LIBRARY OF THE UNIVERSITY OF CALIFORNIA. Class WATER AND WATER SUPPLIES BY JOHN C. THRESH 1 1 D.SC. (LONDON); M.D. (VICTORIA); D.P.H. (CAMBRIDGE); HONORARY DIPLOMATS IN PUBLIC HEALTH, ROYAL COLLEGES OF PHYSICIANS AND SURGEONS, IRELAND. MEDICAL OFFICER OF HEALTH TO THE ESSEX COUNTY COUNCIL. LECTURER ON " PUBLIC HEALTH," LONDON HOSPITAL MEDICAL COLLEGE. FELLOW OF THE INSTITUTE OF CHEMISTRY. MEMBER OF THE SOCIETY OF PUBLIC ANALYSTS. ASSOCIATE MEMBER OF THE BRITISH ASSOCIATION OF WATERWORKS ENGINEERS. EXAMINER IN HYGIENE, LONDON UNIVERSITY, ETC. THIRD EDITION, REVISED AND ENLARGED UNIVERSITY OF PHILADELPHIA P. BLAKISTON'S SON & CO. 1012 WALNUT STREET 1901 Printed In All rights reserved PREFACE (TO THE THIRD EDITION). A THIRD edition of this work being called for, the publishers have kindly afforded me the opportunity of bringing it up to date, and of including additional chapters on the Protection of Water Supplies. I have to thank many Medical Officers of Health and Waterworks Engineers for the verification of statements and for information furnished. The legal portion has been revised by my friend, Mr. John C. Freeman, Clerk to the Maldon Rural District Council, and my thanks are due to him for his valuable assistance. I have also to thank my assistant, A. E. Porter, M.D., D.P.H., and my late assistant, R. W. C. Pierce, M.B., D.P.H., now Medical Officer of Health for the Guildford District, for revising the proofs and assisting me generally in preparing this edition for the press. JOHN C. THRESH. Ill TEMPLE CHAMBERS, LONDON, E.G., May, 1901. 161911 PREFACE (TO THE FIRST AND SECOND EDITIONS). IT is now fully recognised that an abundant supply of pure water is an absolute necessity for the preservation 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 Engineering, yet it is hoped that it contains sufficient detail to enable any one who has studied it to consider intelligently 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 improperly vi WATER SUPPLIES constructed and unprotected shallow wells, 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 im- portance of a good water supply, and have no knowledge of how to set about remedying the present conditions even if regarded as unsatisfactory. 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 impression 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 unsatisfactory. Such reports are not sufficient to overcome 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 practicable. 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 successful completion, is embodied in various chapters, and I hope will prove of PREFACE vii value to all who are interested in the well-being of our rural populations. A brief resumd 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 questionable 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. CHAPTEK 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 Potable waters, classification of Pages 1-13 CHAPTER II. RAIN AND RAIN 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 Bain-water separators Storage for domestic purposes Rainfall source of all water supplies Natural waters in order of purity Composition of rain water Pages 14-30 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 31-44 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 Buda Pesth and Perth examples of towns supplied from subsoil Quality of subsoil water How 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 45-58 CHAPTER V. NATURAL SPRING WATERS. Perennial, intermittent and variable springs Origin of springs Cold, hot, ascending and descending springs Artificial springs The natural springs of Clifton, Bath, 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 59-73 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 Advantage's 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 74-89 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 90-108 CHAPTER VIII. QUALITY OF DRINKING WATERS. Colour of pure and impure waters Taste and odour, by what in- fluenced Organisms found in water Pathogenic and other bacteria affecting odour or tasteEffect of mineral, animal and vegetable impurities Turbidity, to what due Soluble con- stituents of potable waters, inorganic and organic Typical analyses What constitutes a good potable water Pages 109-132 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 hcematobia, Filaria sanguinis, Filaria dracunculus, etc. Diseases of animals caused by impure water .... Pages 133-177 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 how little dependence can be WATER SUPPLIES placed upon the results of a chemical analyses : 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 178-217 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 218-241 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 242-252 CHAPTER XIII. THE PURIFICATION OF WATER ON THE LARGE SCALE. Sedimentation Filtration, efficiency of, how determined Prof. 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' x scrubbers American filtering machines Polarite, spongy iron, magnetic carbide and other filtering materials ; where used ; efficiency of Sand washing "Softening " purifies water Pages 253-277 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 278-287 CONTENTS xiii CHAPTER XV. THE SOFTENING OF HARD WATER. Softening by boiling ; by addition of chemicals Clark's lime process Colne Valley Waterworks Atkins' process Southampton Water- worksThe "Porter-Clark" process The Stanhope water softener The Howatson " Softener " Stroud Waterworks Cost of various processes Saving effected by using soft water in houses, institu- tions and towns Pages 288-304 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 305-318 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 319-341 CHAPTER XVIII. THE PROTECTION OF UNDERGROUND WATER SUPPLIES Nature of pervious surface Purifying action of soil Epidemics due to use of polluted subsoil water Growth of typhoid bacillus in soil Abba's experiments on the filtering power of the subsoil at Turin Subsoil sterile beyond a certain depth Bate of motion of subsoil water Motion affected by pumping Protective areas- Protection of tube-wells Necessity for periodical examination of sources of water supply Pages 342-357 xiv WATER SUPPLIES CHAPTER XIX. THE PROTECTION OF SURFACE-WATER SUPPLIES. Surface-water supplies rarely responsible for outbreaks of disease Necessity for control of gathering ground Difficulties involved in obtaining control Necessity for ample storage Desirability of filtration Vegetable growths in reservoirs The Local Govern- ment Board circular on the supervision by sanitary authorities over the public supplies for which they are responsible Pages 358-363 CHAPTER XX. WELLS AND THEIR CONSTRUCTION. Shallow wells How usually constructed Improved methods of constructing Tube wells Koch's advice with reference to shallow wells 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 364-391 CHAPTER XXI. 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 392-418 CHAPTER XXII. THE STORAGE OF WATER. Impounding reservoirs Settling reservoirs Service reservoirs Classi- fication of water-works 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 House cisterns . . . Pages 419-433 CONTENTS xv CHAPTER XXIII. 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 434-446 CHAPTER XXIV. 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 Owners Reservoirs and Water Supply Further Facilities Act, 1877 Important legal decisions affecting water supplies Pages 447-468 CHAPTER XXV. 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 469-483 CHAPTER XXVI. WATER CHARGES. Water rates, basis of Domestic purposes Supply by meter Water charges in various districts Pages 484-497 GENERAL INDEX Pages 499-517 INDEX OF PROPER NAMES ....,, Pages 519-527 OF THE UNIVERSITY OF WATER SUPPLIES. CHAPTER I. WATER, ITS COMPOSITION, PROPERTIES, ETC. FROM 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 demon- strating 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. Aa oxygen is sixteen times as heavy as hydrogen, the composi- tion of pure water is as under : By Volume. By Weight. Oxygen ... 1 part . . 8 parts. Hydrogen ... 2 parts . . 1 part. 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 sd 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 popu- larly 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 filtration 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 excep- tions all fluids expand when heated and contract when cooled. The most important exception is water between WATER, ITS COMPOSITION, PROPERTIES, ETC. 3 certain temperatures. As the effect of heat upon water has a direct bearing upon certain points con- nected 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 thermo- meter 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 experiment, 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 liquefaction, is again given off when water freezes. As the surface of a sheet of w^ter freezes, the water, in the act of solidification, gives up a certain amount of heat. This raises the temperature 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 temperature sank below zero, ice would so quickly form that our lakes, reservoirs, streams, etc., would 4 WATER SUPPLIES 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 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 to a temperature 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 thermometer 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 con- tinue the colder and would be the first to freeze. Solidifica- tion would take place from below upwards. The result would be that during a severe winter our streams and lakes WATER, ITS COMPOSITION, PROPERTIES, ETC. 5 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, 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 mean barometric pressure (760 mm.) water boils at 100 C. When the atmospheric 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 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 heat is lost, the temperature is reduced so low that the water freezes as it boils. If boiled in an open vessel water rapidly and visibly evaporates, but this evaporation takes place in- visibly at all temperatures, the more slowly the lower the temperature. Even snow and ice slowly disappear by evaporation 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 evaporation approaches its minimum. The bearing of these facts upon the subject of rainfall and the Storage of water will be discussed in subsequent chapters, 6 WATER SUPPLIES 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 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 con- stituents 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 WATER, ITS COMPOSITION, PROPERTIES, ETC. 7 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 greyish- white residue will be found on the bottom of the vessel. This consists of the mineral (and possibly some organic) 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). (b) 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 8 WATER SUPPLIES 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 removable hardness is called " temporary," whilst the hardness remaining after boiling, and which is chiefly due to the presence of sulphates of lime and magnesia, is called " permanent/' Waters under 5 or 6 of hardness may be considered " 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 Govern- ment 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 WATER, ITS COMPOSITION, PROPERTIES, ETC. g lead-poisoning by the drinking-water supplied to their populations." The districts of Lancashire and West York- shire 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 interfered with the investigation, and it is not yet completed. 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 present 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. Assuming it to be true that the rain can in this manner acquire some degree of acidity, it may be questioned whether it is ever possible for it to acquire an amount of acid in any way comparable with the extreme amount found to be present in certain moorland waters. Moreover, the gathering grounds yielding the most acid waters are by no means always situated the most closely to such manufacturing areas. Others, again, believe that the acidity of moorland waters arises from the slow oxidation of iron pyrites in the soil. That iron pyrites, in the presence of oxygen and moisture, forms sulphuric acid is of course a fact familiar to all chemists. But it may be doubted whether the distribution of iron pyrites on moorland gathering grounds is such as to render this explanation a generally applicable one, io WATER SUPPLIES The comparative absence of silica and carbonate of lime has been suggested as the cause of the action of moorland waters on lead, but it is tolerably certain that there are accompanying factors, and that the absence of these sub- stances bears no direct causal relationship to plumbo- solvency. Mr. W. H. Power, as far back as 1888,* suggested that as chemistry had signally failed to give us a clear insight into the antecedent cause of the acidity of moorland waters, the study of the question from the biological point of view might prove of service. Again, in 1895, f Mr. Power pointed out that his original forecast had in great measure been confirmed by the labours of the experts employed by the Local Government Board to study the question. In summarising the work done up to the time of writing his report, Mr. Power drew attention to the following facts and inferences : Moorland waters when they have left the moor, when they have become divorced as it were from the peat, have completed their history so far as acidity is concerned. Thus the storage of such waters under a variety of conditions never leads to any increase of acidity, and usually there is an appreciable decrease. Moist peat soil is invariably acid in reaction, and certain microbes isolated from peat possess the power when grown in a neutral decoction made soldi/ from peat of rendering the liquid acid and giving it as well plumbo-solvent ability. The inference is that the acidity and plumbo-solvent ability observed in moorland waters is possibly (if not probably) to be traced to the washing out of the products of the life processes of these bacteria from the substance of peat soil. Further, Mr. Power laid considerable stress on the value of the observations carried * Supplement by the medical officer to the seventeenth Annual Keport of the Local Government Board, 1888. f Report of the medical officer, Local Government Board, 1893-4. " Lead Poisoning by Moorland Waters," by W. H. Power, F.R.S, WATER, ITS COMPOSITION, PROPERTIES, ETC. n out on the Burnmoor moorland gathering ground in their negative aspects. Thus he says : " They (i.e. the Burnmoor observations) tend to indicate, by a plurality of determina- tions spread over many months, not only that the ability of a particular water to dissolve lead is closely associated with acidity of such water, but also that this action in regard of lead is not to be so associated with any other observed condition to which the water was liable." Dr. Scatterty, M.O.H., Keighley (Public Health, April, 1895), also pointed out this acid-producing property of peat, and referred to the acid so produced as the cause of the plumbo-solvent action of moorland waters. 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. Certain hard waters from the Bagshot Sands act upon lead, but all those which I have examined either con- tained 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 exception- ally 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, 12 WATER SUPPLIES 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 com- pound 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 which contains an appreciable amount of zinc WATER, ITS COMPOSITION, PROPERTIES, ETC. 13 is heated in an open vessel, before it commences to boil an iridescent film is observed upon the surface, sometimes giving rise to the impression that the water is " greasy." Waters acting upon zinc should not be stored in zinc or galvanised iron vessels, or passed through galvanised iron pipes. In a few instances I have come across waters which had an appreciable action upon copper, and cases are recorded of water used for domestic purposes corroding brass fittings and becoming contaminated with the constituents of the alloy. 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 deleterious or objectionable organic sub- stances are also present, the water is impure. Where the mineral constituents are, either from their quan- tity 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 com- pounds, " sulphuretted " ; if containing sulphate of magnesia or other mild purgatives, " aperient," etc. These 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 water. Deep-well water. Spring water. River water. Each of these sources will be separately considered. CHAPTER 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 boiling 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 saturated 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. (H) RAIN AND RAIN WATER 15 Somerville estimates that " 186,240 cubic miles of 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 7,000 ft) weight of water are evaporated every minute, on an average, throughout the year from each square mile of ocean."* 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 vegetation. When dis- cussing 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 hemi- sphere 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 tempera- ture 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, (b) 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 over- * " 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. 1 6 WATER SUPPLIES rated, 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 therefore into colder regions. The lowest stratum of air only can be chilled by contact with the ground. As Eaton * 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 expansion 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 Reading 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 Devon- shire, the average exceeds 75 inches. Up to about 2,000 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 2,000 feet, and where they are cut through by valleys, more rain is deposited on the lee side of the * Proc. Brit. Met. Soc., 1861. RAIN AND RAIN WATER 17 hills and over the country opened out by the valleys. The following gaugings by Mr. Bateman, taken along the line of the Rochdale Canal across the Pennine Chain * " show to a marked degree the abstraction of moisture caused by the intervention of a range of hills " : ANNUAL RAINFALL. At Rochdale . . 34-25 inches At foot of western slope. White Holmes, Blackstone^ 52<55 1,200 feet above sea-level. edge ^ . . ./ Toll Bar 53-16 1,000 feet above sea-level. Black House 51-80 ,, 1,000 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 rainfall is over 400 inches. Probably the wettest district in England is the Stye Pass, in the Cumberland Hills, where about 200 inches fall 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 j- 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 Republic come under the same category. * De Ranee, The Water Supply of England and Wales, f Elementary Meteorology. 2, 1 8 WATER SUPPLIES 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 Novem- ber are the wettest months. The mean monthly rainfall at Kew, Greenwich, and in Massachusetts for various periods is given in the subjoined table : Kew. Kew. Greenwich. Massachusetts. * 1813-72. 1865-80. 1881-90. January . 1-9 2-2 1-3 3-7 February 1-5 1-7 1-8 3-6 March 1-5 1-3 1-3 3-9 April 1-7 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 1-7 3-0 October . 2-7 2-5 1-9 3-7 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 * Average deduced from long-continued observations in various parts of the State. Report on Water Supplies, 1889-90. RAIN AND RAIN WATER ig the amount of water which can be collected, and for com- paring 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 Taking Observations) : : " Rain-gauge. The rain-gauge should be made of copper, FIG. 1. Snowdon Rain-guage. 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 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 20 WATER SUPPLIES firmly 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 reading 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 rainfall. Each division represents the one-hundredth of an inch, 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 desirable 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 RAIN AND RAIN WATER 21 observations, a special form of rain-gauge must be used.* Mr. Symons' pattern is admirably adapted for this purpose (Fig. 2). The cylinder in which the water is collected will FIG. 2. Symons' Mountain Rain-guage. 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 * MM. Richard Freres of Paris make a self-registering rain-gauge. 22 WATER SUPPLIES 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. One inch of rainfall corresponds to nearly 4| 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 evapora- tion or from any other cause, would be 46| gallons. To obtain anything approaching this amount, however, the rain would have to be heavy and continuous. If it fell in a series of slight showers spread over any considerable interval, and especially 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-continued showery weather which yields sufficient water to percolate into the subsoil to feed the springs and raise the level 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 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 from the air all floating impurities, whatever their nature. The rain which first falls always contains the largest proportion of these impurities. In the neighbour- hood 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 sub- stances, and the exhalations from the bodies of men and RAIN AND RAIN WATER 23 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 Eain, 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 organ- isms may occur in a single pint of rain water. 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 24 WATER SUPPLIES solution and accentuating 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 nitration ; 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 under- ground, 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 rainfall, and must be properly constructed. (2) The first portion of every shower which washes the roof or other collecting 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 RAIN AND RAIN WATER 25 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 3,200 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, about 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 capacity 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 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 5J feet deep. For larger roof areas the size of the storage cistern can easily be calculated. 26 WATER SUPPLIES 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 inserted and fastened to the side of the house. When a building 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.* 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 considered good enough in which to store the rain, and little or no care is taken to so securely cover the receptacle as to prevent impurities getting in. Separators are not yet generally used, and therefore the water which is col- * 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 ran into the tank, whilst the pure water ran into the drain. RAIN AND RAIN WATER 27 lected is more or less filthy from the first. Occasionally there is some pretence to filtration, the stack pipe dis- charging over a bed of sand and gravel with or without FOUL FIG. 4. charcoal. For filtration to be of any service the material must be so fine as to allow the water to pass through but slowly. As a rule, the more rapid the filtration the less 28 WATER SUPPLIES 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 pur- poses 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 J 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 ren- dered 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 pumping. 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 supposing 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 for a period of three months (an exceptionally long drought) at 20 gallons a RAIN AND RAIN WATER 29 head daily, an ample quantity for all individual and house- hold purposes. Tanks can be built at a cost varying from 3 to 5 per 1,000 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 contamina- tion. 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 excessive, and many mansions are now being satisfactorily supplied in this manner. To purify the water a simple filter at the end of the suction pipe in the under- ground tank, supplemented 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 1,500 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 as 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 30 WATER SUPPLIES " upland surface 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 subsoil under im- pervious 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. Kiver water. Subsoil water under villages and towns. The R.P.C. give a lengthy Table of Analyses of carefully- 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. Tank Water. Total Solids . . . 2-76 16-8 grs. per gallon. Nitric Nitrogen . . -004 -78 ,, Chlorine ... -43 1-6 Hardness ... -42 7-9 Free Ammonia . . -50 1-15 pts. per million. CHAPTER 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. Rain 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, however, though very compact and hard, 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 super- ficial 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 evaporation from the surface of tjie soil, and from the (31) 32 WATER SUPPLIES fronds and leaves of the plants covering it, the remainder slowly finding 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 evaporation 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 de*bris 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, Westmoreland, 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 crystal- line limestone) may be said to be absolutely impervious, as may also the slates of the other series. The sand- stones, however, are more or less porous, and absorb some portion of the rainfall. 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. SURFACE WATER 33 The non-calcareous carboniferous rocks (Yoredale rocks, millstone grits and coal measures) occur in South Wales, Derbyshire, Yorkshire, Lancashire, and North Staffordshire, 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 being only 6. They are there- fore 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 dis- tricts 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 moun- tain limestone and limestone shales) of Northumber- land, 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 sandstone, conglomerate sandstone, and magnesian limestone formations yield from their 3 34 WATER SUPPLIES uplands a water closely 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 decreas- ing 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 SURFACE WATER 35 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 that they were in the least polluted by household waste. The excess of chlorine in the others indicated that they con- tained 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 44. 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. Careful filtration is always advisable, to keep back the organisms which otherwise will get into the mains and render the water, at times, un- sightly. 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 imper- vious 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 <^ the vegetable matters contained 36 WATER SUPPLIES 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. Suspended matters in surface waters may be removed by continued 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 Massachusetts 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 adjoining 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 E-heidol 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 about 15,000, and in summer a considerable number of visitors reside SURFACE WATER 37 there. The scheme was completed in 1883, and the town has now an abundant supply of water of unexceptionable purity. The source of supply is the Llyn Llygad Rheidol Lake, situated on Mount Plynlimmon, 16J miles from Aberyst- with, and about 1,650 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 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 2,500 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^ months. The area draining into the lake is 133 acres. The actual rainfall is unknown, but the late Mr. Symons (the first authority on the subject) put 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 imper- 3$ WATER SUPPLIES meable 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 is 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 distributed in the town, is discharged into a service 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 is equal to a head of 200 feet. The capacity of the reservoir is 1,000,000 gallons. From the service reservoir the water is 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. . 8,529 5 10-inch main from service reservoir, 2,338 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 . 1,514 8 7 Laying pipes and jointing them . . . 1,214 8 Extra for junctions and special pipes . . 110 Carriage of pipes . . . . . . 1,055 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 2,019 11 6 Contingencies, law charges, and engineering at 7i per cent 1,173 4 6 Total . . . 16,816 13 3 The works were duly executed, but the estimate was exceeded by about 1,000, a detour with the water main SURFACE WATER 39 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 compensation 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 in 1893, in Edinburgh, the engineer to the City Waterworks gave a description of the Loch Katrine Water- works supplying Glasgow. The paper contains much that is interesting, and to it I am indebted for many of the following particulars. When the scheme was first pro- pounded, 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 (1898) being supplied with water is 1,000,000, and the con- sumption of water has risen from 40 to 54 gallons per head, so that 54,000,000 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 orna- mental 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 square miles. By means of a small masonry dam at the outlet the loch has been raised four 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 surrounding hills rise to a height of from 2,300 feet to nearly 3,000 feet; and as a result of this and the proximity of the 40 WATER SUPPLIES 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, yielding very little mineral matter to the rain falling upon it. The district is practically uninhabited, and by a payment 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). Notwithstanding 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, including 11| miles of tunnelling, 10 J miles open cutting and bridges, 13| 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. Dupli- cation of these works is now being carried out which, it is SURFACE WATER 41 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 1,300,000. The domestic water- rate, which in 1856 was Is. 2d. per 1 of rental, has been reduced to 5d. per 1 (1900). The Derwent Water Act (1899) marks an epoch in the history of water supplies, dealing exhaustively with the whole of the water available in the Derwent watershed, and allocating it amongst all the districts having claims thereto. It provides for a Water Board, consisting of representatives elected by the Derbyshire County Council and by the Corporations of Derby, Leicester, Sheffield and Nottingham. The works which this Board can carry out will be capable of affording a supply of 30,000,000 to 33,000,000 gallons per day, and the estimated expenditure of the Board on the proposed works is 5,500,000. The supply is allocated as follows: For the use of the districts within the County of Derby 5 million galls, per day. Derby Corporation 7 ,, ,, Leicester . . . . . . 10 Nottingham Corporation . ... 4 Sheffield . 7 This scheme will afford a supply of 6,000,000 gallons of water per day per million of money expended. A scheme for supplying Birmingham from the Elan and Claerwen watersheds, now approaching completion, is estimated to give 10,000,000 gallons per day for the same sum, but the collectable rainfall in the Welsh valleys is 40 per cent, more than in the Derwent Valley. ganoq t ui T 1 r 1 pasn uaSXxo 1 sa^ia^t^ : p 9 ; : : 9 : :9> ! "Biuorauiy piduiumqiv o o ? ; Tf ^i vrs i i qX ip ip ip p (M i-H OS O 00 ip CN 4f o-i * p op S op p t^ CM p yi "& Q * to o O Tf Tf c^i 8 WIM p p p p PT< | 1 ^ o p p CO O O o o p SPTPS IKOX I-H r-l C s ^ >> % n If 1] I 1 I i * 1 o P "S llS'llal pllpf F PM >H m cc 05 iJ S3 ^ .3 3 3 a 3 2 3 * C3 fe bfi 1 O 3 w I: Granite Trai Lower Si Cambria Siluri Lower Si | d & & ^ PM Q M 3 OH Cu tf , | |a 11 1 02 I & J? | I * ^g 2 $ ^ S 11 3 & O ^ ^ 1 g ji x H H H Ll "S" p" >2 ff '" r S"rS'OT"r5 ^ "- - M H,' 5 ' ^ ^ ^ H ft s-<" ^ fe ft ft "i 5($ i rH Ci CO ^i US P CO be 1-1 : : co > f^ 3 ^ > 1 r-< a g i PH o ? , , R i X 0 01^ 00 S S ^ O5 i 44 WATER SUPPLIES pq 93BJ8AV FI i^> OO l>- O O> OvO^ pep H i 1 i 1 r- 1 r-H i I ^saqSiH lO CO rH r^l *& r i <& .00 pop ?p t^- ;05 IO Tfl 93UI8AV 8 ipcpo CO5OOS O5l^l>- r-irH co'oooo 05 ao (>i T* 1 T* co 4t< B i i 1 OO l>. CO IO C^ -^ .05 r 1 i 1 qsaqSiH < * Tt< ?o ^r^o t^ :co i < i i i i ^s qsaAvoi 4fi ' ^-( ipip An ib o5 -aui8Av Q cocoos i AH cb -r-t OrHrtl **! (^ ooooo o 4t< b ao -as i 1 i I lO i ( i 1 t^co ^t ^saAvoi i 1 ip ?O M i I t^- CX) .11 i 1 r 1 OO CO 1^- OO t* ' -*H t^co coos : i ... o ... ^ ... O o3 '2 ' ' | 1 -a =.-2 -^ . > S CS . .03 GEOLOGICAL FORMATION. 1. Igneous Rocks 2. Metamorpllic, Cambrian, Silurian, and De 3. Calcareous portion of Silurian and Devonif 4. Yoredale and Millstone grits, and non-c Coal Measures .... 5. Calcareous portion of Coal Measures 6. Mountain Limestone . 7. Lias, New Red Sandstone, Conglomerate a stone 8. Oolite (one sample only) . 9. Lower London Tertiaries and Bagshot Bed in "EVnrr, nnHiirQ + a^ TOT,,} 2 2 ' if ill ill 3-S.e 4 > H CHAPTER 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 FIG. 5. A, Pervious subsoil ; A', Portion saturated with water ; B, Impervious stratum ; (7, spring. as surface 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 immediately beneath the soil is " subsoil " or " ground " water. Where the pervious subsoil fills in a (45) 46 WATER SUPPLIES hollow in the more impervious 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, forming 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 impervious substratum, the subsoil water will be constantly in motion, travelling towards the lowest point, where the impervious rock outcrops. There it will either issue as a spring, or FIG. 6. A, Pervious rock ; B, Subsoil water ; C, Spring ; I), Stream ; E, Clay or other impervious stratum. act as the invisible feeder of a stream or lake. " The action of the soil in regard to water is in reality of a threefold 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 permeability; 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." * Clay exhibits in a high * Miers and Crosskey, The Soil in relation to Health. SUBSOIL WATER 47 degree the property of imbibing water, but 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 than 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 48 WATER SUPPLIES marked in wells near the river, and least in those at a 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 limestone 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 three 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 indicated by the rise and fall of the water-level. This underground 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. The whole of the rain falling upon a pervious soil does not percolate into it. Some will run off the surface, the amount varying with the slope and the nature of the SUBSOIL WATER & 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 watershed by which the water is collected and the porosity of the subsoil. During dry weather the pumping opera- tions 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 4 $o WATER SUPPLIES area which can be collected must be equal to the quantity which it is desired to abstract. If the area of the water- shed 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 rainfall 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 sub- SUBSOIL WATER 5* terranean river may even convey more water than the visible stream. In the Thames valley it is estimated that the flow beneath the river considerably 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 outwards through the silt or mud at the bottom of rivers and pools can only take place slowly, and no definite measurements 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 backward 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 gravels generally, yield soft water, if uncontaminated. The living earth has such remarkable powers of purification and filtra- tion, 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 pro- cess of purification 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 Commissioners 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, 5 2 WATER SUPPLIES as is usually the case, near privies, drains, or cesspools. Such water often consists largely of the leakage and soakage from receptacles for human excrements ; but, notwithstand- ing 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 con- siderable 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 condemn these waters as dangerous to health. Koch,* comparing 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 * Water Filtration and Cholera. Translated by A. J. A. Ball. SUBSOIL WATER 53 bring this perfectly 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 pump, 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. Buda-Pesth 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 2,000 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 54 WATER SUPPLIES capable of yielding 1,500,000 gallons daily in a dry season. Maiden and Revere may be cited as examples of towns supplied exclusively with subsoil water, not supplemented by water percolating from lakes or streams.* " 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 1.61 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 ascertained. 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 depression 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 enter- ing 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 * Report of State Board of Health, 1890. SUBSOIL WATER 55 much less impure than that from the 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 1,400 persons upon it, I found that the water along three sides of the patch was remarkably constant and uni- form 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 defective drains, sewers, cesspits, 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 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 therefore 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. WATER SUPPLIES OQ ^ 6 ^ B * ^J O 4-l 3 ^ o S cc co ,> C> eg CC 1 SI- 1 - 1 11 iz; W EH Oj^ ^ fi 5 "fi' s o 3 i tf s i IB i i ejnoq f m pesn uaSA'xo C^ O5 Oi ^ IO ; ; sa^u^i^j p p p p . un CO rJH CO O ppppp CO p o 00 p *p ppppp o 00 V ^ o :o . : ^co' < c^ p ; > ^ - - - - ^ . _ .'d ,2 c ~ ^2 ^j i o 1^ 6 r I L c3 * " " ^ " 1 2 1 13 : a > .... s o CO o OQ C Rawtenstall I Cu g cS .a Elbourne Ware ishop Stort- ford ngatestone fl | 5 o S c * 2 >H 4> "3 O -5,5 S25^ ^ I-H c^' co * o* c5 O 0) 1 p ^H CO PQ J 58 WATER SUPPLIES a E g o O -H s i 1 o co fl .2 i) a s -s o M HH I O O a co a o 3 1 ^ fc & ^i XO O ip O O O -H O l>- C^J pppp cpppp (N p * pop p ,25 a W T 1 (M CO O- CO O CO OO t> Tfl rH iO 1O OS T 1 T 1 I r^lOT^CO T^T^Op -IIP! I 1 H W ococo-* cbooiooi ssssss O) i * .3 . . . . 1 s S fl '2 "i d 9*3*8 1 upon Silurian Rocks ar Devonian Rocks Yoredale and Mil Coal Measures Mountain and M stone New Red Sandstc Lias Oolite , Upper and Lower Wealden Beds Chalk . avel on London Clay igshot Beds . uvio-Marine series luvium and Gravel " S3 IT.I 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 constituents 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 delight- ful 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 comparatively 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, (59) 60 WATER SUPPLIES yielding millions of gallons per day 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 elevation. Such springs, if of any large volume, are often of great value, since the water can be conveyed by gravita- tion 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 mountainous 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 7,000 feet, has no visible outlet ; but about 1,000 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 sup- porting 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 NATURAL SPRING WATERS 61 Variable, markedly affected by the rainfall, ceasing to flow during a drought and flowing freely after heavy rains. The constancy of flow 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 nitration, 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 direction 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 -carbonic acid gas under pressure, which it absorbs. As the 62 WATER-SUPPLIES 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 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. FIG. 7. Artificial springs are formed wherever a communication is made between the surface of the ground and the water imprisoned under pressure in a pervious stratum lying between two impervious formations. Where the pressure is sufficiently 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 NATURAL SPRING WATERS 63 elevation 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 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 irregu- larities 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 waters 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 surface, 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 64 WATER SUPPLIES springs will be sufficient for the supply of a town or village can only be ascertained by actual measurements of the now 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, 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 magni- tude. 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 obviously 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 NATURAL SPRING WATERS 65 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 supplying mansions and small villages with water, even when the 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 supply- ing houses at a lower level 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 5 66 WATER SUPPLIES 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 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 occasion- ally 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." . NATURAL SPRING WATERS 67 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 w Q ,r of high quality. Passing on to the chalk formation and 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 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. 68 WATER SUPPLIES " 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, somewhere near and above Well Hall, which would inter- cept 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. " 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 knowledge. 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." Excellent examples of the utilisation of natural springs for the supply of water to a number of small villages are the works recently carried out in the Chelmsford Rural Sanitary District by the Authorities' Surveyor, Mr. I. C. Smith, and in the adjoining Rural District of Maldon by Mr. H. G. Keywood, Surveyor and Engineer. These works are described in a later section. 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 are sold NATURAL SPRING WATERS 69 throughout the state, " particularly in cities and towns where the regular water supply is thought to be unsatisfac- tory, or where the water, as is not infrequently the case with surface water supplies in the summer time, has an un- pleasant taste and odour." " There is also a large amount consumed in bottled form, as soda water and other effer- vescing drinks." Waters were examined from forty-five springs, and most of them found to be of the highest purity. Even those samples taken from populous districts and near sources of pollution showed that a high degree of purifica- tion 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 underground, 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 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 Sandstones. Very whole- some 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 Limestone. Bright, colourless, and very palat- able, 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 " permanent/' jo WATER SUPPLIES 4. Yoredale Rocks, Millstone Grit, and Goal 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 palat- able and wholesome, the water furnished by these sands varies much in character. The hardness may be less 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 wholesome- ness, though often the hardness is too great for washing purposes. It varies from 8 to 22, with an average of 17. Of course it is almost entirely due to car- bonate of lime and can be readily removed where necessary. 10. Gravel and Drift. Va.ries to an astonishing degree. The Bagshot gravels and sands usually furnish a soft water, whilst some gravels yield water of excessive NATURAL SPRING WATERS 71 hardness. 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 greensand, 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 forma- tion they are still charged with water and easily accessible to the boring rod." The most constant and largest springs are derived from the chalk, oolite, new red sandstone, 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. 72 WATER SUPPLIES H I I TJ -d . 2 a'-o5 ^ -f^ C/5 -*^ _rr i j 2 5 a. S sa-c "So w CQ 2 --H r3 ^ OS S-l = g << , zs a ^ s h K -paqjosqy ua8xo fc : : p rf cp ^ : cp cp 00 pj 3 "Biuomray < d 'oiUV^JQ : g ?? g g g S PHJ^ ^ "Biuouimv O T-H CO 00 00 s s ss9upaH 05 100 pp c^p p O id TO. (>I CO J $ SJ 5 s 9 ? z. .PHOS,^ kO rh GO p p p 'P cp I I ii Mjl! | :.-.' Is ffi " i 1 i 03 H EH ^^ i i o o o >> ^ ^ 1 St. Austell Melrose Abergavenn ItssS o If * Atherstone Grantharn NATURAL SPRING WATERS 73 a -->' -' 42 si g 8 qft ^ ft - OTJH 05 OCOO * ' ' g g : ^8 : : : : : : : : : : : : pop pp pop p op p p pp ppppp O .O pp OOP rH CO ^ O5 I VJ T4 -^fH ^Q ^> <^> ^] -^ QQ 1-H l-H CN ^H 1-1 ^H CN ; ; O >o o ^o i>- o co o ^ ' l-^^o r -4, i,!!^! i ICO cp ip cp p ppippcp l'-^ * C00 10-^OiCNCO I 1 1 1 1 1 1 1 CO Op ip O5 OO Oi O OO C^ CO t^ (M (N r*ip ^^,-H^g. AH A-i ' b S a S?3 S33^ O O id 1O ^ O lO O C^ O *O ^fH CO ( *rf( O OO l^- ^D T^ OO l^ C^ C*^ IO O VO l-H T-H ^H C^l 00 || do o SH 1 ^ III > ^ ^ -d PH^ . 1 -1 5 = g s s S|H a o -ego ^ l ^ i ^ | s 1^ *^H ^ t> ^^Sl ^ I >H r 3^3^3 |J -l6iC^^^n3 J a3HHg " - -Q W ^ ^ .M ^P S A ^ >j ^ i 1 i 1 i 1 CO i 1 CO i 1 CHAPTER VI. DEEP- WELL WATERS. THE term " deep " in reference to wells is somewhat ambiguous, 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 be- neath. 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 filtration 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." yDeep 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 (74) DEEP-WELL WATERS 75 early 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 commenced in 1835, and was carried to a depth of about 1,800 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. 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 FIG. 8. 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 6, 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 76 WATER SUPPLIES pervious 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 depressed 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 occasion- ally 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 of the " river " theory, the Commissioners reported as follows : DEEP-WELL WATERS 77 " We are of opinion that the analogy of a cistern is inaccurate 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 ad- dition 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 passu 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 supported 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 78 WATER SUPPLIES John Evans, when they said that pumping from a well tapping an underground stream flowing in a 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 magnesiaii 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 continuous, 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 ex- pense. The oolites, according to the R. P. C., " contain vast volumes of magnificent 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 rainfall 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 under- ground 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 impossible to devise, even regardless of expense, any artificial arrange- ment for the storage of water that could secure more , - .^r-THE I UNtVE * DEEP-WELL WATERS 79 x. favourable conditions than those naturally and gratuitously afforded by the chalk, and there is reason to believe that the more this stratum is drawn upon for its abundant and excel- lent 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, 1J 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 excep- tionally 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 carefully 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 course 8o WATER SUPPLIES of time the water may become affected. Many wells have had to be closed for this reason. At Liverpool, 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, Grumblings, or other irregularities. 3. The continuity of the water-bearing strata and their superficial 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 thickness and extent of the porous stratum. The thickness may vary considerably. Thus the chalk at DEEP-WELL WATERS 81 Norwich is nearly 1,200 feet thick, in Wiltshire 800 feet, in 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 underground water-bearing deposit, and of the un- reliability of maps, Mr. Hodson, C.E., states * 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 underground 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 evidence 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; * A paper on Underground Water Supplies, communicated to the Incorporated Association of Municipal Engineers, May, 1893, 6 82 WATER SUPPLIES hence if a well be so placed that its supply of water 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 76). The multiplication of deep wells in and around London has lowered the water-level con- siderably, 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 unnecessary, 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 population. The expense of boring a well to any considerable depth prevents such supplies being obtained for single houses or small com- munities, 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 DEEP-WELL WATERS circumstances, 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 1| miles. Certain very deep wells in Essex are found to affect others within a radius of 1^ miles. In the Lea valley the underground water-level has been carefully ascertained. From Chadwell springs to Cheshunt there is a fall of four 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, com- pressed as it is by great thickness of clay above it. The effect, therefore, of the excessive abstraction 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 COVENT GARDEN 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 Beading Beds . Thanet Sand 584 39 195 234J 55 8 124 132 f 100 260 Chalk . 100 334 20 152 98 358 WATER SUPPLIES SOUTHEND WATER- WORKS, ESSEX. WALTHAM CROSS, HERTS. STREATHAM COMMON, SURREY. Thick- ness. Depth. T S- "epth. Thick- ness. Depth. Surface Soil 3 3 (Gravel) 13J 13J (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 1,800 to 7,200 gallons per ho-ur from single bores. No attempt appears to have been made to sink a well of any considerable diameter into the chalk under London. Doubtless such a well, with adits, would yield water in much larger quantities than the bores now made. There are great engineering difficulties, however, in sinking through the sands lying between the clay and the chalk, and driving adits at such a depth would be no simple task. The East London Water Company, however, have sunk such a well at Barking, where the chalk is not nearly so deep, and are obtaining some 2,000,000 gallons of water per day therefrom. I am informed that the pumping was at the rate of 5 million gallons per day, when driving the adits, in order to* keep down the water to the necessary level. At Bourn, in Lincolnshire, Messrs. Isler and Company recently bored a well for the supply of the town of Spalding. At a depth of 134 feet in the limestone beds of the lower oolite water was reached, and rushed out of the bore pipe above the surface at the rate of over 200,000 gallons per ;ho^ H s o A 'S EH ^.^ Q - ~ " ^. = " ri ft w o -p-nue^o i CM - Oi ^f CO tO Gf (MrH C<1 -2 .2 fl ^ --iS^ ^ H I | "&-I J ^! a 'f 1 '^ ^ ? ^ -S ' J J U-S^ 1 * S Pn-S ^ I f^;i s 6 w DEEP-WELL WATERS i- i- mi 1 a" . S **"&&*"* s GO GO CO l>- t- l>- i 1 p : : TT-I p p ^ p co i> ^00 iO OS !M rH CN t^ (N ip !s ? : : ': : iPP*? | p p p p p |W ; ; ;sggss o p p p p p CO T-I CO rH p p ?S ^ P p p ss? 00 CO ib 00 t^ OS CO O CO iO 10 Tl* O O GO O C'l TJH CO C^) rH ip ip p S g SSScoSSSS i I i I i I r I i i CO i I O O O O GO OS CO 4t< CO 11 kOOO i t XO i IGOGOI>-OOIOCO *JI CO CO CO * CO GO CO OS O 8 8 o p p ^000 O O r lCOGOOGOTt 785 the cross section of the water ; R therefore equals \d. RIVER WATER 103 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, g, which is approximately 32 feet per second. The mean velocity at the end of any number of seconds, t, will be ^-i_! = -J r , the space traversed, A -j s, in that time will be -/, and the velocity at the end of A that period tg. Eliminating t, we find that V 2 = 2sg = 2 x 32 x s, therefore v = 8 V s. 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 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 . *> = 8 ,/s = 5i Js. 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 formulae 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. Blackwell's 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 Q = cw Vs 3 - io 4 WATER SUPPLIES 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 = 1 inch = 2 inches = 4 = 5 = 6 = 7 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 s = 6, c = 4-5 and w = 5 Q = 4-5 x 5 x J& Q = 333 cubic feet per minute. 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. Theoretically the velocity of the water passing through the sluice would be 8 Js, but from friction and other causes it is always less 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 *Js = approximately 5 A Js. If A and s be expressed in feet, Q will be the flow in cubic feet per second. RIVER WATER 105 Where the river is of considerable dimensions, and it is 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. FIG. 11. 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. 106 WATER SUPPLIES 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 200 feet. Limited supplies of water can be obtained from streams having a good fall, by aid of rains, turbines, or water-wheels, when the place to be supplied is at too great an elevation to be directly supplied 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, Ripon from the Ure, York from the Ouse, Knaresborough from the Nidd, Leeds from the Wharfe and Washburn, Doncaster from the Don, Wakefield in part from the Calder, Ely from the Ouse, Leamington from the Learn, Shrewsbury, Worcester, and Tewkesbury from the Severn (Cheltenham 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 has been considered. On the other * There are objections to this procedure. RIVER WATER 107 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 spring water collected in brick- built reservoirs (this water when stored has a tendency at certain seasons of the year to acquire a disagreeable odour from the growth of Chara and numerous minor vegetable organisms), 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, or about 100 days' supply for the town, 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. This water is subject at certain seasons to acquire a red tint from a growth in it of Crenothrix. 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 recent dry seasons and the increased requirements of the town have impelled the Cheltenham Corporation to utilise these powers, and the filter beds existing at Tewkesbury having been largely augmented, a water main has been laid from Tewkesbury to Cheltenham (9 miles), and powerful pumping engines installed. 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, io8 WATER SUPPLIES but that there is any evidence of this pollution at Tewkes- bury is denied. Worcester has taken its supply from the Severn for forty years, and although the nitration is said to have been in past time 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 purified, 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 have never been unduly affected by typhoid fever. During the last three dry summers the Severn supply has had to be largely resorted to by Cheltenham, and during the periods of its use no increase of typhoid fever cases have occurred. The amount of typhoid, in fact, has never been less in Cheltenham than during these years. 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. CHAPTER VIII. QUALITY OF DRINKING WATERS. MUCH has 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 drinking 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 complica- tions, 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 require- ments. 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. (109) no WATER SUPPLIES 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 con- FIG. 12. Tubes for comparing the colours of potable waters. densed 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 particles 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." Experimenting with sea-water, he found that a blue colour corresponded 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 invariably due to peat; whilst a reddish tint indicates the presence of iron. Surface waters from hills and moorlands often contain QUALITY OF DRINKING WATERS in peaty matter in solution and are discoloured thereby, but this discolouration forms only a sentimental objection to the 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 manu- facturing 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 water was occasionally 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 waters as " sulphuretted," In some parts of Essex ii2 WATER SUPPLIES the water derived from veins of sand beneath the boulder clay has a faint but decided odour of this gas ; the smell 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 in- admissible as a domestic supply. Odorous waters appear to be much more commonly met with in some districts, and in some seasons, than in others. In Massachusetts, out of 1,404 samples of drinking water examined, from reservoirs, ponds, lakes, rivers and brooks, only 275 were entirely destitute of odour, 458 had a " vegetable or sweetish " odour, 202 a " grassy " odour, 84 a " mouldy " odour, 146 an " aromatic " odour, 47 a " fishy " odour, 92 a " disagree- able " 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 ex- plained. 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, QUALITY OF DRINKING WATERS 113 one of which, the Uroglena 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 " cucumber " odour * of the Boston water in 1878, attri- buted it to the decomposition of a fresh - water sponge (Spang ilia ftuviatilis). 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 * " Odours in Drinking Waters " : Report of Massachusetts State Board of Health, 1892. 8 i!4 WATER SUPPLIES like odour, Cryptomonas furnishes a " candied violet " odour, Asterionella and Tabellaria (Diatoms) an " aro- matic " odour. Crenothrix, 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 de- composing 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 Bo 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 1,472, of whom 900 were goitrous, whilst at St. Bon, a village some 2,600 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 there- from. 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 IMPURE WATER, ITS EFFECT UPON HEALTH 133 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 distribu- tion 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 containing dolomitic rock, and it would appear to occur principally in water. Whether its nature is organic or inorganic is a question that evades our answering/ 7 Plumbum. Natural waters rarely contain lead, and probably 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 conveyed through leaden service pipes. The amount of lead dissolved depends upon the character of the water, the time during 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 pro- duced by the small amount of lead dissolved are rarely so serious as to cause death, or even the severe colic or para- lysis 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 indigestion, 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 supposed, 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 (Yorkshire) says in his report for 1891 : " Lead poisoning has been common in 140 WATER SUPPLIES the town during the year. This is a matter that, from its importance, claims your serious attention. As lead poison- ing 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 appreciated by the sufferers. There is a mistaken feeling amongst those who are lucky enough to escape, that the risks of this 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. Soon after the report appeared, the Bradford Corporation, who have control of the water supply, began to add 3 grains of chalk to each gallon, and have continued so to do< ever since. The result has been that no case of lead poisoning has been recorded for several years. Dr. Barry, of the Local Govern- ment 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. Water which has stood in the pipes all night naturally becomes most seriously contaminated, and probably, wer"e 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 IMPURE WATER, ITS EFFECT UPON HEALTH 141 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 estimated, since the quantity present in the water may have varied almost with every time of using. It is possible that there are individuals so sus- ceptible 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 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 interrogating 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 correspondent, 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 i 4 2 WATER SUPPLIES years. The pipes from the cold water cistern were un- affected. 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 " inactive " 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 impunity, yet in almost all cases it is found that sooner or later outbreaks of disease occur, pointing to some specific polluting material having gained access to them. The danger naturally is greatest where the filth which contami- nates 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 typhoid 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 IMPURE WATER, ITS EFFECT UPON HEALTH 143 malarial fever, a disease which in many countries is far more prevalent 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 organism causing this disease is usually introduced into the system by the bite of a certain species of mosquito ; but its life history is not sufficiently well known to enable us to prove or disprove possible infection by means of drink- ing water. 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, 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 I 4 4 WATER SUPPLIES 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 malignant 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 dissatisfaction 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." Notwithstanding 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 certain seasons of the year. He concludes that there is not sufficient proof of the disease being conveyed by water, notwithstanding that such a belief is universal in all districts in which the disease prevails. Surgeon-Mapr R. R. H. Moore, in a recent article on " Water Supplies and Malarial Fever " (Journal of State Medicine, vol. vi., p. 116), criticises the evidence with reference to the outbreak on the ship " Argo," and quotes another account, which says that " during the passage of eighteen days salt provision had to be used owing to the scarcity of fresh water, and which, from being stored in old casks, quickly became bad. Under these insanitary conditions, disease of a serious nature se t in 3 symptoms of IMPURE WATER, ITS EFFECT UPON HEALTH 145 typhoid fever appeared, and about 30 of the soldiers died either on board ship or in lazaret at Marseilles." He contends that the great objection to most of the instances in which water is alleged to have caused malarial fever is that they have occurred in places where the disease is endemic, and where it is almost impossible to demonstrate positively that the poison did not enter the system through the medium of air. He is unable to understand how it is that the idea still holds its ground, considering how little there is to be said in support of it, unless it is due to the great influence of Parkes ; for it is evident from his work that the water theory was a favourite one with him. Many continental epidemiologists have given up this theory, but the most recent observers (Laveran, Babes, and Van- dyke Carter) believe that the infection may be caused by the drinking water. Enteric or Typhoid Fever. The production of typhoid fever by the use of polluted drinking water is an indis- putable 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 contami- nated 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 * 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 under- ground, and it was suspected that this stream really fed the * In August, 1872. Deutscli. Arch. f. klin. Med. Bd. xi., 1873, S. 237. IO 1 4 6 WATER SUPPLIES 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 pres- ence 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 (Somerset- shire) which Dr. Ballard investigated on behalf of the Local Government Board. He found that the brook supplying the village with water had been specifically polluted by the drainage of 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 regularly. The disease spread rapidly, and no less than 2,035 persons, or nearly one-tenth of the whole population, were attacked within a very short period. In 1882 a serious outbreak occurred at Banger (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 that 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 IMPURE WATER, ITS EFFECT UPON HEALTH 147 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, attack- ing simultaneously various localities in the town. In 1879 an epidemic occurred at Caterham and Redhill 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 2,258 houses in the two parishes, 1,343 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 reservoirs and had sunk a shaft down to the conduit. One of the labourers employed in this conduit had contracted 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. 1,900) 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 148 WATER SUPPLIES 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 Report 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 outbreak 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 pollution was Discovered. In the following there was proof only of the contamination of the water by sewage. This 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 possi- bility of such specific contamination was proved. In 1867 an outbreak of typhoid fever occurred at Sherborne 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 Caius College, Cambridge. Twelve of the IMPURE WATER, ITS EFFECT UPON HEALTH 149 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 comprises 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 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 intermissions 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 epidemic of typhoid fever occurred in 1867. Out of a population of about 900, no less than 260 were attacked 150 WATER SUPPLIES 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. The very serious outbreak of typhoid fever which recently occurred (1897) at Maidstone is worthy of more detailed attention. Here the implicated water, though said to be derived from a spring, was really collected beneath the ground surface, and was nothing more than a very shallow well supplied with water directly from the subsoil, and indirectly through a series of adits, in this case consisting of drain pipes laid only 2 to 3 feet below the ground surface. The only houses near were a farm house upon higher ground, and a row of cottages on lower ground. Very much nearer, however, was an erection used for the temporary accommodation of hop-pickers, and, so far as I could see, without any sanitary conveniences whatever. From my examination of the locality, I should certainly say that both the farm and the cottages were without the sphere of influence, and could not possibly have con- taminated the water. The top of the well, however, was not raised above the ground surface, but in a little hollow, and only covered by a wooden framework and lid. The hop-pickers, or anyone else for that matter, could micturate or defsecate in the hollow without let or hindrance, but it is not necessary to suppose that such direct pollution took IMPURE WATER, ITS EFFECT UPON HEALTH 151 place. The subsoil water level was at this point close to the ground surface, and at the highest point above in the hop gardens the subsoil water cannot have been more than 2 or 3 feet from the surface, or the pipe drains would not have been laid at that depth. These drains ran under the hop garden, and it is the subject of common know- ledge that such gardens are very highly manured. Assum- ing that this two or three feet of soil always retained its maximum purifying and filtering powers, no one would dare to assert that it was sufficient to prevent any specific polluting matter laid on the surface from entering the drains and passing into the well. But in dry seasons the soil becomes parched and cracked, and in this condition filth could probably be washed directly into the drains; in any case the filtering would be seriously reduced in efficiency. The study of this case therefore teaches no new lessons, and there is no cause for surprise that water from such a source should sooner or later become specifically infected, and produce an epidemic of typhoid fever. The case has been more particularly referred to because it has caused a great deal of needless alarm, and an unreasoning prejudice against the use of subsoil water for 'public water supplies. 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 3,600. 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, ultimately increasing from 4 grains to 24 grains per gallon. Specific pollution, however, was not demonstrated, as no case of typhoid fever was known to have occurred at the farm for years. 152 WATER SUPPLIES Dr. Maclean Wilson recently investigated for the Local Government Board an outbreak of enteric fever at Chester- le-Street, between Durham and Newcastle. Of the 1,100 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, 1892, and January and February, 1893, 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 sup- plied 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 surroundings 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 IMPURE WATER, ITS EFFECT UPON HEALTH 153 of water supply. As few rivers of any magnitude escape pollution 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 filtra- tion be secured at all seasons and under all circumstances? To the temporary break-down of a filter bed, Koch attri- butes 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 specifically 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 154 WATER SUPPLIES twelve months about one-third more deaths than in the city of Boston with four times the population. The cause of this excessive prevalence of typhoid fever was investi- gated, and it was found that prior to the outbreaks the Lowell water supply had been contaminated by the faeces 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 tne river (Merrimac) and its branches during the chemical examination 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 presented, 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 IMPURE WATER, ITS EFFECT UPON HEALTH 155 long enough to pass from the Lowell sewers to the water mains of Lawrence. It was calculated that the Lowell 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 conclusion 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 156 WATER SUPPLIES 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 Newbury- port, 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 con- nection 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 exten- sive 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 1,463 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, IMPURE WATER, ITS EFFECT UPON HEALTH 157 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 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 population in the above districts obtained their water from the river Tees through the works of the Darlington Corporation and the Stockton and Middles- borough 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 drainage 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, appeared 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. Thorne, the 158 WATER SUPPLIES Medical Officer to the Local Government Board, " has a case of the fouling of water intended for human con- sumption, 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." Not/withstanding this strongly expressed opinion on the 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 com- parative purposes. He also pointed out that many villages and hamlets supplied with Tees water altogether escaped, and that the distribution generally coincided with differ- ences 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 intro- duction 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 unsupported hypothesis." Mr. Wilson's evidence caused the Commissioners to refrain from express- IMPURE WATER, ITS EFFECT UPON HEALTH 159 ing 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 1,000 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 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 balancing conflicting evidence, to guardedly express their opinions. It is now strongly suspected that polluted waters may often be the cause of the endemicity of enteric fever in certain localities, and of the sporadic cases which occur in many towns and districts. This view is borne out by Dr. Bruce Low's Report (L.G.B. Report 1893-4) on the occurrence of enteric fever amongst the population of the Trent valley, in Lincolnshire and part of Nottinghamshire. The Trent and its numerous tributaries are shown to be excessively polluted by the sewage of towns and villages, 160 WATER SUPPLIES 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 denied at so many points that no opportunity is afforded for the natural causes of purifica- tion 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/' In the Gainsborough Rural Sanitary District, the Infectious Disease Notification Act' had not been adopted, and the number of cases of typhoid fever which had occurred during recent years had to be ascertained by inquiry from local practitioners, some of whom could only give information from memory. Based upon statistics so obtained, Dr. Low shows that, during the previous four and a half years, the enteric fever attack-rate in the villages using well water only averaged 1.92 per annum per 1,000 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 arrangements 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 IMPURE WATER, ITS EFFECT UPON HEALTH 161 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 was until recently supplied from the Trent, and the other half from polluted shallow wells. During the last three and a half years in which Trent water was used, 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 was obtained from the new red sandstone at Edingley. The amount of typhoid fever suddenly decreased with the intro- duction of the new water supply, as is shown in the following table, and it has since remained very low. There is no other circumstance known which could have produced this effect, and we have either a marvellous coincidence or a proof that the use of polluted waters may cause a high incidence of typhoid fever without serious epidemic out- bursts. This is an exceedingly important subject, well worthy of further investigation, and, in connection there- with, the history of the prevalence of this fever within the metropolitan area is instructive. In London many cases of typhoid fever occur annually the source of which cannot be traced, and in the report by Dr. Shirley Murphy, Medical Officer of Health, for the year 1894, the distribution of these cases and their relation to periods of flood, etc., is discussed. He says : " The distribution of cases of enteric fever throughout the year was characterised by an increase of prevalence in the 49th, 50th, and 51st weeks. Previous experience of the distribu- tion of cases of this disease in London during the period 1890-3 shows that this behaviour of the disease in 1894 was exceptional, and further inquiry shows that the increase was not due to any special local prevalence, but was manifested over a large area of the county. . . . Study ii 162 WATER SUPPLIES ^ fe o I rH 5 55 g la W >! P is 3 sg S I! H H 01 - "E^ S3 -2 tfi M If '? |3 J - a -D IS II I s i J s 10 O5 CO 00 t- ^ GO t- 00 o 1 00 " O m rH rH o e rH o o o 10 CM TH CO CO rH CM o to i CO CM rH - " CM rH rH T 1 J 1 ! rH 3 CM . rH rH CM CM rH 00 si P rH t- CM i I 00 CM O O rH O o | CO rH . ' rH CM C s 00 o CO o rH rH CM O . I CO o rH TH o T-H rt o 1 CM 10 . . o o O O O o i rH 00 O rH H o i t- rH H S o o O O i - 8 rH CO rH rH rH rH o O o H CM CO i CO g> g 00 & & GO & & GO 00 s GO IMPURE WATER, ITS EFFECT UPON HEALTH 163 of the results of chemical examination of the waters supplied by the London water companies, and which are published by these companies, shows an intimate relation between the condition of the waters as supplied and the condition as to flood of the rivers from which these waters are derived. Certain notable floods in November materially altered the condition of the waters supplied, at a time when there is reason to suppose that some new factor in the causation of enteric fever in London must have come into operation. Inquiry as to the behaviour of enteric fever in populations in the vicinity of the county gives indication of some difference of behaviour of this disease in the population supplied by water from the Thames and Lea, and in the population otherwise supplied, the population supplied from these rivers experiencing an increase of disease in the 49th, 50th, and 51st weeks, corresponding with that experienced in London. " The hypothesis of water-borne contagion appears better able than any other to afford explanation of the increase of disease in the weeks in question." During recent years quite a number of limited outbreaks of typhoid fever have been more or less definitely 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 investigator 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 164 WATER SUPPLIES from such a person may poison a water supply without its ever being discovered, however experienced the investigator. Surgeon-Captain Haynes states that in the Bolan Pass in 1877 typhoid fevej 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. 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 has 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 circum- stances 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 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 several 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 IMPURE WATER, ITS EFFECT UPON HEALTH 165 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, Westminster, 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 simul- taneously 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 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 1 66 WATER SUPPLIES 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, supplied with water from the pump, 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 Keport 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 1,000, whilst amongst those drinking water drawn between Battersea and Waterloo Bridge it was 16.3 per 1,000. 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 pure water supplies had reduced the cholera mortality in the towns which had been attacked by successive epidemics. In. the following table the total number 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. IMPURE WATER, ITS EFFECT UPON HEALTH 167 Year of Cholera Epidemic. 1832 1849 1854 1866 Total deaths in Manches- ter and Salford . 890 1,115 50* 88* Total do. in Glasgow 2,842 3,772 3,886 68* Total do. in Paisley and Charleston Not known 182 173 7* Total do. in Hamilton 63 251 44 2* 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 Weymouth returned home via 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 water, nine were attacked with cholera of so malignant a type 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 * Indicates that prior to this outbreak the town had substituted a pure water supply for an impure one. 168 WATER SUPPLIES 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 epidemic of cholera at Hamburg in 1892 was inter- esting 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 8,000 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 com- munity, 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 lake which is hardly at all exposed to contamination with fsecal matter; Hamburg obtains its water in an unfiltered condition from the Elbe above the town, and Altona obtains filtered water from the Elbe below IMPURE WATER, ITS EFFECT UPON HEALTH 169 the town. Whereas Hamburg was notoriously badly visited by cholera, Wandsbeck 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.* 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 com- pletely 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 supplied with unfiltered water from the Elbe is seriously visited by cholera ; the population supplied with filtered water is only visited by the disease to a very small extent. This * Many of these statements have since been disputed. Vide Lancet 25th May, 1894, i 7 o WATER SUPPLIES 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 explanation 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 infec- tious 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 sub- mitted 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 decomposition 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 ; IMPURE WATER, ITS EFFECT UPON HEALTH 171 but the 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 sub- stances 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 remove 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 172 WATER SUPPLIES 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 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 hcematobia, Filaria sanyuinis hominis, 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 hcematolria. This entozoon is the cause of the endemic hsematuria 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 further stage of develop- ment 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 em- bryos 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 IMPURE WATER, ITS EFFECT UPON HEALTH 173 bathing. This organism, which produces endemic hsematuria 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 Fedschenko 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 consequences 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. Bhabdonema intestinale. Sonsino states that this para- site 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 affected is by the introduction of the parasite at some stage of its develop- ment with the drinking water. Both in England and elsewhere the .excessive prevalence of lumbrici has been 174 WATER SUPPLIES noted over localised areas where the inhabitants resorted to polluted ponds or shallow wells for drinking water. Trichoce.phalus dispar, or whip worm. Half the inhabi- tants 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 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 European countries. Part of its life cycle is passed in damp earth, and it has been frequently observed that the disease induced by it is confined almost entirely to the lower classes, and more especially to those who drink water from shallow pools and watercourses. Tcenia echinococcus. The hydatid stage of this tape- worm occurs in man. The tape-worm itself develops in the intestines of the dog, and the ova passed may easily find their way into water, and by this means be introduced into the human stomach. Hydatid tumours are common in Iceland, parts of Australia, Switzerland, and Southern Germany. Many other parasites which affect domestic animals are 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. IMPURE WATER, ITS EFFECT UPON HEALTH 175 The Effect upon Animals of drinking Polluted Water. This has been but little studied, but evidence is accumulat- ing tending to prove that drainage from farmyards is not quite so innocuous 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 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 inducing 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 pollution 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 attributed to the same cause ; but whether the milk itself was originally infected or merely became infected by the admixture 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 supplied 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 i 7 6 WATER SUPPLIES 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 1,000 head of cattle were supplied with water. Within a very short time 10 per cent, of these died of anthrax. Some years ago, when wool 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 patholo- gists 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. IMPURE WATER, ITS EFFECT UPON HEALTH 177 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. k At the present time no one would contend that wate* fouled by cattle was fit to be used by man for drinking purposes, 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. 12 CHAPTER 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 worth- THE INTERPRETATION OF WATER ANALYSES 179 less or even misleading. 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 labora- tory, 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 examina- tion, 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 objectionable, 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 significance 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 ma.ny manufactories, alkali works, mines, etc., i8o WATER SUPPLIES are also rich in chlorine. Prom these various sources, therefore, the chlorides found in waters are derived. Where the geological strata contain 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 * 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 ar.ea, 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 approximately calculated. It must be remembered, how- ever, 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 * I part of chloride of sodium equals '61 part of chlorine. THE INTERPRETATION OF WATER ANALYSES 181 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- 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. 57), the normal chlorine did not exceed 2.5 grains per gallon, yet in that parish sub- soil 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, but if in any case the amount found exceeds the average, the possibility of sewage pollution must be considered. The same remark applies to deep-well waters (Table VI.). If the source of the water be not known, reliance upon the chlorine estima- tion 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 i82 WATER SUPPLIES 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 examin- ing 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 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 con- taminating 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. The quantity of chlorides present in a water may some- times be so considerable as to raise the question whether such water is suitable for a public supply. Quite recently I have had to give an opinion on this point. A deep boring had been made to obtain, from the Essex chalk, a supply of water for a small town. The bore was 500 feet deep, and the water contained over 70 grains of common salt per gallon. This amount gives a distinctly perceptible flavour to the water, and I expressed the opinion that this quantity was in excess of what should be permissible in a public supply. The Local Govern- ment Bo* 0^ . aaaW a N rH CN CO * O CO t-^ CO OS* O i ( THE INTERPRETATION OF WATER ANALYSES 197 p : - ^ ^'P CO' CO O 4t< 4j< ' ' CO AlCN T I 0) : : I : : :? I : : : : : ICO T I O ; ;OC ^ 73 : ! ! : ! : l ! : ! ! : : Sl1 II : 3 = o| ^ o * l-l i-H ^" " t ^Oi i-H I-H I '5! 'I ' * ' 'o 2 . " S -2 i ll '|-| i* ;: {}! ::::r: : O O PQ ft t>S ig8 WATER SUPPLIES 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 interpreted 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 foregoing table the erroneous conclusions which may be deduced from a too great dependence upon analytical data are fully exemplified. 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. THE INTERPRETATION OF WATER ANALYSES igg 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 Government Board, on the occurrence of enteric fever amongst the population using the Trent water, 1893. 6. Analysis of the well water supplying Hough ton-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, 200 WATER SUPPLIES 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 foe 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 " 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 con- sumers, is of good and wholesome quality." 12. Analysis of the Middlesborough water supply by Dr. THE INTERPRETATION OF WATER ANALYSES 201 Frankland, F.R.S., 1st January, 1891. Report " Of excellent quality for dietetic and all domestic purposes/' 13. Analysis of Darlington water supply by 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 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 investigate the pollution of the river Tees, the late Professor Tidy examined a number of samples of water therefrom. 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. Not- withstanding 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 2 WATER SUPPLIES sewage discharged into the river at Barnard Castle was enormously greater than at present, the self- purifying 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 pre- judiced (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 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 animalcule 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 albuminoid 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 River, 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, THE INTERPRETATION OF WATER ANALYSES 203 21. Analysis of water from the Chicopee River supply- ing 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 albuminoid ammonia yielded by the latter does not exceed that yielded by the former. 24, 25 are waters from a deep well in Essex ; (24) 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 Report by Dr. George Turner on an 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 204 WATER SUPPLIES 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. 31. Upon this meagre analysis this water, derived from a deep boring in the chalk, was condemned, and the analyst said that it could not possibly be derived from the chalk. As a matter of fact the water was exceptionally pure, and typical of the deep chalk waters of the district. Quite a number of instances have come under my observation in which good waters have been condemned as sewage-polluted by analysts who were ignorant of the character of the water derived from particular strata. 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. When still more recently the actual microbes causing these diseases had been identified, and processes were said to have 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 fully realised, and the results of an ordinary bacteriological examination may be as misleading as those of a chemical analysis. The reason for this is not difficult to explain, when the significance of certain of the dis- THE INTERPRETATION OF WATER ANALYSES 205 coveries 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 im- portant 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 assimilated 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 therefrom matters of a harmless character. The microbes found in water are chiefly bacilli. Micro- cocci are comparatively rare, whilst spirilla are not uncommon, especially in polluted waters. Already over 200 distinct species of microbes have been discovered in potable waters, and amongst these are several which are pathogenic or disease producing. According to Professor Percy Frankland,* these are Typhoid bacillus Cholera spirillum, or " comma bacillus " Tetanus bacillus Anthrax Tubercle Bacillus brevis ,, capsulatus ,, proteus fluorescens ,, coli communis * Journal of State Medicine, January, 1894. " The Bacteriological Examination of Water." 2o6 WATER SUPPLIES Bacillus hydrophilus fuscus pyocyaneus Staphylococcus pyogenes aureus, and the organisms causing septicaemia in mice and rabbits (To these must now be added the bacillus enteritidis sporogenes) 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, and at least that he should be able to discover such organisms as are more or less characteristic of sewage. The multitude of other bacilli present, however, renders the search for one par- ticular organism 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 identification 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 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, THE INTERPRETATION OF WATER ANALYSES 207 to the use of which Koch and others, who investigated the outbreaks, attributed their occurrence. At the commence- ment of the second serious epidemic of typhoid fever at Worthing, two samples of the water were submitted to bacteriological examination 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 exami- nation, " that both samples of the Worthing water rank as very pure water." Considering that during the con- struction 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 * 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 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 * From Report in the Sussex Coast Mercury, 22nd July, 1893. Worthing has a population of about 17,000, and during the year 1893 nearly 1,500 cases of typhoid fever occurred. 2oS WATER SUPPLIES 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. 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 justify the opinion that the water was pol- luted, the typhoid bacillus was next 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 THE INTERPRETATION OF WATER ANALYSES 209 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 fsecally polluted may be capable of producing this disease when all the circumstances are favourable, and therefore they must be looked upon with the gravest suspicion, whatever the results of bacteriological or chemical analyses. All surface waters contain large numbers of micro- organisms, 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. Frankland says that such a water, containing only, say, 5 microbes per cubic centimetre when freshly drawn, may, even if kept in a sterile flask and 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 num- bers again very soon fall below those found in impurer surface waters." It follows, therefore, that the purest water which has been kept a few days may be confounded with a water from the filthiest source, and that even if the number of micro-organisms 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 centimetre (15 drops). In ordinary river waters from 1,000 to 100,000 may be found in the same volume, whilst in sewage there: may be sieveral millions. Rain, hail, snow, and ice are not free from 14 210 WATER SUPPLIES bacteria, though usually the number contained therein is small. Professor Sheridan Dele*pine, in a recent article in the Journal of State Medicine,* referring to the various modes of examining waters, states that, in his opinion, a bacteriological examination is capable of giving more reli- able data than a chemical analysis, especially if the amount of polluting matter is small. He continues : " Our present position with regard to the value and interpretation of bacteriological results will be made clear by a few references to the views held by several authorities. " Koch (1885) says that the number of micro-organisms in water is of the greatest importance, as it indicates whether or not the water is contaminated with organic matter undergoing decomposition. When decomposing organic matter, which always contains a large number of bacteria, gets mixed with water, this water becomes rich in micro-organisms. Even if one were unable to discover any pathogenic germs in such a contaminated water, the fact that it contains decomposing organic products, among which pathogenic bacteria might be present, is enough to render this water suspicious. " In his well-known paper on water nitration, Koch, in 1893, has fixed at 100 the maximum number of colonies that may be allowed to be present in 1 c.c. of water pro- perly filtered through sand. Koch admits at the same time that a few of the bacteria which are found in the unfiltered water may pass through the filter and be found in the filtered water. There does not seem to me, therefore, any very good reason for admitting a standard for unfiltered and another standard for filtered water. " Supposing we admit a numerical standard, we must, if we follow Koch, regard 100 bacteria as the highest number compatible with purity of drinking water. * Vol. VI., p. 145. "Bacteriological Survey of 'Surface' Water Supplies." THE INTERPRETATION OF WATER ANALYSES 211 " Miquel (1891) has given a scale of purity, which I give only to show the arbitrary nature of the classification of waters based on numbers only. It must be remembered that the methods used by Miquel reveal a larger number of bacteria than the usual methods : Excessively pure water . to 10 per 1 cubic centimetre. Very pure water . . 10 to 100 ,, Pure water . . . 100 to 1,000 Mediocre (or passable) water .... 1,000 to 10,000 Impure water . . 10,000 to 100,000 Very impure water . 100,000 and over ,, ,, " Crookshank gives in 1896 the following scale, equally arbitrary : Very pure water may con- tain up to . . . 100 bacteria to the cubic centimetre. Water containing . . 1,000 bacteria, or more, should be filtered. Water containing more than 100,000 bacteria is contaminated with surface water or sewage. " Mace (1897), after explaining that the mere number of bacteria must be taken only as an indication and not as affording an absolute criterion, gives the following scale of purity : Very pure water . to 10 bacteria to the cubic centimetre. Very good water . 20 to 100 Good water . . 100 to 200 Passable (mediocre) water . . . 200 to 500 Bad water . . 500 to 1,000 Very bad water . 1,000 to 10,000 and over ,, " Migula (1890) argues that the mere number of the colonies affords us no means of judging of the fitness of water for drinking purposes, but that, on the other hand, a. great deal depends on the number of kinds present. 212 WATER SUPPLIES " Good pure spring water from mountains contains only a few species ; water which has been contaminated by drainage contains, on the contrary, an exceedingly great number of species. " Migula holds that there should never be more than ten different species of bacteria in good drinking water. He qualifies this statement by saying that a water con- taining fewer species may have to be condemned on account of the nature of the bacteria, whilst sometimes a water containing more than ten kinds may be considered fit for drinking purposes. " As regards the number of colonies, Migula is inclined to admit a maximum of 500, i.e., the limit admitted by most observers. For a time bacteriologists attached a considerable importance to the presence or absence of liquefying bacteria, but I think that as there are several rapidly liquefying bacteria often present, even in unpol- luted water, it is necessary to distinguish between those liquefying bacteria which are associated with pollution and those which are not, if the presence of liquefying bacteria is to be used as a criterion at all. " Meade-Bolton, jLustig, G. Roux, all well known in connection with the bacteriological examination of water, have expressed views similar to but less categorical than those just quoted. " I need not say more to show that there is, as yet, no consensus of opinion among bacteriologists with regard to the interpretation of the results of water analysis. There is, however, a general tendency to admit that much judg- ment has to be used in interpreting these results. " There is no difficulty with regard to very bad waters. Those who propound numerical standards all agree that a water containing 1,000 germs is not good. This in itself is already a very important point gained, for in many sus- picious or bad waters which might chemically appear good, the presence of organic impurities can easily be detected THE INTERPRETATION OF WATER ANALYSES 213 in this way. But when we have to deal with waters containing less than 1,000 bacteria to the cubic centimetre, there is a considerable divergence in the views expressed by various writers." Professor Dele'pine adopts a comparative method in all his investigations, and says that it has, so far, yielded him results which appear free from ambiguity when applied to the investigation of surface and subsoil waters. He selects waters from sources which by examination are shown to be free from the possibility of pollution, and taking these for his standards compares therewith other waters from the same subsoil, or from other portions of the same collecting surface. In the Report of the Medical Officer to the Local Govern- ment Board (1897-8) there are interesting reports by Drs. Klein and Houston, showing that contaminating matters in waters which, from the chemist's point of view, would be classed as " of high degree of organic purity " can be detected by bacteriological examination, the bacillus coli and bacillus enteritidis in a water being taken as evidence of its previous sewage contamination. These results I have been able to verify, but occasions have arisen when one or other of these organisms have been found in a water which, from an examination of the source, I could vouch for being " safe." I am not certain, as yet, however, that I have ever met with a " safe " water which contained both these organisms. In a more recent report (L.G.B. Report 1898-9) these observers state, as the results of the investigations recorded, " that not only is bacteriology capable of detecting, in a water . . . microbes characteristic of sewage, but is capable also of detecting these bacteria when the degree of sewage pollution of the water is from ten to one hundred times less than that in which the organic matter contributed by the sewage to the water has failed to get recognition by the methods commonly in use by the chemist." n 2i 4 WATER-SUPPLIES In another article in the same report by Dr. Houston, it is asserted that the presence of streptococci in any number in a water " is positive evidence of a sort to go far to justify the bacteriologist in condemning a sample of water as unfit for domestic use/' since such organisms appear only to be found in water recently polluted by sewage. I have, however, found streptococci in " new " wells free from the possibility of pollution. Koch would regard even filtered river water containing over 100 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 filtration. The Royal Com- missioners 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 11 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 suspen- sion; 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 acknow- ledging 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 con- sumers in ;Londo most trustworthy observers in other towns using polluted river water, leads to a very different conclusion. 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. CHAPTER XIII. THE PURIFICATION OF WATER ON THE LARGE SCALE. THE water derived from deep wells, springs, and the subsoil 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 is 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 organ- isms 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 pro- cesses of purification, such as boiling, distillation, and precipitation, are only applicable in special cases or on the small scale ; and even after the water has been submitted (253) 254 WATER SUPPLIES 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 albuminoid 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 demon- strated 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 discovered. 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 it is now generally acknowledged 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 specific bacilli passing through in large numbers. Evidently, therefore, neither chemistry nor the physical test of PURIFICATION OF WATER ON LARGE SCALE 255 transparency can determine whether any process of nitra- tion 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 sedimentation; (2) The filtration should not exceed a certain rate; (3) The depth of fine sand should be con- siderable; and (4) The filtering materials should be renewed frequently. The effect of subsidence in diminish- ing the number of bacteria in water, and, therefore, in diminishing the risk of disseminating 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 . . 183 256 WATER SUPPLIES West Middlesex Company at Barnes Thames water as abstracted at Hampton . 1437 After passing through first reservoir . . 318 After passing through second reservoir . . 177 By far the most important and extended series of obser- vations on the purification of water by sand nitration 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 some- times 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 economi- cally, 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 unfiltered water." The experiments were made with water to which approximately known numbers of the B. prodigiosus or B. typhi abdomi- nalis 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 thousands 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 con- structed on a large scale." PURIFICATION OF WATER ON LARGE SCALE 25? 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 Filter 36 A consisted of 58 inches of sand of an effective 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, 1J inches thick, of coarse sand, and below this successive layers of gravel, increasing in size, the whole having only a depth of 3J inches. It was found best to pack the sand dry, as, when introduced with water, 258 WATER SUPPLIES 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 sample. This size is such that 10 per cent, of the sand is of smaller grains, as ascertained by sifting, whilst the remainder is of larger grains. The results of the Massachusetts experiments may be briefly summarised as follows : (a) Increased rapidity of filtration 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. (b) 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. (cT) 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 PURIFICATION OF WATER ON LARGE SCALE 2$g shallow than in deep niters, 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. (h) 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 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. (1) Filters used continuously require less frequent scrap- ing 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 ascertain 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 260 WATER SUPPLIES multiply 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 nitration 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 particulars 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 effec- tive agent in removing 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 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; PURIFICATION OF WATER ON LARGE SCALE 261 usually they were much below 20 to 30 being the average. In January, 1892, the number of micro-organisms suddenly increased to from 1,000 to 2,000 per c.c., and in February an outbreak of typhoid fever occurred. Suspicion was expressed that nitration 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 1,516, 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 examined, 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. Koch also points out that winter with its period of frost is not the only enemy of filtration. Occasionally in summer, river and stored surface-water is so rich in vege- table 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 experi- ence of Altona, Berlin, and other places. To secure efficient filtration Koch lays down the following rules : 262 WATER SUPPLIES 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,* 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 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 * The average size of these is one acre. PURIFICATION OF WATER ON LARGE SCALE 263 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 albuminoid 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 mad 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. 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, however, in the light of recent bacteriological research, of very secondary importance in the purification of water. Any considerable chemical purification cannot be con- stantly 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. 264 WATER SUPPLIES 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 inter- mittent action is difficult to explain. The Massachusetts investigators think that the action probably only com- mences 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 f rom 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 moorlands 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 holding 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 J-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 observations can be made as to the rate at which the water is passing through PURIFICATION OF WATER ON LARGE SCALE 265 the bed. The filtered water is then conducted 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 4 to 4J feet. 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 Metropolitan 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 266 SUPPLIES A < C- O goo Iff x^a ? S oo so .2 p cp i I Oi OO l^. CO J3 Oi t^. O '-O O CO t w KNE F r . CN O O kO OO 10 CO 4j1 l^ 07) SO ^ .P :o Q 1 03 O H gH PURIFICATION OF WATER ON LARGE SCALE 267 reniedied by increasing the number of filter beds or by having recourse to double nitration ; " 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 Prof. P. 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 -t' cubic feet, F the filtering rate in feet, and A the required area in square feet. This area must always be available; hence a-n 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 : Population. No. of Filter Beds. 2,000 ...... 2 10,000 . . . . . . 3 60,000 . . . /- ... 4 200,000 ...... 6 400,000 8 600,000 12 1,000,000 16 These include filter beds out of use for cleansing. In all cases a sufficient number of filter beds should be 268 WATER SUPPLIES 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 arrangement 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 water 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 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 jt only passes through soil which is constantly saturated PURIFICATION OF WATER ON LARGE SCALE 269 \ with water, and therefore never aerated, and destitute of any oxidising powers. In such cases also the nitration is liable to be inefficient, and to allow of bacteria and other participate matters passing into the collecting channels. Many attempts have been made to filter water on the large scale without employing filter beds, which are ex- pensive not only on account of the space required, but of the constant 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 filtration can be secured by passing the water through two " scrubbers " in succession, and affords, naturally, safef 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 ayo WATER SUPPLIES with the Atkiii "scrubbers/' with "the great sanitary improvement of daily cleansing in addition." Such machines for rapid nitration 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 filtering turbid river-water. A commission appointed by the city of Pittsburg has recently (1899) presented a report containing the results of a number of experiments comparing the efficiency of sand and mechanical filters when used for the river water supplying the city. They found that the use of a coagulant was necessary in both systems, but preference was given to sand filtration. The report states : " With an amount of sulphate of alumina which makes the cost of the two processes substantially equal the mechanical filters yield effluents containing from two to three times as many bacteria as the sand filters." Dr. P. S. Wales, Medical Director, United States Navy, states that, with these mechanical filters, 98 per cent, of the micro-organisms can be removed, but that spores readily pass 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 satisfactory results. The system of rapid filtration is pursueid, amongst other places, at Oakland, Gal., capacity for 24 hours . 4,000,000 gallons Atlanta, Ga. . 3,000,000 Long Branch, N.Y. . 2,000,000 Ottumwa, Iowa ,, . 1,500,000 Athol, Mass. . 1,000,000 PURIFICATION OF WATER ON LARGE SCALE 271 The city of Alleghany, Pa., was contemplating erecting a plant for filtering 30,000,000 gallons per day, when Dr. Wales's paper was published.* 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. Tjhe addition of about half a grain per gallon, on the average, is sufficient. At the Atlanta Waterworks, during 1890, 253 Ib. of alum were used per day, corresponding to 617 grains per 1,000 gallons. Some waters, such as that of the Potomac, cannot be clarified without a coagulant. Ferrous sulphate has been used in some cases instead of alum, and with advantage. 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 Aluminoferric, was used as a coagulant, and the water then filtered through vertical sheets of flannel. This not proving satisfactory, various recently-introduced filter- ing and purifying materials were experimented with. Finally, at my recommendation, 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 for several years answered admirably, and the use of the alum was discontinued. Two beds were prepared, so that one could be used whilst the other was cleansed and allowed to rest for re-aeration. A fresh source of supply is now being sought. 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. * Transactions of International Congress of Hygiene, London, 1891, vol. vii. 272 WATER SUPPLIES 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 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 -^ to 1 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 7,000 per cubic centimetre, were reduced to an average of about 40. The bacterio- logical 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 PURIFICATION OF WATER ON LARGE SCALE 273 organic matter; but unless supplemented by careful sand nitration 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 filtration 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 therewith, or in layers. A carbide of iron (Spence's Magnetic Carbide) 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 colour- less, 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, polar ite, 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 18 274 WATER SUPPLIES 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. Walker the Water- works 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 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 subsequent 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 2 J feet of polarite, giving an area of 40 yards 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 su- per per day. From 1st January of the present year (1894) to the 31st of March last, 190,218,319 gallons of water have passed through these chambers giving an average of PURIFICATION OF WATER ON LARGE SCALE 275 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 every- day 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,' 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. An addition has since been made by the construction of a covered filter-house, having four sets of chambers capable of purifying 1,000,000 gallons per day. This occupies an area of 424 yards, including brickwork. These chambers were set to work in June 1898, and have given very satisfactory results. It is now 9 years since polarite was introduced in the Reading works, and Mr. Walker's further experience has confirmed his previous report. 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 #re carrieo!. off by an outlet at the rim of the 276 WATER SUPPLIES 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. The addition of chalk or limestone to soft waters to prevent the action upon lead can scarcely be described as a process of purification, but inasmuch as it is a process which would usually be associated with that of nitration it may be mentioned here. By the admixture of limestone or chalk with the sand the acidity of the water is neutralised, and usually a small amount of carbonate of lime passes into solution. Dr. Scatterty (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 peaty 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 niters, and by this means it is hoped to completely destroy the solvent action of the water on the lead piping." At ditherae (Lancashire) a peaty water is filtered and rendered incapable of acting upon lead by being passed through beds of sand, Welsh anthracite coke, and polarite, the works costing XI 9, 000. This process removes the peaty colour, renders the water neutral, and increases the hardness to 2, which is found sufficient to prevent action upon lead pipes. Water, when softened by the addition of lime, usually undergoes an improvement in quality, the precipitate of carbonate of lime carrying down with it a certain pro- portion of the microbes previously suspended in the water. The filtration through sand which follows, to PURIFICATION OF WATER ON LARGE SCALE 277 remove the last trace of carbonate, still further purifies the water, so that the softening 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. At Oudshoorn (Holland) the water supply is being treated with ozonised air and is said to be sterilised thereby. Machines have been devised for sterilising water on a large scale by means of heat, I recently tested one of these, but found that it failed to (destroy the typhoid bacilli which had been introduced. Several forms of high-pressure niters have been intro- duced into this country of recent years, and have been adopted for filtering turbid water for manufacturing pur- poses. They are doubtless very useful for clarifying water, but my experience leads me to the conclusion that they may be worse than useless if used for filtering water for domestic purposes. In two instances, recently, I have had to recommend small water companies, who had purchased these filters, to abandon their use, since I found the clarified water contained many more micro-organisms per c.c. than the unfiltered water. CHAPTER XIV. DOMESTIC PURIFICATION. THE water supplied by a public company can scarcely be considered wholesome if it requires nitration by the con- sumer, yet in many towns unfiltered surface water is distributed, and as this often contains visible suspended impurities, some form of nitration 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, (b) 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 it cannot DOMESTIC PURIFICATION 279 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 FIG. 14. should not be 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 280 WATER SUPPLIES carbon. The water passes in from the 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 com- posed of compressed fossil earth (Eietelguhr), 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 Ib. 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 Ib. 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 DOMESTIC PURIFICATION 281 bacteriologically 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 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. 282 WATER SUPPLIES 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 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. Rain 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; thjey were coarse strainers and nothing more. The so-called " table filters " are usually the least reliable, since the amount of DOMESTIC PURIFICATION 283 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 nitration 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 slow in action. The tubes must be frequently removed, washed, first with water, then with a FILTER PAPER FIG. 16. 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 following is a description of a cottage filter costing only a few pence : Take a large-sized earthenware flower- 284 WATER SUPPLIES 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 J to J inch square). Upon these place a layer of small, clean- washed gravel, and upon this 6 to 12 inches of well-washed, fine, sharp sand. Cover the smooth surface of the sand with a circular piece of coarse filter 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 rrfuch 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 charcoal, 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 contact with it forms a favourable medium for the growth of low forms of life, and bacteria grow within its pores. Professor 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 DOMESTIC PURIFICATION 285 other forms of charcoal also are used as filtering media, but they do not possess the decolourising and oxidising powers of animal charcoal. 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 niters, but possess no advantage over good sand. Sponge sioon become foul, and only acts as a coarse strainer; its use is not recommended. 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 renewal. 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 contain- ing 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. 286 WATER SUPPLIES 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 substances 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 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 astringent 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 solution of permanganate should be added gradually and with constant stirring, until a very faint but per- manent pink tint is perceptible. A little alum is then added, and the water allowed to clear by subsidence. Such waters also are improved in quality by being stored in well-charred casks. Very foul waters, when kept, often undergo a kind of fermentation, and become clear, bright, and palatable. A method for sterilising potable water, of which an DOMESTIC PURIFICATION 287 abstract will be found in the Journal of State Medicine, vol. viii., p. 198, has been devised by the chief army surgeon of the Prussian army. The process is especially adapted for troops on the march or in camp, and consists in adding to the water a measured quantity of bromine dissolved in bromide of potassium, the- bromine being subsequently fixed by the addition of alkaline bases. It was found that .06 gramme of free bromine was sufficient to sterilise a litre of water, and that after the bromine had been saturated with the corresponding quantity of ammonia, the taste of the water was hardly distinguishable from that of the original sample, and that so little of the bromine salt was present as to be without influence on the general health. The solution of bromine (Br 21.91, KBr 20, water to 100 grammes) was contained in sealed glass cylinders, each cylinder holding 22 c.c. It was found by experiment that each tube was capable of killing all the typhoid and cholera bacilli in about 67 litres of water, which had been artificially infected with these organisms. The alkaline mixture was in the form of a powder in corked tubes, each charged with twelve grammes. The formula of the mixture was Sodium Sulphite 7.2, Anhy- drous Sodium Carbonate 3.0, and Mannite 1.8. This quantity of powder is enough to neutralise the bromine contained in one of the sealed glass cylinders. Drs. Parkes and Rideal, in a paper read before the Epedemiological Society on Jan. 18th, 1901, recommend the use of tabloids of sodium bisulphate for destroying the bacillus of typhoid fever in water. They find that 15 grains of this salt added to one pint of infected water kills the bacillus in 15 minutes, and they express the opinion that the use of this salt would diminish the inevitable suffering of our soldiers from thirst and protect them from the ravages of water-borne disease, CHAPTER XV. THE SOFTENING OF HAKD 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 consumer 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 distilla- tion; 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 1,000 gallons of water by boiling for half-an-hour would cest about 7s. 6d. The same quantity of Thames water softened by soap would cost 9s., so that boiling is not much less expensive than softening by soap. THE SOFTENING OF HARD WATER 289 (b) 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 a portion of the carbonate of magnesia if any be 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 again increases the hardness. 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 universally 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 precipitated. Most of these are more especially designed for softening water for manufacturing purposes and for use in steam boilers, rather than for water for domestic use, but certain of them can be adapted for either purpose. 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 complete clarification required at least 6 to 8 hours. Large tanks were necessary, and these had frequently to be cleansed. Messrs. John Taylor, Sons, and Santo Crimp have kindly 19 2 go WATER SUPPLIES furnished me with the following particulars of the process employed by the Colne Valley Water Company : This company derives its water from wells sunk in the chalk, and is at the present time supplying upwards of two millions of gallons per diem during the summer months. The whole of the water is softened by Clark's process. Buxton or other suitable lime is purchased, brought on to the works and tipped into a building marked on the accom- panying diagram (Fig. 17) " Lime Slaking House." Quantities as required are placed in slaking trough and slaked, and afterwards water is added to bring the lime into the consistency of cream. This cream of lime is passed through a screen and allowed to gravitate into one or other of the " lime water tanks." The lime water tank is then filled with softened water and the liquid thoroughly agitated by means of air which is forced through pipes to the bottom of the tank by a special air pump. The liquid lime water is then allowed to rest and clarify; samples are extracted from the tank and tested for strength, and if the solution is not saturated further blow- ing with the air-pump takes place. After the lime water has thoroughly clarified it is run off by means of a floating pipe into one or other of the " softening tanks." The lime water tank is again filled with softened water, and the operations above described repeated. By means of decanting the clear liquid through the floating arm the impurities and unburnt portions of the lime accumulate in the bottom of the lime water tanks, and provision is made for cleaning out the tanks by means of a chain pump. It will be seen from the diagram that there are 3 lime water tanks, and these are used in rotation; thus, while one is filling, a second is standing full for clarification, and the clear liquor in the third is being withdrawn into the softening tanks. The dimensions of each of these tanks are 32 feet long, 26 feet wide, and 19 feet 6 inches deep. THE SOFTENING OF HARD WATER 291 T EN 1 N /V2. TAN /V3. 5 /V4 FIG 17. 2Q2 WATER SUPPLIES After the lime water has been decanted into one or other of the softening tanks, this tank is filled by means of the pumping machinery with the hard water, and the agitation due to the water entering the tank is sufficient to cause an intimate mixture with the lime water. Samples are tested from time to time as the filling of the softening tanks proceeds to ascertain when the lime water which was first added has entirely been utilised by the hard water which has been mixed with it, and when the action is complete, and no further free lime is present, the tank is shut off from the pumps and the liquid is allowed to stand for a few hours to allow the precipitated chalk to deposit. When this has taken place the clarified liquid is drawn off from the tanks by means of floating arms, and is pumped into the service reservoirs. When the liquid has been drawn down to within two or three feet of the bottom, the tank is shut off, a fresh quantity of lime water is admitted, and the operations proceed as described. There are 4 softening tanks, each tank being about 85 feet long, by 70 feet broad, by 18 feet in depth. The cycle of the 4 tanks in general working is two standing full clarifying, one filling, and one being emptied after the water has been softened and clarified. The exact amount of lime water to be added depends upon various circumstances, but in working practice it is found that with the particular water in question 10 per cent, of lime water effects the largest amount of softening. After the softening tanks have been in use for a few weeks there has accumulated from 2 to 3 feet of chalk deposit. The tank is then thrown out of use, and the chalk deposit is pumped into pits, where it is allowed to dry and accumulate. 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. These processes all require a special plant. THE SOFTENING OF HARD WATER 293 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 proportion. The mixture then flows into a " soften- ing 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 con- structed 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 spray pipes are attached in such a manner as to play over the whole sur- face of the discs when set in motion, and the filters are rapidly cleansed. At Henley (population 6,500) such an apparatus, with five filters, has been in use since 1S82, 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 79,000} about 3,500,000 gal- lons of water per day are softened, and the plant is said to be the largest in the world. It includes nineteen filters, a softening tank 76 feet by 45 feet by 5i feet, four " lime " cylinders, mixer and limeh-slacking mills, 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 5,000,000 gallons per day.* The cost of softening at Southampton is Jd. per 1,000 gallons for working expenses and another Jd. for interest and repayment of loans, making a total cost of Jd. per 1,000 gallons. At Lambeth workhouse, with 1,500 * Much dissatisfaction at one time arose at Southampton in conse- quence 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 was declared to be the fault of the process employed and insufficiency of the filtering area, the patentees asserted that it was entirely due to the careless way in which the system was worked. Since additional filters have been provided, and the plant has been modified, excellent results have been obtained. 294 WATER SUPPLIES inmates, there is an installation for softening 300,000 gal- lons 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 2,000, and the total expense of treat- ing the water supply is said not to exceed ,50 per year, or, including interest on capital, about Jd. per 1,000 gallons. The saving in soap, soda, fuel for boilers, repairs to boilers, tea, etc., is believed to amount to over XI, 000 per year. 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 prepara- tion 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 approximate price of a plant softening, automatically, 1,000 gallons an hour, is 200; for softening 2,000 gallons, 280. The London and North- Western Railway Company use this system at various depdts. 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 2,000 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 THE SOFTENING OF HARD WATER 295 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 containing 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 soften- ing by this process is stated by the makers to average Id. per 1,000 gallons, though this will depend upon the character of the water treated. It appears to be a favourite with manufacturers, especially woolwashers 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 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 prin- ciple 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 WATER SUPPLIES FIG. 18. The "Stanhope" Water Softener. THE SOFTENING OF HARD WATER 297 FIG. 19. The "Stanhope" Water Softener (Clarifying Tower). 2g8 WATER SUPPLIES 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 portions 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 will soften 1,000,000 gallons of water per day, but the amount actually softened is only 300,000 gallons. Messrs. Archbutt and Deeley have recently devised an apparatus which they regard as having many advantages 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 THE SOFTENING OF HARD WATER 299 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 con- tains 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 combustion of coke in a special stove. The water when sufficiently carbonated no longer deposits in the tubes. By this process the labour involved is no greater for softening 20,000 gallons than for 2,000, and with large quantities the expense for labour is said not to exceed d. per 1,000 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 mag- nesia. 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. The Maignen " Filtre Rapide " Co. are the makers of a plant which softens and niters 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 sediment is deposited. Finally it traverses one of their rapid filters and reaches the storage tank in a completely 3 oo WATER SUPPLIES pq OJ OO -^ CO ^ CO t^ r^l Ttl . .CO S ^ 0 l^ OO UJ i* g 10 CO VLLON. CO Tfl rt< O i I pojcpt.- . .T* CN I-- VO ' ' CO o?q ^ (N ^ I O 03 O5 O t"- i O5 Tt< CO r-( ^ r-i O CO CO O o^ CO i-H O lO , M O5 i 1 O? t>- CO i 1 H^ 3 w CO 1 O5 COO51-H O O5 OO CO -* t> . O O C^l (M (M 'CO 1^.10 CO (N O5 i 1 O OO O CO CO CO (M t>- n kO OO ;Jr Oi 10 Oa CO ^ r-H * * O o O ^ (N ^ iQ CO CO O coi-i CO OO rH I 1 1 1 i ( * oo co t^- t^ l^ (N -CO ^? P TJ OO (N CO O5 cbi-i ^j '-^ " -2 |l 3 *..... . . ^ o . H QJ S* II P . ~cS ^ ^ be s^ 20J g s 'S ^ce^^SrS O^ w._^ g o 'rt r^ O "Pn^ ^ O * Q '3 Q $ S g be Bd jjiiiii lltS^I |. M M !' jf'iis'S^ ^^ J ^ "o M g o 5b"^ bx) bjo bo ^ III* s o Q THE SOFTENING OF HARD WATER 301 clarified condition. This is one of the processes which can be used on the small scale, for private houses, etc. Although certain of the processes described would appear to require very little personal attention, according to the statements of the inventors, yet, if uniformly satis- factory 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 occasion- ally to see that these proportions are being maintained, 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, 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 3 o 2 WATER SUPPLIES 1,000,000 gallons for lime and labour. This may be taken as a fair estimate of the cost for lime and labour of soften- ing an average sample of such hard waters as are being used for town supplies. Assuming that the interest of capital expended in plant, buildings, land, etc., increases the cost to Id. per 1,000 gallons, or 4 3s. 4d. per 1,000,000, and that the hardness to be reduced is only 16, the follow- ing may be taken as a low estimate of the saving effected by the softening 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 T V 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 popula- tion. 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, and in many cases the cost of softening is said to be less than that given above, and a larger proportion 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 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 THE SOFTENING OF HARD WATER 303 which have not been taken into account in the above estimate, yet which can be made to show a very con- siderable pecuniary balance in favour of softened water. Under the most adverse circumstances, where the water contains both lime and magnesia salts, and is " per- manently " 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 1,000 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. 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. Apparently these organisms become entangled in the pre- cipitate 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 tg be sewage 3o 4 WATER SUPPLIES contaminated, is being treated, the nitration must aim at removing all the micro-organisms which may have escaped precipitation, or have passed through the rapid niters supplied with certain of the machines that is, this rough nitration must be supplemented 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. Mr. Kent makes a machine in which water is softened and partially sterilised by heat. The water flows through a coil of tube, heated by a gas flame, oil furnace, or other source of heat. The water at near boiling point trickles down a tube containing a series of metal discs, and upon these much of the lime salt is deposited. The incoming cold water cools the treated water. This process, though less troublesome, is much more expensive than softening by Clark's method. CHAPTER 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 house- hold, 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 pur- chased 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 circumstances. On the other (35> 20 306 WATER SUPPLIES 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 ; (f) 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 * measured the water expended in * Parkes' Practical Hygiene. WATER REQUIRED FOR DOMESTIC PURPOSES 307 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 : 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 municipal 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 tdwns. The Rivers Pollution Commissioners, in their Sixth 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 the 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: 303 WATER SUPPLIES 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 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 botb systems varied enormously. With a constant supply Hey- wood and Middlesborough furnished the two extremes. At the former town, with 5,200 houses and 30 factories, only 20 gallons per house per day were consumed ; at the latter, with 7,000 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 men- tioned as supplying 7,000 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 WATER REQUIRED FOR DOMESTIC PURPOSES 309 examine the taps and fittings to prevent waste. With an intermittent supply, Huddersfield, with its 8,500 houses and 600 factories, only used 49 gallons per house daily, whilst Berwick, with 1,150 houses and 7 factories, used 330 gallons per house. That these enormous differences 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. Town. Population. nater He ad Daily. Saffron Walden . 6,108 11 gallons Melrose 1,300 13 Bridlington . 9,806 16 Halstead 6,100 17 ',' Chepstow 3,387 15 to 16 M East Ham . . 33,000 20 } , 5,000 20 St. Austell . 3,400 21 M Chelmsford . . 11,079 23 n Bristol , . v . 222,000 23 Bedford " . ' . 28,023 25 Weston-super-Mare . 15,869 26 " Swansea 93,864 27 Barking . 15,115 26 to 30 ," Nottingham . 211,984 28^ f >l Wolverhampton . . 82,620 29 ,, Grantham . 16,746 30 Yeovil 9,648 31 ,, Walthamstow , V . V . 49,400 36 The variations here, though not nearly so great as in the River Pollution Commissioners' table, are still very con- siderable. Having recently to make an examination of the Halstead supply, I verified the above figures. The supply 3 io WATER SUPPLIES 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 is engaged during the week at the crape factories, and Saturday is the great washing-day. The amount used on a Saturday was as under : From 8 A.M. to 2 P.M. . . . 9,800 gallons per hour 2 P.M. to 4 P.M. . . . 9,500 4 P.M. to 5 P.M. . . . 6,000 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 Wolverhampton the careful records kept at the Corporation 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 38J 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. Look- ing 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 WATER REQUIRED FOR DOMESTIC PURPOSES 311 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 considerably decreased. The following table * is interesting as showing the actual amount of water supplied daily by the London Companies and the wide difference in the supply per head. 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 Southwark 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. * Report of Royal Commission on Metropolitan Water Supply, 1893, 3 I2 WATER SUPPLIES 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 1893 17-10 9-8 26-9 100 Bradford 1891 18 to 20 20-0 38 to 40 100 Manchester 1893 15-0 9-0 24-0 100 Birmingham 1893 17-0 8-75 25-75 100 Glasgow . 1893 36-0 16-0 52-0 100 St. Helens 1893 18 to 21 18 to 20 36 to 41 100 Swansea 1893 23-4 4-2 27-6 32 All waste is included in the amount set down for domestic supply. The amount of water supplied per head per day in many cities in the United States is enormous. The following figures are taken from Vol. xxxix. of the Engineering Record (p. 322). New York in 1870 used 82 gallons per head per day, in 1899 the amount had risen to 119 gallons. In Boston, in 1895, 90 gallons were supplied and used as under : For municipal purposes For trade purposes For domestic use Unavoidable (?) waste . 5 gallons 30 40 15 90 In Philadelphia (Engineering Record, vol. xxxix., p. 430) no less than 230 gallons are supplied, but it is stated that half to two-thirds is recklessly wasted. On the other hand, certain continental cities have a much more limited supply than London. In Berlin, for example, the daily supply is said to be only 20.56 gallons per head per day, 20 per cent, being used for municipal purposes and 80 per cent, for domestic purposes. Waste of water arises from two distinct groups of causes (a) those over which the consumer has no control, and (b) WATER REQUIRED FOR DOMESTIC PURPOSES 313 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 sup- plemented by an unnecessarily great consumption, due to the use of imperfect 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 instrument resembling a large stethoscope the faults can be localised. 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 neighbourhood can be heard, the more distinctly the nearer the defect. The ear can also be applied to the uncovered main for a similar purpose, but it 3 i4 WATER SUPPLIES 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. I am informed that an. experienced man can during the quiet hours of the night detect defects by listening with this instrument in contact with the ground over the mains. 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 considerable, averaging 150 for each 1,000 houses con- trolled. 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 1,800, and an annual expenditure of 926 for staff and establishmental expenses. Each 1,000,000 gallons saved cost therefore 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 WATER REQUIRED FOR DOMESTIC PURPOSES 315 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 in which there are few or no manufactories. Towns in which there are very few water-closets often us 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 abundant 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 fittings, and all undue consumption checked by byelaws, or by insisting upon the use of water meters by large consumers. 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 316 WATER SUPPLIES supply to 23 gallons without any restrictions being placed upon the consumers. At Shoreditch, with a population of 87,000, 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 introduc- tion 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 expendi- ture 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 were 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 arrangement, 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. WATER REQUIRED FOR DOMESTIC PURPOSES 317 In America water meters are being largely used to prevent waste, and with great advantage. For example, in Milwaukee before meters were generally adopted the water used per tap was 1,781 gallons per day. Now, when the great majority of houses are furnished with meters, the amount used per tap is only 644 gallons. 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 supplied, and in Calcutta 35.4 gallons of filtered water and 8.9 gallons of unaltered, total 44.3 gallons; but in many other 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 require- ments 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 Liver- pool, during 1893,* 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, * Duncanson, loc. cit. 318 WATER SUPPLIES November, and December, and was about 9 per cent, below the average. (Vide Chapter XXI.) 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. CHAPTER 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 con- taminated with sewage or intermittently liable to such contamination, water containing mineral matter in ex- cessive 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 manufacturing 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 the filtration is conducted according to most modern methods. Where (319) 320 WATER SUPPLIES 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 he 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 construction 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 arrange- ment. The pipe is rarely of sufficient size, and sometimes SOURCES OF WATER SUPPLY, ETC. 321 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 contains little or no carbonate 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 considerably 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 have also been referred 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 sufficient for the purposes required. Many springs which flow freely in the late winter, spring, and summer fail completely 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 fyas passed away. 21 322 WATER SUPPLIES The less variable the flow, the more likely is it 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 prin- ciple 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. SOURCES OF WATER SUPPLY, ETC. 323 Depth. Flow per Minute. Flow per Day. Depth. Flow per Minute. Flow per Day. j 31 446 9 9-8 14,112 I 88 1,267 3 12-9 18,576 | 1-62 2,333 J 16-3 23,472 1 2-50 3,800 4 19-9 28,656 !i 3-48 5,011 4* 23-8 34,272 1 4-57 6,580 5 27-8 40,032 If 5-76 8,294 5| 32-1 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. 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 attention 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 imper- vious stratum beneath, 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 else- where. " 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 subsoil water flowing towards its natural outlet. Near the sea, however, the 3 2 4 WATER SUPPLIES 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 1J miles from the shore. The chlorine, which is normally about 3 grains per gallon, gradually increased, until a maximum of 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 one, the search for water is much more difficult, but a careful study of the local geology, to ascertain the dip 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 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 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 abundance 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 SOURCES OF WATER SUPPLY, ETC. 325 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 personally, and the twig through him. Twigs of other trees do not answer, since they do not possess the necessary elasticity, 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 deception, 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. A recent success was 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 the surface water was found. ... I should add that some time since an engineer made experi- ments 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 oil 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. 32 6 WATER SUPPLIES 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 dimensions 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 configuration, 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 con- tamination. Rapid fluctuations usually indicate variation in quality, as well as quantity, of the available water. Where limited amounts only are required, and the possi- bility 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 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 SOURCES OF WATER SUPPLY, ETC. 327 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 otherwise 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. Many attempts have been made to devise formulae for calculating the yield of water from wells and galleries (vide Friihling's Handbuch der Ingenieurwissenschafen). Certain of these have been discussed by Fuertes (Engineering Record, vol. xxxix., p. 28). The following is given for calculating the yield from a well sunk in a sandy or gravelly subsoil : Q = 3-142X (H 2 - /i 2 ) -f natural log. (2K -f- d), 328 WATER-SUPPLIES where Q = the yield in gallons per second. H = depth, of water in well, at rest, in feet. R = radius of zone of depression. h = depth after pumping in feet. d = diameter in feet. X = PV, where P the percentage of void in the sand or gravel (usually 30 to 40 per cent.) and V the coefficient of velocity of flow of water in the gravel = about -29 times the square of the effective size of the sand or gravel in millimetres. Obviously there are so many factors which cannot be determined with certainty that such a formula can have little value. Where the limited space available necessitates 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, 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. Good water can, in some cases, 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. XVIII.). According to the per- meability of the subsoil, the area capable of being drained SOURCES OF WATER SUPPLY, ETC. 329 by the well will vary in diameter from 15 to 160 times the normal depth of water in the well. In a loamy isoil 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 be nearly 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 XX., 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 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 J of an acre (1,210 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 330 WATER SUPPLIES 56,550 gallons for the year, or 155 gallons per day, a supply which would suffice for ten persons, allowing 15 gallons per head, or for 15 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-estimated the result being that in exceptionally dry seasons something like a water famine has occurred. The approximate 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 conditions, so variable in themselves, depend in a very great measure two other factors the loss by evaporation and by percola- tion. The only factors which are uninfluenced by the weather are the area, configuration, and character of the collecting 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 SOURCES OF WATER SUPPLY, ETC. 331 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 " catchment basin." In one such catchment basin, branching ridge lines may form two or more second- ary drainage areas. The area from which the water is to be collected may either be ascertained by actual measure- ment or be calculated from an ordnance map. The configuration, character of the surface and of the subsoil, and nature and amount of vegetation, 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 pene- trates the ground in one part of the area may reappear 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 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 consists 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, 332 WATER SUPPLIES in this country at least, it would be cultivated or used for pasturing cattle, and would therefore tend to pollute the water. The amount of water which may be lost by percola- tion 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 rainfall 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 a 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 ' ; purposes, and (f) 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 = 62 A (f Urn - E). In this equation ~Rm represents the average rainfall of a long series of years, and 4 Rra the estimated average of the three driest consecutive years. E = the loss of rainfall by evaporation, 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, SOURCES OF WATER SUPPLY, ETC. 333 the average amount of water which can be collected yearly during the three driest consecutive years would be 22,620 A x (4 Era - 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 1,500 or 1,600 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 country the loss by evaporation and percolation is given by the following authorities as under : Mr. T. Hawkesley, 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 for- 334 WATER SUPPLIES mula, therefore, will vary from ~ + 9, to - - + 19, -^ b bo being the unavoidable waste. 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 versa. Over the western half of this country, and in the more moun- tainous districts, 120 days' storage has been found sufficient, but in 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 collecting 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 surface 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 D = 1,000 -f JF. 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 SOURCES OF WATER SUPPLY, ETC. 335 experienced 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 available in the subsoil can be estimated have already been considered. 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. Where, however, two or more wells are required, necessitating a corresponding number of pumping stations, a considerably increased expenditure is incurred. 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. 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 324 as being affected by the sea, 1J miles away, is sunk in the chalk. Cases are also recorded in which impurities have 33 6 WATER SUPPLIES been found to enter a well after travelling a very consider- able 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 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 4J feet wide. The storage capacity of these and the lower part of the well is about half a million gallons (Borough Engineer's 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 accessible over very large areas to the well-sinker or borer, but it must not be forgotten that there is a little un- certainty 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 SOURCES OF WATER SUPPLY, ETC. 337 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 excesively hard and the latter salty. At Rugby a well sunk 1,200 feet yielded only brackish water, and at Middlesborough 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 1,000 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 crumpling the London clay back upon itself, so that this stratum had to be twice pierced. When the second layer had been pene- trated 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 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 considera- tion of the conditions bearing thereupon, referred to in Chapter VI., will assist us in arriving at fairly safe con- clusions. The information contained in the next chapter, gathered from experienced well-sinkers, engineers, geo- logists, 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. I cannot do better than close this chapter with a quotation from an address by Mr. W. WJiitaker, F.R.S., recently delivered at the anniversary meeting of the Geological Society. He says : " Underground water is 22 338 WATER SUPPLIES indeed a very complicated and difficult subject, making strong calls on our reasoning powers. In the case of springs and streams we are dealing with facts, things that anyone can see; but in the case of underground water it is a very different matter; we have to make inferences, and though our inferences may be warranted by all that is known on the subject, yet it is seldom that we can speak with certainty. There is, therefore, a certain charm in questions as to underground water that is wanting in the more prosaic subject of surface-waters. " The source must be some permeable formation of good thickness and with a broad outcrop, as the quantity of water in any permeable bed must depend on the amount of rain that falls upon it, and this latter greatly on the area of surface exposed. A well, therefore, must either be upon the formation that is to be the source of supply or upon some overlying formation through which it can be carried to the water-bearing stratum. These two classes of wells sometimes differ greatly. " In the first case, the well should be at a part towards which underground water flows : away, therefore, from an escarpment or ending-off of a formation, and towards the line of outcrop or where the next overlying formation comes on. It should also be in low ground, as a rule, so as to avoid needless depth. In the second case, when a well has to be taken through some thickness of overlying beds to reach the water-bearing bed, different conditions some- times arise, unless the well is near the outcrop of the water-bearing formation. " The method of flow of water through the rocks must also be considered. In some, this is mostly through the pores or the spaces between the particles of which the rock is built up ; but in some water-bearing rocks very little passes in this way. Sometimes the planes of bedding afford a sort of channel, but at others these are closed and well packed together. Often the flow is along joints, or SOURCES OF WATER SUPPLY, ETC. 339 structural planes that have been formed after consolida- tion : fault-planes may act in a like way. " Though, of course, every opportunity of studying the rocks at the surface should be taken, it must not be expected that they will show the same features when found at great depths, beneath a thick mass of overlying beds. Often it is ascertained that beds which are fairly open in sections that can be seen have their fissures, etc., more or less closed up below ground : for instance, at Richmond, where the Chalk has been worked horizontally under a great depth of Tertiary beds (from a little under to a little over 300 feet), a very great length of gallery has been driven with the result of cutting comparatively few fissures, and none of those large, so that but little water has been got ; while in the waterworks for Southampton, placed on the Chalk close to its outcrop, so that there was no occasion to sink to a great depth, a very much less amount of gallery has yielded a very much larger quantity of water. " Moreover, the Kent Company, which gives our largest supply solely from wells, has done comparatively little in the way of driving galleries, but has depended largely on simple wells and borings, which are either on bare Chalk or where there is no great thickness of other beds above the Chalk. " Again, the underground condition of a rock may vary greatly in places near together. The Brighton Waterworks give a good example of this; for, while at the Lewes Road Station the fissures in the /Chalk are many and small, in the Goldstone Bottom Station, not far to the west, the fissures are mostly large, but few. Yet the two stations are at about the same horizon in the Chalk, and there is no apparent reason for this difference between them. A somewhat similar case is that of Croydon, where the old works in the town give a much larger supply, without galleries (or at least with merely short connexions between 346 WATER SUPPLIES the wells), than that which is got from the new works, but little lower in the Chalk, at Addington, where there is a great length of gallery. " These are cited as illustrations of the uncertainty of underground work, an uncertainty with which many of my engineering and some of my geological friends are fairly familiar; and they should prepare us to be somewhat cautious in predicting, at all events before we know. " Not only do we find that beds pierced at great depths often have a character different from that which they put on at their outcrop, but also that waters found at great depths often vary much in their mineral contents from those in the same beds much nearer the surface. A well- known case of this sort is that of the waters in the Chalk under London, where the Chalk is thickly covered by Tertiary beds, those waters differing greatly from the waters in the bare Chalk northward and southward, in the increase of alkaline salts and the decrease of lime-salts. " Other like cases have been described in waters from Jurassic beds, as at Swindon anjd at Woodhall Spa, in both of which a large amount of common salt occurs, while in the latter case there is a regular mineral water. It is found, too, that waters in wells from the sandy beds of the Wealden Series often contain a goodly proportion of car- bonate of soda. " Such matters, and the occurrence of mineral waters generally, point to the need of alliance with chemists, and the advantage of getting full analyses of well-waters, which show the mineral contents and do not merely refer to organic purity or impurity. With this help we may be able not only to trace the origin and history of a water, but may also some day learn something of those slow, quiet, unseen changes that go on underground, through the agency of water in the rocks : a subject of which, I think, we know little as yet, at all events in this country." It is advisable in all cases to derive the whole supply SOURCES OF WATER SUPPLY, ETC. 341 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 elsewhere has not been favourably received. Apart from the enormous additional expense necessitated by a duplicate system of mains, it has many other objection- able features. At Berlin the water of the Spree, after nitration, 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 unsatisfactory, 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 niters through the natural gravel bottom, and is collected in earthenware 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 and other works are given by Palmberg and Newsholme in their Treatise on Public Health and its Applications in different European Countries, CHAPTER XVIII. THE PROTECTION OF UNDERGROUND WATER SUPPLIES. NOTWITHSTANDING the immense progress which has been made in this country in recent years in practical sanitation and in sanitary administration, outbreaks of preventable disease due to the pollution of water-supplies have been all too frequent. Common sense suggests that if it is desired to obtain a pure supply of water, a source should be selected, removed as far as possible from any contaminat- ing agencies, and that every reasonable precaution which science or experience can suggest should be taken to prevent either wilful or accidental pollution. At present only underground sources are being considered, waters derived from streams and rivers being discussed later. Both, of. course, are derived from the same source the rainfall but the modes by which they may become polluted are somewhat different, and the precautions which require to be taken to prevent pollution are also different. Whilst streams are fed in a great measure by the rainfall which has not penetrated the ground, but merely run over the surface, the subsoil water and the water in the deeper pervious strata is derived entirely from the rainfall which has been absorbed by the soil, and which has percolated to the depth at which it is found. It is obvious, therefore, that the collecting areas in the two- cases must be very different in character. The one requires an impervious or but slightly pervious strata, the other a pervious surface. The pervious surface will almost certainly, in this country (342) PROTECTION OF UNDERGROUND WATER SUPPLIES 343 at least, be tilled for agriculture, and more or less highly manured. Such manurial matters as are soluble will be dissolved by the rainfall, and the finer particulate matter will become suspended in the water. All underground waters, therefore, are more or less liable to pollution at what may be regarded as their source, the rain which has fallen upon the pervious ground, and if they did not afterwards undergo some efficient process of purification, underground sources would have to be abandoned. In shallow wells constructed near houses the water is fre- quently very impure, and is notoriously liable to specific pollution, a large proportion of the outbreaks of typhoid fever recorded in this country being due to the use of shallow well water. Too great proximity to houses and sewers can be avoided, but that no house drainage or human excreta shall be placed upon the gathering ground is a matter beyond control. Circumstances, therefore, compel the use of water liable to specific pollution, and the point for consideration therefore is, Can this water undergo naturally such a process of filtration as will render it for all practical purposes absolutely safe for domestic use? The word " filtration " rather than purification is here used intentionally, because the specific material which has to be removed from the water is not something in solution, but particulate matter in suspension, and as has been already remarked this particulate matter, though of ex- tremely minute dimensions, is capable of being removed by filtration. This particulate matter also must be living, and there is every reason to believe that neither the typhoid nor the cholera organism can survive more than a limited time in water, especially if the water be free from polluting matter, and that they will not live long in unpolluted soil. If therefore the subsoil can so filter the water passing through it as to remove these living organ- isms, or if these organisms in traversing the subsoil find themselves in such an unfavourable environment that 344 WATER SUPPLIES life is impossible, it is obvious that water which has percolated through a sufficient depth or flowed longi- tudinally through a sufficient thickness of the subsoil, will contain none of the specific organisms, and can be used without risk of producing these specific diseases. The water which falls upon the surface of a porous soil tends in a downward direction until it reaches the level of the subsoil water. It then takes on a lateral direction, flowing through the interstices in the stratum towards its natural outlet, whether this be a well-defined spring, a flowing stream or the ocean. During its progress the organic im- purities at first absorbed are more or less completely removed. The organic matter in solution becomes oxidised or " burnt " up, and we find the ashes, carbonates, nitrates, sulphates and phosphates only in the water if the oxidation has been complete. The living organisms are more or less completely removed, in part by the natural filtration and in part probably by other agencies which cause their destruction. A water originally very impure, and specifically polluted, may become hygienically pure and wholesome by passing through a sufficient thickness of subsoil. The upper portions of the soil, to which air has comparatively free access, especially if covered with vegetation, have the most powerful action. Nitrifying organisms abound, and convert the dead organic matter into simpler inorganic compounds, and the living organisms are more or less completely filtered out. So complete may be this purifica- tion that from properly constructed deep wells water may often be obtained almost, if not absolutely, free from organic matter, living or dead. These natural purifying processes have not as yet been sufficiently studied, but sufficient is known to enable fairly safe conclusions to be drawn as to the means which must be adopted to obtain a pure water supply from underground sources. Before referring more fully to these natural processes of purification, the brief consideration of the sources of PROTECTION OF UNDERGROUND WATER SUPPLIES 345 underground water supplies known to have caused out- breaks of typhoid fever or cholera will prove instructive. The late Dr. Ernest Hart prepared a historic summary of local outbreaks of typhoid fever in Great Britain and Ireland, occurring between 1858-1893, due to specifically polluted water, which summary contains a tabulated analysis of 205 epidemics. Considering only those due to the use of subsoil water and these form about two- thirds of the whole it will be found that nearly all were due to the use of water derived from shallow wells situated within a very few ieet of defective cesspits, leaky cesspools or sewers. Take two examples selected at random from the more recent outbreaks. " Well sunk in gravel with strong clay watertight bottom. Drain ran close to the well used by the first patient and leaked into the well. Evacuations thrown into the common ashpit and adjacent sink. All w r ells in the locality open to the same water movement and sunk in soil charged to overflowing with impurities of every kind." Or again, referring to a much more serious epidemic, " Water supply obtained from three wells with three headings, two headings serving as connect- ing tunnels between the three wells. The heading driven from one well only in the early part of the year, a large fissure struck, the inrush of water being so great that the men in the tunnel had to fly for their lives. Soil overlying the chalk in which were sunk these wells liable to sustained pollution by sewage." With each outbreak the same story is related. Wells sunk in a sewage-polluted subsoil, near drains, sewers, or cesspools, or in a fissured stratum, the fissures of which communicated more or less directly with the source of pollution. In no instance is there a record of an outbreak being produced by water derived from a well sunk in a carefully selected site, and in which the simplest precautions had been taken to prevent pollu- tion. The wells were so situated that anyone possessing a smattering of knowledge of sanitary matters would have 346 WATER SUPPLIES said that sooner or later they would become specifically infected and an outbreak of disease result. If the various reports upon outbreaks of cholera are consulted the same conditions are found, the absence of all precautions, and the source of fjecal contamination easily traceable. The evidence gained from dearly bought experience is in each series of cases the same. Professor Pettenkofer has long taught that a polluted soil is the best nidus for the propagation of the typhoid bacillus, and Dr. Hauser, of Madrid, expresses similar views with reference to the cholera bacillus. That the soil is the natural nidus of these disease-producing organisms outside the human body is now generally conceded, but there are soils and soils, and to explain all the facts it is necessary to assume that only certain soils are favourable, and that in others the conditions are so unfavourable that multiplication therein is impossible. The favourable soils appear to be those which contain organic matter, especially of animal origin, sewage and excremental matters generally. The unfavourable soils are those which contain least organic matter, and more especially are free from sewage pollution. These, of course, are not the only factors, but they are the only ones bearing directly upon the subject under con- sideration. In an investigation made on behalf of the Local Govern- ment Board, a preliminary report of which has recently been published, Dr. Sidney Martin found that the typhoid bacillus and the colon bacillus (an organism allied to the typhoid bacillus, and found in large numbers in all sewage matters) rapidly increased in the sewage-sodden soil from Chichester, whereas in virgin soil under similar conditions they very speedily died out. When black mould containing organic matter was used, both bacilli retained their vitality for a considerable period, whereas in none of the experi- ments with virgin soil did any growth whatever occur. Still more recently Dr. Robertson has published the results PROTECTION OF UNDERGROUND WATER SUPPLIES 347 of a series of experiments conducted at St. Helens, of which town he was the Medical Officer of Health. The results were very suggestive, and proved that the typhoid bacillus was capable of multiplying rapidly under certain conditions. He inoculated a large quantity of broth with the typhoid ' bacillus, and with this infected various patches of ground. Upon the patches which were manured with dilute organic solutions the typhoid bacillus throve lustily, upon the patches not so treated they languished and died. A very significant fact is also recorded by Dr. Robertson. When the ground was infected 18 inches beneath the surface the bacilli grew to the surface; when the surface was inoculated they only grew downwards to a depth of 3 inches. This inability of the rainfall to carry the organ- isms deeper into the soil, and the fact of the deep cultures growing upwards to the surface confirm the view that it is only in the surface soil that any active propagation can take place. At a little depth below the surface the conditions become so unfavourable that any growth which may take place is in an upward direction ; at a greater depth probably no growth whatever would occur, and the organisms would quickly die. Abba, Orlandi, and Rondelli * have recently conducted certain investigations at Turin to test the filtering power of the subsoil from which the water supply to the city is obtained. For this purpose they used diluted broth cultures of Bacillus prodigiosus. They found that this bacillus penetrated to a depth of 3 metres (about 10 feet) but did not pass into the ground water save after heavy and persistent rains. Whatever may be the explanation, there is much evidence to prove that at a very limited depth beneath the surface of a compact porous soil the subsoil and the subsoil water are practically sterile. Koch appears to attribute this to * Zeitschrift fur Hygiene, vol. xxxi., 1899, p. 66. Abstracted by Dr. McWeeney in Journal of State Medicine, vol. viii., p. 47. 348 WATER SUPPLIES a mere process of natural filtration, since in his paper on " Water Filtration and Cholera," he says, " Rain water when it sinks into the ground and ultimately becomes sub- soil water passes through far thicker layers and with far less rapidity than river water when passing by artificial filtration through sand filters. If the sand is only suf- ficiently granulated we have in soil filtration a much more perfect process than is at our disposal in artificial filtration. 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 in the case of Berlin, is quite free from germs. In other places the same results have followed from investigations made on this point." Quite recently I have confirmed these observations in some experiments made with sand taken from various depths beneath the surface. Up to a depth of about 4 feet organisms were present, but at 4 feet they appeared to be anaerobic, below 5 feet I could not find any organisms whatever. The bacterial purity of subsoil water, however, is not altogether due to the efficiency of the natural process of filtration. No doubt the conditions which obtain under- ground are very unfavourable to the growth of many organisms, and there is abundance of evidence to prove that the bacteria producing typhoid fever and cholera are in a more or less unfavourable environment when in water, and can only survive for a very limited period. Most of the experiments recorded, having reference to the vitality of the typhoid bacillus in water, have little or no bearing upon the subject under consideration, the conditions under which they were conducted being so different from those which obtain in nature. Others again are unreliable on account of fallacies underlying the methods of examination adopted. This question of survival is a point of the utmost importance. Again, as far as is known, typhoid fever and cholera are exclusively human affections, and PROTECTION OF UNDERGROUND WATER SUPPLIES 349 there is no evidence to prove, nor are there any recorded facts which necessitate the assumption, that cattle of any kind suffer from these specific diseases and discharge ex- cremental matter capable of specifically infecting the soil. The remarks already made with reference to soil pollution apply equally to those cases in which the source of pollu- tion is beneath the surface, as to those in which the filth is deposited upon the surface. Fortunately all sewage contains microbes which, during their growth and develop- ment, tend to break down the dead organic matter upon which they subsist, into simpler and more stable forms, that is to say, under suitable conditions sewage will purify itself. This fact, which is only just beginning to be recognised, is being taken advantage of for the purification of sewage, in the so-called bacterial filters of Dibdin, Ducat and others. Everyone who has had to watch the process of excavation in the vicinity of defective sewers and cess- pools has observed that there is little or no evidence of pollution in the subsoil, except in the immediate vicinity of the defects which permitted the pollution. This purifying action of the subsoil is easily demonstrated on any fairly large patch of drift upon which a village stands. On the side furthest from the natural outlet of the water, the wells yield what may be called the normal water of the patch, containing very little organic matter and only comparatively small quantities of chlorides and nitrates. Within the village many of the wells will be found to be highly polluted, but almost invariably some will be found which, either on account of their better construction or their greater distance from a source of pollution, are also practically free from organic matter, though containing large quantities of chlorides and nitrates. On the side nearest the natural water outlet the same condition is found, the only evidence of the previous pollution being the ashes of the consumed organic matter. Besides the chemical change the natural process of filtration has taken 350 WATER SUPPLIES place. Subsoil water travels horizontally at a very slow rate indeed, compared with the rate at which water is passed through artificial filter-beds, and it is practically impossible for particulate matter, living or dead, to be carried any distance by the current. In certain places, however, the subsoil water may flow with an appreciable velocity, and in channels more or less defined. The reason for this can easily be understood. Suppose that a valley scooped out of some impervious stratum, such as the London clay, were to become ob- literated by being filled with sand and gravel. A portion of the rainfall upon the now exposed area would percolate into the sand and tend towards the centre of the original valley, finally makinjg its way to the lowest point. The greatest flow would be along the bottom of the valley, and doubtless here in the course of time, it might be ages, the resistance would diminish from the washing away of the finer particles, and after reaching this channel, possibly no further purification or filtration would take place. Herein lies one of the dangers of the use of subsoil springs. These springs are but the natural outlet of the subsoil water, and impurities entering the subsoil immediately over the line of flow are much more likely to be dangerous than impurities entering elsewhere. The nearer the spring or the line of flow the greater the danger and the greater the need for protection. In the neighbourhood of rivers also, there is often a considerable flow of water in the subsoil, rendering it necessary to direct particular attention to the protection of the ground above the point at which water is being abstracted. So far it has been taken for granted that a subsoil of uniformly compact consistence was being considered, such as deposits of drift, beds of sandstone, etc. ; but there are other pervious water-bearing strata, of which chalk is the best example, which are not uniform, but full of fissures. It is obvious that water which has once entered these open PROTECTION OF UNDERGROUND WATER SUPPLIES 351 fissures will undergo little further chemical nitration, and that polluting matters may be carried great distances thereiyi. Here again, however, the upper surface of such a stratum is almost certain to be fairly compact, the fissures being obliterated by the surface soil, and water passing through will be more or less completely purified. In travelling along the open fissures, the velocity of flow (save in the immediate vicinity of the natural or artificial outlet) must be very slow, giving time for sedimentary matters to be deposited, and for such organisms as the typhoid and cholera bacilli to die and be carried down therewith. Water collected from deep wells in fissured strata, at points many miles removed from the exposed collecting area, is usually found to be particularly free from organic matter, and to contain few if any bacteria; but the freedom with which water can traverse these fissures has too often been painfully obvious in counties near the coast, inasmuch as wells sunk at great cost have had to be abandoned on account of the rapid infiltration of sea water. By continuous pumping, the water level had been so depressed that a return current from the sea was set up. The area which may be directly drained by a well in a fissured stratum is therefore enormously larger than that which can be affected in a uniform porous stratum. To ensure a continuous supply of hygienically pure water from an underground source, many points have to be taken into consideration; and no general rules can be laid down applicable to all circumstances. There are many wells used for large public supplies which ought to be abandoned, on account of their proximity to groups of dwelling houses. In many cases these houses have been erected since the works were established; too small an area of land was acquired in the first instance, and the mistake cannot now be rectified. There should be an area of ground around each such well under the absolute control of the purveyors of the water. The well should be con- 35 2 WATER SUPPLIES structed so as to admit water only at the lowest point possible. If the pumping machinery is in or over the well care should be taken to prevent dirt of any kind, especially from the workmen's boots, reaching the water. The im- mediate vicinity of the well should either be uncultivated or laid down to grass, but not fed. An outer ring should be similarly laid down, but cattle might be permitted to feed thereon. These two rings may be called the inner and outer protective areas, and the inner ring should be so enclosed that no one can enter " except on business." The area of this inner ring should be, at least, as large as the area of the cone of depression produced by the pumping. For example, suppose that 45,000 gallons are being pumped per day from a sandy subsoil, and that the depression of the water level in the well caused by the pumping is 9 feet. Each cubic foot of the saturated sand would yield about H gallons of water. To yield the 45,000 gallons therefore, 30,000 cubic feet of the subsoil would be drained. The cone of depression having a depth of 9 feet, the area of its base would be 10,000 square feet, representing a circle with a radius of 57 feet, the well being at the centre. The cone, however, has not straight sides, and to be perfectly safe therefore a radius of 30 yards had better be allowed. The outer protective area should have a radius double or treble that of the inner area. In a uniform subsoil the rapidity with which the water travels toward the well decreases as the square of the distance. If within 3 feet of the well the movement of the water is at the rate of 1 foot per second, at 30 feet the movement of the water will only be at one one-hundredth of that, or 1 foot in 100 seconds, and at 30 yards the rate will be 1 foot in 900 seconds. Therefore, at a certain distance away from the well the movement of the water is so slow that perfect nitration is secured. That is to say, the water passes through the subsoil very much more slowly than it passes through the sand in an ordinarily PROTECTION OF UNDERGROUND WATER SUPPLIES 353 constructed filter, and for that reason the protective area need not extend, assuming my views to be correct, more than a limited distance round the well. I am strongly of opinion that this protective area should in future always be insisted upon, but its extent may have to be denned in each individual case. The conditions vary so greatly that no general rule can be adopted. In deciding, many factors have to be taken into account : the contour of the ground, the depth and nature of the subsoil, the height of the subsoil water and the range of its fluctuations, the possible sources of pollution, the amount of water to be abstracted, etc. The direction of the flow of the subsoil water must also be considered, since polluting matter entering the soil on the side upon which the water is flowing towards the well is naturally more dangerous than if it enters on the side where the flow is from the well. Naturally also a much larger protective area will be required where the subsoil water is only a few feet from the surface, than where it is 15 to 20 or more feet below. Where the underground water is known to be flowing in a fairly well defined underground channel, the protective areas had better be elliptical, the longer axis having the direction of flow, the well being on this axis but nearer the end towards which the water is flowing. This elliptical protective area will in most cases be desirable for springs, for reasons which are so obvious as not to require enumeration. In many instances the protection of the water is rendered more difficult, and the problem becomes more complex, from adits or collecting channels being driven or trenched in one or more directions in order to increase the available supply of water. These drains should be laid as low as possible. Only under exceptional circumstances should they be less than 10 feet deep, and the trenches should be very carefully filled in and tightly rammed. The whole 23 354 WATER SUPPLIES of this trenching should be well within the inner pro- tective area. Where the subsoil is fissured the danger of pollution is greater and protection more difficult, since the source of the danger may be concealed and may almost defy detec- tion. A striking example of these dangers was furnished by the outbreak of typhoid fever at New Herrington, Durham. Any fissure so directly connected with a well would probably give indications of its existence soon after heavy rains by the effect upon the water in the well by rendering it more or less turbid. In all cases where such turbidity is produced, however slight, there is cause for anxiety, and both the well and its surroundings should be examined to ascertain the cause. If a heavy rainfall can wash into the well visible particles it could still more easily carry with it the minute organisms which cause disease, should such unfortunately happen to be within its sphere of influence. Surrounding such wells there should be protective areas, but their form and dimen- sions could only be defined after a careful survey of the district, more especially with reference to the dip of the stratum, and the general direction of the fissures. The locality where any fissures were suspected of reaching near the surface would require an especially careful examination. If within the well or adits there were numbers of fissures yielding water some useful information might possibly be obtained by an examination, chemical or chemical and bacteriological, of the water from those flowing most freely. Such wells require careful watching, and frequent sys- tematic analyses should be made to ascertain to what extent, if any, the quality of the water is affected by the rainfall. The greater the variation the greater the risk, especially if the variations rapidly follow the rainfall and are accompanied by an equally rapid variation in the flow. If the variations in character and quantity are but slight, and only occur some time after the rainfall, and especially PROTECTION OF UNDERGROUND WATER SUPPLIES 355 if there is never any indication of turbidity, then the risk is a minimum and may possibly be ignored. Deep wells drawing water from subterranean sources overlaid by thick beds of impermeable clay are generally considered to yield the purest and safest of waters. Doubt- less where the site has been judiciously selected and the well carefully constructed, such is the case, but deep wells as well as shallow wells may be defective in construction and admit of pollution taking place. Wherever constructed the gathering ground feeding it must be some distance away. This outcrop should be examined, the more care- fully the nearer it is to the well. It is desirable to know if any possible sources of danger exist, even if they cannot be removed, especially if within one or two miles of the well. At a further distance, possibly they may be neglected as powerless for harm, the time which would elapse between the rainfall reaching the ground surface and the well being ample to secure a satisfactory purification. The chief source of danger is from the admission of possibly polluted subsoil waters. It is often difficult to effectually block out the water from superficial strata, but it can be done, and should be done. For further security there should be a small protective zone kept free from all pollu- tion. Greater care also should be taken within the well to> prevent dirt, especially from the shoes, defiling the staging and being washed into the well. Samples of the water collected on a uniform plan, and at regular intervals, should be submitted to analysis and careful records kept. For this, however, to be of real service the water must be derived entirely from the deep source. If there is a variable admixture with subsoil water, the value of the analytical record is greatly decreased. Such careful and( systematic analysis will detect any variations in the character of the water, and possibly sound a note of warning on the approach of danger. Where bored tube wells are used and the tube forms the 356 WATER SUPPLIES suction pipe of the pump, danger of insuction of subsoil water, possibly contaminated, certainly exists and should be carefully guarded against. The action of the pump is to withdraw the atmospheric pressure from within the tube, and the excess of pressure outside will force air or water through the most minute defect, through apertures so minute that under ordinary circumstances neither would have passed. When this action has once been set up, the openings are bound to increase in calibre and insuction becomes still more easy. Whilst the deep wells constructed to supply large com- munities are usually carefully made, sufficient care does not always appear to be taken in the construction of deep wells when only intended to supply a farm or a few cottages. I have known several hundreds of pounds spent in boring and sinking such a well, and then, to save a few additional pounds, the sunk portion has been so defective and the top so badly protected that the water has become polluted. Whether underground water be drawn from a superficial or deep water-bearing stratum, there is no doubt that the chief factor in protecting it from pollution is the provision of an area round the well or point of collection which is under the control of the owners of the well, and which is kept free from all matters of an objectionable character. In the past too little care has been taken, but it is tolerably certain that in future both Parliament and the Local Government Board will insist upon efficient protection, and the provision of ample protective areas. Existing sources of supply should be examined and steps taken to secure the necessary protection when this is defective. If such is not possible and in some instances this will probably be found to be the case efforts should be directed towards providing a less dangerous source of supply. It will be better to voluntarily abandon the works now than to wait until an outbreak of 1 typhoid fever or cholera arouses public indignation and compels their abandonment. PROTECTION OF UNDERGROUND WATER SUPPLIES 357 Finally, all public supplies should be periodically examined even to the minutest detail and the results recorded. These inspections should be supplemented by chemical or chemical and bacteriological analyses at more frequent and regular intervals. Were the precautions above indicated universally adopted, I am convinced that there would no longer be any fear of the specific pollution of our underground water supplies, and that one of the most frequent causes of the epidemic prevalence of cholera and typhoid fever would cease to exist. CHAPTER XIX. THE PROTECTION OF SURFACE-WATER SUPPLIES. MUCH more attention has been given in recent years to the protection from pollution of river, spring, and well water, than to the protection of surface-water sources of supply. This is doubtless due to the fact that all the recent large outbreaks of typhoid fever have been due to the use of river or spring water, and the smaller outbreaks to polluted shallow wells. Reference to the Local Government Board and other re- ports on outbreaks of typhoid fever shew that surface-water collected on a large scale for the supply of a town or series of towns or villages has rarely been charged with the spread of that disease. This is a subject of congratulation to those towns, so numerous in the north of England, deriving their water from such sources. I attribute this immunity entirely to one cause, the storage of the water in large reservoirs. The storage usually amounts to from 100 to 200 days' supply. During this storage the water is fully exposed to the air for oxidation, and to sunlight for insola- tion, and the long period of rest secures more or less thorough sedimentation. I feel tolerably certain that the typhoid organisms, if introduced into such a reservoir, have but a remote chance of surviving and reaching the water mains in a living condition. The environment is dis- tinctly unfavourable ; the sunshine quickly kills them as they approach the surface, and by sedimentation they are deposited with the mud at the bottom of the reservoir. (358) THE PROTECTION OF SURFACE-WATER SUPPLIES 359 We cannot be certain, however, that special conditions may not arise permitting such organisms to reach the mains ; hence, apart from sentiment, no reasonable effort should be spared to prevent the pollution of the water by any matter which could possibly be infected. To secure at all times a thoroughly wholesome, bright, and palatable water should be the aim of every authority having control of any public water supply. Where full control of the collecting area is secured and the whole converted into prairie land without houses or farms, mines or other works upon it, and with but few public thoroughfares, and the storage reservoir is of very large size, filtration, may possibly be dispensed with, but although it ceases to be a very important factor, I should always regard it as highly desirable. To obtain full control of a gathering ground is, however, a very difficult and often impossible procedure. The subject was thoroughly discussed recently before a Parlia- mentary Committee when a Bill was being considered in which a water authority sought to obtain this complete control. Partial control had already been obtained and many houses demolished. Certain farms had been acquired and laid down entirely to grass. There were many foot- paths, certain highways, stone quarries, etc., and the evidence showed that so many interests were involved, public and private, that absolute control was impossible. People walking along these footpaths and mads in secluded districts cannot be prevented from obeying the calls of Nature. Accommodation may be provided at quarries, but no one can compel the men to use them and them only. Hence when all has been done there are risks which must be run and against which some other mode of protection must be devised. In this country, which is becoming more and more thickly populated, and where even the most remote districts have charms for tourists, I doubt very much whether any upland surface can be kept absolutely free from pollution. 360 WATER SUPPLIES Ample storage may possibly be in many cases a sufficient safeguard but, as we shall see shortly, there are other reasons for preferring nitration also. There are many gathering grounds, however, where such efficient protection is impossible, and where a certain, amount of pollution by manurial or sewage matter is unavoidable. These are districts in which more or less of the land is under cultivation. The land may be so valuable that purchase is out of the question, or there may be other insurmountable difficulties with reference to its acquisition. Even in these cases very often great improvements may be effected by efficient supervision of the sanitary arrange- ments, scavenging, etc., by constructing drains and sewers to convey the polluting matter beyond the boundary of the watershed, by arranging that no manure containing human excrement shall be used. Where such arrangements cannot be made the question must arise as to whether the water- shed should not be abandoned or whether the storage with nitration can be depended upon for preventing any infective matter reaching the mains. Every case of this kind must be discussed on its merits, and after a thorough and systematic examination of the watershed. I have seen reservoirs inefficiently protected and with footpaths along the banks. On these footpaths I have seen human excre- ment, and in the water I have seen drowned animals. It is obvious, therefore, that so far as is possible both animals and human beings should be prevented from gaining access to the reservoirs. Sometimes the water from such an unsatisfactory collecting area can be utilised as compensa- tion water for manufacturing purposes. Where surface-water supplies are used a large storage is always necessary, in order to impound water during the wet seasons for use during the dry. This alone assures storage sufficient for hygienic purposes, for bleaching, more or less completely, peaty waters, for allowing sedimentation, and time for the destruction of the typhoid microbe. The THE PROTECTION OF SURFACE-WATER SUPPLIES 361 greater the storage, the better for all these purposes. As previously stated, such storage is probably sufficient, save under very exceptional circumstances, to insure safety. If the water gets very low, however, in the early autumn, and very heavy rains come on suddenly, it is quite possible for impure water to reach the mains. After a long dry season, polluting matter, if any, would accumulate on the watershed and be washed down with the first storm. The water then would be unusually polluted, and it would have unusual facilities for rapidly traversing the storage reservoirs and reaching the consumers. Efficient filtration would now be the last and only line of defence. Filtration, efficiently conducted, would at such times prevent 99 per cent, of the organisms from entering the mains, and experience teaches that the risk of using such a water, properly filtered, is very small indeed. But apart from protection from infection filtration is almost indis- pensable, if we wish at all times to supply a bright and palatable water. We cannot prevent low forms of vegetable and animal life being carried into the reservoirs, nor can we prevent their multiplication therein. If the water is not filtered, these are delivered with the water to the consumers, and impart to the water an unsightly appear- ance, and sometimes a very disagreeable odour. Even when not visible at the time of delivery, they may so rapidly multiply afterwards, that vessels in which the water has stood for a night or two become coatecl with a more or less slimy deposit, or with a distinct green growth. This condition is one which frequently causes loud complaints, and such a water cannot be regarded as sufficiently satis- factory for a- public supply. To sum up, I strongly advocate three distinct lines of defence : 1. The utmost possible control of the watershed or collecting area. 2. Very ample storage. 3. Sand filtration. 362 WATER SUPPLIES Where the water is acid, or has a plumbosolvent action, the filtration should be through a mixture of sand and limestone, and the softer the limestone the better, the object being to neutralise the acid and cause the water to dissolve a small quantity of carbonate of lime, as by this means the plumbo-solvent action is more or less completely destroyed. The Local Government Board has recently issued a circular bearing upon the protection of water supplies, and suggests that every sanitary authority should obtain accu- rate information in such matters as the following : 1. Where water is derived from gathering-grounds or from springs. Whether drainage from human habitations, farm-yards, and the like finds its way directly or indirectly into the reservoir or to any part of the water service, and whether risk of access to the water of human excreta and similar refuse is likely to arise. 2. Where water is derived from deep wells. Whether surface or other water liable to be contaminated by drains, sewers, cesspools, and the like reaches, or is liable to reach, the wells. The existence and direction of fissures in the strata deserve especial consideration in this respect. 3. Where water is derived from shallow wells. Whether the wells are so circumstanced that they run risk of contamination by reason of drains, privies, cesspools, or middens, or by the deposit of manure whether derived from human excreta or n,ot in or on the ground in the neighbourhood of the wells. The district councils are reminded that they are respon- sible for the wholesomeness of water which they themselves supply, and that they should by careful inquiry make themselves acquainted with the sources, nature, and quality of the various supplies in all parts of their districts. This circular letter would have been more complete had it also directed attention to section 7 of the Public Health (Water) Act, which renders it obligatory on the part of THE PROTECTION OF SURFACE-WATER SUPPLIES 363 every rural sanitary authority from time to time to take such steps as may be necessary to ascertain the condition of the water supply within their district, and authorises the payment of all reasonable costs and expenses incurred by them for this purpose. CHAPTER XX. 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 population 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 department 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 conservative 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 (364) WELLS AND THEIR CONSTRUCTION 365 lining the well with bricks, set dry, and resting upon a wooden curb, still almost universally prevails. The brick- work 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 consider- able 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, how- ever, 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 steindng, or lining with a cylinder of brickwork or of iron or other material will only be necessary to keep out the water from 366 WATER SUPPLIES the more pervious surface soil. If bricks be employed they must be well bedded on the rock with cement, and the whole of the brickwork lined inside with hydraulic cement, arid 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 brick- work 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 precautions 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. 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 man can easily work inside and undermine the edge, when the weight will cause them to descend. Of course the joints are afterwards " pointed " 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. Or the well may be con- structed in the ordinary manner, dry steined with 4|-inch brickwork if necessary, and the tubes then lowered and WELLS AND THEIR CONSTRUCTION 367 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 12 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. Probably the best plan is to solder a baffle plate to the suction pipe and imbed this plate in the side of 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, 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 fr.Qm above., *' To achieve this. 3 68 WATP:R SUPPLIES 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 nitration of the great waterworks. In fact it really gives a greater pro- tection, since it is not exposed to the many disturbances in the process of nitration 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,* 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 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 thickness. 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 organ- isms," arrived at the following conclusions : " White crystal sand, yellow sand, and garden earth have no 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 de'adly 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. * And of typhoid fever nd other diseases disseminated by water. WELLS AND THEIR CONSTRUCTION 36$ be carried through 2J 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, since 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 1J 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 a sample drawn for examination, and the quantity available ascertained. If either the quantity or quality be unsatis- factory, the tubes can be driven deeper, or they can be withdrawn and redriven in another spot. A well of this 24 WATER SUPPLIES 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 " Abyssinian " 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 circumstances, 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 th,e fine particles and debris from around the terminal tube and the formation of a natural cavity in which the water accumulates. In suitable locali- ties these tube wells answer ad- mirably, and not only are cheaper to sink, but yield a safer supply of water than a sunk well. One FIG. 20. Abyssinian Tube Well. WELLS AND THEIR CONSTRUCTION 371 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. What- ever 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 provided. 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. IJin. 150 to 600 Le Grand and Sutcliff 2 . 300 to 1,200 3 600 to 2,400 4 1,200 to 4,400 li 150 to 900 C. Isler and Co. 2 300 to 1,500 3 450 to 3,000 > Messrs. Le Grand and Sutcliff have kindly furnished me with the following table (see page 372), 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 contamina- tion, but they are much less expensive. The probable cost of a well can easily be calculated from the following estimates (see page 373). WATER SUPPLIES bear tum r- ra r r^r^ 11 ^3 nS t3 a a ft "a . WELLS AND THEIR CONSTRUCTION 373 Twelve-Feet Tube with Hire of Plant and Man to Superin- tend Driving. Add for each additional Foot. Pump, Column, and Foundation. 1^-inch tube 240 3s. 2 10 to 3 10 2 3 10 4s. 6d. 3 7 10 10s. 3 10 to 4 10 4 9 15 13s. " . To the above must be added the man's time in travelling, railway fares, carriage of materials, etc. A well recently driven in one of my districts to a depth of 17 feet, a 2-inch tube being used, cost 8 12s. 4d., the items being as under. 17-feet 2-inch tube well . 4-inch column, pump, and foundation Hire of man and plant . Man's time travelling Railway fare and carriage Total 2 14 6 380 1 10 076 12 4 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 R. 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. 374 WATER SUPPLIES 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 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 18 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 (6) to provide a receptacle for the pumps. It is, however, found that in many cases the dug well can, with advantage, 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 srr x-' AND THEIR CONSTRUCTION 375 that only water from that particular spring is supplied. In the older wells the tubes lining the bore are usually not continuous^ 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 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. R. 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 3,050 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 1,500 gallons per hour, the quantity obtained by the 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 376 WATER SUPPLIES 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 drawing from a tube well could get 950 gallons per hour plus 40 per cent. ; that is to say, 1,330 gallons per hour. Therefore, the tube well would in 10 hours yield 13,300 gallons a gain, in that time, in spite of absence of storage, of 1,800 gallons; and the pumping from the tube well could be continued uniformly 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 decreas- ing 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 WELLS AND THEIR CONSTRUCTION 377 feet under water. These facts are of the highest import- ance 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 considered 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 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 the water would rise 100 feet before it came 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 communica- tion in spring A are small, and the friction is depriving us of the advantage of the great head of water. The channels of communication from spring B are free and large. One may, however, be deceived unless the test of pumping is a prolonged 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 prolonged period of rest. This proves that while the channels of communication are large, the area which is being drawn from is small. Under such circum- stances a multiplication of wells would be of no advantage; but in many instances th 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 378 WATER SUPPLIES 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 2,000 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. 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 imperfect joints very frequently admitted of 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, and 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 WELLS AND THEIR CONSTRUCTION 379 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 constructed 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 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." Notwith- standing 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 reasonable doubt that neither of the tubes was 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 WATER SUPPLIES 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 attach- ment. 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. At 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 pro- fessional well-borers, and pay treble the price for a properly-constructed well, than to employ the local men. Sir R. Rawlinson, in his Official Report to the Local Government Board on Water Supplies, etc., gives the follow- ing 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. Diameter. Inches. Cost of Cast or Wrought-iron Pipes per Foot. First 100 Feet. Second 100 Feet. Third 100 Feet. Fourth 100 Feet. 3 or 4 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. WELLS AND THEIR CONSTRUCTION 381 The following schedule of prices for borings from the surface from 3 to 12 inches in diameter, is exclusive of lining tubes but includes 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. 300ft. 400 ft. 500 ft. 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 : 3-inch internal diameter, J inch thick, 4s. per foot 4 5s. 6 T %- 9s. to 10s. 7i Us. to 13s. 8^-inch diameter and & inch thick, 15s. to 17s. 10 18s. to 20s. 11 23s. to 25s. The approximate depth at which water may be reasonably expected to be found, and the nature of the strata to be penetrated, 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 tables on pp. 383-4 give the details of a number of 382 WATER SUPPLIES 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 feet to 60 feet descended is a fair average. A well 1,000 feet deep, therefore, may be expected to yield a water having a temperature 16 to 20 higher than that of the subsoil water in the same locality, so warm in fact as to be decidedly unpalatable. 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 invariably predicted. The supply obtainable may be increased in various ways. By driving two or more tubes, and connecting 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 successful. 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 WELLS AND THEIR CONSTRUCTION 383 ?L bo sfsMOf I" 8 - >5 III cS^. So <^> -8 1 lllil 43 *A S^ o gggggg J^Sj |-8 | S.S-S.SriB 1 S NS * ?D I"- t CO 03 g OT 1 -S O O *$ O 54-1 1 i ater-bearing Stratum. |.|j l||l||l ? I ^^ Locality. flfjii 02 O PH O2 H C/2 WELLS AND THEIR CONSTRUCTION 385 below the water level, so that pumping may go on con- tinuously, if necessary, until the head of water has been reduced about 80 feet. 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 surrounding 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 Company placed a charge of gelatine, weighing 18 lb., 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 recent years by the respective governments. Queensland. During the last few years many wells have been bored by the Government under the supervision of the official hydraulic engineer. The number of successful bores during the past eight years (1892-1900) appears to be 424, and the cost about 1,000,000. Three hundred of these wells overflow, yielding over 190 million gallons of water daily. All the borings made have not been success- ful; in some instances no water was found, in others the water was not fit for domestic purposes, and some bores were abandoned for other reasons. The chief wells are : 386 WATER SUPPLIES District.. Depth. Yield per Day. Temp, of Water. Cost, Barcaldine . 691 ft. 175,000 galls. 102 F. 1,340 Blackall 1,663 , 300,000 119 F. 5,074 Charleville . 1,571 , 3,000,000 106 F. 3,525 Cunnamulla 1,402 , 540,000 106 F. 2,316 Muckadilla . 3,262 , 23,000 124 F. 7,382 " 65-mile bore " 2,362 , 104,000 3,073 About 715 public and private wells have been sunk, varying in depth from 86 to 2,484 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 1,502 feet deep, and yields 3,500,000 gallons of water daily (112 F.), at a pressure of 200 Ib. to the square inch. The yield at the present time from all the wells is estimated at over 200,000,000 gallons per day. The flow of a largfc proportion is uncontrolled, and most of it wasted. A bill was recently introduced to regulate the flow from these bores and prevent the lower- ing 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 1,220 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. 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 2,000 feet without water being dis- covered ; in others the water obtained was unfit for domestic WELLS AND THEIR CONSTRUCTION 387 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 Offieer-in- Charge for Water Conservation, issued a report on Artesian boring, containing sections and descriptions of all the Government 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 40 other bores in progress. Particulars are also given of forty-five private bores. The wells vary in depth from 53 to 2,000 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 1,000 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 1,000 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 legislation, as is already done in some of the North American States. 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 1 per cent, of this finds its way into the rivers. It 388 WATER SUPPLIES 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 under- ground water. Since the commencement of operations in May, 1891, out of a total of 341 holes bored, water was WELLS AND THEIR CONSTRUCTION 389 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 Colesburg, 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 1,200 feet), but the results are not encouraging. In Bushmanland and Bechuanaland, where the general geo- logical 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 2,000 ; in the San Joaquin Valley, California, about 3,000; in the San Louis Valley, 2,000; in Deseret, 2,000, 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 3 go WATER SUPPLIES the reclamation of the Great 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 ultimately 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 Purbeck and Portland stone often contain a considerable amount of water in their fissures, but under the latter rock WELLS AND THEIR CONSTRUCTION 391 water may be found in the porous stratum between it and the elay 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 limestone 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 meta- morphic 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. CHAPTER XXI. 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 four following types (a) Lifting pumps, (b) Plunger or force pumps, (c) Centrifugal pumps, and (d) Air Lift pumps. (a) The commonest form of pump, the atmospheric, is the simplest form of this type. The essentral 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 'doses, and the water is forced through the valve in the piston, and at the next up-stroke (392) PUMPS AND PUMPING MACHINERY 393 is discharged from the pump. The height at which 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, therefore, 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 connected therewith, into which the water rises with every stroke of the piston. As each stroke not only has to overcome 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 394 WATER SUPPLIES volume of water with such a pump than with a single- barrel of capacity equal to the two together. With 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 intro- duced 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 PUMPS AND PUMPING MACHINERY 395 plunger works is connected with the valve box by an opening near its base, and the plunger does not accurately fit the cylinder in which it works. When pumping is in operation the water rises in the suction pipe to fill the vacuum produced 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 largely employed for raising water to considerable 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. ( 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 pump 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 PUMPS AND PUMPING MACHINERY 401 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 : Diameter of Pump Cylinder. Weight of Corresponding Column of Water 10 Feet High. 2 inches 3 !,' 5 " 6 13-6 Ib. 21-2 30-6 41-6 54-4 85-0 122-4 Example. Required 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 Ib., the pressure of a column 80 feet long will be 244.8 Ib. 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 ?^1 8 = 40.8 Ib. 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 Ib. 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 26 4 02 WATER SUPPLIES 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 : 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. By 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 receiving considerable attention in consequence of the intro- duction 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 anywhere 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 PUMPS AND PUMPING MACHINERY 403 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 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 ,gUJinite height. Where water has 4 o 4 WATER SUPPLIES 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 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 transmission 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. PUMPS AND PUMPING MACHINERY 405 Diameter of Sail. Quantity raised per Hour. Height raised. Daily Supply. Feet. Gallons. Feet. Gallons. Maker A. 10 200 100 1,600 j j 12 250 150 2,000 Maker B. 10 250 100 2,000 9 ) 12 250 150 2,000 12 400 100 3,200 Maker C. 10 240 50 1,920 12 240 100 1,920 Maker D. 10 210 to 300 100 1,680 to 2,400 ii 10 300 to 450 50 to 60 2,400 to 3,600 12 300 to 500 100 2,400 to 4,000 it 30 7,000? 150 Expressed in terms of h.-p., a 10-foot mill will give -1 h.-p., a 12- foot mill 1-1 h.-p., a 14-foot mill l-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 considering those for wind engines it must be remembered that the storage capacity required is much larger than with any other 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 using 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 manage- able 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, 4 o6 WATER SUPPLIES 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 following section and description (Fig. 22) : 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. 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 PUMPS AND PUMPING MACHINERY 407 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. 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 consequent 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 raised may be caused to act upon a second ram and raise a portion of the water to a height of 1,500 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 30 times the height of the fall, but it is not safe to depend upon delivering it at more than 25 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, 4 o8 WATER SUPPLIES 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 L 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 Efficiency Rtttin6d fov Height raised. Degree of Efficiency. Blake's Rains. * 86 per cent. i 76 78 per cent. i 70 83 * 66 72 * 63 f 60 75 i 58 i 56 TV 54 TV 52 69 '" 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 y 1 ^ should give an efficiency of at least 54 per cent. With perfect efficiency the amount raised would be 2,000, since 2,000 x 100 = 20,000 x 10 PUMPS AND PUMPING MACHINERY 409 and 2,000 x T 5 ^= 1,080, 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 T ^, 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 consider- able 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 con- nection being made by suitable gearing. Any fall from 1 to 1,000 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 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 4 io WATER SUPPLIES 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. Maur, where four sets of turbines, each with a diameter of forty 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 PUMPS AND PUMPING MACHINERY 411 4 i2 WATER SUPPLIES 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 TAreuse, and throw that supplying the town to a height of over 1,600 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 1,200 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. The efficiency of turbines decreases with the size; hence for small supplies (of from 1,000 to 4,000 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 description. Recently, however, the substitu- tion of light iron wheels for the cumbersome wooden ones PUMPS AND PUMPING MACHINERY 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 overshot. 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 available 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 " 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 4 i4 WATER SUPPLIES water, whilst 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 probably 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 economical, 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 and, owing to the cheapness of petroleum, are claimed to be more .economical than gas engines should the cost of gas be over 2s. 6d. per 1,000 feet. PUMPS AND PUMPING MACHINERY 415 It is also asserted that the cost of the oil used does not ex- ceed 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 15 minutes. As soon as the temperature is sufficiently high the engine will start when the fly-wheel is turned. The vapouriser is afterwards maintained at a sufficiently high temperature by the continuous explosions. When once started the only attention required is periodical lubrication and the occasional replenishing of the oil reser- voir. In fact, after being set in motion it requires no more attention than the gas engine. . i These engines are now made to work up to 40 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 manu- factured 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 works, however, they continue to be the only practical and efficient motQ-rs. In such gases, also, tha 416 WATER SUPPLIES 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 a 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 over- come 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 smoothness 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 dis- charging 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 velocity 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: P UMPS AND P UMPING MA CHINER Y Diameter of Pipe. Volume of Water discharged per Minute with a Velocity of 2 Feet per Second. 1 inch 4-1 gallons 1 inches 9-2 2 16-4 3 37-0 4 65-0 6 148-0 8 260-0 10 410-0 12 590-0 With pipes of such ample diameter the loss from friction is very small and practically negligible. An engine of one * actual horse power will raise 3,300 gallons 1 foot high per minute, and any smaller quantity to a proportionately greater height. From the following simple formula the h.p. required to pump any given quantity of water can easily be calculated : G x H w T> "3,300 =ILP " 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 * 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. 2 7 418 WATER SUPPLIES order to provide for such contingencies as a break-down or laying-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. Thus suppose the total horse power needed were six i.h.p.* 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 water- works 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 Towns). 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 powerful 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. * Indicated horse power. CHAPTER XXII. THE STORAGE OF WATER. 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 " impounding " 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 tc* 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 foundation. The latter can be (419) 420 WATER SUPPLIES 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 decom- position, 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> thi mains, or the amount of com- pensation 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. Referring to storage reservoirs, Whitaker, in his anni- versary address to the Geological Society,"* says : * Quart. Journal Geol. Soc., 1899. THE STORAGE OF WATER 421 " In the selection of sites for reservoirs more particular points have to be considered, especially where high dams are to be constructed. In such work it is well, as far as possible, to avoid places where there is any great disturb- ance, whether by faulting or otherwise. " Masses of Drift, too, are sometimes troublesome, and it may be needful to study the composition of these and their relation to the rocks beneath: irregular mixtures of permeable and impermeable yielding material are likely to cause trouble, and the uneven way in which Drift so often occurs leads to uncertainty as to its thickness. On the whole, therefore, those parts of a valley with much Drift are to be avoided, although sometimes a bank or sheet of solid Boulder Clay may be useful. Professor Boyd Dawkins has lately drawn attention to this matter, in a lecture delivered to the Institution of Civil Engineers,* noticing a case, at the Ogden Reservoir (for Sheffield), where Boulder Clay made a more or less water-tight bottom, and another (Yarrow Reservoir, Rivington) where Drift (sand, gravel, Boulder Oay, and loam) filled up a deep pre-Glacial valley and caused much difficulty. " Tracts in which there are large landslips are clearly dangerous; for, with rocks as with men, where a slip has occurred, there another is likely to happen some day, as witness the Saiidgate landslip of 1893, which was within the area of an older slip. Moreover, the process of cutting into a slipped mass of rock and earth is likely to start fresh slips, and to endanger the stability of the work. An instance of this may be given from the Manchester Water- works in the Valley of the Etherow, several miles east of the city, made many years ago, when the characteristics of old landslipped tracts were not so well recognised as now. The lower part of the deep valley along which the set of reservoirs has been made is in Millstone Grit; but, above * Proc. Inst. Civ. Eng., vol. cxxxiv. (1898), p. 270 ? 422 WATER SUPPLIES this, the part in which most of them are placed has been cut through the Millstone Grit to the Yoredale Beds, especially on the southern side. The Yoredale Beds being largely composed of shale, the conditions are favourable to springs and slips, and, as noted on the Geological Survey map (Sheet 88, S.E.), the greater part of the southern side of the valley is a landslip-area. The features of this are very clear, especially in the neighbourhood of the Woodhead Reservoir, the highest of the series, the dam of which impinges on the landslip, by Crowden Station. Under these circumstances, one is not surprised to hear that this reservoir was, for some years, never filled to within 15 or 20 feet of its height, because it was thought unsafe to fill it, owing to a landslip and to the unsoundness of the embank- ment, until a new embankment had been made. I under- stand, indeed, that the dam is now practically double. ' In the above remarks I am not finding fault with this fine set of works, but only showing how difficulties, of a nature that a geologist would expect, interfered with the plans of so good an engineer as the late Mr. Bateman. I am inclined to think, indeed, that old landslips are more common than most geologists suppose. In my Geological Survey work in Hampshire I found that the right, or western, bank of the Test, near Romsey, was for a long distance a great slip, with the usual irregular features ; and later on the same was found to be the case with the left, or eastern, bank of the Itchen opposite Southampton. In both cases no beds in place could be seen, except the gravel at the top. So far as I know, these two occurrences had never been noticed ; but many others have been observed, especially in the later work of the Geological Survey. " Another matter that may give trouble in a reservoir, and has to be guarded against, is the occurrence of per- meable beds through which the water may find a way to lower ground, under favourable circumstances. An example of this may be given from another set of reservoirs THE STORAGE OF WATER 423 of a like kind to that already noticed, along the valley of the Loxley for the supply of Sheffield. That portion of the valley in which the reservoirs are placed is cut out of the upper part of the Millstone Grit Series, which consists of alternations of grits and shales. From the slight easterly dip of the beds, down the valley and at a higher angle than the bottom-slope, the Middle Coal Measures are carried down to the bottom by the eastern end of the Damflask Reservoir, and in part the sides and bottom of this reservoir consist of a porous grit, down which water passed to below the dam. To* get over this difficulty a long trench had to be made along the southern side and filled with water-tight materials." 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 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 4 2 4 WATER SUPPLIES 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 nitration, 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 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 considerable 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 available. This is especially valuable in connection with THE STORAGE OF WATER 425 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 fraction 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 de- pends 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 Towns, 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 or within it, or one or more high-level tanks within the town. 4. A distributing system. A pumping system may consist of A. 1. A comparatively low-level intake. 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 in- equality 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 imprac- ticable. 1, A comparatively low-level intake. 426 WATER SUPPLIES 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 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 THE STORAGE OF WATER 427 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 subjected to immense incon- venience and anxiety on account of this neglect, or from under-estimating 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. 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 Bo>ard 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. Investigating waters taken from various depths from a deep but small lake, they concluded that vertical circulation took place during the 428 WATER SUPPLIES 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, decreas- ing 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 stagna- tion 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, 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 frequently 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 THE STORAGE OF WATER 429 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 " Crenothrix," and occasionally gives rise to trouble by imparting 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 maxi- mum 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 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 difference between the mean and maximum rate of discharge could ever exceed this amount." Experiments which have been conducted in Germany, how- ever, have shown a greater variation than this. Taking the mean of a number of records from various waterworks, and taking the mean annual consumption as 1.0, the maximum daily discharge was 1.4, and the maximum 436 WATER SUPPLIES 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 compensate for all inequalities in the demand for ordinary purposes, but in small towns there 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 - 200 JP, 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 inhabi- tants, 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, 17 hours' storage in the smaller town and 8 hours' in the larger 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 two or three 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. THE STORAGE OF WATER 431 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 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 432 WATER SUPPLIES 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 constructed above ground, and are in every respect prefer- able. Underground tanks, if cut out of solid chalk or sandstone, merely require lining with cement. Tanks con- structed 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 pumping machinery and an outbreak of fire. A comparatively small qiiantity 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 concerned, 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 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 pumps are worked by a wind engine, or (4) intermittent but at regular intervals, as when manual THE STORAGE OF WATER 433 labour or some form of gas, oil, hot-air or steam engine is used. Leaving (1) out of consideration, with the second or fourth arrangement 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 12 days' domestic 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 emergency. 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 dis- advantages 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. CHAPTER XXIII. 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, cluring 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 XI.) 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, uncovered 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 " inter- (434) THE DISTRIBUTION OF WATER 435 mittent " system, and it is to be hoped that where 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 earthen- ware 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 withstand 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 2J feet. To allow for growth of population, increased demand and corrosion of pipes, a velocity of 1J 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 castoron mains when first laid, Eytelwein's formula is fairly reliable: where V = the velocity in feet per second ; d, the diameter of the pipe ; A, the head of water ; and I, the length of the pipe in feet. In new pipes ^ = 50, but its value decreases with the corrosion, and may sink as low as 32. The factor 436 WATER SUPPLIES 50d may be disregarded in pipes more than a few hundred feet in length. Sharp bends should be avoided, since they 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 with- standing 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 district. 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 1 ? In the first case V = 50 ^-25 x 100 = 2-5 feet per second, 10,000 and the flow = V x 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 XXIII. 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. inch diameter 5 lb. per lineal yard 1 6 ? | > 7J , 1 t 9 - , , 1 > 12 1* 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." (44 2 ) APPENDIX TO CHAPTER XXIII 443 5. Every house supplied with water by the Company (except in 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 on 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 " with 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 water 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. J2. Every " communication pipe " for the conveyance of water to 444 WATER SUPPLIES be supplied by the Company into any premises shall have at or near 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 con- sumer. If placed in the ground such " stop-valve " shall be protected by a proper cover and " guard-box." 18. 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 APPENDIX TO CHAPTER XXIII 445 flushing is employed), shall, within three months after these regula- 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-closing apparatus, shall have an efficient " waste-pre- venting " 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 pro- vided 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 without 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 446 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 Ib. per yard. i . . . 5ib. 1 . . . 7lb. 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. CHAPTER XXIV. THE LAW KELATING TO WATER SUPPLIES. IT generally happens that when a water supply is to be provided, land or water rights, or land and way leaves, have to be acquired. This may be done either voluntarily or compulsorily, 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 pur- chase, and to enable Local Authorities to purchase compulsorily, 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 by reason of disabilities of various kinds, section 6 (447) 448 WATER SUPPLIES 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 voluntarily, 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 roadsides wastes for sinking wells and other water supply purposes ; 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 THE LAW RELATING TO WATER SUPPLIES 4 4 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 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 otherwise 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 communicates 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 neighbour- ing landowners can prevent, by legal proceedings, the water yielded therefrom being used for the proposed water-supply purposes. (b) Whether and to what extent such landowners can, by digging wells, cutting trenches, or executing other works on their o>wn 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." 29 450 WATER SUPPLIES The riparian proprietors whose lands adjoin a water- course may take water from it, but in doing so must have due 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 denned 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? is a question which was raised in the case of 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 RELATING TO WATER SUPPLIES 451 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 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 absolute 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 reasonable 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 interferes 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, 452 WATER SUPPLIES and one for which a riparian proprietor is entitled to take the water from its natural course; for where an unreason- able 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 a right which, unless restrained, would in the course of twenty years confer on the claimant a right of prescription in derogation 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 water 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 denned and natural channel or water- course, and does not extend to water flowing over, or soaking through, previous to its arrival at such water- course. 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 THE LAW RELATING TO WATER SUPPLIES 453 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 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 Wightman as follows : " The plaintiff is the 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 percolates through the strata to the river Wandle, part rising to the 454 WATER SUPPLIES surface, and part finding its way underground in courses which continually vary. " The Croydon Loical 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 inter- rupted underground water (but underground water only) that otherwise would have flowed and found its way into the river Wandle, and so to the plaintiff's mill, and the quantity so 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 per- colates 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 Corporation 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 THE LAW RELATING TO WATER SUPPLIES 455 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 werei 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, 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 Chasemore v. Richards. The very question was then determined by this House, and it was held that the landowner has 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, 456 WATER SUPPLIES 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 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." Since the last edition of this book was written a further interesting case on the rights to underground water has arisen and been decided by the Court of Appeal. The case is reported in the Law Reports, 1899, 2 Chan., p. 217, Jordeson v. Sutton, Southcoates and Dryport Gas Com- pany. The head note to the case is as follows : " The plaintiff was the owner of land with houses on it, and the adjoining land belonged to the defendants, a Gas Company, incorporated by special Act, with power to purchase land by agreement only, and subject to the provisions of the Gas Works Clauses Acts, 1847 an|d 1871. The Company proceeded to excavate their land for the purpose of erect- ing a gasometer. In so doing they penetrated an under- ground stratum of quicksand, or sand loaded with water, geologically know as ' running silt/ which extended under the plaintiff's land as well as their own, the land largely THE LAW RELATING TO WATER SUPPLIES 457 preponderating over the water. In draining their exca- vation the defendants withdrew a large quantity of the running silt from under the plaintiff's land, and thus caused a subsidence of the surface with consequent struc- tural injury to his houses. It was held by the Court of Appeal (Lindley, M.R., and Rigby, L.J.) that the plain- tiff's land was supported, not by a stratum of water but by a bed of wet sand or running silt; and that as the defendants had caused the subsidence by withdrawing this support they had committed an actionable nuisance at Common Law, entitling the plaintiff to damages ; but Yaughan-Williams, L.J., held that the subsidence had been caused by the withdrawal through the defendants draining operations on their own land of subterranean water sup- port of the plaintiff's land, and that on the authority of Popplewell v. Hodkinson, L.R. 4 Ex. 288, the withdrawal of subterranean water support from a neighbour's land in the course of draining one's own land gives him no> cause of action." So, as the law now stands (the decision of the majority of the Court of Appeal standing) in any draining or drawing of water operations, care must be taken to draw nothing but water, or at all events only to a small extent, for if any quantity of silt or sand is drawn with the water and damage is sustained, the withdrawer of the water will be liable for such damage ; 'but if only water is drawn, then, though he may do a considerable amount of damage, until this de- cision is in effect reversed by a decision of the House of Lords, or until some Act of Parliament is passed further denning the rights to underground water, he cannot be mulct in damages. Popplewell v. Hodkinson, whioh was a case of appeal from the old Court of Exchequer, held that an owner of land has no right at Common Law to the support of sub- terranean water. The law as to the making and recovery of water-rates 458 WATER SUPPLIES 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, under certain conditions. " 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, Mid- summer Day, and Michaelmas Day. " Sec. 72. The owners of all dwelling-houses or separate 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 recovered from the owner or occupier of every dwelling-house within 200 feet of any such stand pipe, THE LAW RELATING TO WATER SUPPLIES 459 in the same manner as if the supply had been given on the premises. But if such dwelling-house has within a reason- able distance, and from other sources, a supply of wholesome water sufficient for the consumption and iise 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 provided 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 the use of 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 us 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." Objection is often made that the incidence of a water-rate is unfair, because, assuming the water-rate to be Is. in the 1, 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 460 WATER SUPPLIES 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 gardens, 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 waterworks 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 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 ; THE LAW RELATING TO WATER SUPPLIES 461 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 contained 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 agreement, any land for the purpose of any water supply. The 1894 Act, however, contains useful provisions for the protection of these councils, with regard to the action of the Rural District Councils as to water supply, section 16 providing 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 inhabitants 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 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. 462 WATER SUPPLIES 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 in- clusive; and the Public Health (Water) Act, 1878. In the following paragraphs the former will be referred te- as the P.H.A., and the latter as the P.H.W.A. ; the No. of the section 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 unwholesomeness, and a proper supply can be obtained at a reasonable cost, complaint may be made- to the Local Government 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, or supply the water by meter, or may make special agree- ments with the person receiving the supply. THE LAW RELATING TO WATER SUPPLIES 463 P.H.A. (61). Any L.A. may supply water to an adjoin- ing 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 13s. 4d., 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 464 WATER SUPPLIES sufficient for the consumption and use for domestic purposes of the inmates of the house." 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 " reasonable " 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.* (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 * This section applies to Rural Sanitary Authorities only. THE LAW RELATING TO WATER SUPPLIES 465 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. The following sections are from the Water Works Clauses Acts of 1847 and 1863:- (1847 Act.) Sec. 44. Requires the L.A. to lay down communication pipes, etc., to any dwelling-house (under 10 rental) situate in any street where they have laid pipes (1) either at the request of the owner, or (2) at the request of the occupier, upon payment or tender of the water-rate in respect of such house, by this Act made payable in advance. Sec. 46. The L.A. are at liberty, on refusal to pay for water, to remove pipes and recover expenses. Sec. 58. Imposes a penalty on occupiers or owners of premises permitting people who are not entitled to a supply of water to take water from their pipes. Sec. 59. Any person taking water without right is liable to a penalty of <10. Sec. 60. Any person wilfully injuring any lock, cock, valve, etc., is liable to a penalty. (1863 Act.) Sec. 12. A supply of water for domestic purposes shall not include a supply for cattle, or for horses, or for washing carriages, where such horses or carriages are kept for sale or hire, or a supply for any trade, manufacture, or business, or for watering gardens, or for fountains, or for any ornamental purposes. Sees. 17 to 19. Impose penalties for waste or misuse of water or for unauthorised alteration of service pipes. 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 3 466 WATER SUPPLIES 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 subsequently 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. Subsequently, 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 THE LAW RELATING TO WATER SUPPLIES 467 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 conclusion 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 interferes at all r 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 boring of a hole a't the 468 WATER SUPPLIES 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 (Scotland) 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 an. 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 expendi- RURAL AND VILLAGE WATER SUPPLIES 473 ture 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 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 grate- ful acknowledgments of the boon conferred. 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 thesa 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 some- what 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 474 WATER SUPPLIES 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 * may fairly 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 town- ships, 2,817 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 1,000, 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 con- sumed 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. * " 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 475 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 difference at first, whether the money is lent to be repaid by equal annual instalments, or annual instalments of principal 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. The Maldon Rural District Council have just completed a scheme for supplying eight parishes with water. The total population is only 2,437, spread over an area of 20,000 acres. There are 26 miles of mains. The water is derived from a spring which yields from 60,000 to 100,000 gallons per day of excellent water. The pumping station is near the springs, and the plant consists of two vertical boilers, two horizontal duplex steam pumps so arranged that either boiler will supply steam to either pump. The duty of each pump is to deliver 6,000 gallons of water per hour through a rising main 1,200 yards long into the service reservoir on ground 110 feet above the pumping station. This reservoir is constructed of Portland cement concrete, partly below and partly above the surface of the ground, and supplies the various parishes with water through the 26 miles of mains. Stand posts are fitted at the ends of all the branches, and along the route. They are of the banjo pattern, fitted with self-closing cocks, which can only be opened by a key. 476 WATER SUPPLIES A large proportion of the cottages and farms will be directly connected with the mains. The total cost was close upon 13,000. The district is purely agricultural, and the rateable value is only 5,630. The cottages are supplied with water at a rate of 2d. per week. Most of the farms are supplied by meter. The estimated revenue from water rents and rates is 408 per annum. The balance is raised with the sanitary rate. The whole of the works were designed and carried out by Mr. H. G. Keywood, the Council's Sur- veyor and Engineer, and admirably exemplify what can be done in a purely rural district. Similar works of equal magnitude have been in exist- ence some years in the adjoining Rural District of Chelmsford, and every year the mains have to be extended to meet the constantly increasing demand for water. The demand has already become so great that the District Council have acquired an additional spring and connected it with the existing system. Spring and Rain. 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 1,200 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 1,303, 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 RURAL AND VILLAGE WATER SUPPLIES 477 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 2,000. 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 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. 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 : ' " 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 * 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 exceeding high pressure (200 Ib. per square inch) and give a constant flow. The water is drawn from the above cistern and delivered through 1,125 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 * Derived from the river Wye. 478 WATER SUPPLIES 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 3,000 to 4,000 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 1,000, 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, Gloucestershire, a windmill has been successfully used for supplying the village with water. The population is 1,250, and the number of inhabitants supplied about 1,000. 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 RURAL AND VILLAGE WATER SUPPLIES 479 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 b paid off in thirty years. The water rate is 3d. in the pound. Messrs. Johns Brothers, Lechlade Foundry, carried out the scheme, from the designs of Mr. J. H. Bardfield, London. The total cost of the works was 1,800. 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 organic purity but is remarkably clear and sparkling. It is collected at the very springhead into a perforated iron container, and there have been placed around the outside of the container several hundred loads of flint, gravel, and chalk. There is a 12-inch overflow, the surplus water running into the brook course. The con- tainer 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 casWron 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 designed and constructed by the same firm. An 480 WATER SUPPLIES 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 bottom by a 12-inch drain and carried to the sea. From the turbine, which runs about 600 revolutions per minute, the power is com- municated by a 10-inch pulley to a large pulley on the over-head shafting, and from thence the power is trans- ferred 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 1,200 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 RURAL AND VILLAGE L WATER SUPPLIES 481 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 un- covered, 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 Win frith. 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 by an Oil Engine. At a recent gathering of Medical Officers of Health, Dr. Ashby, of Reading, gave a very interesting account of the water- works 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 1,783 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 4,000 feet from the com- mencement of Sonning village, its bottom being about 48 feet above the highest, and 83 feet above the lowest parts of the village. The distributing mains consist of 4,390 feet of 4-mch pipe and 3,935 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 1,840. With the sanction of the Local Government Board 1,800 was borrowed; of that sum 400 has to be repaid in fifteen years and 1,400 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 3 1 482 WATER SUPPLIES 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 4,398. 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 ard September to 30th September, 1894, we pumped 31 J 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 consequently use rather m'ore oil in starting the engine than would be absolutely necessary. In that time the pumps made 57,397 revolutions, an average of 1,822.1 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 2,405.2 per hour. The supply per head of the population per day was about 7 gallons, RURAL AND VILLAGE WATER SUPPLIES 483 The consumption of materials was as under : s. d. 12 gallons of tea rose oil .... at 5d. 5 1 battery charge at Is. 10 1 zinc for battery at 3d. 4 24 fluid ounces of sulphuric acid . . at 2d. per Ib. 5 Total cost of material consumed by the engine . . 6 10 3 pints of lubricating oil for engine and pumps at 2s. a gall. 10 Cotton waste at 4d. per Ib. 3 Total cost of materials consumed by engine and pumps 8 Cost of materials for engine per 1,000 gallons of water raised 100 feet high .... 1-082 penny Total cost of materials for engine and pumps per 1,000 gallons of water raised 100 feet high . 1-267 penny Consumption of oil per h.p. per hour . . . 1-5 pint. Spring Water pumped by Gas Engine. Great Baddow and Springfield are two adjoining villages with a popula- tion of about 4,000. The waterworks are situated in a piece of ground near the spring. The spring yields 80,000 to 100,000 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 recently a new seven horse-power (Crossley Otto) engine with a set of three-throw pumps has been erected as a duplicate. There are four reservoirs 24' x 12' x 6' brick-built and covered with brick arches, each holding 10,350 gallons. 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. 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 1,000 feet. The total expense for working is about 180 per year, exclusive of the cost of repairing mains. The amount of water rents collected from the houses supplied is about 350 per annum. Where water is supplied by meter the charge varies from Is. 6d. to Is. per 1,000 gallons, according to the amount con- sumed. CHAPTER XXVI. WATER CHARGES. A COMPARISON of the charges for water in different places is a difficult matter. In some districts the charges made to the consumers defray the total cost of the water including repayment of principal and interest. In other cases a certain portion of this cost is paid out of the General Sanitary Rate. Where the waterworks are owned by companies the prices charged may or may not include a profit; sometimes the water may even be supplied at a loss. Occasionally the charges are based on the rental, more frequently on the rateable value. The rateable value is very variable, and consequently where the assessments are low the rates will be correspondingly high, and vice versa. For domestic purposes water is almost invariably charged at so much per centum on the annual or rate- able value; for other purposes the supply is usually by meter. Where the owners of cottage property pay the rate whether the cottages are occupied or not, a reduction of from 10 per cent, to 30 per cent, is generally made. Meters are almost invariably supplied by the Water Authority and an annual rental (10 per cent, on cost) charged. It is difficult to define " domestic purposes," but Sec. 12 of the 26 and 27 Viet., cap. 93, enacts as follows: "A supply of water for domestic purposes shall not include (484) WATER CHARGES 4 8 5 a supply of water for cattle or for horses, or for washing carriages, where such horses or carriages are kept for sale or hire, or by a common carrier, or a supply for any trade, manufacture or business, or for watering gardens, or for fountains or for any ornamental purpose. " In many private Acts there are still more extended definitions of what " domestic purposes " does not include. Generally water to one water-closet is included in the rate ; extra closets being charged at from 5s. to 10s. per annum. One bath may be allowed and others charged extra, or a single bath may be an extra. There is also generally a stipulation that if the bath holds, when filled for use, more than a given amount, usually 40 or 50 gallons, a further charge is made. I have recently had occasion to prepare for the Essex County Council a list of the charges made by all the Water Authorities in that county, and these are briefly summarised in the subjoined table. The following typical scales are given in full : EAST LONDON WATERWORKS AREA OF SUPPLY. The East London Company have two scales of charges, one for the Metropolitan area and one for districts out- side the metropolis. In the Metropolitan area the basis is the Rateable Value, outside the Metropolis it is the Net Annual Value. Other- wise the figures in the two scales are identical. Outside the Metropolis. High Service, Net Annual Value. ** Baths. Water Closets. %SftSSX the Pavement. Not exceeding 30 5 4s. each Nil. "j Exceeding 30 5 4s. ,, 4s. each 1 25 per cent. 50 5 6s. 6s. in addition. 100 5 8s. 486 WATER SUPPLIES The basis to be adopted will be that laid down in the judgment of the House of Lords, namely, " The rent at which the property would let, deducting the probable average annual cost of repairs, insurance, and other ex- penses (if any) necessary to maintain the premises in a state to command such rent." (Such deductions amount generally to about 10 per cent.) To remove misappre- hension consumers are informed that the " Parish Assess- ment " is not imposed as the basis, and the directors cannot accept it. The following uses are not included in the charge : Steam engines, warming, ventilating machines, appara- tus, horses, cattle, washing carriages, gardens, fountains, ornamental purposes, flushing sewers or drains, or for any trade, manufacture, business or pursuit requiring an extra supply of water. With regard to trade purposes a charge is mad according to a scale laid down in the Company's Act which varies, according to the quantity of water taken, from 9d. to 6d. per 1000 gallons. Terms of supply for any of these purposes to be a matter of agreement. No charge is fixed by the Act. The owners of tenements not exceeding the " annual value " of 20 shall be liable for payment of rates instead of occupiers upon the same scale. See Section 81, East London Water Company's Act, 1853. BOBOUGH OF COLCHESTER. i For Domestic Purposes. Per Annum. S. D. Where the annual rackrent or value of the premises so supplied does not exceed 5 per annum . . . 070 Exceeding 5 and not exceeding 10 per annum 10 10 15 15 15 20 100 20 25 150 25 30 1 10 30 40 200 WATER CHARGES 487 Where above 40, at a rate not exceeding 5 per cent, per annum of such annual rackrent or gross value. Note. A supply of water for domestic purposes does not include a supply for more than one water-closet, or for cattle, or for horses, or for washing carriages where such horses or carriages are kept for sale or hire, or by a common carrier, or for trade or business purposes, or where the same are kept in or upon premises the rent of which is not included with and taken as part of that of a private dwelling house, or are the property of a dealer; or for steam engines ; or for railway purposes ; or for working any machine or apparatus; or for any trade, manufacture, or business whatsoever ; or for watering gardens by means of any tap, tube, pipe, sprinkler, or other such like ap- paratus ; or for flushing sewers or drains ; or for public baths ; or for any fixed bath, hydrant, lavatory, or urinal ; or for any ornamental purpose whatever. For extra water-closets, each per annum, 5s. For fixed baths, each per annum, 10s. For urinals and lavatories, by arrangement. For fountains, by meter only. For Gardens. If a hose or sprinkler be used, the water to be taken by meter at the same rate as is charged for water supplied for trade or business and upon the samei conditions. In the case of detached or market gardens, arrange- ments to be made with the Superintendent. S, D. For one horse (where chargeable) 2 6 per qr. For every horse above one 16,, For carriages, each ,, 16,, For cows, each 10,, For pigs, each 06,, 488 WATER SUPPLIES For Building Purposes. S. D. On entire value or contract price of work for the first 1,000 or part of 1,000 . 5 per cent. For the second 1,000 ....40,, For the third and each subsequent '1,000 . 30 ,, For slaughter-houses, by meter only. Water will be supplied by meter by special arrangement. As to Supplies by Meter. If water is supplied by meter, it will be by special agreement in each case. Where water is supplied by meter for both domestic and other purposes a minimum charge will be fixed allow- ing the consumption of a certain quantity of water. All water beyond that quantity will be charged for as follows : Where water is used solely for trade purposes there will be no minimum charge. S. D. Up to 50,000 gallons per quarter beyond the quantity allowed by the minimum charge . . 1 2 per 1,000 gallons. Exceeding 50,000 and not exceed- ing 100,000 .... 1 1 Exceeding 100,000 and not exceed- ing 150,000 .... 1 Exceeding 150,000 and not exceed- ing 200,000 .... 11 Exceeding 200,000 and not exceed- ing 250,000 .... 10 Exceeding 250,000 and not exceed- ing 300,000 .... 9 Exceeding 300,000 and not exceed- ing 500,000 .... 8 Exceeding 500,000 .... 7 The Council will be prepared to supply and keep in repair the meter, at a rent in accordance with the follow- ing scale, viz. ; WATER CHARGES 489 Size of Me inch 4 1 , 1 14 2 3 4 ter. Rate per Quarter. S. D. bore 16 1 9 6 3 3 3 2 4 5 8 11 21 In addition to the meter rent in accordance with the above scale, the consumer must bear the expense of all necessary fittings to, and the fixing of, the meter. MALDON RURAL ^ DISTRICT. On Sept. 26th, 1900, the District Water Committee controlling the new public supply to Purleigh and other parishes, resolved 1. That a charge be made of 2d. per week for cottages, the annual value of which is 6 and under, for the use of the water. 2. Also that a rate of Is. 6d. in the for 12 months be charged on houses, the annual value of which is above 6. 3. Also that water (other than for domestic purposes) should be supplied by meter, and that consumers requiring meters must provide the same, but obtain them from the Council. 4. Also that where water is taken by meter a minimum charge of 10s. per quarter be made; that up to and in- cluding 20,000 gallons a charge of Is. 3d. per 1,000 gallons, and above that quantity a charge of Is. per 1,000 gallons be made. 5. Also that a minimum charge of 15s. be made for taking water from swan neck standposts, from the present time until Christmas. 6. Also that owners can obtain keys of standposts from 490 WATER SUPPLIES the Engineer at their own expense, for the use of each cottage, and that in cases where keys have already been distributed, the charge for same is to be requested. In Southminster where there is a separate public supply the water rate is Is. 4d. in the 'pound on the rateable value, and Is. per 1,000 gallons by meter. CLACTON-ON-SEA URBAN DISTRICT. No. 1. Ordinary Charges. Payable quarterly in advance by owners or occupiers of private dwelling houses for the supply of water for domestic purposes only as authorised by 61 and 62 Viet., cap. 185. Houses of the Annual Gross Estimated Rental. Charges per Quarter. s. D. s D. Not exceeding 5 2 2 10 4 15 6 20 8 25 9 9 30 11 6 35 13 3 40 15 45 16 6 50 18 55 19 6 60 1 1 65 1 2 3 . 70 1 3 6 75 1 4 9 80 1 6 85 1 7 90 1 8 95 1 9 100 1 10 Where such gross estimated rental shall exceed 100, at a rate per centum not exceeding 5 10s. per annum. WATER CHARGES 491 Note. A supply for domestic purposes does not include a supply of water for cattle, or for horses, or for washing carriages where such horses or carriages are kept for sale or hire, or by a common carrier ; nor does it include a supply of water for any trade, manufacture or business whatsoever, or for watering gardens, or for fountains, greenhouses, or vineries, njor for watering roads or pave- ments, no>r for any ornamental purpose, nor for the purpose of washing the fronts or windows of houses, or other build- ings, by means of any gutta percha, india rubber, or other tubes or pipes, nor for any of the special purposes for which additional charges are notified in the Table No. 2. Every supply for domestic purposes includes a supply to one water-closet free of charge ; for each water-closet beyond the first included in such domestic supply, an additional charge of Is. lOJd. per closet per quarter will be made. Baths. Each supply to a private fixed bath will be charged the additional sum of 2s. 6d. per quarter, but no bath will be permitted which contains, when filled for use, more than 50 gallons of water. Where an outbuilding is appurtenant to, or taken with, a dwelling, the charge for water will be on the aggregate annual value of the whole premises, and no deduction will be made by reason of any portion being unoccupied. Terms of Payment. For all houses of or under the value of 10 the owners are required to pay for the supply of water, 61 and 62 Viet., cap. 185. Owners may compound for groups of houses of the above description not being fewer than three in number, and will be allowed a deduction of 20 per cent. ; but the owners of such houses will have to pay whether such houses be occupied or not. All rates, additional charges, charges under agreements, and rents of meters are payable quarterly in advance and 492 WATER SUPPLIES accrue due at the usual quarter-day, viz. : Christmas Day, Lady Day, Midsummer Day, and Michaelmas Day. The first payment becomes due at the time when the pipe by which the water is supplied is made to communi- cate with the consumer's pipes, or at the time when the agreement to take water from the Council is made. The Council reserve to themselves the right of modify- ing the above stipulations in favour of the consumer. In all cases notice in writing will be required from those intending to discontinue taking a supply of water ; and should this notice be given at any other time than on one of the abov-mentioiied quarter-days, or in t/he absence of such notice, the consumer must pay the full rates and charges up to quarter-day next ensuing after the date upon which such notice is given, or upon which such discon- tinuation of supply took effect (10 and 11 Viet., cap. 17). No. 2. Additional Charges. Payable quarterly for supply of water for the following special purpose, viz. : Per Quarter. S. D. Carriages with 2 wheels . ... . . . 20 4 . . '-.-' . . . 30 Horses, each . . . .... . 26 Cows, not exceeding 2 . .... . . . 30 4 ...... 5 6 6 ...... 8 Laundresses, upwards from . -. . . . 26 Butchers . . . . . . . ". . 3 Bakers ...;..,.. 3 Fishmongers 30 Gardens attached to a house and included in the gross estimated rental, if watered by hose, to be charged by meter. Lock-up shops, offices and warehouses, by agreement. Lock-up shops, offices and warehouses will be charged in addition for each water-closet . . . . 16 Urinals ....... t . 1 10 WATER CHARGES 493 All other purposes not particularly named herein to be charged by special agreement. No. 3. Meter Supplies. (Allowed only in special cases, and at the option of the Council.) Charges for Water delivered through Meter. For trade and special purposes, payable quarterly, at the following rates; a minimum quantity of 10,000 gallons per quarter being charged for in any case : Quantity used per Quarter. Gallons. i^iw Gals. S. D. For the first .... 50,000 and under 2 3 For the quantity from . . 50,000 to 100,000 2 , ^ . 100,000 to 150,000 1 9 above . . 150,000 1 6 Larger quantities by special agreement. Hire of Meters. The Council will provide, fix and maintain the meters, charging a quarterly rent for their use according to size of meter, viz. : s. D. s. D. For a in. meter . 1 6 For a 1J in. meter . 3 4 .16 1J .36 I .20 ,,2 ,,.46 1 26 494 WATER SUPPLIES o O A 1 i J . .^j ^^ . . ^__ , , , 5^^ 1 ^ . . o 1 rt 1 1 ; ; i - : ; ; ; Sr j d ^^ 0~^0~^0~~~ C^ o o fr . SO ^O ^^, ^O CD CO SO SO o 6 O .OO 003 -^-^kftiO o" HIM -2-2 3-2-2 so 6 ^ fl pif t^r 5 HOIH^I o ^r Lj ~o o o CO 10 ^^t^Oi OOrHlOO so o. i>- "*f 1-1 t^-t^ so <^ oo S3 1 1 oo" co~ti" ocT 0" ccTccr O~00"H(N so" c S it5 ^ iO tj p OF CHARGE. S OJ ps 75 7s -3 3^>is ^> g g^!> ^ ^ W h , ^3 " OT CJ fl 3 1 sable Value II if ^ackrent nual Value D Bable Value OH "S DH rt ~cl PH ll 3 1 pq * . 6* a 1 If -SI o d I 5 IIJJ Jpl sail ^|1| ScSSco floiOoi |||| Jl^l PQPQPQO OOWM Herts and Essex Maldon Borougl Southend Co. Stanstead Co. Tendring Co. Shoeburyness U South Essex Co. 1 1 WATER CHARGES 495 jjrf 13 -L * -|J ___0 ?- T O 03 .j b r d ' >^ " 5 <" ^ J Jig rC 03 o S Pi 3 a >... -2 sf : B :':*lf 5 ^2 : : : * S > = ~-~- 2 1 "> So : : ^ * ^ i X K "S : r : 1 ^ O) T3 '-3 ^ o^ : --S Mil 1 A* boo ^ US 1 111 I 3 : :.SP f g g ^o S I *i-s c3^-2 rt;3 d O ^ c^5r ?5~ oo" W PM || ll o~~" 1 1 5 ^ . t io" > P< . J2 c< : : : fl : o : o * (^ ^ \ -5 "3 FQ^i -~2 CO" 10 1 a ^ g 2 ^ z a| .w S-^g ( &S- ^ _ ^ 5r if IssT i ) o 1^1 l| L bfi 3 ; ' S l ; : : 53 d o ~~- lO '"3 CO ^ 33 1 1 1 rt Sa | I fi 1 , , a I i :| i g- o ^ ; $ 1 - s |-SfS ! o" ^ o" rH . .^ . ' ' ' f . . g-g, _d ^ O JO _O r-( "'S-S ' o ' o DISTRICT. Braintree Urban Burnham Urban Brightlingsea Url Chelmsford Boroi Clacton Urban Colchester Borou East London Wa Halstead Urban Herts and Essex Maldon Borough South end Co. Stanstead Co. Tendfing Co. Shoeburyness Ur South Essex Co. Saffron Walden E 496 SUPPLIES g a -2 11 - . j 8S*^JI {M| CQ CO O CO (N O CO Oi i ( i I i I O 3 .I t 1 . CO f^ COf^^CQ O CLiCOCO -2o> W fflPQ RURAL AND VILLAGE WATER SUPPLIES W sb 'S ?- 53 * 1111 |.2| faJ-o.g 1 ma j'Ss SS" a .aSss all II >a s 1.2! H|UJ Hcq H^a IrH O r-H ill 9 l 1 U o A 13 Jfi -5 W 02 02 (NOSOO (N C 00 ^ .2 5 ^B S "3 "8 P P M ft P W * ^ GENERAL INDEX. ABYSSINIAN tube wells, 369. yield of, 370, 372, 375. cost of, 373. Acid waters, 9, 362. Action of frost on water mains, 440. ,, of water on metals, 8. Adits, 353. Advantages of softened waters, 127. ,, underground sources of water, 82. Alum, clarification by, 286. Amount of nitrates in chalk and other water, 185. water available, factors influencing the, 95. raised by pumps, 398, 402. required for domestic and other purposes, 305. used, constant supply, 308, 434. by cattle, 317. ,, intermittent supply, 308. in tropical climates, 317. Analyses, vide Tables. interpretation of, 178. ammonia, 188. chlorine, 179. nitrates, 183. nitrites, 184. organic ammonia, 191. carbon and nitrogen, 190. oxygen absorbed, 193. phosphates, 189. well waters, 56, 58, 88, 89. Analysis, systematic, 354, 355, 357. Animal charcoal, properties of, 284. parasites, diseases due to, 171. Animals, effect of polluted water upon, 175. Annual water charges, 494, 495. Aqueducts, fall of, 435. Area of filter beds, 266, 267. Artesian wells, 74, 378, 383, 384, 386. Asterionella, 114. ' Atmosphere, moisture in, 14. (499) 500 GENERAL INDEX BACTERIA in water, 120, 204. effect of sunlight upon, 250-358. ,, ,, sedimentation upon, 247. removed by sand nitration, 257. Bacteriological examination of water, 204. Ball hydrants, dangers of, 238-240. Beggiatoa alba, 117. Blasting of deep wells, 385. Bogs, marshes and swamps, 45. Boiling-point of water, 5. Boils, oriental, 171. Bored tube wells, 355. Bore-tube, advantages and disadvantages of pumping from, 375. ,, varieties of, 378. Boring wells, cost of, 380. Brine yielded by well, 340. Burial of carcases, pollution by, 227. Bursaria gastris, 113. CARBONIC acid in water, 6. Cast-iron mains, 437. ,, ,, acted upon by soft water, 233. Catchment basins, 90, 331. Cattle, amount of water used by, 317. ,, pollution by, 227. Causes of rain, 15. waste of water, 313. Cesspools and house drainage, pollution by, 219, 222, 226. Chalk, water held by, 48, 78, 335, 350. Chara foetida, 116. Character of water from springs, 69. Charcoal, animal properties of, 214. ,, vegetable properties of, 284. Chlorine in surface waters, 34. signification of, 179. Cholera, 164. and defective filters, 170. and improved water supplies, 166, 357. and water filtration, 214, 215. death-rate, effect of changed water supply upon, 167. organisms, influence of soil on, 368. outbreaks of, Altona, 168, 206, 257, 260. Hamburg, 168, 206. ,, London, 165. Poonah Jail, 168. Theydon Bois, 167. Vadakencoulam, 168. Wandsbeck, 168. Cisterns, action of water on, 231. ,, galvanised iron, 232. house, 230, 434. GENERAL INDEX 50! Cisterns, rain-water, 24. zinc, 232, 234. Clarification of water by alum, 280. Classification of mineral waters, 13. ,, of odours of water, 112. of potable waters, 13, 30. Cleansing of filter beds, 265, 268. Coal gas, pollution by, 228. Collecting areas, 342, 359. ,, channels, 353. Collection of rain-water, 28. Colour of water, 2, 110. ,, removal by filtration, 263. Communication pipes, 436. Composition of water, 1. Conduits, open, 435. Conferva Bombycina, 115. Constant supply, 308, 434. Constituents of natural waters, 7, 123. Construction of filt'er beds, 264, 274. of wells, 364. Consumption of water, daily variation in, 317. ,, ,, hourly variation in, 310, 429. Control of gathering ground, 359, 361. Cost of public water supplies, 38, 40. boring wells, 380. softening hard water, 289, 294, 300, 302. tube wells, 373. ,, well sinking, 373. Cottage filters, 283. Crenothrix, 114, 429. Cryptomonas, 114. Cultivated land, pollution from, 219. DAIRY farms, 450. Dead animals, odour of water caused by, 118. ends, 438. Decomposing animals in water, diarrhoea due to, 136. Decomposition of water by electricity, 1. Deep-well water, 30, 74, 84, 336, 362. ,, ,, pollution of, 80, 228. Deep wells, blasting of, 385. boring of, 379. cost of, 380. effect of pumping on, 82, 351. increased supply by blasting, 385. pollution of, 80, 228. protection of, 355, 356. site, selection of, 81. yield of, 84, 86, 337, 386. Defective filters and cholera, 170. 502 GENERAL INDEX Defective mains, 149, 240. Density of water, 4. Depth of mains, 437. Description of public water supplies, 37, 39, 473. Deserts, 17. Detection of waste of water, 313. Diameter of mains, 436. Diarrhoaa, 133. due to distilled water, 286. ,, decomposing animals in water, 136. ,, sewage in water, 135. ,, ,, sewer gas in water, 134. ,, sulphuretted water, 134. turbid river water, 134, 135. Direction of flow of underground water, 353. Diseases due to animal parasites, 171. ,, specific organisms, 142. parasitic, 171. Discharge of water from pipes, 417. Distillation of water, 14, 280, 289. ,, sea-water, 280. Distilled water, diarrhoea due to, 286. Distributing mains, 436. Distribution of water, 434. pollution of water during, 233, 238. Divining rod, 324. Domestic and other purposes, amount of water required, 305. ,, consumption of water, 310. filters, 278. dangers of, 282. high pressure, 278. limited utility of, 282. low pressure, 278. self -supplying, 281. purification of water, 278. Drainage area, 331. of deep wells, 48, 323. of shallow wells, 48, 328. Drinking water, qualities of, 109. typhoid bacilli in, 206, 207, 214. Dual supply, 341. Dust, exposure to, pollution by; 241. Duties of sanitary authority as regards water supply, 463. Dysentery, outbreaks due to impure water, 136, 203. EARTH, living, action of, 51. Eels in water mains, 118. Effect of scraping filter beds, 258. Efficiency of filtration, 255, 261. ,, of pumps, 399. Electricity, decomposition of water by, 1. GENERAL INDEX 503 Engines, pumping, gas, 415. oil, 414. steam, 415. water, 405. wind, 402. Enteric fever vide Typhoid fever. Entoza, affecting man, 172. Estimation of rainfall, 20. Evaporation, loss of water by, 332. rate of, 14. ,, from the ocean, 15. Examination of water, bacteriological, 204. Expansion of water when freezing, 4. Exposed reservoirs, effect of temperature on water in, 428. FACTORS influencing amount of water available, 95. Farmyards, pollution from, 151, 219, 223. Ferrule machine, 438. Filter-beds, 264, 271. action of slime on, 260. area of, 266. to calculate, 267. cleansing of, 265, 268. construction of, 264, 274. effect of scraping, 258. polarite, 271, 284. Filters, cottage, 283. domestic, 278. ,, high pressure, 278. limited utility of, 282. ,, low pressure, 278. self-supplying, 281. Filtration and cholera, 214, 215. at Altona, 260. by machinery, 269. efficiency of, 255, 261, 360, 361. natural, 343, 348. testing of, 347. nitrification during, 263. of rain water, 28. rapidity of, 262. removal of colour by, 263. typhoid bacilli by, 256. sand, 362. Finding water, 324. Fire extinction, water reserve for, 430. Fissured strata, 351, 354. Flow of river, purification by, 242. underground water, direction of flow of, 353. water over notched boards, 323. ,, ,, through mains, 436. 504 GENERAL INDEX Force required to work pumps, 401. Formation of springs, 46, 47, 61. Formulae, Pole's, for yield of catchment area, 332. Hawksley's, storage, 334. Eytelwein's, for velocity, 435. Burton's, for fire reserve, 430. Freezing, expansion of water when, 4. ,, point of water, 3. Friction, loss of head by, 436. Frost, action on mains, 440. Fungi, higher, in water, 122. GALVANISED iron cisterns, 232. Gas engines, 415. Gathering ground, control of, 359, 361. Gauging of springs and streams, 100, 322. wells, 327. Goitre, 137. alleged causes of, 138. ,, localities in which prevalent, 138. Granite, water held by, 48. Gravel, pocket of, 46. Graveyards, pollution from, 227. Gravitation works, 425. Ground water, vide Subsoil water. HARD water, 7. cost of softening, 289, 294, 300, 302. influence on health of, 124 ,, softening processes, 288. ,, waste caused by, 127. Hazel twig, effect of water upon, 324. Head of water, 268. ,, loss by friction, 436. Health, effect of impure water upon, .133. ,, effect of zinc upon. 236. "Health" pipe, 141, 439. Heat, latent, of water, 3. Hemp stuffing, fouling of water by, 233. High-pressure filters, 278. Horse-power, definition of, 417. ,, equivalent in water raised, 418. Hourly consumption, inequality of, 429. variation in supply, 310. House cisterns, 230, 434. ,, drainage and cesspools, pollution by, 219, 222, 226. ,, service mains, 436, 439. Hydrants, ball, dangers of, 238. Hydraulic rams, 406. ,, efficiency of, 408. GENERAL INDEX 565 IMBIBITION, 46. Impervious strata, 45. Impounding reservoirs, 289, 423. Improved water supplies, cholera and, 166, 357. Impure water, dysentery owing to, 136, 203. ,, effect upon animals, 175. health, 133. ,, saline constituents of, 132. Impurities in rain water, 22. ,, metallic, in water, 8, 12, 139, 236. Incompressibility of water, 2. Inequality of hourly consumption, 310, 429. Influence of rain on well water, 354. ,, of soil on cholera and typhoid organisms, 368. on health of hard water, 124. on infusoria, 251. Insuction at water joints, 238. of filth by mains, 238. subsoil water, 356. Interlacing system of mains, 438. Intermittent pollution, 194, 215. ,, supply, dangers of, 238. ,, to various towns, 308, 434. Interpretation of water analyses, 178. Iron in water, 8, 12. Isolated houses, supply for, 320. Is water analysis a failure ? 194. JOINTS of water mains, 437. ,, fouling of water, by hemp stuffing, 233. insuction at, 238. LAKES, 36. ,, as reservoirs, 35. Land and water rights, purchase of, 447. Latent heat of water, 3. Laws relating to rural water supplies, 447. rivers and water-courses, 449, 450. springs, 449, 450. subsoil water, 449, 452. water supplies, 447. Lands Clauses Consolidation Acts, 447. Limited Owners Reservoir, etc., Act, 464. Public Health Act, 447, 458, 460, 462. Public Health (Scotland) Act, 468. Public Health (Water) Act, 447, 458, 462, 470. Settled Land Act, 448. Waterworks Clauses Acts, 458, 460. Cases Borough of Bradford v. Pickles, 454. Broadbent v. Ramsbottom, 452. 506 GENERAL INDEX Cases (continued) : Chasemore v. Richards, 453. Dudden v. Guardians, Glutton Union, 450. Embrey v. Owen, 451. Holmfirth Local Board v. Shore, 466. Jordeson v. Button, Southcoats and Dryport Gas Co., 456. Milner v. Gilmour, 451. Pogglewell v. Hodkinson, 457. Smith v. Archibald, 468. Swindon Water Co. v. Wilts and Berks Canal, 452. Wandsworth Board of Works v. United Telephone Co., 467. Lead cisterns, 140, 232. in water, 8, 12, 24, 140. pipes, 234. ,, poisoning, 8, 139. symptoms of, 139, 235. Legal decisions affecting water supplies, 450. Lime, softening of water by the addition of, 289. Limestone, water held by, 48, 78. Limited Owners Reservoirs andWater SupplyFurther Facilities Act,464. utility of niters, 282. Living earth, action of, 51. Loss of head by friction, 436. of water by evaporation, 332, 333. ,, ,, percolation, 333. Low forms of animal and vegetable life in water, 122. pressure niters, 278. Lyngbya muralis, 117. MACHINERY, nitration by, 269. Magnesia, sulphate of, 337. Magnetic carbide, 273. Mains, action of frost on, 440. cast-iron, 437. dead ends, 438. depth of, 437, 440. diameter of, 436. distributing, 437. eels in, 118. flow of water through, 436. house service, 436, 439. insuction of filth by, 238. interlacing system of, 438. joints of, 437. trunk, 436. velocity of water in, 435. Malaria, 143. decrease in England, 143. outbreak on board ship, 144. where prevalent, 143. Marshes, swamp and bogs, 45. GENERAL INDEX 507 Maximum consumption of water, 429. ,, density of water, 4. rainfall, 96. Mean consumption of water, 429. Metallic impurities in water, 8, 12, 139, 236. Metals, action of water on, 8. Methods, special, of tracing pollution, 151, 204. Metropolis Act, 440. Metropolitan Water Supply, Royal Commission Report on, 76, 92, 93, 98, 195, 265, 311. Mineral waters, classification of, 13. Minimum rainfall, 96. Moisture in atmosphere, 14. Moorland waters, 9, 30. Movements of subsoil water, 48, 225. NATURAL reservoirs, 427. ,, water, constituents of, 7, 123. ,, classification of, 13, 30. Nitrates and nitrites, 183, 184. ,, how formed, 222. ,, ,, in chalk waters, 185. ,, reduction of, 187. ,, ,, signification of, 183. Nitrification during filtration, 263. process of, 222, 344. purification by, 52, 221, 263. Nitrogen, organic, 190. Nitrogenous organic matter, 191. Nostoc, 115. ODOUR of water, 2, 111, 361. caused by Asterionella, 114. Beggiatoa alba, 117. Bursaria gastris, 113. Chara fcetida, 107, 115, 116. Conferva Bombycina, 115. Crenothrix, 114, 189, 429. Cryptomonas, 114. Lyngbya muralis, 117. Nostoc, 115. Oscillatorise, 116. Spongilla fluviatilis, 113. Tabellaria, 114. Uroglena Americana, 113. Volvox globator, 113. due to dead animals, 118. hemp joints, 233. ,, sulphuretted hydrogen, 111. ,, tar varnish, 437. Odours of water, classification of, 112. 5 o8 GENERAL INDEX Oil engines, 414. Oolite, water held by, 48, 78, 336. Open conduits, 435. Organic ammonia, 191. ,, carbon and nitrogen. 190. matter in water, 7, 190. Organisms in water, 120. Bacteria, 121, 204. Higher fungi, 122. Low forms of animal and vegetable life, 122. Oriental boils, 171. Origin of rivers, 90. Oscillatorise, 116. Oxidation by air, 358. ,, in running water, 244, 344. Oxidising effects produced by sand filtration, 263. Oxygen absorbed by water, 193. in water, 6, 244, 246. PALATABILITY of water, 119. Parasitic diseases, 171. Parish Councils and water supplies, 460. Peaty water, 10, 32. ,, effect of storage on, 427. Pebble beds, water held by, 48. Percolation, 45, 49. loss by, 333. Periodic examination of public supplies, 357, 362, 363. Permanganate of potash, purification by, 286. Permeability of subsoil, 45. Pervious strata, 45. Phosphates in water, 189. Pipes, action of water on, 233. ,, communication, 436. Plumbo-solvent action of water, 8, 11, 362. how prevented, 12, 235. Pockets of gravel, 46. Polarite filter beds, 271, 273, 284. Pole's formulae for yield of catchment area, 332. Polluted water, effect on health, 133. ,, ,, effect on animals, 175. Pollution of deep-well water, 80, 228. rain-water, 23, 219, 361. rivers, 91, 219. subsoil water, 52, 221. surface water, 219. water at its source, 219. during distribution, 233, 238. storage, 229, 241. owing to sewage, 135, 136, 146, 149. ,, sewer gas, 134. GENERAL INDEX 509 Pollution owing to sulphuretted hydrogen, 134. ,, surface water, 136. ,, ,, suspended mineral matters, 133. sources of, action of water on cisterns and tanks, 231. pipes, 233. burial of carcases, 227. cattle, 227. cesspools and house drainage, 219, 222, 226. coal gas, 228. cultivated land, 219. exposure to dust, 241. farmyards, 151, 219, 223. graveyards, 227. insuction through ball-hydrants, 238, 240. defective mains, 149, 240. stool taps, 148, 238. sewage, 195. sewer gas, 6, 134. snow, melted, 230. sulphuretted hydrogen, 134. tar varnish, 437. tow joints, 233. washings from roof, 219. Pollution, special methods of tracing, 151, 204. of rivers, Royal Commission on, 30, 44, 71, 73, 78, 92, 124, 166, 183, 185, 188, 190, 233, 236, 288, 307, 316. Ponds, 35. Potable water, definition of, 128. classification of, 13, 30. Prevention of waste of water, 313, 316, 438. Previous sewage contamination, 185. Protection of surface water supplies, 358. underground water supplies, 342. Protective area round springs, 352. wells, 353, 355, 356. Public Health Act, 447, 458, 460, 465. Public Health (Scotland) Act, 468. Public Health Water Act, 447, 458, 461, 470. ,, water supplies, cost of, 38, 40, 474 to 483. ,, ,, ,, description of, 473 to 484. wells, England and Scotland, 466, 468. Pumping, effect on deep wells, 82, 351. from bore tube, 356, 375. ,, mains, velocity of water in, 435. Pumps, amount of water raised by, 398. ,, and pumping machinery, 392, 400. efficiency of, 399. ,, varieties of, 392. Purchase of land and water rights, 447. Pure water, definition of, 2. ,, saline constitutents of, 129. 5 10 GENERAL INDEX Purification of waters by alum, 286. fermentation, 286. filtration, 256. flow of river, 242. nitrification, 52, 221, 263. permanganate of potash, 286. sedimentation, 253, 255. softening process, 303. domestic, 278. Koch's remarks on, 260. Massachusetts, experiments on, 256. Purity, standards of, 215. Purposes for which water is required, 306. QUALITY of drinking water, 109. Quantity of water obtainable from different sources, 330. required for domestic and other purposes, 305. supplied by various London companies, 311. in different towns, 309, 312. .used by cattle, 317. ,, in towns with constant supply, 308. ,, intermittent supply, 308. ,, tropical climates, 317. yielded by artesian wells, 383, 384, 386. tube wells, 371, 372. RAIN-BEARING winds, 16. Rain, causes of, 15. Rainfall, 16, 17, 37, 96, 342. at Equator, 17. at Kew, Greenwich, Massachusetts, 18. available supply of water from, 28, 329. collected by rivers, 96. how estimated, 20. in gallons per acre, 22. Rain-gauge, 19. ,, mountain, 20. ,, position, 19. Rain water, 14, 22. action on lead, 24. cisterns, 23, 24. collection of, 28. filtration of, 28. how polluted, 22, 219, 361. ,, impurities in, 22. ,, separator, 26. storage of, 24, 29, 432. Ram, hydraulic, 406, 408. Rapidity of filtration, 262. Rate of evaporation, 14, 15. Regulations under Metropolis Act, 440. GENERAL INDEX 511 Eemoval of colour by filtration, 263. Reserve for fire extinction, 430. Reservoirs, 35, 358, 431. ,, impounding, 419. lakes as, 35. natural, 427. service, 424, 427. settling, 423. Revolving purifier, 272. River water, 30, 90, 342. ,, revolving purifier, 272. ,, suitability of, for public supplies, 94, 247. ,, towns supplied by, 106. Rivers and watercourses, amount of water available from, 96. ,, laws relating to, 449, 450. ,, origin of, 90. percentage of rainfall collected in, 97. ,, pollution of, 91. M pollution, Royal Commission on, 30, 44, 71, 73, 78, 92, 124, 166, 183, 185, 188, 190, 233, 236, 288, 307, 316. rainfall collected by, 96. self-purification of, 92, 242. ,, ,, subterranean, 50. ,, ,, velocity of flow, 100. Rock, saturation of, 46. Roofs, water collected from, 26. Running water, oxidation in, 244, 344. Rural water supplies, 469. law relating to, 447. SALINE constituents of impure water, 132. ,, ,, pure water, 129. Sand filtration, 362. ,, experiments on, 256. ,, ,, oxidising effects produced by, 263. ,, ,, requisites for efficiency, 259, 260, 258. washing, 265, 275. Sandstone, water held by, 48, 78, 336. Sanitary Authority, duties of, to supply water, 463. Saturation of rock, 46. Saving effected by softening water, 294, 303. Scale of purity, 211. Scrubbers, 269. Sea-water, distillation of, 280, 286. ,, for sewer flushing, 109. Search for water, 324. Sedimentation, 247, 358, 360. Selection of source of supply, 319. Self-purification of rivers, 92, 242. effect of bacteria, 250, 512 GENERAL INDEX Self-purification, effect of infusoria, 251. ,, ,, ,, oxidation, 246. ,, ,, sedimentation, 247. ,, sunlight, 250. Self-supplying filters, 281. Separator, rain-water, 26. Service pipes, 439, 442. ,, ,, unsuitable, 321. reservoirs, 424, 427. Settled Land Act, 448. Settling reservoirs, 423. Sewage in water, diarrhea due to, 135. pollution by, 135, 136, 146, 149, 220. Sewer gas, pollution by, 6, 134. Shallow wells, 50, 343, 362. pollution of, 223, 345. Site of deep wells, selection of, 81. Slime on filter beds, action of, 260. Snow, pollution of water by, 230. Soft water, 7. advantages and disadvantages of, 127, 128. Softening of water, 288. by addition of lime, 289. Archbutt & Deeley's process, 298. Atkin's process, 293. boiling, 288. distillation, 289. Howatson's process, 295. Maignen's process, 299. Porter Clark's process, 294. Stanhope's process, 295. cost of, 289, 293, 299, 302. purification effected by, 303. saving effected by, 294, 303. Soil, undisturbed, as a filter, 222. ,, influence on typhoid and cholera organisms, 368. Solvent power of water, 6. Source, pollution of water at its, 219. Sources of supply, 13, 319. Specific organisms, diseases due to, 142. Spongilla fluviatilis, 113. Spongy iron, 271, 284. Spring water, 30, 59, 69, 320. Springs, 59, 362. and streams, gauging of, 100, 322, character of water from, 69. how formed, 46, 47, 61, law relating to, 449, 450. utilisation of, 64. varieties of, 60, 321. yield of, 63, 321. GENERAL INDEX Stand pipes, 459. Standards of purity, 215. Steam engines, 415. Stool taps, dangers of, 148, 238. Storage of water, 361, 419. amount of, 334, 358, 360, 425, 431. effect of, 428. of rain water, 24, 29, 432. ,, pollution of water during, 229, 241. Strata, chief water-bearing, 78. Streams, vide Rivers. Subsidence, effect of, on number of micro-organisms, 255. Subsoil, percolation into, 45. permeability of, 45. pollution of, 52, 221. by gas, 228. saturation of, 46. water level in, 47. yield of water from, 50, 268, 328, 335, 352. Subsoil water, 30, 45. law relating to, 452. movement of, 48, 350, 352. ,, effect upon health, 225. towns supplied by, 53. Subterranean rivers, 50. water, cistern theory, 76. river theory, 76. Sulphate of magnesia, 337. Sulphuretted hydrogen, odour of water due to. 111. ,, ,, pollution by, 134. ,, water, diarrhoea due to, 134. Sunlight, effect on organisms, 250, 358. Supply, dual, 341. ,, for isolated houses, 320. from rainfall, 28, 329. Surface water, 30, 31. affected by nature of soil, 34. chlorine in, 34, 179. from cultivated ground, 30, 34, 360. from uplands, 28, 31. pollution of, 136, 219. supplies, storage, 360. yield of, 37, 329. Suspended mineral matters, pollution by, 133. Swamps, bogs, marshes, 45. Symptoms of lead poisoning, 139, 235. Systematic analysis, need of, 354, 355, 357. TABELLARIA, 114. Tables- Amount of water raised by pumps, 398, 402. 33 GENERAL INDEX Tables (continued] : Amount of nitrates in chalk waters, 185. Analyses of deep-well waters, 89, 82. rain waters, 33. river and other waters, 196, 197. spring waters, 72, 73. subsoil waters, 56, 57, 58. surface waters, 42, 43, 44. Annual water charges, 494, 495. Area of filter beds and rate of nitration, 266. Artesian tube wells, yield, etc., 383, 384, 386. Bacteria removed by sand nitration, 257. Cholera death-rate, effect of changed water supply upon, 167* Cost of boring wells, 380, 381. tube wells, 373. Discharge of water from pipes, 417. Effect of subsidence on number of micro-organisms, 255. Efficiency of hydraulic rams, 408. Filtration, rapidity of, 270. Flow of water over notched boards, 323. Force required to work pumps, 401. Quantity of water raised by water wheel, 413. windmill, 403. ,, per stroke of pump, 398. supplied daily per head in various towns, 309, 312. ,, by various London companies, 311. yielded by artesian wells, 383, 384, 386 tube wells, 371, 372. rainfall, 18. percentage collected in rivers, 97, 98. Water rates, 496. Well sections around London, 83, 84. Tanks for storage, 432. ,, for rain water, 431, 432. Tar varnish, causing odour, 437. Taste of water, 2, 119. Temperature, effect on water in exposed reservoirs, 428. of deep-well waters, 382. Tow joints, pollution by, 233. Towns supplied by deep-well water, 88, 89. lake water, 36, 42, 43. river water, 106. spring water, 72, 73. subsoil water, 54. surface water, 42, 43. Trade winds, 15. Tropical climates, amount of water used in, 317. Trunk mains, 436. Tube wells, 355, 372, 383. cost of, 373. Turbidity of water, 119. GENERAL INDEX 5I5 Turbidity of water, diarrhoea due to, 134, 135. Turbines, 409. Typhoid bacilli, experiments with, 347. in drinking water, 206, 207, 214. influence of soil on, 346, 368. if water, etc., on, 214, 250. removal by filtration, 256. fever caused by water, 345, 357, 358. Typhoid fever, outbreaks of Ashton-in-Makerfield, 229. Bangor, 146. Beverley, 148, 198, 221. Bolan Pass, 164. Buckingham, 198. Caius College, 148, 238. Caterham, 147. Chester-le-Street, 152. Croydon, 238, 240. Houghton-le-Spring, 199. Lausen, 145. Maidstone, 150. Massachusetts, 153, 202. Mountain Ash, 149, 202, 239. Nabburg, 147. Newark, 161. New Herrington, 151, 354. Nunney, 146. Over Darwen, 146 Paisley, 229. Pennsylvania, 230. Sherborne, 148. Tees Valley, 156, 201. Terling, 149. Trent Valley, 159, 199. Worthing, 207. UNDERGROUND sources of water, 47, 342, 452. tanks, 432. water, advantages of, 82. Undisturbed soil as a filter, 222. Unnecessary consumption, 313. Upland surface waters, 30, 359. ,, surfaces, pollution of, 359. Uroglena Americana, 113. Utilisation of springs, 64. VARIATION in daily consumption of water, 317. ,, hourly consumption of water, 310, 429. Varieties of bore tubes, 375. ,, pumps, 392. Velocity of rivers, estimation of, 100. 5i6 GENERAL INDEX Velocity of water iii mains, Eytelwein's formula, 435- pumping mains, 435. Volume of water held by various rocks, 48. Volvox globator, 113. WASHINGS from roof, pollution by, 219. Waste caused by hard water, 127. of water, amount of, 314. ,, causes of, 313. detection of, 313. prevention of, 313, 316, 438. preventers, 313, 439. Water, acid, 9, 362. boiling-point, 5. charges, 484, 492. composition ; properties, etc., 1. domestic purposes, 484. different sources, 13. meters, 484, 488, 493. rent of meter, 489, 493. trade purposes, 486, 438. finders, 324. law relating thereto, 458. mains, vide Mains, rates, 459, 479, 496. ,, supplies and parish councils, 460. Royal Commission Report on, 58, 124, 158, 159, 234, 243. wheels, quantity of water raised by, 413. works, classification of, 425 . Watercourses, vide Rivers.' Watersheds, 330, 360. available water from, 330, 332. Waterworks Clauses Acts, 458, 460. Well sections around London, 83, 84. sinkers, 364. sinking, cost of, 373. waters, analyses of, 56, 58, 88, 89. pollution of, 53, 222, 228, 229, 364. ,, temperature of, 382. Wells, Abyssinian, 369. artesian, 74, 378. construction of, 364. cost of, 373. deep, 30, 74, 84. boring and lining, 379. cost of boring, 380. effect of pumping on, 82, 328. pollution of, 228, 229. yield of, 84, 86, 327, 337, 385, 386. drainage area of, 48, 83, 224, 352. GENERAL INDEX 517 Wells, gauging of, 327. public, 468. shallow, 50. ,, drainage area of, 48, 224, 328. improved construction of, 365. pollution of, 53, 222, 228. yield from, 371. Windmills, 402. ,, quantity of water raised by, 403. Winds, rain-bearing, 16. YELLOW fever, 170. Yield of Abyssinian tube wells, 369. deep wells, 84, 86, 337, 386. springs, 63, 321. surface water, 37, 329. water from subsoil, 50, 268, 328, 335, 352. ,, various sources, 320. ZINC cisterns, 232, 234. effect upon health, 236. ,, in water, 12. Zoo-parasitic diseases, 171. INDEX OF PROPER NAMES. ABBA, 347. Abbots Langley, 378, 383. Abel, Sir F., 246. Abergavenny, 72. Aberystwith, 36, 37, 38, 42. Abyssinia, 172. Adams, Dr., 115, 116, 240. Addington, 340. Africa, 173. Agra, 272. Aldershot, 378, 383. Algeria, 390. Alleghany, 271. Allen, A. H. , 200. Alnwick, 383. Alps, 60. Altona, 168, 169, 170, 206, 257 261, 262, 267. America, 175, 317, 397, 398. American Desert, 390. Anderson, W., 272. Ansted, 15. Antwerp, 271, 272. Archbutt and Deeley, 298, 299. Argentina, 390. Argentine Republic, 17. Aristotle, 1. Armstrong, Dr., 310. Artois, 75. Ashby, 481, 482. Ashley, H., 396. Ashton-in-Makerfield, 229. Ashton-under Lyne, 496. Assam, 17. Aston, 384. Atherstone, 72, 309. Athol, 270. Atkins, 269, 270, 293. Atlanta, 270, 271. Attfield, D. H., 251. Attfield, J., 61, 293. 260, Australia, 17, 174. Axe Edge, 91. BABES, 145. Bahia, 173. Ball, A. J. A., 52. Ballard, 146. Bangor, 146. Barcaldine, 386. Bardfield, J. H., 479. Barking, 84, 309. Barnard Castle, 157, 201, 202. Barnes, 256. Barnstaple, 43. Barrow-in-Furness, 496. Barry, Dr., 94, 140, 156, 157, 158, 159, 199. Bateman, 17, 333, 422. Bath, 63, 184, 496. Batley, 43. Battersea, 166. Baynes, 198. Beardmore, 99, 100, 102. Beccles, 372. Bechuanaland, 389. Bedford, 309. Berlin, 48, 52, 53, 114, 228, 261, 312, 341, 348. Berwick, 309. Bettington, 143. Beverley, 148, 198, 221. Bhagsoo, 138. Bindon Hills, 480. Birkenhead, 88, 496. Birmingham, 312, 496. Bishop Stortford, 57. Blackall, 386. Blackburn, 496. Black wall, 246. Blackwell, 103. Blaxall, Dr., 148. (519) 5 20 INDEX OF PROPER NAMES Bolan Pass, 164. Bolton, 116, 496. Bombay, 817. Bona, 144. Boston, 43, 113, 114, 154,192,203,312. Boudin, 144. Boulnois, 316. Boulogne, 272. Boultbee, 387, 388. Bourn, 84, 384. Bozel, 138. Bracebridge, 135. Bradford, 140, 266, 312, 316, 438, 454, 497. Braintree, 185, 494, 495. Brazil, 174. Brentford, 122. Bridlington, 309. Brightlingsea, 494, 495. Brighton, 89, 339, 396, 496. Bristol, 64, 72, 309. Bristown, 389. British Islands, 16, 18. Brodie, Sir B., 92. Brown, Dr., 189. Brunner, Dr., 245. Brussels, 341. Buchanan, Dr., 148, 149, 238, 240. Buchanan, Sir G., 195. Buchner, Prof., 250. Buckingham, 198. Buda-Pesth, 48, 53, 225. Buenos Ayres and Rosario Railway Company, 390. Bulnois, 316. Burnham, 57, 372, 494, 495. Burnley, 496. Burnmoor, 11. Burton, 372, 378, 418, 425, 430. Bury, 496. Bushmanland, 389. Buxton, 2, 42, 63, 184, 477. CALCUTTA, 273, 317. California, 389. Calkins, G. N., 112. Calverley, 235. Cambre, 341. Cambridge, 148, 238. Camden, 294. Canterbury, 89, 301. Cape of Good Hope, 172, 388. Cape Town, 273. Cardiff, 383, 497. Carlisle, 106, 266, 497. Carnforth, 42. Carter, Vandyke, 145. Castle Donington, 89. Caterham, 61, 147, 301. Cavendish, 1. Chadwell Springs, 83. Chaldon, 479. Charlestown, 167. Charleville, 386. Chatham, 89, 185, 384. Chaux de Fonds, 412. Chelmsford, 68, 309, 372, 494, 495. Chelsea, 266, 311. Cheltenham, 63, 73, 106, 107, 108, 114, 116, 117, 497. Chepstow, 72, 309. Cherraponjee, 17. Chertsey, 245. Cheshunt, 83. Chester, 497. Chester-le-Street, 152. Chewton Mendip, 64. Chicago, 122. Chichester, 346. Chicopee, 156, 203. Chili, 222. China, 17, 74. Church Coppenhall, 474. Cirencester, 383. Clacton-on-Sea, 490, 494, 495. Clark, 289, 290, 298, 301, 304. Clark, Prof., 127. Clifton, 63. Clitheroe, 276. Clown, 56. Colchester, 89, 185, 486, 494, 495. Cold Norton, 89. Colesburg, 389. Collins, E., 314. Colne Valley, 290, 384. Connecticut, 113. Cooke, 115. Cornwall, 32. Coventry, 88. Cressbrook, 477. Crookshank, Prof., 207, 208, 211. Crossley, Otto, 483. INDEX OF PROPER NAMES Crowden, 422. Croydon, 226, 238, 240, 336, 339, 453, 454. Cumberland, 16, 32, 125. Cunnamulla, 386. DAGENHAM, 372. Dalton, Dr., 49. Damflask, 423. Danbury, 73. Darlington, 106, 156, 157, 200, 201, 202, 497. Dauben See, 60. D'Aubuisson, 102. Davenport, 474. Dawkins, Prof. Boyd, 87, 421. Day, Justice, 467. Deacon, 314, 439. Delepine, Prof. S., 210, 213. Demerara, 273. Denny, 468. Denton, E. B., 28, 281, 431. Derby, 41, 497. Derbyshire, 33, 91, 138. De Ranee, 17. Deseret, 389. Devon, 16, 32. Dewsbury, 42, 497. Dibdin, 246, 349. Dickenson, 49. Doncaster, 106, 497. Dorchester, 479. Dorset, 148. Ducat, 349. Dudley, 497. Dumfries, 265, 266. Duncanson, T., 311, 440. Dupre, Dr., 202, 246. Durham, 106, 151, 152, 354. East Ham, 309. East London Water Company, 266, 311, 396, 485, 486, 494, 495. East Stratton, 372. Eaton, 16. Eaton Hall, 384. Eberth, 208, 209. Edinburgh, 39, 229, 255. Edingley, 161. Edwards, Dr., 155, 249. Egypt, 172, 174. Elbourne, 57. Ely, 106. Emnierick, Dr., 245. Escher, 412. Essex, 11, 82, 83, 111, 118, 124, 143, 149, 167, 181, 182, 185, 203, 216, 324, 336, 380, 388, 485. Eston, 157. Eton College, 175. Evans, Sir J., 76, 78. Evesham, 56. Exeter, 316, 497. Eytelwein, 102, 436. FARLOW, Dr., 117. Fedschenko, 173. Fisher, W. W., 198. Fliigge, 216. Fodor, 48, 225. Forschammer, 192. Foster, Lott & Co., 479, 480. Fraenkel, C., 52, 348. France, 60, 75. Frankland, Prof., 121, 176, 192, 193, 200, 201, 205, 209, 222, 230, 245, 246, 251, 253, 255, 267, 284, 303. Friihling, 327. Fuertes, 327. GAINSBOROUGH, 160. Garrett, Dr., 11, 114, 116, 117. Gateshead, 497. Gemmi, 60. Geneva, 410. Geradin, 246. Germany, 174, 429. Gibraltar, 170. Gilbert, 49. Glamorgan, 149. Glasgow, 36, 39, 40, 42, 124, 167, 234, 235, 253, 312. Glenfield Co., 396. Glengyle, 40. Gloucester, 117. Gobi, 17. Gooch, Dr., 175. Gorges de 1'Areuse, 412. Gosport, 384. Grand Junction Co., 266, 311. 522 INDEX OF PROPER NAMES Grantham, 72, 309. Gravesend, 372. Great Baddow, 483. Great Britain, 345, 364. Greenwich, 18. Grenelle, 75. Griiber, Max, 216. Giistrow, 248, 249. HALIFAX, 43, 497. Hall, 136. Halsbury, Lord, 455. Halstead, 89, 309, 494, 495. Hamburg, 153, 168, 169, 206, 262. Hamilton, 167. Hampshire, 138, 422. Hampton, 245, 256. Hampton Court, 93. Hanley, 88. Hanover, 389. Harrison, Dr., 135. Hart, E., 345. Harvard University, 117. Harwich, 81, 89. Hassall, 122. Hastings, 78. Hauser, Dr., 346. Havant, 384. Hawksley, 316, 333, 334. Haynes, Surg.-Capt. , 164. Heaton, Dr., 237. Heckmondwike, 42. Hemel Hempstead, 49. Hendon, 175. Henley-on-Thames, 269, 293. Hennel, 267. Hereford, 372. Hertford, 378, 383. Hertfordshire Bourne, 60. Herts and Essex Co., 494, 495. Heybridge, 89. Heywood, 308. Hicks, Dr., 175. Hirsch, 173. Hodson, 81, 82. Hoe Lane, 83. Holland, Dr., 127. Holmfirth, 466. Hornsey, 238. Houghton-le-Spring, 199. Houston, 213, 214, 229, Huddersfield, 309, 497. Hughes, 102. Hull, 497. Humber, 333. Hunter, Lovell, 139, 140, 235. ICELAND, 174. Ilford, 372. India, 138, 167, 173, 222, 225. Ingatestone, 57, 271. Iowa, 176. Ireland, 345. Isle of Wight, 81. Isler & Co., 84, 371, 381, 385. Italy, 174. JANEIRO, 173. Japan, 172. Jessel, 450. Johns Bros., 479. Johnston, Dr., 281. KALAHARI, 17. Kamaon, 138. Karoo, 388. Katrine, Loch, 36, 39, 234, 235, 253. Keighley, 11, 276, 497. Kelly, Dr., 239. Kempster, B., 368. Kennet and Avon Canal, 103. Kent, 81, 304. Kent Co., 311, 339. Kentish Town, 81. Kern County, 389. Kew, 18, 166. Key wood, H. G., 68, 476. Khasia Hills, 17. Kilmarnock, 396. Kingsdown, Lord, 451. Kingsheath, 383. King's Langley, 49. King's Lynn, 65, 73. Kirkheaton, 157. Klein, Prof., 137, 213. Knaith, 199. Knaresborough, 106. Koch, 52, 53, 55, 153, 168, 170, 207, 210, 214, 215, 221, 223, 257, 260, 261, 262, 347, 367. Kiimmel, 248. Kutzing, 115. INDEX OF PROPER NAMES 523 LAMBERT, 479. Lambeth, 293. Lambeth Co., 266, 311. Lancashire, 9, 33, 146. Lancaster, 497. Latham, B., 76, 77, 226. Latham, P. M., 136. Lausen, 145. Laveran, 143, 145. Lawes, 49. Lawrence, 153, 154, 155, 156, 249. Leamington, 88, 106. Lechlade, 372, 478. Leeds, 42, 106, 264, 266, 496. Le Grand and Sutcliffe, 371, 372, 381, 382. Leicester, 41, 266, 496. Leipzic, 341. Leuckart, 174. Lindley, 457. Lincoln, 135, 372. Lincolnshire, 84, 85, 143, 159. Liverpool, 36, 43, 80, 83, 253, 294, 311, 312, 315, 317, 382, 429, 437, 496. Llanelly, 237. Llyn Llygad Rheidol, Lake, 36, 37. London, 81, 83, 84, 93, 124, 136, 161, 163, 165, 166, 185, 186, 214, 238, 244, 249, 252, 255, 257, 262, 264, 265, 267, 308, 311, 312, 316, 340, 433. London and N.W. Railway Com- pany, 294. London Orphan Asylum, 384. Long Branch, 270. Long Eaton, 89, 384. Low, Dr. Bruce, 159, 160, 199. Lowell, 153, 154, 155, 156, 202, 249. Lustig, 212. Lynn, 66, 67, 68. MACCLESFIELD, 496. Mace, 211. Macnaughten, Lord, 455. Madras, 143, 317. Madrid, 346. Maidstone, 150, 240. Maiden, 54. Maldon, 68, 89, 475, 489, 494, 495. Malham Cove, 60, Manchester, 36, 42, 49, 167, 234, 235, 312, 421, 438, 496. Manson, 172. Marseilles, 144, 145. Martin, Baron, 450. Martin, S., 346. Massachusetts, 18, 34, 35, 36, 43, 53, 57, 68, 96, 98, 111, 112, 113, 114, 153, 180, 189, 191, 202, 243, 249, 256, 262, 264, 270, 427. Mather & Platt, 383. Matlock, 63. M'Clellan, Dr., 138. McWeeney, Dr., 347. Meade-Bolton, 212. Mecklenburg, 248. Melbourne, 89. Melrose, 72, 309. Melton, 136, 228. Melton Mowbray, 372. Melville Island, 5. Meriden, 113. Merryweather, 437. Merthyr Tydfil, 43. Metz, 136. Mexico, 134. Michigan, 175. Middlesborough, 106, 156, 157, 158, 200, 308, 337, 496. Middleton, 113. Miers and Crosskey, 46. Miguel, 23. Migula, 211, 212. Millbank Prison, 136. Miller, Prof. W.A., 234. Mills, H. F., 153. Millwall, 372. Milwaukee, 317. Miquel, 211. Mistley, 89, 185. Molesworth, 401. Monte Video, 272. Moore, Surg.-Maj. R. R. H., 144. Morningside, 229. Mountain Ash, 149, 202, 239. Muckadilla, 386. Munich, 48, 225, 245, 251. Munro, Dr., 229. Murphy, Dr. Shirley, 161. Musselburgh, 372, 524 INDEX OF PROPER NAMES NABBURG, 147. Nantiago Lead Mine, 37. Nantwich, 474. Natal, 17. Newark, 106, 161, 162. New Brompton, 73. Newburyport, 155, 156, 249. Newcastle, 152, 310. New Herrington, 151, 223, 354. New River Co., 255, 265, 266, 311. New Ross, 372. New South Wales, 387. Newton, 53, 57. New York, 135, 312. Norfolk,' 185. Normanby, 157. North, 144. North America, 34, 387. Northampton, 497. Northumberland, 33. Norwich, 56, 81, 89, 185, 316. Norwood, 113. Nottingham, 41, 309, 496. Nottinghamshire, 138, 159. Nunney, 146. OAKLAND, 270. Odling, Dr., 246. Ogden, 421. Okehampton, 43. Oldham, 497. Orizaba, 134. Orlandi, 347. Ormesby, 157. Ottumwa, 270. Oude, 138. Oudshoorn, 277. Oven Darwen, 146. Oxford, 245. PAGE, Dr., 148, 151, 198, 199. Paisley, 167, 229. Palmberg and Newsholme, 341. Paris, 23, 92, 174, 247, 341, 384, 410. Parkes, Dr., 143, 145, 228, 286, 287, 306, 323. Parry, J., 429. Parsons, Dr., 198. Patricroft, 383. Pattinson & Stead, 200. Pennine Chain, 17, Pennsylvania, 230. Peru, 222. Pettenkofer, Prof., 48, 225, 346. Philadelphia, 312. Pittsburg, 270. Pittville Park, 115. Plymouth, 42, 106, 113, 497. Plynlimmon, 36, 37. Pole, Dr., 332, 333, 334. Poncelet & Lesbros, 104. Pontefract, 88. Poole, 56. Poonah, 168. Porter-Clark Co., 294. Portsmouth, 228. Power, W. H., 10. Prague, 136. Preston, 42, 497. Prestwich, 47. Procacci, Dr., 250. Pudsey, 139, 235. Purfleet, 246, 372. Purleigh, 489. Putney, 234. QUEENSLAND, 382, 385. RAFTER, 113. Rainham, 372. Rankine, Prof., 306. Rawlinson, Sir R., 373, 380, 416, 420, 437. Rawtenstall, 57. Reading, 16, 245, 274, 275, 481. Redhill, 147. Remsen, Prof., 113. Revere, 54, 57. Richard Freres, 21. Richardson, Sir B. Ward, 126. Richmond, 339. Rideal, Dr., 287. Rigby, 457. Ripon, 106. Rivers Afon Gaseg, 146, 147. Aire, 60. Calder, 106, 273. Chelt, 107. Chicopee, 156, 203. Danube, 53. Don, 106. INDEX OF PROPER NAMES 525 Rivers (continiLed) : Eden, 106. Elbe, 168, 169, 170, 206. Etherow, 421. Exe, 33. Hamps, 60. Harre, 341. Hooghly, 273. Irwell, 243. Isar, 48, 245. Itchen, 422. Kennet, 243, 274, 275. Lea, 83, 86, 93, 94, 106, 108, 163, 249, 251, 252, 267. Learn, 106. Loddon, 99. Loiret, 60. Loxley, 423. Manifold, 60. Medway, 99. Merrimac, 111, 154, 155, 156, 202, 249, 263. Mersey, 33, 243. Mew, 106. Mimram, 99. Mohawk, 135. Mootla, 168. Nene, 99. Nidd, 106. Ouse, 106, 198. Pleisse, 341. Potomac, 271. Schwarza, 341. Seine, 93, 247. Severn, 99, 106, 107, 108, 117. Sorgue, 60. Spree, 48, 341. Sudbury, 96, 97, 98. Tees, 33, 94, 106, 155, 156, 157, 158, 159, 199, 200, 201, 206, 208. Test, 422. Thames, 16, 51, 86, 92, 93, 94, 98, 99, 106, 107, 108, 122, 124, 125, 163, 166, 243, 245, 246, 249, 251, 252, 256, 257, 267, 288. Trent, 159, 160, 161, 199. Ure, 106. Vannes, 341. Wandle, 99, 453, 454. Rivers (continued) : Warnow, 248 (see p. 527). Wash, 65. Washburn, 106, 264. Wear, 106. Wharfe, 106. Witham, 135. Wye, 477. Yare, 106. Rivington, 421. Roberts, 26. Robertson, Dr., 346, 347. Rochdale, 497. Rochdale Canal, 17. Rochester, 385. Rome, 144. Romsey, 422. Rondelli, 347. Roques, 232. Roscoe, Prof., 5. Rostock, 248. Rothamstead, 49. Rotherhithe, 372. Rotterdam, 114. Roux, G., 212. Rugby, 294, 337. Russia, 168, 176. SAFFRON WALDEN, 56, 89, 185, 309, 494, 495. Sahara, 17, 390. Salford, 134, 167. Sandown, 106. Sandgate, 421. San Joaquin Valley, 389. San Louis Valley, 389. Scarborough, 497. Scatterty, Dr., 11, 276. Schenectady, 135. Scotch Highlands, 125. Scott, 17. Sedgley Park, 135. Sedgwick, Dr., 155. Sedgwick, Prof. W. F., 114. Sheffield, 9, 41, 333, 421, 423, 497. Sherborne, 148. Shields, 16. Shiplake, 243. Shoeburyness, 494. 495. Shoreditch, 314, 316. Shrewsbury, 106. INDEX OF PROPER NAMES Silcock, 67, 68. Slagg, 104. Sleaford, 384. Slough, 384. Smith, Angus, 23, 233, 321, 478. Smith, I. C., 68. Smith, Prof. W. E., 247. Snow, Dr., 165. Snowdon, 19. Soignes, 341. Somersetshire, 146. Somerville, 15. Sonning, 481. Sonsino, Dr., 172, 173. Southampton, 57, 167, 293, 339, 383, 384. South Australia, 386. Southend, 84, 89, 185, 494, 495. South Essex Co., 494, 495. Southminster, 73, 490. Southmoor, 152. Southport, 88, 497. South Stockton, 156. South wark and Vauxhall Co., 234, 266, 311. Sowerby Bridge, 17. Soyer, 127. Spalding, 84. Spear, J., 202, 239. Spence, 271, 273. Springfield, 73, 483. Staffordshire, 33, 60. St. Albans, 378, 383. Staleybridge, 43. Stampfel, 230. Stanstead, 494, 495. St. Austell, 72, 309. St. Bon, 138. Steeple, 89. Stephenson, 382. Stevens, Dr., 146. St. Gothard, 174. St. Helens, 312, 347, 497. St. Maur, 410. Stock, F. K., 200, 201. Stockholm, 341. Stockport, 383. Stockton, 106, 156, 157, 158, 201. Stoddart, F. W., 186, 187. Stoke Newington, 255. Stratford, 185. Streatham Common, 84. Stroud, 43, 56, 73, 298. Stye Pass, 17. Styrian Alps, 341. Sudbury, 89. Suffolk Asylum, 136, 203, 378. Surrey, 81, 147. Sussex, 138. Sutcliff, B., 375. Swansea, 72, 309, 312, 372, 497. Swindon, 340. Switzerland, 145, 146, 174. Symons, 15, 21, 37. Syracuse, 115. Syria, 171. TASMANIA, 136. Taylor, J., Sons & Santo Crimp, 289. Teddington, 93. Tegeler, Lake, 114, 341. Tendring, 494, 495. Tenterden, Lord, 449. Terling, 149. Tewkesbury, 106, 107, 108. Thanet, 78. Theydon Bois, 167. Thirlmere, 36. Thorne, Dr., 147, 157, 200. Tidy, Dr., 192, 193, 199, 201, 245. Torksey, 199. Totnes, 72.' Towyn, 42. Tring, 301. Troy, 143. Tunbridge Wells, 384. Turin, 347. Turner, Dr. G., 136, 137, 203, 378, 379. Tyndall, Prof., 110, 122. UNITED STATES, 248, 270, 312, 389. Uruguay, 390. Utah Territory, 389. Uxbridge, 384. VADAKENCOULAM, 168. Vaughan, 175. Vaughan- Williams, 457. Venables, Dr., 237. INDEX OF PROPER NAMES 527 Veuterstad, 389. Victoria, 386. Victoria, West, 389. Vienna, 125, 216, 341. Vries, Prof. Hugo de, 114. Vyrnwy, Lake, 36, 253. WAKEFIELD, 106, 266, 273, 497. Walden, 57. Wales, 16, 32, 33, 146. Wales, Dr. P. S., 270, 271. Walker, 274, 275. Wallingford, 383. Waltham, 53, 57. Waltham Abbey, 83. Waltham Cross, 84. Walthamstow, 83, 309. Wandsbeck, 168, 169. Wandsworth, 234. Wanklyn, Prof., 191. Ware, 57. Warrego, 386. Warrington, 383. Warrington, Dr., 222. Washington, 270, 389. Watford, 378, 383. Watson, Baron, 450. Webster, J. & J., 477. Weld, 480. West Indies, 174. West Lulworth, 412, 479, 480. West Middlesex New Eiver Co. 255, 256, 266, 311. Westminster, 165. Westmoreland, 16, 32. Weston-Super-Mare, 72, 309. West Biding of Yorkshire, 8. West Worthing, 239, 383. Weymouth, 167. Wheatley, Dr., 229. Whitaker, W., 65, 67, 76, 337, 420. White, Dr. Sinclair, 9. Wickham Bishops, 337. Widford, 372. Wigan, 43. Wightman, Mr. Justice, 453. Wildbad, 184. Willesden, 294. Wills, Chas., 162. Wilson, A. C., 158, 201. Wilson, Maclean, Dr., 138, 152. Wiltshire, 81. Wimbledon, 185. Wimborne, 383. Windsor, 245. Winfrith, 479, 481. Winogradsky, 222. Witham, 185, 372. Wolverhampton, 88, 309, 310, 497. Woodhall Spa, 340. Woodhead, Dr. Sims, 281. Woodhead Reservoir, 422. Wooldale, 466. Woolwich, 384. Worcester, 106, 107, 108. Worthing, 56, 89, 206, 207, 255. Wraysbury, 372. Wright, Justice, 467. Writtle, 55, 57, 181. Wynaad, 144. YARROW, 421. Yeovil, 73, 309. York, 106. Yorkshire, 33, 60, 139, 148, 176. Yorkshire, West Riding, 8, 140. ZURICH, 412. THE ABERDEEN UNIVERSITY PRESS LIMITED. UNIVEESITY OF CALIFOENIA LIBEAEY, BEEKELEY THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW Books not returned on time are subject to a fine of 50c per volume after the third day overdue, increasing to $1.00 per volume after the sixth day. Books not in demand may be renewed if application is made before expiration of loan period. FEB 24 193i ) llhn'616M ..D m 20m-ll,'20 10970 y