certain springs and streams rising in or flowing through
that farm, which were purchased many years ago by the
Bradford Waterworks Company, and from which the Cor-
poration obtained a valuable supply of water for the domestic
use of the inhabitants of Bradford. In 1892 the respondent
Pickles began to sink a shaft on his land adjoining Trooper
Farm, and also to drive a level through his land for the
professed purpose of draining the strata with the view to
the working of his minerals. These operations had the
effect of diminishing the water supply obtainable from the
springs on Trooper Farm. The Corporation of Bradford
brought this action to restrain the defendant Pickles from
continuing to sink the shaft or drive the level, and from
doing anything whereby the waters of the spring and the
stream might be drained off or diminished in quantity.
Lord Halsbury, in delivering judgment, said : " The acts done
or said to be done by the defendant were all done upon his
own land, and the interference, whatever it is, with the flow
of water, is an interference with water which is underground
and not shown to be water flowing in any defined stream,
but is percolating water which, but for such interference,
THE LAW RELATING TO WATER SUPPLIES 389
would undoubtedly reach the plaintiffs waterworks, and in
that sense it has deprived them of the water which they
would otherwise get ; but although it has deprived them of
water which they would otherwise get, it is necessary for
the plaintiffs to establish that they have a right to the flow
of water, and that the defendant has no right to do what he
is doing. I am of opinion that the question whether the
plaintiffs have a right to the flow of such water is covered by
the decision in the case of Chasmore v. Richards. The very
question was then determined by this House, and it was held
that the landowner had a right to do what he had done,
whatever his object or purpose might be, and although the
purpose might be wholly unconnected with the enjoyment of
his own estate."
In delivering his judgment, Lord Macnaughten stated :
" The position of the appellants is one which it is not easy
to understand. They cannot dispute the law laid down by
this House in Chasemore v. Richards. They do not suggest
that the underground water with which Mr. Pickles proposes
to deal flows, in any defined channel. But they say that
Mr. Pickles' action in the matter is malicious, and that,
because his motive is a bad one, he is not at liberty to do a
thing which every landowner may do with impunity if his
motives are good. It may be taken that his real object was
to show that he was the master of the situation, and to force
the Corporation to buy him out at a price satisfactory to
himself. Well, he has something to sell, or, at any rate, he
has something which he can prevent other people enjoying
without paying for it. Why should he, he may think,
without fee or reward, keep his land as a storeroom for a
commodity which the Corporation dispense, probably not
gratuitously, to the inhabitants of Bradford. He prefers his
own interests to the public good. He may be churlish,
selfish, and grasping. But where is the impulse. Mr.
Pickles has no spite against the people of Bradford. He
bears no ill-will to the Corporation. They are welcome to
390 WATER SUPI'LIES
the water, and to his land too, if they will pay the price for
it. So much, perhaps, might be said in defence, or in
palliation of Mr. Pickles' conduct, but the real answer to the
claim of the Corporation is that in such a case motives are
immaterial. It is the act, not the motive for the act, that
must be regarded. If the act, apart from the motive, gives
rise merely to damage without legal injury, the motive,
however reprehensible it may be, will not apply without
element."
The law as to the making and recovery of water-rates and
water-rents is much in need of consolidation and amendment.
The Waterworks Clauses Act, 1863, and certain provisions
of the Waterworks Clauses Act, 1847, are incorporated with
the Public Health Act, 1875, and the following clauses of
the 1847 Act may be referred to, as to water-rates and
water-rents :
"Sees. 48 to 52. Any owner or occupier of a dwelling-
house may open ground, and lay communication or service
pipes to connect house with mains.
"Sec. 53. Every owner and occupier, when he has laid
such communication pipes and paid the water-rate, is entitled
to a sufficient supply of water for domestic purposes.
" Sec. 68. Water-rates (except as in sec. 72) are to be paid
by the person receiving or using the supply of water, and to
be payable according to the annual value of the tenement
supplied, any dispute arising as to such value to be settled by
two justices.
" Sec. 69. When several houses, or parts of houses in the
separate occupations of several persons, are supplied by one
common pipe, the several owners or occupiers are liable to the
payment of the same water-rates as if each were supplied by
a separate pipe.
"Sec. 70. Water-rates to be paid in advance, by equal
quarterly payments, at Christmas Day, Lady Day, Midsummer
Day, and Michaelmas Day.
" Sec. 72. The owners of all dwelling-houses or separate
THE LAW RELATING TO WATER SUPPLIES 391
tenements, the annual value of which does not exceed ..10,
are liable to payment of the water-rates instead of the
occupiers."
To make the owner or occupier liable, it is not necessary
that the water should be laid on to the house, section 9 of the
Public Health Water Act, 1878, enacting that where a stand
pipe has been provided water-rates or water-rents may be re-
covered from the owner or occupier of every dwelling-house
within 200 feet of any such stand pipe, in the same manner
as if the supply had been given on the premises. But if
such dwelling-house has within a reasonable distance, and
from other sources, a supply of wholesome water sufficient
for the consumption and use of the inmates, no water-rate or
water-rent is recoverable from the owner or occupier until the
water supplied from the stand pipes is used by the inmates of
the house. This section applies to rural districts only.
Where stand pipes are used questions are often raised by
householders, who seem to object to water-rates, even more
than to other rates, on the ground that their houses are pro-
vided with water from some ancient well, or other source. A
little patience is generally not wasted on them, for if left
alone they soon find using the water from the stand pipe to
be so great a convenience that they take to using it, and then
pay the water-rates with as good grace as they do other rates.
In some cases, however, where a water-rate hater insists on
continuing to use water from some polluted well or other
source, it becomes necessary to compel him to pay the water-
rate, even though he does not use the water from the stand
pipe, on the ground that his supply is not wholesome. When
compelled to pay the rate he will soon begin to use the water,
to get over his objection to being made to pay for what he
does not use.
" Sec. 74. If a person liable to pay water-rates neglects to
do so, water may be cut off, and water-rates and expenses of
cutting off the water recovered in manner mentioned in the
section."
392 WATER SUPPLIES
Objection is often made that the incidence of a water-rate
is unfair, because, assuming the water-rate to be Is. in the <!,
one occupier of a house rated at, say, 15, and using very
little water, pays as much for his water-rate as another
neighbouring occupier of a similarly-rated house, or house
and shop, possibly using many times as much water as his
neighbour. This may be often so, for the quantity used will
depend on the number and habits of the household, and
whether baths and water-closets are used or not ; but section
12 of the Waterworks Clauses Act, 1863, provides that a supply
of water for domestic purposes is not to include a supply of
water for cattle or for horses, or for washing carriages, where-
kept for sale or hire, or by a common carrier, or a supply
for any trade, manufacture, or business, or for watering gar-
dens, or for fountains, or for any ornamental purpose.
Where water is used for flushing sewers, road watering,
etc., a charge should be made on the general district rate for
the water so used. In some districts the rates paid by the
users of the water cover not only the annual repayment of the
loan, with interest, but also the cost of maintenance. In this
case the tenants or owners of the property pay for the water-
works in the course of a term of years, at the end of which
they are the absolute property of the L.A., and not of those
who have paid for them. In other cases the water-rates only
cover the interest and cost of maintenance, the principal being
paid off from the general district rate. This seems a perfectly
fair arrangement, as the works ultimately become the property
of the L.A., which has paid for them. In other instances the
sum to be paid by the users of the water is fixed in an arbitrary
manner, and the balance raised from the general district rate.
The mode in which the cost of public supplies is met, in
different districts, is referred to in the subjoined chapter on
rural water supplies.
Up to the passing of the Local Government Act, 1894, the
Rural Sanitary Authority was, under the Public Health Act
1875, the only body having power to provide water-supply
THE LA W RE LA TING TO WA TER SUPPLIES 393
works in rural parishes; but under section 8 of the 1894 Act
a Parish Council has power to utilise any well, spring, or
stream, within their parish, and provide facilities for obtaining
water therefrom, but so as not to interfere with the rights of
any corporation or person; and the Parish Council have
power also under the same section to contribute towards the
expense of doing this, or to concur or combine with any other
Parish Council to do so, or contribute towards the expense of
such water supply. It is probable that these powers will be
seldom used, because the Rural District Councils have already
full power to provide water supplies for any parish in their
districts, the expense of so doing being a special charge upon
that parish ; and it is provided in section 8 that nothing con-
tained in that section shall derogate from the obligation of the
District Council with respect to the supply of water ; also that
Parish Councils are not to acquire, otherwise than by agree-
ment, any land for the purpose of any water supply. The
1894 Act, however, contains useful provisions for the pro-
tection of these councils, with regard to the action of the
Rural District Councils as to water supply, section 16 pro-
viding that where the Rural District Council has determined
to adopt plans for the water supply of any parish, it shall
give notice thereof to the Parish Council of the parish for
which the works are to be provided, before any contract
is entered into for carrying out the works. Also that
where a Parish Council has resolved that a Rural District
Council ought to have provided the parish with a supply of
water, in case where danger arises to the health of the in-
habitants from the insufficiency or unwholesomeness of the
supply of water, and a proper supply can be obtained at a
reasonable cost, the Parish Council may complain to the
County Council, who, if satisfied that the District Council
has so failed, may resolve that the duties and powers of the
District Council, for the purpose of the matter complained
of, shall be transferred to the County Council, and they shall
be transferred accordingly ; or instead thereof may make a
394 WATER SUPPLIES
similar order to that mentioned in section 299 of the Public
Health Act, 1875, and appoint a person to perform the duty
of providing the district with a water supply.
Before giving details of schemes which have been selected
as typical, it may be well to mention categorically the more
important clauses of certain Acts of Parliament bearing upon
the provision of water supplies by Sanitary Authorities, some
of which have already been referred to.
The Acts more particularly applying to water supplies are,
the Public Health Act, 1875, clauses 51 to 70 inclusive; and
the Public Health (Water) Act, 1878. In the following
paragraphs the former will be referred to as the P.H.A., and
the latter as the P.H.W.A. ; the No. of the clause will be
placed in brackets, and L.A. will signify the Local Sanitary
Authority.
P.H.A. (64). By this clause all existing public cisterns,
pumps, wells, reservoirs, conduits, aqueducts, and works are
vested in and under the control of the L.A.
Where a spring or other source of water is vested in the
L.A., and can be utilised for a public supply, there are no
water rights to purchase.
P.H.A. (51). The L.A. may provide their district, or any
portion of their district, with a supply of water, and for this
purpose may (a) construct waterworks, dig wells, etc. ; (b)
lease, or hire, or purchase waterworks ; or (c) contract with any
person for a supply of water.
P.H.A. (54). The L.A, have the same powers, etc., for
carrying water mains as they have for carrying sewers.
P.H.A. (299-301). If a L.A. neglects to supply any portion
of its district with wholesome water, where the present supply
is a danger to health on account of its insufficiency or un-
wholesomeness, and a proper supply can be obtained at a
reasonable cost, complaint may be made to the Local Govern-
ment Board by any person, and the Local Government Board
may order the L.A. to provide a supply.
P.H.A. (56 and 58). The L.A. may charge water-rates,
THE LAW RELATING TO WATER SUPPLIES 395
or supply the water by meter, or may make special agree-
ments with the person receiving the supply.
RH.A. (61). Any L.A. may supply water to an adjoining
district, with the consent of the Local Government Board.
P.H.A. (62). Where the Surveyor to the L.A. reports
that any house within the district is without a proper supply
of water, and that a supply can be had at a reasonable cost,
the L.A. may compel the owner to provide a supply. If he
makes default the L.A. may execute the works, and either
recover the expenses in a summary manner, or may levy a
rate on the premises.
P.H.A. (70). The L.A. may apply to a court of summary
jurisdiction for an order to close any well, tank, or cistern,
public or private, which is reported to be so polluted as to be
injurious to health.
P.H.W.A. (3). It is the duty of every Rural Sanitary
Authority to see that every occupied dwelling-house has a
proper supply of water. A portion of this clause resembles
that of the P.H.A. (62), but is less ambiguous in its wording,
and the Medical Officer of Health or Sanitary Inspector is
empowered to report, and not the Surveyor. By a reasonable
cost is meant a sum of 8 : 13 : 4, the interest of which, at 5
per cent per annum, is 2d. per week ; or, on the application
of the L.A., such other cost not exceeding a capital sum
(13), the interest on which, at the rate of 5 per cent per
annum, would amount to 3d. per week. The owner may
object on various grounds, one of which is that the L.A.
ought themselves to provide a supply of water for the district,
or the portion thereof in which the house is situated.
P.H.W.A. (6). No new house shall be inhabited until a
certificate has been obtained from the L.A. to the effect that
it has, " within a reasonable distance, such an available supply
of wholesome water as may appear to such Authority, on the
report of their Inspector of Nuisances or of their Medical
Officer of Health, to be sufficient for the consumption and use
for domestic purposes of the inmates of the house."
396 WATER SUPPLIES
One of the effects of this, clause has already been referred
to. Another is that, where the clause is enforced, new houses
cannot be built to replace the old ones, in those districts
where a water supply cannot be obtained at a "reason-
able" cost, because water certificates will not be granted.
The inhabitants, therefore, must continue to tenant the old
cottages, however dilapidated, unless the latter be condemned.
In such cases the L.A. must either provide a public supply,
and so enable new cottages to be erected, or the people must
be allowed to tenant the old places, or be turned out to find
homes elsewhere.
P.H.W.A. 1 (9). Where the L.A. provide stand pipes they
may recover water-rates or water-rents from the owners or
occupiers of every dwelling-house within 200 feet of the stand
pipe, unless such house has a good supply of its own.
The L.A., therefore, can provide stand pipes, and charge
rates on all the houses using the water within 200 feet of
each. Houses beyond this distance cannot be rated. In one
of my districts numerous stand pipes are provided, and the
owners need not lay on the water to the houses. In another,
stand pipes are only provided under exceptional circumstances,
and, wherever possible, the owners are compelled to lay on
the water to the houses. By carrying a service main within
200 feet of a house not having a proper supply of water, and
fixing a stand pipe, the house can be rated.
P.H.W.A. (8). Upon application to the Local Govern-
ment Board, the Board may fix a general scale of charges,
instead of the fixed charge referred to in (3).
The " Limited Owners Reservoirs and Water Supply
Further Facilities Act, 1877," enables a landowner to charge
his estate with the cost of constructing works for the supply of
water thereto, or he may enter into an agreement with the L.A.
or any company or person for the supply of water for any term
not exceeding the number of years during which the cost of
the improvement is a charge on the estate.
1 This section applies to llural Sanitary Authorities only.
THE LAW RELATING TO WATER SUPPLIES 397
The Justice of the Peace of 8th June 1895, commenting on
the provisions of the Public Health Act, 1875, as affecting
water supplies, says : " Turning now to the provisions of the
Public Health Act, we find there a code of -rules regulating
the manner in which a water supply is to be carried on by
the District Council. We do not intend to go through the
sections, but only to call attention to one or two matters as
affected by recent decisions. An interesting case arose
under section 64 of the Public Health Act, 1875 the case
of Holmfirth Local Board v. Shore which we reported in
last week's issue, ante, p. 344. By that section, all existing
public cisterns, pumps, wells, reservoirs, conduits, aqueducts,
and works used for the gratuitous supply of water to the
inhabitants of the district of any Local Authority, are to vest
in and be under the control of such Authority. In the
Holmfirth case, it appeared that at Holmfirth there was, near
the top of a hill, a well called Flacketer Well, supplied by a
natural spring of water, flowing into a trough or cistern, and
the overflow ran down the hill to another well or trough, or
cistern of stone, called Ing Head Well or Trough. It was the
Ing Head Well that was the subject of the litigation. The
overflow from this place ran down the hill to a third well or
trough or cistern in South Lane. It was in evidence that
the Ing Head Well had been used by the neighbouring
inhabitants for drawing water for domestic purposes, and for
watering cattle, without any interference or opposition from
any one for more than fifty years. Prior to the existence of
the Plaintiff Authority, the district in which Ing Head Well
was situated had been under the Wooldale Local Board, and
that Board had laid pot pipes instead of a brick rubble drain
from Flacketer Well all the way to South Lane. The
Wooldale Local Board and other Local Authorities subse-
quently amalgamated, and formed the present Authority.
In 1884 the defendant, who occupied a house near Ing
Head Well, put up a gate to keep cattle away from it, and
began to try to prevent the public from using it. Subse-
398 WATER SUPPLIES
quently, he put a pipe in the bottom of the trough, leading
into his own house, where it terminated in a stopcock, and
by means of this pipe and stopcock he could draw off all the
water in the trough, or as much as he pleased. Among the
defences set up before the County Court Judge was the
defence that a trough was not a well at all, nor anything else
mentioned in section 64. But the County Court Judge
found as a fact that it was a well within the meaning of the
section. On the question whether it vested in the Plaintiff
Authority within the meaning of the sections, he also found
that it did. These findings were seriously contested in the
Divisional Court, but the appeal failed. Day, J-., said :
' After looking at the photograph, I have come to the con-
clusion that this is not a "well," but a "public cistern,
reservoir, conduit, or aqueduct," or certainly a " work used
for the gratuitous supply of water," within the meaning of
section 64 of the Public Health Act, 1875, and I cannot find
any fault with the decision of the learned County Court Judge
that it comes under one or other of these descriptions.'
Wright, J., on the question of the ' well ' vesting in the
Local Authority, said : ' The leading authority, so far as I
know, for construing those words " vest in and be under the
control of," as regards streets, is now the case of Wandsworth
Board of Works v. United Telephone Company, 48 J. P.
676, and it seems to me to be applicable to wells as well as
to streets. Looking at that, and the other cases as to streets,
it seems to me now impossible to deny that the Local Authority
have, in respect of the streets and wells vested in them by
force of the statute, a right of property not an absolutely
unqualified right of property, but one capable of limitation
in point of time, and limited in some respects as regards user
but still a right of property and of possession which is
sufficient to enable them to complain of anything that inter-
feres at all, not merely that injuriously interferes, with their
occupation of the street or well for the purposes for which
it is vested in them by the statute. Now, certainly, the
THE LAW RELATING TO WATER SUPPLIES 399
boring of a hole in the bottom of a cistern or well must
interfere, whether injuriously or not, with the possession of
it as a cistern or well. Therefore, on that point, the judgment
of the learned County Court Judge was right.'
"A similar question arose under the Public Health (Scot-
land) Act, 1867. By section 89 (4) of that Act 'the local
Authority may cause all existing public cisterns, pumps,
wells, reservoirs, conduits, aqueducts, and works used for the
gratuitous supply of water to the inhabitants to be continued,
maintained, and plentifully supplied with water.' It will be
observed that the * wells ' do not vest in the Local Authority ;
it merely enables the Local Authority to cause them to be
maintained. In Smith v. Archibald, 5 App. Cas. 489, the
alleged rights of the owner and the rights of the Local
Authority came in dispute. It appeared that there was a
well in the corner of a private field. A footpath ran from
the road to the entrance of the field, and a cart-road from
this entrance to the public road, going through the village
of Denny. The inhabitants of this village had for a prescrip-
tive period used the water of the well for domestic purposes, .
and had had the well cradled with stones at their own expense.
The Local Authority caused the well to be covered in with
an iron plate, and placed therein a hand pump with the
avowed object of keeping the well free from pollution. The
proprietor of the field claimed the well as his private property,
and instituted proceedings to have the cover and pump
removed. The House of Lords held that the well was a
public well within the meaning of section 89 (4), supra, and
the Local Authority had not done anything in excess of their
powers."
CHAPTER XXIII
RURAL AND VILLAGE WATER SUPPLIES
PROBABLY every centre of population in the United Kingdom
which aspires to the dignity of being called a town has, at
the present time, some form of waterworks, of a more or less
satisfactory character, supplying water by means of mains
for the use of the inhabitants. For certain reasons it has
been assumed that villages and hamlets and rural districts
generally could not be so supplied, and the conditions as to
water supply continue much as they have been from time
immemorial. In rural districts, especially of an agricultural
character, the inhabitants are very conservative in character,
too prone to be satisfied with things as they are, and too
lethargic to strongly desire or to express a desire for change,
especially if such change will throw any additional burden
on the rates. What was good enough for their forefathers
is good enough for them. They have grown up under con-
ditions to which they have become accustomed, and their
exceedingly limited experience of other conditions does not
enable them to comprehend the advantages which may be
derived from a change. Where a public supply has been
introduced into a village, it has frequently been as the result
of an outbreak of some disease, an epidemic which, in all
probability, would have been avoided had a proper supply
been obtained earlier. In rural districts also the population
is scattered. A parish may contain a fairly compact village,
or it may contain one or more groups of houses which may
RURAL AND VILLAGE WATER SUPPLIES 401
be called hamlets, or the cottages may be scattered over the
whole area. In any case, to supply a given number of houses
much longer mains are required than in a town, and the
cost of obtaining a public supply is proportionately increased.
Again, the wages earned in the country are much lower than
in the towns, and the poorer classes are the less able to bear
any additional burden in the form of rates. Unfortunately,
also, landowners and property owners generally are affected
by the depressed state of agriculture, and do not look with
favour upon any scheme which, however much it may benefit
the inhabitants, will not apparently confer any immediate
benefit upon themselves, or an advantage in their opinion
not commensurate with the expense they will have to bear.
Still another difficulty arises from the fact that under the
Public Health (Water) Act, 1878, no newly-erected house
can be inhabited without the Sanitary Authority having certi-
fied that there is within a reasonable distance an available
supply of wholesome water. There is no definition of the
words "reasonable distance," "available supply," and
" wholesome," and they are very differently interpreted by
different authorities. By some, a quarter of a mile is con-
sidered a " reasonable distance," a water obtained on suffrance
from a neighbour's property is considered "available," and
tank water, pond, or even ditch water is considered " whole-
some." A well water is almost invariably considered to be
good whatever its source or the character of the surroundings
of the well. In growing villages, therefore, we have often a
large proportion of the houses rejoicing in the possession of
these certificates, and if the Authority or its officers propose
a public supply they are forthwith produced to prove that
such is not required. If an owner has really been put to
considerable expense to obtain a reasonably good water, it
seems somewhat unjust that he should afterwards be called
upon to contribute towards .a similar benefit being conferred
upon the tenants of other properties, whose owners have
failed to obtain such a supply. In rural districts, also, the
2D
402 WATER SUPPLIES
officers employed rarely receive such remuneration as secures
the services of men with wide experience, capable of working
out the details of a waterworks scheme, and presenting it
to the Authority so as to show its feasibility and convince
them of its great advantages or of its necessity. Unless
they are able to do this there is little likelihood of public
water supplies being generally adopted in our villages and
rural districts. The initial expense of calling in an engineer
will have to be borne by the general rates unless a scheme
be ultimately accepted and carried out. At this stage it
may be doubtful whether it be possible to obtain a supply
at a reasonable cost, and the Authority naturally hesitates at
incurring this expense. I am perfectly convinced that none
of the parishes in my districts, which are now enjoying all
the advantages of having water mains ramifying in their
midst, would ever have been so supplied had not the Surveyor
been able to draw up all the details of the various schemes,
prepare the plans, and superintend the carrying out of the
works. Confidence engendered by the successful execution
of one scheme, and the ultimate expressions of appreciation
by those who at first opposed the innovation (for these are
usually the first to acknowledge its advantages), pave the
way for further extensions, and make each successive step in
the march of sanitary progress less difficult.
That the water supplies of our parishes, derived from
shallow wells, pools, ponds, land springs, rain-water tanks,
or the hawker's cart, are often miserably inadequate in
quantity, and most unsatisfactory in quality, requires no
proof beyond that already given in preceding chapters of
this work. Neither is it necessary to dwell upon the
advantages of having an abundant supply of pure water
which can be drawn from the tap at the very door, or,
better still, within the house, so conducing to the cleanliness
of person, cleanliness of the household, and of the parish
generally. Cleanliness may not be next to godliness, but
its importance in maintaining health and vigour is too well
RURAL AND VILLAGE WATER SUPPLIES 403
established to need further demonstration. It is much to
be regretted that whilst this is universally admitted with
reference to man, it still appears to be entirely ignored with
regard to cattle. Yet, the vital processes in the one are
so closely akin to those in the other that it does not admit
of reasonable doubt that all the conditions which make for
health in the one are necessary for the other. Of especial
importance to us, however, is cleanliness in connection with
milch cows and dairy farms, since in this country it is the
almost universal custom to consume the milk raw. Milk
contains all the necessary ingredients for supporting life;
not only the life of the higher types of the animal kingdom,
but also that of those lowest forms, be they animal or veget-
able, the so-called microbes, many of which, when they gain
access to the human system, are capable of producing disease.
Some of these multiply with extraordinary rapidity when
introduced into milk, and alarming outbreaks of disease
have been traced to such infected milk. There is little
doubt that many of these epidemics could have been pre-
vented had the cattle been supplied with more wholesome
water, had the milk -cans been cleansed with pure water,
and had the teats of the "cows and the milker's hands been
clean. The importance of an abundant supply of pure water
for dairies and dairy-farms is an additional argument in
favour of public rural supplies.
Where water mains are laid in rural districts, the erection
of cottages and houses is encouraged, since the owners are no
longer under the necessity of sinking wells, constructing rain-
water tanks, fixing pumps, etc., with their initial expense and
perpetual trouble to keep in repair. Very often the interest
on the original expenditure for a well and pump exceeds that of
the water rate which would suffice to pay for a public supply.
The difficulties in the way of supplying thinly-populated
areas with water have been greatly overrated, and probably
in few cases are they insurmountable. In recommending a
really good scheme, one can always feel the utmost confidence
404 WATER SUPPLIES
in asserting that, however much it may be opposed by those
intended to be benefited, and local opposition always arises
when a Sanitary Authority decides to provide waterworks,
the works will not be in existence long before the growlings
are replaced by grateful acknowledgments of the boon con-
ferred. Simple and inexpensive supplies can often be
obtained by collecting the water from a spring, and laying
mains from the reservoir or tank to hydrants along the route.
Where pumping is necessary the motive power may often be
obtained by aid of a ram, turbine, or water-wheel, at a
reasonable initial expense, and at a cost of very few shillings
per year for attention and repairs. If these machines cannot
be utilised, a windmill may be employed ; although, on
account of the large size of the storage tank necessary, the
expense in the first instance will be somewhat greater. Gas,
oil, and hot-air engines also require but little attention, and
only such as can be given by an intelligent labourer. The
weekly labour bill, however, is an important item when the
works are small, but sometimes a supply of water near at
hand can be utilised by pumping with one of these machines,
whereas the nearest source available for working a ram or
similar machine may be a considerable distance away. In
such a case the cost of pumping may be less than the interest
on the extra outlay which would be involved in laying the
additional mains.
In connection with this subject it will probably be of
interest to record what has been done in a few districts in
the way of supplying water to villages, hamlets, and scattered
cottages therein. What has been done here may be done
elsewhere, and the examples given, showing how certain
difficulties have been overcome, may be incentives to others
to attempt to do for our rural districts what has already been
so well done for our towns.
The Nantwich Rural Sanitary Authority l may fairly
1 " Public Waterworks for Rural Districts." J. A. Davenport, C.E. ,
Surveyor, Nantwich, R.S.D. (Sanitary Record, 3rd March 1894).
RURAL AND VILLAGE WATER SUPPLIES 405
claim to be pioneers in carrying water mains through thinly-
populated rural districts. They commenced in 1878 by
supplying the township of Church Coppenhall, and since
then the mains have been extended, until, at the end of 1893,
the Authority had supplied, in 32 townships, 2817 houses,
with a population of upwards of 14,000. There are 93
miles of mains, and extensions involving the laying of 27
more miles have been decided upon. "The cottages are
supplied with water, pure in quality, plentiful in quantity,
and conveniently at hand, with taps within each house, at
twopence farthing per week." This payment by the tenants,
however, does not cover the whole cost of the supply. The
mode in which this is defrayed is thus described by Mr.
Davenport, the engineer and surveyor to the district.
" Supposing the cost of a water supply to a township is
.1000, the annual charge upon that amount borrowed from
the Public Works Loan Commissioners would be about 60
per annum, which would clear off principal and interest in
thirty years. Supposing there are sixty houses to be supplied,
the annual cost of furnishing the water, founded upon the
average quantity of water consumed per house (as shown in
the Authority's statistical tables from actual measurement
and cost), would be about 18 per annum, making a total
expenditure of 78 per annum. Taking thirty of the houses
to bring in 20s. each per annum to the water rate, and the
other thirty to bring in 10s. each, which is the minimum,
the water rate would only raise 45 per annum, leaving a
deficiency against the township of 33 per annum for thirty
years. By the system of guarantee referred to (a guarantee
on the part of the owners of estates benefited, to pay a sum
not exceeding 6d. per acre per annum for thirty years), the
owners of property step in and pay this, and where either
the whole, or a considerable portion of a township, is
supplied by these public mains, Id. in the pound, if
needed, is contributed by the general township rate, in
reduction of the deficiency. It will make some little
406 WATER SUPPLIES
difference at first, whether the money is lent to be repaid
by equal annual instalments, or annual instalments of prin-
cipal and interest ; in the former case, the instalments being
the same each and every year, and in the latter they are
rather heavier for the first fifteen years, and lighter for the
last fifteen years." This system of guarantee has been very
successful in this district, and several landowners have also
given considerable amounts for the laying of mains for the
benefit of property with, which they are connected.
Spring and Ram. In Chapter V. reference was made
to a water supply in one of the Essex rural districts.
The water, which was first carried to the village of Danbury
only, is derived from a public spring on the common, a mile
away and 180 feet below the highest point to be supplied.
By aid of a ram the water is raised into a tank of 4000
gallons capacity, elevated on a small tower placed on the
highest point in the village. It flows through 3 miles of
mains, and communicating pipes are laid on to about 60
houses, and stand pipes in the lanes supply the remainder.
The whole parish contains 195 inhabited houses and 839
inhabitants, and 'its area is 3495 acres. The total cost was
807. Only the houses actually supplied that is, which
have the water laid on, or are within 200 feet of a stand
pipe are rated. The rate is Is. in the pound, and produces,
within <2, the whole annual sum required to pay off the
principal and interest in thirty years. The sole burden
upon the general sanitary rate is this 2 per annum, and
this alone affects the land. As the cottages are rated at 4
on the average, the tenants enjoy an abundant supply of
water for the modest sum of 4s. per year.
Spring and Gravitation Works. In 1893 the water
running to waste after serving the Danbury ram was caused
to supply by gravitation portions of four other parishes. The
district is very poor and thinly populated. About 15,000
yards of 4-inch and 3-inch, and 1000 yards of 2-inch mains
have been laid, and the water laid on to every house en route
RURAL AND VILLAGE WATER SUPPLIES 407
(277 at present). Only a few stand pipes have been fixed.
The cost was under 3000. All cottages are rated at 8s. 8d.
per year (2d. per week), and larger houses at Is. 6d. in
the pound of their rateable value. This produces nearly
sufficient to pay the annual instalments of principal and
interest. At the present time the Authority is contemplating
very considerable extensions (into adjacent parishes), since
applications for the water to be laid on are numerous.
Where the houses are far from the mains the owners requir-
ing the water defray the whole or a portion of the cost of
laying a service main (vide p. 64).
Spring and Ram. In another small village in one of my
districts a spring rising at the outskirts supplies a ram,
which pumps water into a tower supported upon iron
columns. The tank has a capacity of 1200 gallons. The
water is laid on to several houses and to stand pipes in the
street. The total cost was only 200 ; a portion was raised
by subscription, and the remainder paid out of the rates, the
payment being extended over three years.
Spring and Steam Pumping. In another parish, with 321
houses and a population of 1303, a water supply has been
inaugurated which furnishes water to about two -thirds of
the population. Over a spring yielding some 30,000 gallons
of water per day a covered tank holding 12,000 gallons has
been constructed. Upon a brick tower, 70 feet high, a
wrought-iron tank holding 15,000 gallons has been fixed.
The water is raised from the spring to the tank by a six
h.p. engine, through 4 -inch suction and rising mains.
From the tank it flows through over 2 miles of mains 4-inch,
3-inch, and 2-inch in diameter, to supply the village. The
total cost, including the land and spring (which are in an
adjoining parish), was slightly over 2000. The cost of
pumping, including wages, is about 45 a year. The loan
and interest is being repaid in equal half-yearly instalments,
spread over a term of thirty years. An annual sum of 25
is paid for the water supplied to a malt kiln, and a small
408 WATER SUPPLIES
sum is paid out of the general rate for the water used for
road watering, etc. ; the balance is raised by a rate of Is. 4d.
in the pound levied on the users of the water.
Subsoil Water raised by Steam Pump. In an adjoining
parish, having a population of 2334, of which about 1700
are supplied with water from the public mains, subsoil water
is raised by pumping into a tank of 12,000 gallons capacity
situated on a brick tower, from which it passes by gravitation
to supply numerous stand pipes in the village. Year by
year the demand for water increases as a larger proportion
of the houses desire to have the supply laid on. During
the first year the amount used only averaged 5 gallons per
head per diem, but in five years it has increased to 15
gallons. The total cost was 2300, and this is being paid
off by sixty equal half-yearly instalments of principal and
interest. The parish pays 25 per year for the water used
for sewer flushing and street watering. The cost of pumping,
including wages, is about 45. The water rate is only Is. in
the pound, and is levied only on the consumers of the water.
Subsoil Water Gravitation Works. Another village in one
of my districts, with a population of about 1000, is supplied
by gravitation works from two chains of wells sunk in the
sand on rising ground outside the village. The water flows
directly on to two small filter beds of sand and polarite,
from which it passes into a small covered reservoir, and
thence into the mains. The cost of the works is being paid
off by a rate of 9d. in the pound. As the filters require
attention, and the water is turned off during the night, a
man is paid a small sum annually for taking charge of the
works. There are no stand pipes, the water being laid on
to all the houses.
Spring Water raised by a Water-wheel. The hamlet of
Cressbrook, near Buxton, Derbyshire, has recently been
supplied with spring water by pumping, and the following
description of the works has been furnished by the engineers,
Messrs. J. and J. Webster of Bridge Street, Buxton :
RURAL AND VILLAGE WATER SUPPLIES 409
" The spring water is conveyed for a distance of 400 yards
through 3-inch cast-iron pipes, where it is delivered into a
cistern of 120 gallons capacity. The power is obtained for
driving the pump with a breast- water wheel, 8 feet diameter
by 4 feet wide, constructed of iron and Siemens steel. The
driving water l to the wheel is also carried a distance of 400
yards. To the water-wheel is attached a three-cylinder pump,
specially designed and constructed by us, to meet the exceed-
ing high pressure (200 Ibs. per square inch) and give a constant
flow. The water is drawn from the above cistern and delivered
through 1125 feet of 3-inch pipe to the reservoir, situated
410 feet higher than the pump. The reservoir has a capacity
of 35,000 gallons, and is cut out of the solid limestone rock,
which is lined with a wall 2 feet thick, then lined with bricks
set in cement, and further grouted between the brickwork
and wall with fine, clean gravel and cement. The reservoir
is divided into two halves, so that one half can be working
whilst the other half is being cleaned out. The supply to
the houses, Cressbrook Hall, and mills is through 3-inch cast-
iron gravitation pipes. The taps are enclosed in cast-iron
boxes, specially designed to protect them from frost. Provision
has been made at the mills to use the water in case of fire.
When tested with a hydrant it was found that a stream of
water could be thrown about 20 feet higher than the roof
of the mills. The total length of pipes is about 2 miles.
All the cast-iron pipes are coated by Dr. Angus Smith's
process. The quantity of water guaranteed to be delivered
into the reservoir is from 3000 to 4000 gallons per day, but
12,000 gallons can be delivered without running wheel and
pumps at an excessive speed."
The total cost was a little under 1000, and was borne by
the owner of the estate. The water is laid on to 15 stand
pipes for the supply of the cottages, and a charge of IJd.
per week is made for the use of the water.
Deep -well Water raised by a Windmill. At Lechlade,
1 Derived from the river Wye.
410 WATER SUPPLIES
Gloucestershire, a windmill has been successfully used for
supplying the village with water. The population is 1250,
and the number of inhabitants supplied about 1000. The
windmill was made by the Ontario Company, and has sails
of 18 feet diameter. The pumps are double -action, with
4-inch cylinders. A tank capable of holding 60,000 gallons
of water is supported on a brick tower 10 feet high, in which
the pumps are placed, and on the top of this is the windmill
working a shaft passing through the tanks to the pumps
which are directly over the well. The well is a tubular one
4 inches in diameter, driven to a depth of 24 feet through a
bed of clay into water-bearing gravel. The windmill has an
automatic action, shutting off when the tank is full and
collapsing when the wind pressure is beyond that for which
the sails are set. The supply has never failed during the
four years the works have been in existence, the storage in
the tank having proved ample to tide over the calm periods
when the pumps were out of action. The water is supplied
to stand pipes in the streets, but any house can have it laid
on by paying a rate of 10s. a year. The money was borrowed
by the Sanitary Authority and has to be paid off in thirty
years. The water rate is 3d. in the pound. Messrs. Johns
Brothers, Lechdale Foundry, carried out the scheme, from
the designs of Mr. J. H. Bardfield, London. The total cost
of the works was 1800.
Spring Water supplied by Gravitation. The village of
Winfrith, Dorsetshire, has been supplied with water from a
spring at the outskirts. The works were designed and
carried out by Messrs. Foster, Lott, and Co. of Dorchester.
The springhead is situated on the hillside above the rectory
farm and close to the Chaldon road. The water springs from
the limestone rock, and is not only of analytical purity but
is remarkably clear and sparkling. It is collected at the very
springhead into a perforated iron container, and there has
been placed around the outside of the container several
hundred loads of flint, gravel, and chalk. There is a 12-inch
RURAL AND VILLAGE WATER SUPPLIES 4"
overflow, the surplus water running into the brook course.
The container and chamber are hermetically sealed, and the
water is beyond all possible chance of contamination from
the foul Chaldon brook, nor can it be intentionally polluted.
From the spring the water is conveyed by 4-inch cast-iron
pipes into the village, and waste-preventing hydrants of the
latest pattern are placed at convenient distances for public use.
There is quite an 18 feet head at the spring, and an ample
pressure to carry the water many miles farther if required.
All the valves are Lambert's high-pressure diaphragm valves,
of the same pattern as at the Dorchester Waterworks, as also
are the boxes and castings. There is an entire absence of
expense after the initial outlay, the water being conveyed by
the natural force of gravity to the various deliveries.
Spring Water pumped by a Turbine. The waterworks at
West Lulworth, referred to in Chapter XIX., were also de-
signed and constructed by the same firm. An attempt to
supply West Lulworth with water was made about ten years
ago, a spring on the Bindon Hills having been tapped and
pipes laid on to various points. This was opened in May 1886,
the whole cost having been borne by the Weld estate ; but
from the first it was found to be wholly inadequate. The
reservoirs and pipes being intact the former situated on the
hillside quite 300 feet above the sea-level it was suggested
that the same plant might be utilised. Attention was directed
to the great spring under the rocks close to the cove, and Mr.
Foster was consulted. A portion of the water is conveyed
from the spring to the old mill-pond on the other side of the
road, which has been thoroughly cleared out and now forms
quite an ornamental lake, to pump the supply to the reservoirs
in the hillside 300 feet above. From the pond the water
passes to the top of a new stone tower, which contains a vortex
horizontal turbine. The turbine is fixed in the pit at the
bottom of the tower, and is 20 feet below the level of the
water in the pond. The water falls to the turbine by means
of an upright vertical pipe, the waste being taken at the
4T2 WATER SUPPLIES
bottom by a 12 -inch drain and carried to the sea. From
the turbine, which runs about 600 revolutions per minute,
the power is communicated by a 10-inch pulley to a large
pulley on the over-head shafting, and from thence the power
is transferred to a set of high-pressure three-throw plunger
pumps. It is estimated that these pumps, driven by the means
mentioned, which are equal to five horse-power, will lift 1200
gallons an hour continuously, and they run with a surprising
degree of smoothness and absence of noise or friction. The
pumps are fitted with a pressure gauge which not only registers
the pressure but the height of the water in the pipes and
tanks. Notwithstanding the recent drought, which has had
a material effect on the spring, there is quite sufficient
water to pump up more than double the quantity that Mr.
Foster contracted to deliver at the reservoir. The tower is
built of local stone, and forms quite an ornamental feature
in this pretty village. The reservoirs are 120 feet by 20 feet,
and will hold 60,000 gallons. Formerly they were uncovered,
and not only exposed to the air but to various contaminations.
They are now covered with concrete and trapped and locked
in the same way as the spring at Winfrith. Besides making
a large number of connections in the village, a set of hydrants
and hose for use in case of fire have been provided.
Deep-well Water raised l>y an Oil Engine. At a recent
gathering of Medical Officers of Health, Dr. Ashby of
Reading gave a very interesting account of the waterworks
recently established for the supply to a village (Sonning) in
his district. He stated that the water was derived from a
boring in the upper chalk, 75 feet deep, yielding about 70
gallons per minute. The reservoir has a capacity of 35,000
gallons, and the rising main from the well to the reservoir
is 4 inches diameter and 1783 feet in length. The main
enters the top of the reservoir at about 100 feet above the
level of the water in the bore-hole. The reservoir is about
4000 feet from the commencement of Sonning village, its
bottom being about 48 feet above the highest, and 83 feet
RURAL AND VILLAGE WATER SUPPLIES 413
above the lowest parts of the village. The distributing
mains consist of 4390 feet of 4-inch pipe and 3935 feet of
3-inch pipe. There are sixteen hydrants, five air-valves, and
seven sluice-valves, besides one on the draw-off pipe at the
reservoir. The engine-house cost 124, the engine and
pumps 260, the tube well 73, making a total of about
457 for the entire pumping station and well. The total
cost of the works was 1840. With the sanction of the
Local Government Board 1800 was borrowed; of that sum
400 has to be repaid in fifteen years and 1400 in thirty
years. To repay the annual instalments of principal and
interest, and to cover the cost of pumping and other expenses,
a rate of Is. in the pound on houses and 3d. on land is required,
besides the water rate charged on the occupiers of premises
actually supplied. The charges for domestic supplies are 7s.
a year for all houses under 14 rateable value, and 2J per
cent on the rateable value of all other houses, and some extra
charges for farmyards, cowkeeping, and livery stables. The
expense is considerable, but, as Dr. Ashby remarks, " it would
have cost but little more to have supplied a considerably larger
place." Sonning has a population of 515 persons, and its
rateable value is 4398. The oil engine is of two brake
horse-power, and the pumps are a set of treble ram pumps,
with gun metal plungers 4 inches in diameter by 9 inches
stroke. They are fixed to the suction pipe at the top of the
lining tube of the bore-hole. Dr. Ashby made a very careful
series of observations, showing the capacity of the pumps and
the cost of pumping. He says :
"From 3rd September to 30th September 1894, we
pumped 31 \ hours on 11 days. During the whole of that
time I was present and took exact observations of all the
materials which were consumed. We could have done the
pumping in four days, but we pump more frequently in order
to keep a good stock of water in the reservoir in case of any
fire occurring, or in the event of the machinery requiring any
repairs, so that the village may not be without water. We
414 WATER SUPPLIES
consequently use rather more oil in starting the engine than
would be absolutely necessary. In that time the pumps
made 57,397 revolutions, an average of 1822-1 an hour.
There are 7 '2 revolutions of the engine to 1 revolution of
the pumps, so the engine ran at an average speed of 218*65
revolutions per minute. The total quantity of water raised
was 75,764 gallons, or an average of 2 40 5 "2 per hour. The
supply per head of the population per day was about 7
gallons.
" The consumption of materials was as under :
s. d.
12 gallons of tea rose oil ... at 5d. 5
1 battery charge . . . . at Is. 1
1| zinc for battery . . . . at 3d. 4^
24 fluid ounces of sulphuric acid . at 2d. per Ib. 5A
Total cost of material consumed by the engine . . 610
3^ pints of lubricating oil for engine and pumps
at 2s. a gall. 1(
Cotton waste . . . . at 4d. per Ib. 3
Total cost of materials consumed by engine and pumps . 8
Cost of materials for engine per 1000 gallons of water raised 100
feet high 1*082 penny
Total cost of materials for engine and pumps per 1000 gallons of
water raised 100 feet high 1 '267 penny
Consumption of oil per h.p. per hour . . l - 5 pint."
Spring Water pumped by Gas Engine. Great Baddow and
Springfield are two adjoining villages with a population of
about 4000. The waterworks are situated in a piece of
ground near the spring. The spring yields 120,000 gallons
per day. For the past fifteen years one eight horse-power
gas (Crossley Otto) engine and set of pumps have been
sufficient to raise all the water required ; but this year a
new eight horse-power (Crossley Otto) with a set of three-
throw pumps has been erected as a duplicate.
There are four reservoirs 24'xl2'x6' brick-built and
covered with brick arches, each holding 10,350 gallons.
RURAL AND VILLAGE WATER SUPPLIES 415
The water is pumped twice daily from these reservoirs to
a tank holding 40,000 gallons on the top of a tower 96
feet high.
The villages are then supplied by gravitation. One engine
will work both sets of pumps at once, raising 20,000 gallons
per hour.
The amount of gas used in pumping is 200 feet per hour
for the new engine and 250 feet per hour for the old engine.
Gas at 3s. 4d. per 1000 feet. The total expense for working
is about 180 per year. The amount of water rents collected
from the houses supplied is about <350 per annum. Where
water is supplied by metre the charge is Is. per 1000
gallons.
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APPENDIX
1. CRENOTHRIX, CAUSE OF DISAGREEABLE ODOURS
IN WATER.
CKENOTHRIX, a fungoid growth of thread-like form, can only thrive in
water containing protoxide of iron and organic matter, and, by its
decomposition, often causes water to acquire a disagreeable odour and
taste. The Berlin water supply from wells sunk near the Tegeler Lake
had to be abandoned on account of the abundant growth of this
organism. Its appearance in the Rotterdam water supply led to the
formation of the "Rotterdam Crenothrix Commission," and Prof.
Hugo de Vries reported that Crenothrix was not a ground water
organism as was generally supposed, but that it was found in many
surface waters. As the result of his observations and experiments, he
expressed the opinion that two factors are necessary for its growth to
become so rapid as to render a water unpalatable. These two factors
are the presence of decomposing organic matter, and the presence of
protosalts of iron. For a detailed account of this organism and its
relation to water supplies, an exhaustive article by Prof. "W. F. Sedgwick,
in the Technological Quarterly, Boston, 1890, may be consulted. In
the Annual Report of the Massachusetts State Board of Health, there
is also a mass of information bearing upon this subject ; and in Public
Health for October 1896, Dr. Garrett describes the effect of this
organism on the Cheltenham water supply.
2. EFFECT UPON HEALTH OF ZINC- CONTAMINATED WATER.
Zinc poisoning from the use of water which has been stored in
galvanised iron receptacles is of comparatively rare occurrence.
Obstinate constipation is, so far as experience extends, the one notice-
able effect produced, and possibly zinc-contaminated water may be a
more frequent cause of this condition than has hitherto been suspected,
but Myelius states that the water of the parish well at Tutendorf
contains half a grain of zinc per gallon, and has been used for about
a century without any perceptible effect.
APPENDIX 419
3. PLUMBO-SOLVENT ACTION OF MOORLAND WATER.
In 1890 the Medical Department of the Local Government Board
was entrusted with an investigation respecting the causes of the lead
poisoning which has been referred to public water supplies derived
from moorland sources. This investigation has been undertaken by
Mr. W. H. Power, F.R.S., and an interim report has just been pre-
sented, based upon data collected for the West Riding of Yorkshire by
Dr. Barry, and for Lancashire, Cumberland, and Westmoreland by
Mr. T. W. Thompson. With reference to this subject, Dr. Thorne, in
his last Report to the Local Government Board, says
" Observations were, in the first instance, confined to the gathering
ground at Burnmoor, near Settle, in Yorks, water from different parts
of which were, for some eighteen months, examined week by week as
to their physical, chemical, and bacteriological features, the results
being recorded along with concurrent meteorological and other condi-
tions, and compared with the ability of the same water week by week
to take lead into solution. With the latter only one chemical condi-
tion has been found generally parallel, while none of the other condi-
tions observed have been at all parallel. This is the amount of acidity
of the water. And a similar correspondence was found to exist when
the experience of Burnmoor was applied to other gathering grounds.
For although the amount of lead taken up by one water as compared
with another was not always found to be in direct proportion to the
relative acidities of the two, yet, for a particular water, variations in
its lead-dissolving property were always associated with corresponding
variations in the amount of its acid.
" The problems of plumbo-solvency of a moorland water thus came
to be, in large measure, problems of the particular acidity connected
with it, and accordingly experiments were undertaken to determine
the nature of this acidity and its source. Having ascertained that a
moorland water has not in itself any power of developing or increasing
in acidity, it remained to be discovered where in its moorland history
the water acquired its acid properties. It was soon ascertained that
it was from the peat that the water derived this quality ; and the
question next arose whether the acidity of the water was due to merely
chemical and physical reaction of the water and the peat or to active
organic life in the peat itself. The answer is indicated in the experi-
ments so far reported on. They show that while neither moorland
water nor a sterile decoction of peat can of itself develop acidity, the
addition to either of a minimal amount of moist peat soil will cause
bacterial growth in it, with increasing development of acid reaction
and ability to dissolve lead.
420 WATER SUPPLIES
"And they have further indicated two species of microbes which,
alone among the many kinds of micro-organisms found in the samples
of peat examined, have the power of producing acidity when added to
a sterile decoction of peat.
"At this stage, then, Mr. Power's forecast of 1887 would seem to
be borne out as the result of the labours of the experts who have been
engaged in this inquiry. The investigation is, however, by no means
completed, and it is being continued throughout the current year."
Dr. Scatterby (Public Health, May 1895) describes the filtering
arrangements made to neutralise the plumbo-solvent action of the peaty
water supplied to Keighley. He says : ' ' These works, completed at a
cost of 18,000, consist of three beds of Welsh coke (to extract the
grosser peat} 7 impurities), four sandstone and limestone niters, four
polarite chambers, and a clean water reservoir." By this filtration the
acid so invariably found in moorland water supplies is neutralised by
the limestone of the filters, and by this means it is hoped to completely
destroy the solvent action of the water on the lead piping.
4. POLLUTION OF WATER IN RESERVOIR. OUTBREAK
OF TYPHOID FEVER.
During the latter half of 1893 an epidemic of typhoid fever
occurred in and around Paisley, affecting over 800 people. Dr. Munro,
the County Medical Officer, attributes it to the pollution of the water
supply, and upon visiting the reservoir a month after the beginning
of the epidemic he found that until the 6th of July there had existed
close to the margin of the water an inhabited farm house, "the
drainage or soakage from which could only escape into the reservoir."
Dr. P. Frankland, who examined the collecting ground and the filter
beds, proved that the filters were in an unsatisfactory state.
5. POLLUTION OF WATER SUPPLY BY MELTING SNOW.
OUTBREAK OF TYPHOID FEVER.
In 1885 an outbreak of typhoid fever occurred in Pennsylvania.
1200 people were attacked and 150 died. Stampfel states that during
the early spring the dejecta from a typhoid patient was thrown upon
the snow lying on a hill sloping towards the source of the public water
supply. A sudden thaw setting in, the impurities would be carried
down with the melted snow. This occurred on 25th March, and on
10th April the epidemic commenced. Just at that time the water
from this particular source was being used to an unusual extent.
Those who derived water from other sources were not affected.
APPENDIX 421
6. POLLUTION OF WATER IN MAINS.
Mr. M. A. Adams, 'F.R.C.S., Medical Officer of Health for the
borough of Maidstone, in his Annual Report for 1894 (quoted in
Public Health, July 1895) states that he found in May that the water
from a particular hydrant was polluted. Upon investigating the
cause, the main was found to be defective at two points near a disused
drain. Mr. Adams explains the insuction of foul matters by stating
that there^was a tendency for this service pipe to empty itself in favour
of the lower placed hydrants, and when the taps at these lower places
were shut off, a wave of water pressure was sent forward to the higher
level ; when this wave reached the hydrant implicated, the water
recoiled upon itself, and set up a sudden and strong retreating .current
in the opposite direction, which produced the insuction. He adds,
"This seemingly small matter ought not to be lost sight of ; it teaches
a practical lesson in hydraulics of the greatest sanitary importance."
7. POLLUTION OF A DEEP WELL NEAR EDINBURGH.
In the Edinburgh Medical Journal for November 1894, Dr. A. C.
Houston gives an account of a well at Morningside, 294 feet deep,
which yielded polluted water. The pollution was apparently due to
the discharge of sewage into a quarry 800 feet away, since the pollution
ceased soon after the sewage was diverted into the Edinburgh sewers.
8. TYPHOID FEVER IN THE BOLAN PASS.
Surgeon - Captain Haynes states that in the Bolan Pass in 1877
typhoid fever was caused by drinking a few ounces of water from a
well in which a dead camel was found, yet that the natives who had
been drinking the water some time did not contract the disease. He
also remarks that native troops can live in barracks which have had
to be vacated by our men on account of the prevalence of typhoid
fever and cholera.
9. SELF-PURIFICATION OF STREAMS.
The effect of the sun's rays upon the organisms found in water has
been studied by many observers. Dr. Procacci exposed water in deep
cylinders to the nearly vertical rays of the sun, and found that all the
organisms in the water up to a certain depth were killed. After three
hours' exposure the water in the cylinders to 1 foot depth was nearly
sterile, whilst at a depth of 2 feet they were unaffected. Prof. Buchner
exposed gelatine plates sown with typhoid bacilli in water at various
422 WATER SUPPLIES
depths for a period of four and a half hours, and found that all those
plates covered with less than 5 feet of water, were sterilised. Those
exposed at a depth of 10 feet were not affected. Percy Frankland has
proved that in the Thames and Lea there are often twenty times more
organisms present in the water in winter than in summer, but this he
thinks may in part be due to the greater proportion of spring water
contained in the streams in summer, since spring water contains
comparatively few organisms. When a little common salt is added to
water the sterilising effect of the sun's rays is said to be increased.
With reference to the great variation in the number of bacteria in
river water during the course of the year, Prof. E. Frankland, in his
Report on Metropolitan Water Supply, 1894, says, "that the number
of microbes in Thames water is determined mainly by the rate of the
flow of the river, or, in other words, by the rainfall, and but slightly, if
at all, by either the presence or absence of sunshine, or a high or low
temperature."
Dr. D. Harvey Attfield (Brit. Med. Journ., 17th June 1893)
describes the results of a series of experiments undertaken by him -in
Munich to ascertain the effect of Infusoria upon the bacteria in polluted
water. He concludes that "Infusoria would seem to have some powerful
influence in the getting rid of bacteria, and, possibly, so aiding in the
' self- purification' of water."
GENEEAL INDEX
ABYSSINIAN tube wells, 310
yield of, 312, 313
cost of, 314
Action of frost on water mains, 375
of water on metals, 8
Advantages of softened water, 120
Alum, clarification by, 255
Amount of water required for domes-
tic and other purposes, 272
used, constant supply, 274
by cattle, 283
intermittent supply, 274
in tropical climates, 282
available from various sources,
285
Analyses, vide Tables
the interpretation of, 160
ammonia, 169
chlorine, 161
nitrates, 164
nitrites, 165
organic ammonia, 172
organic carbon and nitrogen,
171
oxygen absorbed, 173
phosphates, 170
Animal charcoal, properties of, 253
Animals, effect of polluted water
upon, 157
Aqueducts, fall of, 370
Artesian wells, 70, 320
Aster ionella, 108
BACTERIA in water, 113, 185
effect of sunlight upon, 223, 421
sedimentation upon, 220
Bacteriological examination of water,
185
Ball hydrants, dangers of, 212
Beggiatoa alba, 110
Blasting of deep wells, 325
Bogs, marshes, and swamps, 41
Boiling point of water, 5
Bore-tube, advantages and disadvan-
tages of pumping from, 316
varieties of, 319
Brine, yielded by well, 302
Bursaria gastris, 108
CARBONIC acid in water, 6
Cast-iron mains, 372
acted upon by soft water, 206
Catchment basins, 86, 295
Chalk, water held by, 44, 74, 301
Ghara fcetida, 109
Charcoal, animal properties of, 253
vegetable properties of, 253
Chlorine in surface waters, 31
signification of, 161
Cholera, 148
and improved water supplies, 150
and defective filters, 153
and water filtration, 190
organisms, influence of soil on,
309
outbreaks of, Altona, 151, 187
232
Hamburg, 151, 187
London, 148
Poonah Jail, 151
They don Bois, 150
Vadakencoulam, 151
Wandsbeck, 151
Cisterns, action of water on, 205
house, 204, 369
rain-water, 21
424
WATER SUPPLIES
Clarification of water by alum, 255
Classification of potable waters, 11,
27
Collection of rain water, 25
Colour of water, 2, 105
removal by filtration, 235
Communication pipes, 371
Composition of water, 1
Conduits, open, 370
Conferva Bombycina, 109
Constant supply, 274, 369
Constituents of natural water, 7, 115
Construction of wells, 305
Consumption of water, daily varia-
tion in, 283
hourly variation in, 277, 364
Cost of public water supplies, 35,
37, 82
boring wells, 321
tube wells, 314
well sinking, 314
Cottage filter, 252
Crenothrix, 108, 364, 418
Cryptomonas, 108
DAIRY farms, 383
Dead ends, 373
Deep-well water, 27, 70, 80
wells, boring of, 319
cost of, 320
effect of pumping on, 78
increased supply by blasting,
325
pollution of, 75, 203, 421
site, selection of, 77
yield of, 80, 83, 303, 326
Density of water, 4
Depth of mains, 372
Deserts, 15
Diarrhoea, 122
due to distilled water, 254
decomposing animals in water,
125
sewage in water, 124
sewer gas in water, 123
sulphuretted water, 123
turbid river water, 123, 124
Diseases due to animal parasites,
154
specific organisms, 130
Distillation of water, 12, 254, 257
sea water, 254
Distributing mains, 371
Distribution of water, 369
Divining rod, 290
Domestic consumption of water, 277
filters, 247
dangers of, 251
high pressure, 247
low-pressure, 247
limited utility of, 251
self-supplying, 250
Domestic purification of water, 247
Drainage area, 295
Drinking water, qualities of, 104
Dual supply, 303
Duties of Sanitary Authority to
supply water, 395
Dysentery, outbreaks due to impure
water 125. 184
EARTH, living, action of, 47
Eels in water mains, 111
Electricity, decomposition of water
by, i
Engines, pumping gas, 353
oil, 352
steam, 353
water, 344
wind, 341
Enteric fever vide Typhoid fever
Entozoa, affecting man, 155
Evaporation, loss of water by, 297
rate of, 12
from the ocean, 12
Expansion of water when freezing, 3
FACTORS influencing amount of water
available, 91
Ferrule machine, 373
Filter beds, 236, 242
area of, 237
area of, to calculate, 238
cleansing of, 236, 239
construction of, 235, 245
effect of scraping, 230
polarite, 242, 253
Filters, cottage, 252
domestic, 247
high pressure, 247
low pressure, 247
limited utility of, 251
self-supplying, 250
Filtration and cholera, 190
GENERAL INDEX
425
Filtration at Altona, 232
by machinery, 240
nitrification during, 234
rapidity, 232
removal of colour by, 235
efficiency of, 227, 233
Finding, water, 290
Fire extinction, water reserve for,
365
Flow of water through mains, 371
Formulae, Pole's, for yield of catch-
ment area, 297
storage, 299
Eytelwein's, for velocity, 370
Burton's, for fire reserve, 365
Freezing point of water, 3
Friction, loss of head by, 371
Frost, action on mains, 375
GALVANISED iron cisterns, 205
pipes, 257
Gauging of springs and streams, 95,
287
wells, 292
Goitre, 126
alleged causes of, 127
localities in which prevalent, 126
Granite, water held by, 44
Gravel, pocket of, 41
Gravitation works, 360
Ground water vide Subsoil water
HARD water, 7
cost of softeuiiiff, 257, 261, 266,
268
influence on health, 117
softening processes, 256
waste caused by, 119
Hazel twig, effect of water upon,
290
Head of water, 239
loss by friction, 371
Health, effect of impure water upon,
122
" Health " pipe, 130, 374
Heat, effect on water, 214
latent, of water, 3
Horse-power, definition, 354
equivalent in water raised, 355
Hourly variation in supply, 277
consumption, inequality of, 364
House cisterns, 204, 369
Hydrants, ball, dangers of, 212
Hydraulic rams, 344
efficiency of, 346
IMBIBITION, 42
Impervious strata, 41
Impounding reservoirs, 257, 358
Impure water, effect upon animals,
157
e fleet upon health, 122
Incompressibility of water, 2
Inequality of hourly consumption,
364
Influence of soil on cholera and
typhoid organisms, 309
Insuctiou at water joints, 210
Interlacing system of mains, 373
Intermittent pollution, 174, 192
supply, dangers, 211
to various towns, 274, 369
Interpretation of water analyses, 160
Iron in water, 8, 10
Is water analysis a failure ? 175
Isolated houses, supply for, 285
JOINTS of water mains, 372
fouling by hemp stuffing, 372
Joints, insuction at, 211
LAKES, 33
as reservoirs, 33, 35
Laws relating to water supplies, 381
Lands Clauses Consolidation Acts,
381
Limited Owners Reservoir, etc.,
Act, 396
Public Health Act, 381, 390,
392, 394
Public Health (Scotland) Act,
399
Public Health (Water) Act, 381,
391, 394, 401
Settled Land Act, 382
Waterworks Clauses Acts, 390,
392
Cases-
Borough of Bradford v. Pickles
388
Broadbent v. Ramsbottom, 386
Chasemore v. Richards, 387
Dudden v. Guardians, Glutton
Union, 384
426
WATER SUPPLIES
Cases
Embrey v. Owen, 384
Holmfirth Local Board v. Shore,
397
Milner v. Gilmour, 385
Smith v. Archibald, 399
Swindon Water Co. v. Wilts
and Berks Canal, 386
Wandsworth Board of Works
v. United Telephone Co., 399
Lead cisterns, 205, 206
pipes, 109, 208
in water, 8, 21, 129
Lead poisoning, 8, 128
symptoms of, 128, 209
Legal decisions affecting water sup-
plies, 384
Limestone, water held by, 44, 74
Limited Owners Keservoirs and Water
Supply Further Facilities Act,
396
Living earth, action of, 47
Loss of watep by evaporation, 297
percolation, 297
Lyngbya muralis, 110
MAGNESIA, sulphate of, 302
Magnetic carbide, 244
Mains, cast-iron, 372
dead ends, 373
depth of, 372, 374
diameter of, 370
distributing, 371
eels in, 111
flow of water through, 371
house service, 371, 374
insuction of filth by, 211
interlacing system of, 373
joints of, 372
trunk, 371
velocity of water in, 370
Malaria, 131
decrease in England, 131
outbreak on board ship, 132
where prevalent, 132
Maximum consumption of water,
365
density of water, 4
rainfall, 92
Mean consumption of water, 365
Metallic impurities in water, 8, 10,
128, 210
Metropolitan Water Supply, Royal
Commission report on, 72, 88
89, 94, 191, 238, 277
Mineral waters, classification of, 11
Minimum rainfall, 92
Moisture in atmosphere, 13
Moorland waters, 27
Movements of subsoil water, 44, 200
NATURAL water, constituents of, 7
classification of, 11, 27
Nitrates and nitrites, how formed,
196
in chalk waters, 166
reduction of, 168
signification of, 164
Nitrification during filtration, 234
process of, 196
Nitrogen, organic, 171
Nitrogenous organic matter, 171
Nostoc, 109
ODOUR of water, 2, 106
caused by Ast&rionella, 108
Begyiatoa alba, 110
Bursaria gastris, 108
Charafoetida, 102, 109
Conferva Bombycina, 109
Crenothrix, 108, 364, 418
Qryptomonas, 108
Lyngbya muralis, 110
Nostoc, 109
Oscillatorice, 110
Spongilla flumatilis* 108
Tabellaria, 108
Uroglena Americana, 107, 108
hemp joints, 207
tar varnish, 372
due to dead animals, 111
sulphuretted hydrogen, 106
Odours of water, classification of
107
Oolite, water held by, 44, 74, 302
Organic matter in water, 170
Organisms in water, 113
bacteria, 113, 185
higher fungi, 114
low forms of animal and vegetable
life, 115
Oriental boils, 154
Osdttatoricc, 110
Oxidation in running water, 217
GENERAL INDEX
427
Oxidising effects produced by sand
filtration, 236
Oxygen in water, 6, 217, 219
absorbed by water, 173
PALATABILITY of water, 111
Parasitic diseases, 154
Parish Councils and water supplies,
393, 396
Peaty water, 29
effect of storage on, 363
Pebble beds, water held by, 44
Percolation, 43, 45
loss by, 297
Permeability of subsoil, 43
Pervious strata, 41
Phosphates in water, 170
Plumbo-solvent action of water, 8,
10, 419
how prevented, 10, 209, 420
Pockets of gravel, 41
Polarite filter beds, 242, 244, 253
Polluted water, effect on health, 122
effect on animals, 157
Pollution of rain water, 21, 194
rivers, 87, 194
subsoil water, 48, 196
surface water, 194
deep- well water, 75, 203, 421
Pollution of water at its source, 194,
420
during storage, 203, 213, 420
distribution, 206, 211
Pollution by suspended mineral
matters, 123
sulphuretted hydrogen, 123
sewer gas, 123
sewage, 124, 125, 133, 134
surface water, 125
Pollution, sources of, action of water
on pipes, 206
cisterns and tanks, 204
burial of carcases, 202
cattle, 201
cesspools and house drainage,
194, 199, 201
coal gas, 202
cultivated land, 194
exposure to dust, 213
farmyards, 137, 194, 198
graveyards, 202
Pollution, insuction through ball-
hydrants, 211, 421
defective mains, 136, 213
stool taps, 136, 211
sewage, 195
sewer gas, 6, 123
snow, melted, 420
sulphuretted hydrogen, 123
tar varnish, 372
tow joints, 207
washings from roof, 194
Pollution, special methods of tracing,
137, 184
of rivers, Royal Commission on,
27, 40, 67, 69, 74, 88, 117,
149, 164, 166, 169, 171-207,
209, 256, 274, 282
Ponds, 32
Potable water, definition of, 121
classification of, 11, 27
Previous sewage contamination, 166
Public Health Act, 381, 390, 392,
394, 397
Public Health Water Act, 381, 391,
394, 401
water supplies, description of,
404
Pumping from bore tube, 316
mains, velocity of water in, 370
Pumps and pumping machinery,
332, 339
amount of water raised by, 337
efficiency of, 338
varieties of, 332
Purchase of land and water rights,
381
Pure water, definition of, 2
Purification of water by sedimenta-
tion, 225, 227
filtration, 228
fermentation, 255
softening process, 271
alum, 255
permanganate of potash, 255
flow of river, 215
nitrification, 48, 196, 234
Purification of water, domestic, 247
Koch's remarks on, 231
Massachusetts, experiments on,
228
Purposes for which water is required,
273
428
WATER SUPPLIES
QUALITY of drinking water, 104
Quantity of water obtainable from
different sources, 295
required for domestic and other
purposes, 272
supplied in different towns, 276
used in towns with constant
supply, 274
intermittent supply, 274
tropical climates, 282
by cattle, 283
RAIN, causes of, 13
Rain-bearing winds, 14, 15
Rainfall, 14, 15, 34, 92
at equator, 15
Kew, Greenwich, Massachu-
setts, 16
available supply of water from,
26, 294
collected by rivers, 92
how estimated, 16
in gallons per acre, 19
Rain-gaTige, 16
position, 17
mountain, 18
Rain water, 12, 19
action on lead, 21
cisterns, 21
collection of, 25
filtration of, 25
how polluted, 21
impurities in, 20
separator, 23
storage of, 21, 26, 367
Ram, hydraulic, 344, 346
Regulations under Metropolis Act,
375
Reserve for fire extinction, 365
Reservoirs, 33, 366
impounding, 357
natural, 362
service, 359, 362
settling, 359
River water, 27, 86
revolving purifier, 242
suitability of, for public supplies,
90, 220
towns supplied by, 101
Rivers and watercourses, amount of
water available from, 92
origin of, 86
Rivers and watercourses, laws relat-
ing to, 383, 384
percentage of rainfall collected in,
93
pollution of, 87
pollution. Royal Commission on,
27, 40, 67, 69, 74, 88, 117,
149, 164, 166, 169, 171, 207,
209, 256, 274, 282
self- purification of, 88, 215
subterranean, 46
velocity of flow, 95
Roofs, water collected from, 25
Rural water supplies, 400
law relating to, 381
SAND, water held by, 44
filtration, experiments on, 228
requisites for efficiency, 231,
233, 239
washing, 236, 246
Sandstone, water held by, 44, 74,
301
Saturation of rock, 42
Scrubbers, 240
Sea water, distillation of, 254
for sewer flushing, 104
Search for water, 289
Selection of source of supply, 284
Self -purification of rivers, 88, 215,
421
effect of bacteria, 223
infusoria, 422
oxidation, 219
sedimentation, 220
sunlight, 223, 421
Separator, rain-water, 23
Service pipes, 374, 376
unsuitable, 285
reservoirs, 359
Settling reservoirs, 359
Shallow wells, 46
pollution of, 198
Slime on filter beds, action of, 231
Soft water, 7
advantages and disadvantages of,
120
Softening of water, 256
by addition of lime, 257
Archbutt and Deeley's process
263
Atkins' process, 259
GENERAL INDEX
429
Softening of water, by boiling, 256
distillation, 257
Gitteus' process, 263
Howatson's process, 263
Maignen's process, 267
Porter-Clark's process, 259
Stanhope's process, 261
cost of, 257, 261, 265, 268
purification effected by, 271
saving effected by, 259, 268
Soil, undisturbed, as a filter, 197
influence on typhoid and cholera
organisms, 309
Solvent power of water, 5
Sources of supply, 26, 284
Spongilla fluviatilis, 108
Spongy iron, 242, 253
Spring water, 27, 55, 65, 285
Springs, how formed, 57
character of water from, 65
utilisation of, 60
varieties of, 56, 286
yield of, 59, 286
law relating to, 383, 384
Stand pipes, 391
Standards of purity, 191
Stool taps, dangers of, 211
Storage of water, 357
amount of, 298, 360, 366
effect of, 363
of rain water, 21
Strata, chief water-bearing, 72
Streams, vide Rivers
Subsoil, permeability of, 42
percolation into, 43
pollution of, 197
by gas, 202
saturation of, 42
water level in, 43
yield of water from, 45, 239, 288,
300
Subsoil water, 27, 41
towns supplied by, 49
movement of, 44
effect upon health, 199
law relating to, 383, 386
Subterranean water, cistern theory,
72
river theory, 72
Sunlight, effect on organisms, 223
Supply, dual, 303
Surface water, 28
Surface water affected by nature of
soil, 31
from uplands, 26, 28
cultivated ground, 27, 31
yield of, 34, 294
Tabellaria, 108
Tables
Amount of water raised by purnps,
337, 341
nitrates in chalk waters, 166
Analyses of rain waters, 27
deep-well waters, 84, 85
river and other waters, 178
spring waters, 68, 69
subsoil waters, 52, 54
surface waters, 38, 39, 40
Area of filter beds and rate of
filtration, 237
Artesian tube wells, yield, etc.,
323, 324, 326
Baeteria removed by sand filtra-
tion, 228
Cholera death - rate, effect of
changed water supply upon,
150
Cost of boring wells, 321
tube wells, 314
Discharge of water from pipes,
355
Effect of subsidence on number of
micro-organisms, 227
Efficiency of hydraulic rams, 346
Filtration, rapidity of, 241
Flow of water over notched boards,
288
Force required to work pumps,
340
Quantity of water raised by water
wheel, 351
by windmill, 343
per stroke of pump, 337
supplied daily per head, in
various towns, 276, 278
by various London Com-
panies, 278
yielded by Artesian wells, 323,
326
tube wells, 312, 313
Rainfall, 16
percentage collected in rivers,
93, 94
430
WATER SUPPLIES
Tables-
Water rates, 416
Well sections around London, 79,
80
Tanks, rain-water, 366, 367
for storage, 367
Taste of water, 2, 111
Temperature of deep -well waters,
322
effect on water in exposed reser-
voirs, 363
Towns supplied by lake water, 33, 38
river water, 101
spring water, 68
subsoil water, 49
surface water, 38
deep-well water, 84
Trade winds, 13
Trunk mains, 370, 371
Tube wells, 313, 325
Turbidity of water, 112
Turbines, 347
Typhoid bacilli, influence of soil on,
309
influence of water, etc., on, 191,
223
in drinking water, 186, 187, 191
removal by nitration, 228
Typhoid fever, outbreaks of
Ashtou-in-Makerfield, 203
Bangor, 134
Beverley, 135, 177
Bolan Pass, 421
Buckingham, 177
Gains College, 136
Caterham, 134
Chester-le-Street, 138
Croydon, 211, 213
Houghton-le-Spriug, 180
Lausen, 133
Massachusetts, 139, 183
Mountain Ash, 136, 182
Nabburg, 135
Newark, 146, 224
New Herrington, 137
Nunney, 133
Over Darwen, 134
Paisley, 420
Pennsylvania, 212
Sherborne, 136
Tees Valley, 142, 180
Terling, 137
Typhoid fever, outbreaks of
Trent Valley, 145, 177
Worthing, 187
UNDERGROUND sources of water, 41,
386
water, advantages of, 78
tanks, 367
Unnecessary consumption, 279
Upland surface waters, 26
Uroglena Americana, 107-108
VARIATION in daily consumption of
water, 283
in hourly consumption of water,
277
Velocity of rivers, estimation of, 95
of water in pumping mains, 370
in mains, Eytelwein's formula,
370
Volume of water held by various
rocks, 44
WASTE of water, amount of, 280
causes of, 279
detection of, 279
prevention of, 279, 282, 373
Waste preventers, 279, 373
Water tinders, 290
mains (vide Mains)
rates, 392, 416
law relating thereto, 390
supplies, Royal Commission Re-
port on, 54, 117, 144, 145
208, 216
wheels, 351
works, classification of, 360
Watercourses, vide Rivers
Watersheds, 295
available water from, 295, 297
Well sinkers, 305
waters, temperature of, 322
analyses of, 52, 54, 84, 85
pollution of, 49, 197, 203, 305,
421
Wells, Abyssinian, 310
Artesian, 70
cost of, 312
yield from, 312
Wells, construction of, 305
leep, 27, 70, 80
boring and lining, 319
GENERAL INDEX
43 *
Wells, deep, cost of boring, 320
effect of pumping on, 78, 293
pollution of, 203, 421
yield of, 80, 82, 292, 303, 325,
326
drainage area of, 44, 289
public, 399
shallow, 46
drainage area of, 44, 293
improved construction of, 306
pollution of, 49, 197, 203
Windmills, 341
YELLOW fever, 153
Yield of water from various sources
285
ZINC in water, 8-10
cisterns, 205-206
effect upon health, 210, 418
Zoo-parasitic diseases, 154
INDEX OF PROPER NAMES
ABBOTS LANGLEY, 319, 323
Abel, Sir P., 219
Abergaveimy, 68
Aberystwith, 33, 34, 38
Abyssinia, 155
Adams, 109, 421
Africa, 156
Agra, 242
Aldershot, 318, 323
Algeria, 330
Alnwick, 323
Altona, 232 (vide Hamburg)
Anderson, W., 242
An stead, 13
Antwerp, 242
Argentine, 15, 330
Aristotle, 1
Armstrong, Dr., 277
Artois, 71
Ashby, Dr., 412
Ashton-in-Makerfield, 203
Asliton-nnder-Lyne, 415
Assam, 15
Aston, 324
Atherstoue, 69, 276
Attfield, J., 57
Attfield, D. H., 422
Australia, 15, 157
Australia, South, 326
BADDOW, GREAT, 414
Ballard, 133
Bangor, 134
Barking, 276
Barnstaple, 39
Barrow-in-Furuess, 415
Barry, Dr., 90, 103, 129, 142, 419
Batemau, 14, 297
Bath, 59, 165, 415
Batley, 39
Beardmore, 94, 96, 97
Beccles, 313
Bedford, 276
Berlin, 44, 233, 303
Berwick, 275
Beverley, 135, 177
Birkenhead, 84, 415
Birmingham, 278, 415
Bishop-Stortford, 53
Blackburn, 415
Blackston, 15
Blackwell, Mr., 99
Blaxall, Dr., 136
Bolan Pass, 421
Bolton, 108, 415
Bombay, 282
Boston, 39
Boston, U.S.A., 108
Boulnois, P., 282
Boulogne, 242
Bourn, 82, 324
Bradford, 237, 278, 388, 415
Braintree, 166
Brazil, 157
Bridlington, 276
Brighton, 85, 415
Bristol, 60, 65, 68, 276
Broadbent v. Ramsbottom, 380
Brodie, Sir B., 89
Brompton, New, 69
Brussels, 303
Buchanan, Sir G., 136, 175
Buchner, Prof., 421
Buckingham, 177
Buda Pesth, 44, 200
Burnham, 52
Burnley, 415
Burton, 313, 318
434
WATER SUPPLIES
Burton, 356, 360
Bury, 415
Buxtou, 2, 38, 59, 165
CALCUTTA, 244, 282
Calkins, J. N., 107
Cambridge, 136, 211, 288
Camden, 263
Canterbury, 85
Cape of Good Hope, 155, 244, 328
Cardiff, 323, 416
Carlisle, 101, 237, 416
Caruforth, 38
Castle Doningtoii, 80, 84
Caterham, 134, 268
Caterham Springs, 57
Cavendish, 1
Chadwell Springs, 78, 288
Chasemore v. Richards, 387, 389
Chatham, 85, 166, 324
Chaux-de-Fonds, 350
Chelmsford, 64, 276
Cheltenham, 59, 68, 103, 109, 416
Chepstow, 68, 276
CheiTaponjee, 15
Cheshunt, 79
Chester, 416
Cliester-le-Street, 138
Chewton Mendip, 60
Chicopee Falls, 142
Chili, 196
China, 15, 70
Cirencester, 323
Clark, Dr., 257
Clark, Professor, 120
Clifton, 59
Clown, 52
Clutton, 384
Colchester, 85, 166
Collins, E., 280
Connecticut, 108
Cornwall, 29
Coventry, 84
Cressbrook, 408
Crookshank, E., 187
Croydon, 135, 200, 230, 213, 301,
387
Cumberland, 14, 29, 118
DALTON, 45
Danbury, 69, 389, 406
Uarenth, 269
Darlington, 101, 181, 416
Dauben See, 56
D'Aubuisson, 97
Dawkins, Boyd, 83
Day, Justice, 398
Deacon, 279
Demerara, 244
Denny, 399
Denton, B., 25, 366
Derby, 416
Derbyshire, 30, 87, 126
Devonshire, 14, 29
Dewsbury, 38, 416
Dibden, 219
Dickenson, 45
Doncaster, 102, 416
Dudley, 416
Dumfries, 237
Duncanson, 278, 375
Dupre, Dr., 190, 219, 270
Durham, 101
EAST HAM, 276
Eaton, 14
Egypt, 155, 157
Elbourne, 52
Ely, 102
Essex, 10, 106, 111, 146, 131, 163,
183, 289, 302
Eton, 158
Eytelwein, 97
Evans, Sir G., 72, 73
Evesham, 52
Exeter, 282, 416
FARLOW, 10
Fedschenko, 155
Fodor, 44, 200
Forschammer, 172
Fraenkel, 48
Frankland, E., 173, 238, 422
Frankland, P., 114, 159, 189, 196,
218, 223, 225, 227, 253, 422
GAKRETT, J. H., 9, 109
Gateshead, 416
Geradin, M., 219
Germany, 157
Gilbert and Lawes, 45
Gininan, 279
Glasgow, 33, 38, 116, 150, 208, 225,
278
INDEX OF PROPER NAMES
435
Gloucester, 102, 110
Gobi, Desert of, 15
Golden Square, 148
Goodie, Dr., 158
Grantham, 68, 276
Gravesend, 313
Grays Thurrock, 288
Greenwich, 15, 16
Grenelle, 71
Gustrow, 221
HALIFAX, 39, 416
Halsbnry, Lord, 388
Halstead, 85, 276
Hamburg, 151, 187, 233
Hamilton, 150
Hampshire, 126
Hanley, 84
Harwich, 77, 85
Hassall, 115
Hawksley, 297, 298, 299
Haynes, Surg.-Capt. , 421
Heaton, Dr. H., 210
Heckmondwike, 38
Kernel Hempstead, 45
Hendon, 158
Henley-on-Thames, 240
Hennell, 238
Hereford, 313
Herrington, New, 137, 198
Hertford, 318, 323
Heybridge, 85
Hey wood, 275
Hicks, Dr., 158
Hirsch, 127, 156
Hodson, G., 77, 78, 80
Holland, Dr., 120
Holmfirth, 397
Honghton-le- Spring, 180
Houston, Dr., 421
Huddersfield, 275, 416
Hull, 416
Humber, Mr., 298
Hunter, 128
ICELAND, 157
India, 151, 156
Ingatestone, 52, 242
Isler and Company, 80, 312, 323
JAPAN, 155
Jessel, M. H., 384
Johnston, Dr., 249
KALAKAN, 15
Katrine, Loch, 33, 35, 225
Keighley, 416
Kelly, Dr., 212
Kempster, Dr. R., 309
Kennedy, 279
Kent, 77
Kentish Town, 77
Kew, 15, 16
Kingsdown, Lord, 385
King's Heath, 323
King's Langley, 45
King's Lynn, 61, 62, 69
Knaresborough, 102
Koch, 48, 49, 51, 151, 190, 196,
198, 229, 231, 233, 309
LANCASHIRE, 8, 30
Lancaster, 416
Latham, Baldwin, 72, 73, 125, 200
Lausen, 133
Laveran, 131
Lawrence, 140
Leamington, 84, 102
Lea Valley (vide Rivers), 79, 82.
223, 226, 238
Le Chapelle, 324
Lech lade, 313, 409
Leeds, 38, 102, 235, 237, 415
Le Grand and SutcliiF, 80, 312, 313,
322
Leicester, 237, 415
Leipsic, 303
Leuckart, 156
Lincoln, 124, 313
j Lincolnshire, 131
; Liverpool, 33, 39, 75, 79, 225, 261,
278, 281, 283, 325, 415
Llannelly, 210
London, 77, 80, 82, 149, 191, 207,
227, 237, 278, 324
Long Eaton, 80, 84, 124
Low, Bruce, 145
Lowell, 140
Lul worth, West, 350, 411
MACCLESPIELD, 415
Macnaughton, Lord, 389
Madras, 132
Maidstone, 421
436
WATER SUPPLIES
Maldon, 85
Manchester, 33, 38, 45, 150, 278, 415
Mansou, Dr., 155
Marseilles, 132
Martin. Baron, 384
Massachusetts, 16, 31, 32, 33, 39,
49, 53, 65, 92, 107, 108, 139,
162, 170, 172, 183, 190, 216,
222, 228, 234, 363
Matlock, 59
M'Clennan, 126
Melbourne, 80, 84
Melrose, 68, 276
Melton Mowbray, 313
Melville. Island, 5
Mendip Hills, 65
Merthyr Tydfil, 39
Mexico, 123
Middlesborough, 101, 180, 275, 415
Miers and Crosskey, 42
Miguel, 20
Millbank Prison, 125
Miller, 208
Mills, 138
Mill wall, 313
Miluer v. Gilmour, 385
Mistley, 156
Moles worth, 340
Monte Video, 242
Montsouris, 20
Morningside, 421
Mountain Ash, 136, 182, 212
Munich, 44, 199, 218, 422
Munro, Dr., 420
Musselburgh, 313
Myelitis, 418
NABBURG, 135
Nantwich R.S.A., 404
Natal, 15
Newark, 102, 146, 224
Newburyport, 141
Newcastle, 277
New Cross, 313
New South Wales, 327
Newton, 49
Northampton, 415
Northumberland, 30
Norton, Cold, 85
Norwich, 52, 76, 85, 166
Nottingham, 126, 176, 415
Nunney, 133
OLDING, Prof., 219
Okehampton, 39
Oldham, 415
Oude, 126
Over Darwen, 134
PAGE, Dr., 135, 137
Paisley, 150
Paris, 89, 156, 219, 350
Parkes, Dr., 132, 273, 289
Parry, J., 364
Patricroft, 323
Pennine Chain, 14
Pennsylvania, 420
Peru, 196
Pettenkoffer, 44, 199, 200
Plymouth, 38, 102, 416
Plynlimmon, 33, 34
Pole, Dr., 297, 298, 299
Poncelet et Lesbros, 100
Pontefract, 84
Poole, 52
Porter, Dr., 298
Portsmouth, 202
Power, W. R., 9, 419
Preston, 38, 416
Procacci, Dr., 421
Pudsey, 127, 208
Purfleet, 313
QUEENSLAND, 322, 325
RAFTER, 108
Rankine, Prof., 273
Rawlinsou, Sir R., 314, 320, 358
Rawtenstall, 52
Reading, 14, 264
Redhill, 134
Kemson, 107
Richardson, Sir B. W., 118
Ripou, 101
Rivers
Aire, 56
Bourne, 57
Calder, 102
Chelt, 102
Colne, 324
Danube, 49
Don, 102
Eden, 101
Elbe, 156
Exe, 30
INDEX OF PROPER NAMES
437
Rivers
Hamps, 56
Harre, 303
Hooghly, 244
Irwell, 216
Isar, 44, 218
Keimet, 99
Lawrence, 140
Learn, 102
Loddon, 94
Loiret, 56
Manifold, 56
Medway, 94
Merrimac, 106, 141-234
Mersey, 30, 216
Mew, 102
Mimram, 94
Nene, 94
Nid, 102
Ouse, 101, 102, 177
Pleisse, 300
Potomac, 242
Schwarza, 303
Seine, 89, 219
Severn, 94, 102
Sorgue, 56
Spree, 44, 303
Sudbury, 93, 94
Tees, 30, 90, 101, 142, 180
Thames, 14, 88, 89, 94, 102,
117, 216, 219, 222, 223,
Trent, 102. 145, 177
Ure, 101
Waudle, 94, 387
Washbnrn, 102
Weir, 101
Wharfe, 102
Yare, 102
Rochdale, 15, 416
Rochester, 325
Rome, 132
Roscoe, Sir H., 4
Rostock, 221
Rotherhithe, 313
Rotterdam, 418
SAFFRON WALDEN, 52, 85, 166,
Sahara, Desert of, 15
St. Albans, 319, 323
St. Austell, 68, 276
St. Helens, 278, 416
Salford, 123, 150
115,
256
276
i Sandown, 102
I Scarborough, 416
Schenectady, 124
Scott, 15
Sedge wick, Dr., 142, 418
Sedgley Park, 124
Sheffield, 9, 297, 416
Sherborne, 136
Shields, 14
Shrewsbury, 102
Sleaford, 80, 324
Smith, Angus, 20, 286
Smith, Prof. W. K., 190
Smith v. Archibald, 399
Snow, Dr., 148
Snowdon, 17
Somerville, 12
Sonning, 412
Sonsino, 155
Southampton, 52, 323
Southend, 80, 85, 166
Southminster, 69
Southport, 84, 416
Sowerby Bridge, 15
Springfield, 69, 414
Staffordshire, 30, 56
Staley Bridge, 39
Stampfel, 420
Steeple, 85
Stevens, Dr., 134
Stockholm, 304
Stockport, 298, 323
Stockton, 101, 181
Stoddart, F. W., 167, 168
Stratford, 166
Streatham Common, 80
Stroud, 39, 52, 68, 263
Stye Pass, 15
Sudbury, 85
Suffolk Asylum, 125, 184, 203, 319
Surrey, 77
Sussex, 126
Sutcliff, R., 316
Swansea, 68, 313, 276, 278, 416
Swindon Water Co. , 386
Switzerland, 157
Symons, 13, 18
Syria, 154
TASMANIA, 125
Tegler Lake, 303, 418
Tenterden, Lord, 383
438
WATER SUPPLIES
Terling, 137
Tewkesbury, 102, 103
They don Bois, 150
Thirlmere, 33
Thompson, T. W., 419
Thome, 146
Tliorne Thome, Dr., 134, 143, 419
Tidy, Dr., 173, 174, 218
Totnes, 68
Towyn, 38
Tring, 268
Troy, 132
Turner, Dr. G., 125, 126, 184, 319
Tutendorf, 418
Tyler, 279
Tyndall, Prof. T., 114
UNITED STATES, 329
Uruguay, 330
Uxbridge, 324
VAUGHAN, Dr., 158
Venables, Dr., 210
Victoria, 327
Vienna, 303
Vries, Hngo de, 418
Vyrnwy Lake, 33, 225
WAKEFIELD, 102, 237, 244, 416
Wales, 14, 29, 30
Walliugford, 323
Waltham, 49
Waltham Abbey, 79, 80
Walthamstow, 79, 276
Wanklyn, Prof., 172
Ware, 52
Warrington, Dr., 196
Warrington, 323
Watford, 318, 323
Watson, Baron, 384
West Indies, 157
Westmoreland, 14, 29
Weston-super-Mare, 68, 276
Whitaker, W., 61, 72, 79
White, Sinclair, 9
Widford, 313
Wigan, 39
Wightman, Jiistice, 387
j Wildbad, 165
Willesden, 263
Wills, Dr., 224
Wilson, Dr., 127
Wilson, Maclean, 138
Wiltshire, 76
Wimbledon, 156
Wimbome, 323
Winfrith, 410
Winogradsky, Dr., 196
Witham, 156
Wolverhampton, 84, 276, 416
Woodhead, Sims, 250
Woolmer, 288
I Woolwich, 324
Worcester, 102, 103
Worthing, 52, 55, 187, 212, 323
Wraysbury, 313
Wright, Justice, 398
Writtle, 51, 53, 163
YEOVIL, 68, 276
York, 101
Yorkshire, 8, 30, 56
Zurich, 350
THE END
Piinfed by R. R. CLARK, LIMITED, Edinburgh
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