UC-WRLF ':V" I) I WATER ENGINEERING. BY THE SAME AUTHOR. Second Edition, revised and enlarged. SANITARY WORK IN THE SMALLER TOWNS AND IN VILLAGES. Comprising : I. Some of the more Common Forms of Nuisance, and their Kemedies. II. Drainage. III. Water Supply. By CHARLES SLAGG, A.-M.I.C.E. With Illustrations. 12mo. 3. 6d. cloth. "We have in the course of our duty read the work, and we find nothing but good in it. It contains all that such a treatise can be expected to contain, and appears to us sound and trust- worthy in every particular .... the observance of the instructions it contains may save not only money but lives." The Builder. " The information given is just that which is so often wanted by those who have the management of house property in villages and the smaller towns. . . . The information given is excellent, while Mr. Slagg has the power of conveying it clearly and tersely. It is an exceedingly useful handbook, which we have pleasure in com- mending." Engineering. LONDON : CROSBY LOCKWOOD & SON, 1, STATIONERS' HALL COUET, B.C. WATER ENGINEERING A PRACTICAL TREATISE ON THE MEASUKEMENT, STORAGE, CONVEYANCE, AND UTILISATION OF WATER FOR THE SUPPLY OF TOWNS, FOR MILL POWER, AND FOR OTHER PURPOSES. BY CHAELES SLAGG WATER AND DRAINAGE ENGINEER, ASSOCIATE MEMBER OF THE INSTITUTION OF CIVIL ENGINEERS, AUTHOR OF " SANITARY WORK IN THE SMALLER TOWNS, AND IN VILLAGES." LONDON CEOSBY LOCKWOOD AND 7, STATIONERS' HALL COURT, LUDGATE HILL 1888 [All rights reserved] SON T~D> S5 LONDON: PRINTED BY WILLIAM CLOWES AND SONS, LIMITED, STAMFORD STREET AND CHARING CROSS. PREFACE. SINCE a series of articles on * The Water Question,' by the Author, appeared in the * Building News,' frequent requests have been made that they should be reprinted in book-form. Those requests have now been complied with, and the Author has, at the same time, added much new matter, and rewritten some parts of the old. So large a subject could not be treated from the Author's own experience alone, and he has freely referred to such sources of information as were avail- able to him, for those parts of the subject which did not come immediately within his own experience. But, for the most part, the information is derived from direct observation during a period of about thirty years. The authorities referred to are, it is hoped, fairly quoted throughout ; at least it has been the desire of the Author not to assert as of his own observation that which is due to the statements of eminent engineers. LEOMINSTER. May, 1888. CONTENTS. SECTION PAGB I. EMBANKMENTS OF WATERWORKS RE- SERVOIRS. Consolidation in various degrees by different means of raising the bank .. .. 1 II. QUANTITY OF WATEE TO BE STORED. Part only of the rainfall can be dealt with ; the dry-weather flow ; height of bank ; depths of reservoirs .. .. ., .. .. 16 III. APPURTENANCES OF RESERVOIRS. ~ Bye-channel ; waste-weir ; gauge-basin ; valve tower 26 " IV. DISCHARGE OF WATER FROM THE RESERVOIR. Pipes- culverts .. .. 31 ^.APPROXIMATE COST OF A STORAGE RESERVOIR. Work to be done 35 VI. CONCRETE FOR EMBANKMENTS AND DAMS. To be solid or not according to its intended use; washing the materials; inter- stices of the materials '.i .. .. ..45 VII. STREAM GA UGES. Fixing the gauge; con- struction of a temporary gauge ; co-efficients of discharge derived from Mr. Black well's and Mr. Simpson's experiments; the co-efficient of Mr. j. B. Francis ; depth of water measured from a still head compared with the depth upon the outer edge of a weir .. .. .. 51 viii CONTENTS. SECTION VIII. RAINFALL Increases from the West to the gaps in the main range of hills, then decreases Eastwards ; Mr. Symons's records ; rain-gauges 64 IX. AREAS OF RIVER-BASINS. South coast; East coast ; North-east coast ; North-west coast; West coast .. .. .. ..72 X. CONDUITS. Degree of fulness; form of channel ; open and covered conduits ; pipes over ravines ; air in pipes .. .. .. .. .. 78 XI. TUNNELS. Cost of several waterworks tunnels 90 XII. SERVICE RESERVOIRS. Their position and general construction .. .. .. ..92 XIII. PRESSURE AND ITS EFFECT IN PIPES. Head of water ; proof, from observation, that the head is proportional to the square of the velocity; hydraulic gradient; strength of cast- iron pipes ....... .. .. .. 97 XiV. AQUEDUCTS. Large conduits proposed for the supply of London some years ago .. 113 XV. RIVERS AND WATERCOURSES. Various formulae of the mean velocity; the bottom velocity deduced from the observed surface- velccity ............ 120 XVI. COMPENSATION TO MILLS. Wen for separating clear water from flood waters; example of a millowner's reservoir; value of water-power .. .. .. .. .. 127 XVII. OF WATER-POWER IN GENERAL. Basis of calculation of horse-power .. .. .. 135 CONTENTS. ix SECTION XVI II. WATER WHEELS. Various kinds of wheel- overshot, high breast, low breast, undershot, current wheels ; flow of water from openings ; speed of wheels ; force of water-current .. 139 XIX. CORN MILLS. Relative velocity of water and of wheel ; quantity of water used for grinding corn with various forms of wheel .. .. 168 XX. WORK DONE BY WATER WHEELS. Pumping water ; grinding saws, &c. ; working forge hammers .. .. .. .. .. 184 XXI. TURBINES. Elementary form; high and low falls; action of water on various forms of turbine .. .. .. .. .. .. 192 XXII. D OMESTIC WA TER-SUPPL Y. Quantity used for various purposes .. .. .. .. 217 XXIII. SERVICE RESERVOIRS. Situation; puddle lining; banks of sand .. .. .. .. 222 XXIV. DISTRIBUTION OF WATER. Variable flow during the day ; watering roads ; meters ; pre- venting waste .. .. .. .. .. 230 XXV. PUMP1NG-MA1NS AND ENGINES. Stand- pipes ; Cornish engines ; rotative beam engines 241 XXVI. FLOODS. Lowering the water-level of rivers ; weirs on rivers ; flow off the ground ; Thames and Severn compared ; effect of repeated floods 247 XXVII. STORAGE OF FLOOD WA TERS. Not prac- ticable in the lower reaches of a river ; regu- lating dam and storage reservoir separate and combined .. .. .. .. .. .. 263 XXVIII. RELIEF OF LAND FROM FLOODS. Cost per acre ; rating lands .. .. .. .. 271 CONTENTS. SECTION PAGE XXIX. REGULATION OF FLOOD WATERS. - Heavy falls of rain ; quantity flowing off the ground ; reservoir capacity of various sites .. 278 XXX. RIVER CONSERVANCY. Difficulties of the subject ..287 XXXI. COUNTY BOARDS AND WATERSHED AREAS. Various remarks pertaining to the subject ' 295 WATEB ENGINEEKING. SECTION I. EMBANKMENTS OF WATERWORKS-RESERVOIRS. EESERVOIR embankments in general are made with the materials found on or near the site, be they earth, shale, or stone. With earth or shale the English practice makes the watertightness of a reservoir dependent on a wall of puddled clay, carried up in the centre of the embankment from retentive ground below its seat. The thickness of the puddle wall varies from 4ft. to 8ft. at the top, and at the bottom it is as much more as is required for a batter on each side of an inch to every foot in height. But it is not good practice to make the thickness of the puddle wall at the top so little as 4ft., and 6ft. is the least dimension that ought to be given to it, increasing beyond this, according to the quality of the clay, to 8ft. in perhaps most cases. Thus, where the height of the bank is 24ft., the thickness of puddle at the bottom would be 12ft., or half tne height. Where the height is 48ft., the thickness would be 16ft., or one-third of the height; and it has been recommended to make the thickness one-third of the height also in high banks, and this would be, for a bank 96ft. in height, 32ft., although, according to the pro- portions above stated, it would be 24ft., or, in this case, one-fourth of the height. Puddled clay, upon which the watertightness of reser- voir embankments has for so long a time depended, since, 2 EMBANKMENTS OF WATERWORKS-RESERVOIRS. at least, the time of Brindley and canal-making, has come to be regarded with disfavour and distrust where it is itself exposed to the action of water or of the air. When some canal-makers complained to Brindley that they could not stop a run of water, his advice was to " puddle it, puddle it"; and the good reputation which puddle has always had in waterworks-engineering led at one time to its careless use, and it was solely depended upon for the water tightness of reservoir embankments, which, however, was not always effected. Certainly, some reservoir embankments have been made of very great height, and they have stood safely, and there is no apprehension whatever that they will not always continue so, with, of course, due attention to the outer parts, to repair the continued action of the weather frost, thaw, rain. But these embankments have been well- made, not only in the core, which is formed of puddled clay from end to end of the bank, like a wall, but on each side of it ; on the inside to prevent the water in the reser- voir having access to it in any considerable body, and on the outside to prevent the water with which the puddle is made being drawn out of it, whether by evaporation or capillary attraction, by which it might become gradually dried, and the cracks which would be consequently formed might extend so far into the wall as to reduce its virtual thickness materially. Eough stone, for instance, or earth loosely tipped in, would admit the air to it, and the water incorporated with the puddle would continue to evaporate as long as the air itself was not saturated with moisture. Puddled clay does not readily part with the water with which it is incorporated, and not at all if the outer and drier air is wholly excluded from it ; but this can only be done by placing against it a compact material. On the other hand, in the presence of water having any motion, it easily dissolves melts away ; and the best puddle for a wall that is, the closest in texture melts the soonest under this action; nevertheless, it is absolutely necessary that puddle should be so worked as to bring it to a close tex- PRECA UTIONS. 3 ture ; but at its best it is porous, and if water lias access to it under great pressure, it is only a question of degree how much water will be forced through the puddle wall. In the first place, a great deal of water is used in making it ; dry clay will absorb nearly a third of its own weight of water ; and if it be taken, not in a purposely dried state, but in a naturally dry state, it will absorb, in the process of puddling, say an eighth or a sixth of its weight of water. Thus, water acting under pressure on one face of a puddle wall tends to force water out on the other side, being itself incompressible, and the quantity it can force through in a given time is limited only by the smallness of the pores and the length and tortuousness of the course which a run of water must follow. It is, therefore, highly important to protect the puddle from contact with water under great pressure. It might almost seem that if it requires so much protection it can be of little use, and that it might be dispensed with altogether ; but this extreme would be as unwise as that of depending solely upon it without precautions; and as it is so readily procurable, it remains still a necessary material for waterworks- reservoirs. There are two kinds of puddle clay puddle and gravel puddle proper to be used for different purposes, or rather in different positions for the same purpose of watertight- ness ; the one consisting of clay only, the other with stones incorporated. When there is a liability to a wash of water, stones are necessary to hold the clay together, and of stones rounded gravel-stones are the best, besides being generally the more easily obtained, inasmuch as they are more uniformly dispersed through the mass of clay than angular stones can be in the process of working, which is by cutting and cross-cutting with long-bladed tools, reaching down at every stroke, through the layer of clay being worked, into the puddle beneath it. The tool slips past a rounded gravel-stone without much disturbance of the adjoining clay ; but angular stones, when struck by the puddling tool, have a tendency to congregate together. B 2 4 EMBANKMENTS OF WATERWORKS-RESERVOIRS. Oravel puddle is proper to be used where weights have to be sustained, as for the walls of a service reservoir. Clay puddle can hardly be worked stiff enough to support the weight, which squeezes the clay outwards and upwards, and there is an inconvenient settlement of the wall ; but with gravel puddle the weight can be sustained and water- tightness effected also, because with a mixture of gravel the puddle can be worked stiffer. The sketches given below which are numbered 1, 2, and 3, show respectively a longitudinal section, a plan, and a cross-section of an embankment formed of earth, with a puddle-trench and wall. The trench is shown to be cut straight down, so that the bottom is as wide as the top, and the advantage of this over sloping sides is that, in case the ground should not prove watertight at the depth anticipated, the trench may be carried down to any further depth. The trench is filled in with puddled clay up to the surface of the ground, above which, up to and above the top-water level of the reservoir, the puddle is continued as a wall, having a batter on each side of lin. to a foot, and finishing 8ft. thick at the top ; 4ft. is not a sufficient thickness, 6ft. is sufficient with precautions, but 8ft. is advisable ; if, however, there be the means of placing a nearly watertight mass of earth next the puddle, as B B on the sketch, the thickness of the top of the puddle may be 6ft. In the longitudinal section, Fig. 1, the bottom of the Fig. 1. puddle-trench is cut into the hill-side as far down as to pass through loose or fissured ground to a water-tight bottom, which is often found nearer the surface on one side of the valley than on the other. That side should be THE EMBANKMENT. 5 chosen for the discharge-pipe or culvert, but it cannot always be determined before the puddle-trench has been cut. On the plan, Fig 2, A B is the original course of the Fig. 2. stream ; C D, the two ends of the embankment ; E F, an open channel, cut near the bottom of the reservoir; F G, the discharge-pipe, laid in the solid ground ; some- times laid in a culvert of masonry, itself laid in the solid ground. GH, an open channel; H, the gauge- basin ; I, the waste- weir ; I K, the bye- wash. The discharge-pipe has a valve on its inner end, at F, and it is necessary to erect a tower of some kind, from the top of which it can be worked. Access to the top of the tower is procured by means of a bridge, either from the top of the embankment or from the side of the reser- voir, as shown in the sketch. When the puddle-trench is everywhere sunk below the level at which the water is drawn off, the discharge-pipe is taken round the end of the bank, instead of direct from F to G, for the sake of 6 EMBANKMENTS OF WATERWORKS-RESERVOIRS. being in the solid ground, and a tunnel is then preferable io an open trench, as shown by the dotted line F, M, N, G, shafts being sunk at M and N. It may not be quite justifi- able to put the preference of a tunnel on the less dis- turbance of the ground, for with careful timbering, perhaps less disturbance would occur with an open trench. The open trench can, at least, be closely filled in again, which cannot be said with certainty of the space between the crown of a tunnel and the earth above it. Although tunnels have of late been much advocated instead of culverts, it would certainly be unwise to adopt them in every case. In every case, however, there is a necessity for a tower or valve-well, for a valve cannot be satisfactorily worked with sloping rods, and because it is absolutely necessary to place a valve on the inner end of a discharge-pipe, if any regard at all be had to the safety of the reservoir. Certainly, discharge- pipes have been laid under embankments, which have had no valves at the inner ends, the discharge being controlled at the outer ends, at the foot of the embank- ment; but considering that a cast-iron pipe, if of large eize, may be broken by the external pressure of the earth, and that, whatever the size, it is subject to leakage at the joints, where it cannot be got at for repair, this method will not bear repetition. A valve, then, being necessary at the inner end of the discharge-pipe, and a tower for access to it, it becomes desirable to draw off the water, not from the bottom of the reservoir, where it is muddy, but as near the top, at all times, as is practicable, and the tower affords facilities for the insertion of a short pipe through the wall at as many different heights as may be desired. Instead of placing the tower or valve-well in the reservoir at or near the foot of the slope of the embank- ment, it has been sometimes placed almost in the middle of the bank, close to the puddle wall, and the water is conducted to it by a culvert from the foot of the inner slope of the embankment; but this position does RAISING THE EMBANKMENT. 7 not afford the facilities of drawing off the water at different heights that the exposed tower does. With a good masonry culvert or tunnel of sound bricks or thick stonework, a pipe in addition seems superfluous, where the reservoir is constructed for one discharge only ; but if it be so situated that two discharges are required from it, one, for instance, for a town supply, and another for the stream itself, the continuation of the supply-pipe up to the valve-tower, through the culvert or tunnel, is necessary, the discharge to the stream running on the bottom of the culvert or tunnel beneath the supply -pipe, which is supported from side to side so as to leave room beneath it for the stream discharge. The quantity given to the stream, under these circumstances, is usually required to be open to inspection by turning it over a gauge-weir to a depth agreed upon, the length of the gauge being fixed, by which the quantity being dis- charged can be ascertained for the satisfaction of millers and others interested in the stream. The waste- weir and bye- wash are shown in the sketch on the opposite side to the other works, but, according to circumstances, they may be on either side. They are very important parts of the work, for when the reservoir is full at a time of flood nearly all the water must pass that way, and therefore not only must the length of the waste-weir be sufficient to prevent the flood rising to a dangerous height against the embankment, but the bye- wash must be so constructed that it will not be torn up by a great body of water rushing down so steep a channel. In the cross section, Fig. 3, A is the puddle-trench and Fig. 3. wall ; B B, material selected from that excavated as being the most easily compacted ; C C, a rough stone bank 8 EMBANKMENTS OF WATERWORKS-RESERVOIRS. necessary for the outer slope, and advisable also for the inner; DD, the rest of the material excavated, except peat. This is a material which, although sometimes abundant on reservoir sites, is very objectionable in an embankment, even in small quantities. The top of the embankment, when consolidated, has usually been made from 4ft. to 6ft. above the top water level, and in situations much exposed to high winds not less than 6ft. ; for a gale of wind blowing down the reservoir rolls against the face of the bank waves of con- siderable height, and this may occur when the reservoir is more than full, and water going over the waste-weir at a depth of, perhaps, 2ft., thus reducing the clear height to 4ft. The width of the top of the bank has usually been made from 12ft. to 24ft. The proper width is determined by the considerations of whether or not a roadway is required to be made along it, and what width the puddle wall is to be at the top. Leaving out of consideration the question of roadway, which must be always a local requirement, the width necessary to properly enclose and protect the puddle wall is about twice the width of the top of the puddle wall itself. The safety of a reservoir embankment does not depend upon one thing only, as upon the perfection of the pud- dling, but equally upon several others, chief amongst which is the consolidation of that part of the bank which lies within the puddle wall, and into which, therefore, water would penetrate if not prevented, and this preven- tion depends chiefly upon the thickness of the layers of earth with which the embankment is raised. * Thin layers are always desirable ; but. the maximum thickness which may be allowed depends on the material and the means by which it is deposited in the bank. A heavy and dry material may be deposited in thicker layers than one of less specific weight, with equal effect in both cases in forming a solid bank. The thickness allowable has been variously stated at 6in., 12in., 18in., and 2ft. RAISING THE EMBANKMENT. 9 Where the chief consideration has been the urgent pro- gress of the work to meet a demand for water, as was the case when, in order to meet the demands of the approaching summer the embankment of the reservoir on the Dale Dike at Bradfield was urged forward by the Sheffield Waterworks Company, in the early part of the year 1864, and which burst in March of that year ; the earth forming the bank on each side of the puddle wall had been tipped from rail- waggons at a height of 5ft. or 6ft., and more ; but few waterworks engineers would sanction that, except for the outer part of the bank, and even for that part it is too high, because the large and small rock are not evenly mixed ; the large lumps roll to the bottom of the tip and form a layer there of themselves ; the finer stuff lying together upon the coarse layers; whereas, to prevent slipping, which is one great object of all the precautions, the large and the small should be as evenly mixed as is practicable, except in those parts where material is pur- posely selected to be deposited, fine in one part and large in another, for different purposes. If the material tipped into the bank were all stone, the rolling of the large lumps into a separate layer would be less objectionable; and, indeed, with stone for the material it might even be an advantage that the layers should be so arranged, for the one would drain the other, and the bank, as a whole, would retain less water than it otherwise would do ; but with other materials, such as shale, whether blue or dark, or, indeed, any material but stone, the same object would not be effected. In making the inner part of the embankment of a reser- voir the object is to make it as compact as possible to prevent the water reaching the puddle wall, and, there- fore, the material should be small and clayey ; but in the outer part of the bank dryness and stability are the chief objects, for which larger and harder material is more suit- able. The inner slope of an embankment is usually made flatter than the outer slope, as 3 to 1 inside and 2 to 1 outside, for the inner part of the bank is more liable to 10 EMBANKMENTS OF WATERWORKS-RESERVOIRS. slip than the outer. When the water-level in the reser- voir is reduced, if the inner part of the bank has been penetrated by water and become partially saturated, slips are more likely to take place, and the flatter slope meets this tendency ; but outside, with dry materials, 2 to 1 is as good a slope as 3 to 1 inside. As a further precaution against slipping it is desirable to keep up the outer parts, next the slopes, higher than the inner parts next the puddle wall, as in Fig. 4. INNER SLOPE Fig. 4. If rail-waggons be used at all, it is desirable that they should be of small size, to hold, say, not more than one cubic yard ; but if waggons be allowed, there will always be a tendency on the part of those who do the work to make the tips high and the layers thick, to avoid much shifting of the rails if possible, and especially by the use of side- tip waggons ; but if the instruments for carrying the stuff into the bank be confined to barrows, dobbin-carts, and common one-horse carts, it does away with this tendency in a great measure. When large waggons are advocated, it is asserted that the greater weight and the heavier rails compensate for the greater height of the tips, and so an equally good consolidation of the earth is effected. The degree of consolidation, by the weight of the instrument by which the earth is transported, admits of proof. In respect of any one square yard near the middle of the bank, lengthwise, the consolidation of the one immediately preceding it may be shown as follows : Premising that whatever the thickness of the layers, variation in weight of the different kinds of earth, or time of construction, the degree of consolidation by the weight of the carrying CONSOLIDATION OF THE EMBANKMENT. 1 1 instrument must be in the inverse ratio of the weight carried each journey, the weight of the instrument being reckoned twice, going full and returning empty. Thus, if w = weight of earth carried, and W = weight of instrument carrying it, i = degree of consolidation. w The actual weights of different kinds of earth vary much; but, for the purposes of comparison, an average weight of 26001b. per cubic yard may be taken, or 961b. per cubic foot, and the effect of the carrying instrument may be stated thus : BARROW 651b. Proportion of length of plank road .. .. 15 Wheeler 150 Koad-sbifter 140 Earth, 1* c. ft. at 961b. per c. ft 160 530 Keturning empty 370 Mean consolidating weight 4501b. 450 Degree of consolidation = Tgn = 2*81. The quantity of earth which a dobbin-cart will hold may vary from f cubic yard to Ij cubic yard, and may be taken at an average of 1 cubic yard, and its weight at lOcwt. DOBBIN-CART l,1201b. Horse, 10 cwt 1,120 Driver 130 TwoTipmen 280 Earth, 1 c. yd 2,600 5,250 Eeturning empty 2 , 650 Mean consolidating weight .. .. .. 3,9501b. Degree of consolidation = |i?|9 = 1-52. 2,bOO 12 EMBANKMENTS OF WATERWORKS-RESERVOIRS. COMMON CAKT, 12 cwt l,3441b. Horse, as before 1,120 Driver 130 TwoTipmen 280 Earth, 1 c. yd 2,600 5,474 Keturning empty 2 , 874 Mean consolidating weight 4 , 1741b. 4 174 Degree of consolidation = ^^~. = 1'60. 2i , 000 Kail-waggons holding one cubic yard are very handy things for shifting earth. If the gauge of the rails he 3ft., and the waggon held one cubic yard, its weight will be about lOOOlb. The weight of a proportionate length of rails and sleepers will be about 1201b., and the statement will stand thus : SMALL RAIL-WAGGON l,0001b. Proportion of length of rails and sleepers 110 Horse 1,120 Driver 130 TwoTipmen 280 Earth, 1 c. yd 2,600 5,240 Eeturning empty 2,640 Mean consolidating weight 3,9401b. 3 940 Degree of consolidation = ^-^ r- n = 1'51. & , bOU The consolidating effect of a two -yard waggon is less, thus : TWO-YARD WAGGON l,6001b. Proportion of length of rails and sleepers 140 Horse, 11 cwt 1,232 Driver 130 Three Tipmen 420 Earth, 2 c. yd 5,200 8,722 Eeturning empty 3,522 Mean consolidating weight 6,1221b. Degree of consolidation = *j'|^ = 1-18. 5,200 INSTANCES OF FAILURE. 13 These differences of degree are small when compared singly; but when it is considered how often they are repeated, the difference becomes very great in the whole. All other reasons for making the inner part of an embank- ment very compact are strengthened by the consideration that when it is so, the pressure of the water in the reser- voir takes effect upon the bank in a direction perpen- dicular to the slope ; but if water penetrates it the pressure is horizontal. Within the century two reservoirs have burst viz., Bradfield and Holmfirth and Mr. Bateman* referred to these in a discussion on Tunnel Outlets at the Institution of Civil Engineers, and said that the Holmfirth reservoir which burst in 1852 was never filled except on the single occasion on which it burst. The water escaped through the fissures of the rock on which the embankment was constructed, and gradually washed it down in such a way that the top of the embankment was lower than the waste- weir, and when an extraordinary flood came it passed over this low part of the bank and carried the whole away. The Bradfield embankment was constructed on ground liable to slide down upon the face of an underlying flag rock with a smooth surface. But, besides this, the inner part of the bank was of very loose material, and the pres- sure would be horizontal, the puddle wall and the outer part of the bank having to bear the whole pressure of the water in the reservoir because the inside slope was per- meable by water. The puddle trench was sunk through the flag rock into the shale below, but there, on the out- side, lay the flag rock at an inclination of 1 in 4 as smooth as polished marble, and when the pressure came against the puddle wall the whole thing gave way. That was the opinion of Mr. Bateman given in 1879. He was on the spot immediately after the accident, but did not then give any opinion at the local inquiry. Mr. Rawlinson's opinion was different. There were two >x y^> lines of 18in. cast-iron discharge-pipes laid side by side in puddle in a trench excavated in the rock, but above * J. F. Baternan, Esq., F.K.S., M.Inst.C.E. 14 EMBANKMENTS OF WATERWORKS-RESERVOIRS. the bottom of the main puddle trench where the pipes crossed it, and Mr. Eawlinson's* opinion was that the joints of the pipes were opened by reason of the surround- ing puddle sinking in the middle, and allowing water to creep along outside the pipes and so make a beginning of a more serious run of water, as there were no valves on the inner ends of the pipes, and if such a beginning was made the run of water could not have been controlled, the valves being at the foot of the outer slope of the embank- ment. Mr. Beardmore, who together with Mr. Rawlinson conducted the inquiry, concurred in this opinion. But there is another way in which the water may have been let out of the reservoir, and for the purpose of stating it the construction-in-chief of the embankment may here be recapitulated. It was 95ft. high, had a top width of 12ft., and slopes 2J to 1 both inside and out. The puddle trench was sunk to the depth of 60ft. to watertight ground. The thickness of the puddle wall was 18ft., diminishing to 4ft. at the top, but it was very well made. The earth, however, forming the bank on each side of it was tipped from rail- waggons at a height of 6ft., and more. The breach in the bank was 100 yards wide and 70ft. deep, and 90,000 cubic yards of earth were carried away by the water in thirty or forty minutes out of a total quantity in the embankment of 406,000 cubic yards. This breach was near the middle of the length of the embankment. The portion left standing, on the north side, presented this appearance a few days after the accident : Now, considering that the place where this ap- pearance was presented was fifty or more yards from the middle of the breach, the slip which was Fi 5 here apparent the tail end of it as it were was, probably, a very great one at or about the middle of the * Sir Kobert Kawlinson, C.B., M.Inst.C.E. SLIPS. IS bank, and sufficient to withdraw from the inside of the- puddle wall the whole of the earth which supported it against the pressure of the outer part of the bank. If this earth slipped away from the puddle wall for any considerable length and depth, it would almost certainly follow that the top of the puddle wall would fall inwards,, and if only a few feet in height of the upper part of the puddle wall fell in it would let the water begin to flow out and down the outer slope of the bank, and, of course,, the action would go on with quickly-increasing effect, until, in a short time, it would seem to go all at once. But whatever inference may be drawn from it, the slip was a fact to the extent shown in the sketch above. Now what was the cause of the slip? The material of the bank was chiefly shale the dark shale of the coal measures but this is rather a good than a bad material for the purpose, being largely composed of thin, indurated beds of rock. The slip then probably occurred by reason of the large quantity of water which found its way into the bank, the upper portion of it having been raised quickly for the purpose before stated. In the lower portion of an embankment the area is so large that the earth is almost necessarily spread out in thin layers, and the bank is therefore raised by slow degrees, but near the top, as the width diminishes, progress upwards is mora rapid. ( i6 SECTION II. QUANTITY OF WATER TO BE STORED. THE capacity of a reservoir to control the flow of water from a given area of ground used formerly to be calcu- lated on the basis of a proportion of the average rainfall, as two-thirds, one-third being deducted for loss by evapo- ration and absorption, but it was found by further ex- perience that the loss could not in all cases be taken as any certain proportion of the average rainfall, although in many cases one-third was a near approximation. In the case of reservoirs the capacity of which had been calculated on the basis above named, it was occasionally found that some of the water came down to the reservoir when it was full or nearly so, and passed over the waste- weir beyond control, and, consequently, that instead of the reservoir being full at the commencement of a drought, it was sometimes considerably below the top-water level at such times, and that the quantity stored did not keep up the required daily supply for a sufficient length of time. The storage capacity of a reservoir large enough to equalise the flow of water over a long drought, or two or three shorter ones with intervening winter rains of less than the usual amount, and so that the annual rainfall is made to yield its daily average quantity throughout long periods of time, can be found when the past rainfall daily for a long time has been ascertained, the number of dry days in the future being assumed to bear the same relation to wet ones as they have done hitherto, and that the past average yearly quantity of rain will continue the same ; PART OF THE RAINFALL ONL Y CAN BE STORED. 1 7 then the capacity of any reservoir may be found, being measured by the longest period of defect of supply into and discharge out of the reservoir. The rainfall of a long series of years must be con- sidered in connection with that of a short series of dry years, as three or four. When a table of the rainfall of any locality, extending over a long series of years, is ex- amined, it is found that the mean depth of three con- secutive dry years is about one-sixth less than the general average. The wettest year has a rainfall about half as much again as the general average, the driest year one- third less, and the mean of the driest three consecutive years one-fifth less, than the general average. Thus in some years a great deal of water passes off the ground by the streams to the sea which cannot be stored. Mr. Hawksley* stated before the Royal Commission on Water Supply, which sat in the year 1868, that gaugings of the actual quantity of water going over the waste- weirs of reservoirs show that it is about one-sixth of the quantity due to the average rainfall, and this agrees with deductions from the tables of rainfall, showing that reservoirs of the capacities of those which permitted one- sixth of the general average rainfall to pass over the waste-weirs do not deal with more than the average depth of three consecutive years of least rainfall. In these cases therefore one-sixth of the average must first be deducted, then the loss by evaporation, &c., and the depth remaining will represent the available quantity upon which the capacity of a reservoir may be calculated, according to the number of days' storage required. A great portion of the water yielded by light rains is absorbed into the ground, and neither flows directly off the ground by streams nor sinks far into it to issue again in springs, but is evaporated, partly from the surface of the ground itself, and partly from the leaves of the vegetation into which it enters, only a small part being left in the vegetation itself, the greater portion of the * T. Hawksley, Esq., F.R.S., M.Inst.C.E. C 1 8 QUANTITY OF WATER TO BE STORED. water which enters into it being evaporated from its multitudinous surfaces. The annual depth of rain which in this way does not contribute to the streams varies with the nature of the ground on which it falls, being least on a non-absorbent and precipitous area such as mountains of slaty rocks of old geological formation. The longer the time the water takes to reach the reservoir the more of it will be lost, and besides the difference caused by the declivity of the ground the quantity evaporated depends on the humidity or dryness of the air of the locality, and this latter con- dition varies much in different parts of the country. The depth of rainfall which does not contribute water to the streams at the sites of reservoirs varies from 9in. to 18in. in different parts of the country. The number of days' storage a reservoir for the water- supply of a town should contain varies with the average annual depth of rain and also with the frequency with which it falls. Mr. Bateman, in his evidence before the Commission already named, said that whereas 120 days' storage would be sufficient on the western side of the country and some other parts, where the rain falls on a great number of days in the year, 240 days' storage would be required on the eastern side of the country, where the rainfall is both less in depth and less frequent, and it has been estimated that in certain situations on these sides of the country respectively 150 and 300 days' supply would not be too much. For the sake of illustration we may take an instance where the average annual rainfall is 42in. Deducting one-sixth, 35in. would be the depth to be reckoned upon, and supposing the depth allowed for loss by evapo- ration, &c., to be 14in. the available depth would be 21 in.; and, in the absence of exact measurements in every part of the area from which the water from time to time flows, that depth of 21in. must be supposed to extend over the whole area, if it is not of inordinate extent. NUMBER OF DAYS' STORAGE. 19 Where the area is very extensive, that depth of rain- fall may not extend over the whole of it, and this may have been one of the reasons why expected quantities of water have sometimes not been yielded by a drainage area of given extent ; but it is the nearest approximation to the truth which can be made, and some concession towards it may be considered to be made in deducting one-sixLi from the known average rainfall of a few places within the area, although in some cases that quantity has been found to pass actually over the waste-weirs, thus furnish- ing a direct proof that with such reservoir-room as has been there adopted that part of the water could not be stored. When, as is the case sometimes, large areas are dealt with, the available quantity of water is conveniently reckoned per thousand acres of the watershed area. Upon 1,000 acres an available depth of 21in. would yield an average daily quantity of 1,000 x 43560 X 1-75 = 208)800 ^ ^ of ^^ oDO about two-thirds might be used for supply to houses, manufactures, or for power away from the stream, or for irrigation, leaving one-third or thereabouts to the stream itself; or rather, this latter would be first apportioned, leaving two-thirds for other purposes, and the apportion- ment would stand thus One-third = 69,600 cubic ft. per day to the stream. Two-thirds = 139,200 870,000 gallons per day for supply, and so on per 1000 acres, within limits defined by our know- ledge of the real average rainfall over any area, the cer- tainty of the calculated average increasing with the number of places of observation over a given area, but becoming too uncertain for use when the area is very large and the places of observation few. The quantity above set down for the stream would c2 20 QUANTITY OF WATER TO BE STORED. render it more powerful in dry weather than it would be without a reservoir. The average flow of the stream in this case during dry weather would probably not be more than two-thirds of the quantity above stated, for measure- ments of the dry- weather flow of streams show about 30 cubic feet per minute per 1000 acres of the drainage area. This, no doubt, varies with the nature of the ground from which the water flows, being greater or less as the ground is more or less absorbent. Where the ground in the upper and middle portion of a river-basin consists of chalk, oolite, or sandstone the dry-weather flow forms a larger part of the whole quantity flowing off the ground than where it is of hard and impervious rocks, with the steeper surfaces which always accompany those harder rocks ; and the kind of ground which affords a medium dry-weather flow between these extremes is that which consists of alternate formations of sandstone and shale y or of oolite and lias clays, in either case covered in parts with clay and gravel. The rainfall observations, if sufficiently numerous, will show on an average of years that where the annual quantity is great the number of rainy days is greater than in those parts of the country where the rainfall is com- paratively small [this is not, as it might seem to be, a necessary consequence], and so, although more water per day is discharged from a reservoir per 1000 acres of its drainage area in the former situations than in the latter ones, the loss of water is oftener replenished, and in propor- tion to the frequency of this action the capacity of the reservoir may be smaller. The experience in England during the last twenty-five or thirty years has been that, in order to equalise the flow of water day by day during three or four consecu- tive years of least rainfall, the capacity of a reservoir should be sufficient to yield about 120 days' supply where the rainfall is frequent, and 240 days' where it is infre- quent ; but it is here assumed that the reservoir is full at the commencement of a drought, whereas it may not DED UCTING THE DR Y- WE A THER FLO W. 2 1 be so if the previous winter's rain has not yielded a sur- plus over the regular supply sufficient to fill up the re- servoir completely, and in this view the capacity should be increased perhaps to 150 days' supply in the one case and *00 days' in the other. From an examination of Mr. Symons's * annual records of rainfall it appears often that nearly as many rainy days occur in the southern and eastern counties as in the western and midland counties, although the rainfall in these is much greater ; but the days set down as rainy in the records include all those on which one-hundredth of an inch of rain has fallen, and this is so little that it often adds nothing to the run of the streams. The rainy days, the frequency of which affects the capacity of storage reservoirs, are not numerous. If in the example where 21 in. is the available annual depth of water over the initial area of 1,000 acres, the proper number of days' supply were, from its position, say 180, the capacity of the reservoir would be 208,800 x 180 = 37,584,000 cubic feet. Deducting the dry- weather flow due to 1,000 acres at the rate of 30 cubic feet per minute, that is 7,776,000, there remains 29,808,000, or say 30 million cubic feet, as the capacity of the reservoir, which is at the rate of 30,000 cubic feet per acre of the watershed area. Whether the dry-weather flow of the drainage area should be deducted from the capacity of a reservoir in the manner already stated, will depend upon the method by which the number of days' storage is arrived at ; whether upon the basis of (1) the rainfall table, showing the -absolute length of time during which no rain has fallen ; or (2) upon the stream gaugings, showing the daily quantity reaching the site of the reservoir ; or (3) upon the difference between two quantities, one of which is the quantity of water in an existing reservoir at the com- mencement of a drought, to which is to be added the -quantity coming into the reservoir during the drought, * G. J. Symons, Esq., F.E.S., F.R.Met.Soc. 22 QUANTITY OF WATER TO BE STORED. whether from springs or casual rainfall and the other quantity is that which has been discharged during the drought, as ascertained by the daily sinkings of the water-level of the reservoir, in which case it is evident that the total quantity is dealt with on either hand, and, therefore, no deduction can properly be made. But this method is true only of that reservoir, unless the dry- weather flow, where it is proposed to make a new one, is the same, area for area; whereas by the other method the rule becomes general, and is applicable alike to cases where the dry- weather flow is large, com- paratively, and where it is small. It is, therefore, better as a method, although the other is more exact for a particular case already existing. The dry- weather flow of the stream at the site of the reservoir is made up of the numerous small springs issuing within the drainage area, produced because of the absorbency of the ground during wet weather, and its yielding of the absorbed water gradually, and to this extent of the dry-weather production the drainage ground is essentially a part of the reservoir, and for this reason the quantity should be deducted from what would otherwise be the necessary capacity. Were the ground wholly impermeable there would be no run of water in dry weather, and, in that case, the capacity of the reservoir itself would need to be so much larger ; but where, as is assumed in the example, there is a dry -weather flow which, on the average, during a drought, is equal to 30 cubic feet per minute per 1,000 acres, that quantity may be deducted from the calculated storage-room in order to arrive at the actual capacity of the reservoir. The quantity so deducted belongs to the reservoir, and is, in fact, part of the yield reckoned upon in the available depth assumed, as, in the case adduced, 21in., and whether it be conducted past the reservoir and form part of the supply, or it run through the reservoir and form part of the discharge into the stream, makes no difference in the reservoir-room proper to be provided; HEIGHT OF BANK. 23 but where the number of days' supply to be stored is founded on the length of a drought as ascertained from the rainfall returns, the dry-weather flow ought to be deducted. But the formation of the ground on reservoir sites varies much, so that any rule of this kind gives only an approximation to results in particular cases. The height of the top of the embankment above top- water level is often 4ft. in small reservoirs and 6ft. in large ones. Where the depth of water at the site of the embankment does not exceed about 30ft., the top of the bank may usually be 4ft. above top-water, or the level of the waste-weir. With a depth of from 30ft. to 50ft., the top of the bank- may be 5ft. above that level, and where the depth is 60ft. and upwards, the height should be 6ft. ; but it somewhat depends upon the direction in which the reservoir lies lengthwise, and to its exposure to gales of wind. Irrespective of this, a certain height is neces- sary to meet a flood which may raise the water-level above the waste-weir, and as a matter of prudence and safety the waste-weir should be of such length as to pre- vent the water rising, on the occurrence of the greatest flood, to a height more than about 2ft. above the waste- weir. But beyond that, an allowance must be made for the further height to which the water may be driven by wind, and the greater the depth of water at the embank- ment the longer will the reservoir be on the same site, and on a long reservoir the water is driven up by the wind to a greater height than on a short one. In the upper parts of river-basins where reservoirs may be made, the opposite hill-sides approach each other towards the bottom, and almost meet in the stream with straight slopes. This is a general characteristic; but a really good site for the formation of a storage reservoir widens out in the bottom above the site of the embank- ment, and the only way of ascertaining the quantity of water the site is capable of affording, with any given height of bank, is by actual measurement, either by sections across the valley or by contour lines laid down OF THf UNIVERSITY 2 4 QUANTITY OF WATER TO BE STORED. upon a plan every 4ft. or 5ft. in height ; but we may estimate approximately what quantity of water a fairly good reservoir site would probably afford by examining sites the capacities of which have been ascertained, and comparing these with the respective heights of the embankments, or, rather, with the greatest depths of water, D, and their areas, A, taking these also at several different heights on the same site. The results of an examination of 75 such cases where the depth D varies from 20ft. to 80ft., both inclusive, are as follows: In each case the cubic capacity is divided by the area of the water surface, giving the average depth; this then is divided by the greatest depth, D, giving the ratio set down opposite each case. No. Ratio. No. Patio. No. Ratio. No. Ratio. 1 612 20 49 39 452 58 4 2 583 21 487 40 45 59 4 3 580 22 485 41 45 60 4 4 572 23 473 42 447 61 4 5 560 24 468 43 435 62 4 6 543 25 468 44 431 63 396 7 537 26 468 45 427 64 395 8 528 27 466 46 422 65 394 9 526 28 466 47 42 66 38 10 525 29 465 48 42 67 376 11 515 30 464 49 42 68 35 12 515 31 463 50 42 69 35 13 514 32 462 51 42 70 345 14 510 33 46 52 42 71 34 15 504 34 46 53 417 72 34 16 5 35 46 54 407 73 336 17 5 36 46 55 407 74 32 18 496 37 458 56 405 . 75 281 19 496 38 455 57 4 The general average of these 75 cases is about D. y The shape of the ground, as it widens out above the site of the embankment, makes the average width of the reservoir in all these cases about twice as much as it APPROXIMATE DEPTHS OF RESERVOIRS. 25 would be with the straight slopes assumed to meet in the stream at the bottom of the valley, in which case the width of the reservoir is greatest at the embankment ; whereas, in the better sites the greatest width is con- siderably above the embankment, the width there being nearly the average width of the whole reservoir. In the case adduced the area is 3,000 x 450 = l,350,000sq. ft., and, the greatest depth being 45ft., the capacity of the reservoir is A x - D = 27 million cubic feet. SECTION III. APPURTENANCES OF RESERVOIRS. A RESERVOIR for a town supply, as distinguished from a compensation reservoir, sometimes has a bye- channel ex- cavated along the margin of the top-water level from the- head of the reservoir to the bye-wash which takes the water from the waste-weir. It is useful for several purposes, even when not absolutely necessary. To begin with, it furnishes a considerable quantity of materials for the bank ; it enables the bottom of the reservoir to be laid dry for any purpose ; and if a discoloured flood should come down when the reservoir is full, or nearly so, it affords a means of excluding the objectionable water, if made large enough. Where a flood channel is not absolutely necessary, these considerations ought to weigh in favour of a bye-channel being constructed. At the head of a reservoir it is a good arrangement to have a short bank across the stream for the purpose of arresting sand, stones, alluvium, or what else may be- brought down in floods, forming a receptacle known in Lancashire as a lodge, in connection with which the flood-weir and sluices are constructed. Where it is desirable to separate the clear spring waters of a drainage area from the flood waters, an arrangement, depending for its action on the laws of water in motion, which was first introduced by Mr. Bateman, the eminent engineer, may be applied. It consists of a side channel introduced under and across the line of watercourse, into which the water that arrives at the edge of a weir above it without violent motion drops easily down and is carried LODGE BYE-CHANNEL GAUGE-BASIN, &c. 27 by the side channel away from the reservoir, while on the arrival of a flood it overleaps the narrow space down which the purer water drops, and flows over a second weir and away to the flood- water reservoir. In exposed situations and such reservoirs as are here described are usually in such situations the wind acting on the surface of the water surges it against the face of the embankment in such a manner that without some protection the earthwork would be gradually washed away. To prevent this, it is necessary to pitch the face with a harder material, usually stone, to the depth of from 12in. to 18in. Flat-bedded rubble stone makes good work, but where the slope is, as it should be, as flat as 3 to 1, rough rubble spread over it stands well enough where the bank is not exposed to high winds. It is always desirable to know what quantity of water is flowing out of a reservoir, and in some cases, viz., where mills are compensated by a stated quantity per time measurement, it is necessary that the water should be gauged either by allowing it to flow over a weir, or through an opening below the head of water; but the gauging is perhaps, on the whole, more accurately and satisfactorily made over a weir. To bring the water to a sufficient state of rest before it flows over the weir, it is first received into a basin, out of which it flows quietly. Sometimes a flood channel is not made, but the water coming into the reservoir during its construction is got rid of through the discharging pipes or culverts, and if more than they will discharge comes down and seems likely to reach and go over the partly-raised bank, tem- porary shoots are used to convey it over to the outside ; and when no flood channel is made, the, waste- weir be- comes an important feature of safety, or otherwise,, according as its length is properly proportioned to the drainage area or not. No discharge pipes or culverts of practicable dimensions would carry off such a flood as three or four hundred cubic feet of water per second from : each 1,000 acres, and 2 8 APPUR TEN A NCES OF RESER VOIRS. yet such a quantity must be expected to come into the reservoir some time or other when it is full. It is plain, therefore, that even with the utmost watchfulness of the reservoir-keeper in opening the sluices on the approach of a flood into a full reservoir, some other and larger means for its escape must be provided, and for that purpose a waste- weir is formed in the solid ground at one end of Flood Level / the embankment, with a bye-wash to carry the water safely to the stream below. If we consider that with a height of top-bank 6ft. above top- water, or the level of the weir, 4ft. of that space would be little enough to oppose to the wash of water produced by a gale of wind blowing down the reservoir, we shall see that it will be very undesirable, and even unsafe, to allow the water to rise to a greater depth on the weir than about 2ft. Taking that depth, then, as the greatest to be allowed, and 400 cubic feet per second per 1,000 acres to be the greatest flood, and 100 cubic feet per second to be the greatest quantity that the discharge pipes or culvert would deliver, leaving 300 cubic feet per second to go over the waste- weir, it will be seen that the weir would require to be of a length of 37ft. per 1,000 acres of the drainage area. Here it is assumed that 4 would be the proper co-efficient in the equation q = c J~d 3 , d being in inches, for such a depth over such a weir, which would, from its breadth, if built of ashlar, reduce the co-efficient THE WASTE-WEIR. 29 to about that number if the depth were only 1ft. ; and, seeing that the greater the depth the more the weir loses its property of a free fall over, or becomes drowned, it may well be supposed that, if it could be experimentally determined for such a depth as 24in., as it has been for depths up to 12in., the co-efficient would be found not to be higher than 4. Using that co-efficient, then, and limiting the depth over the weir to 2ft., it will be seen that 37ft. or 38ft. length of weir is necessary for every 1,000 acres of the drainage area. This does seem a great length, and it is certainly greater than most waste-weirs possess, but with a shorter weir there might be a risk of the water rising loo near the top of the bank, when that is not more than 6ft. above the top-water level. If questions of economy could be allowed to enter as freely into the design of waterworks reservoirs as they do into that of many other works, an engineer might contrast the improbability of an excessive flood occurring at the very time of a full reservoir, and might conclude to save the expense of a long weir, or to allow the water to rise to a greater height upon it than 2ft. or so ; but, all things considered, he would be a bold man who would allow the water to rise upon the weir to a height more than half the height of the bank above it, where that height is 6ft., and if the water were allowed to rise to the extent of 3ft. on the weir the length per 1,000 acres would require to be 20ft., for a flood over the weir amounting to 300 cubic feet per second per 1,000 acres of the drainage area. An instance in which something like this proportion was adopted is the Grimwith compensation reservoir of the Bradford Waterworks. Here the drainage area is about 7,000 acres, and when the late Sir William Cubitt was referred to to fix the length of the waste-weir of that reservoir being the person agreed upon mutually by the mill-owners and the waterworks proprietors to fix the length of the weir he prescribed a length of 150ft. This is in strong contrast to the length of another weir 3 o APPUR TE NANCES OF RESER VOIRS. in a situation not very dissimilar, and where the drainage area is also nearly 7,000 acres, viz., at Tittesworth, in North Staffordshire, a compensation reservoir "belonging to the Staffordshire Potteries Waterworks, where the waste-weir- for this very large area was made no more than 60ft. in length, the height of the top of the bank being 6ft. above the level of the weir. The consequence of making the length so short was, that in August of the year 1862 the water rose to a height of 5ft. above the weir; and if only the accidental occurrence of a wind blowing down the reservoir had taken place at the same time, there can be no doubt that a great disaster would there and then have happened. In the case of the Bradfield Keservoir, a compensation reservoir belonging to the Sheffield Waterworks, which burst in 1864, it had a drainage area of 4,300 acres and a waste-weir of 60ft., in a horseshoe form; and although the bursting of the embankment was due to other causes than the shortness of the waste-weir, there can be no doubt that if the bank. had been otherwise soundly con- structed upon ground which could not move, its failure would at some time have been imminent from this cause alone. Although, perhaps, in the greater number of cases the waste-weir is made at one end of the bank, in the solid ground, it has been the practice of some engineers to combine it with the structure necessary to be erected at the inner end of the discharge pipe or culvert, for the purpose of working the valves. This structure consists of an enlarged valve well, of such diameter that the circum- ference of its top course shall be of sufficient length for a waste-weir. This valve pit affords a ready and conve- nient access to the inner valve of the discharge pipe, and it admits also of the facility of drawing off the water at different heights, for the water near the top is generally better than that drawn from the bottom, and for this drawing-off purpose valve pits are sometimes built, although they are not made use of as waste-weirs. ( 3' ) SECTION IV. DISCHARGE OF WATER FROM THE EESERVOIR. THERE are two distinct principles involved in the practice of drawing off the water from a reservoir; the one is to discharge it through pipes laid so securely and so guardedly as to form a feature of stability equal to that of any other part of the reservoir as the puddle wall, for instance, or the bank itself thus rendering unnecessary any provision for inspection or repair, in the same way that one has to trust to the stability of construction of the puddle wall, where inspection is impossible. This mode of discharging the water was frequently adopted some years ago, but of late years not so much, if at all ; it consists of one or more lines of cast-iron pipes laid in the solid ground underneath the embankment from the foot of the inner slope to that of the outer one, with valves on them to control the discharge of water. Sometimes these valves are placed at the inner ends of the lines of pipes, and sometimes at the outer ends; the former position being the more secure and the latter the more convenient. Mere convenience, however, in reservoir works, cannot be much considered. When the valves were placed solely at the outer ends of the discharging pipes they were in duplicate, so that in case of one being out of working order the other might be used. When valves were so placed the mouth of the pipe within the reservoir had sometimes a conical plug suspended over it, so that it might be dropped into the mouth in case of emergency. With large pipes or great heads of water, the pressure on this plug would prevent 32 DISCHARGE OF WATER FROM THE RESERVOIR. its being raised again without very great power, if it were not that the main plug contains in its crown a smaller one, which, when it is desired to raise the plug again after use, is first lifted, and, the valve at the outer end of the pipe being closed, the pipe is filled with water and the pressure on the large plug equalised, after which it is easily raised. There are cases where this precaution of either valve or plug at the inner end of a line of discharge pipe is not taken, but these are cases of the boldest and most self- confident treatment, and verge, indeed, on the indiscreet ; and anything even approaching indiscretion in the con- struction of reservoirs is certainly to be discouraged. On this principle of drawing off the water the pipes are made unusually strong, the sockets unusually deep, the depth of lead unusually great, and everything, in fact, is done to render the pipe secure under its circumstances. On the other principle the pipe is not made a special feature of stability, but is enclosed in a culvert of masonry of such a size as to admit of inspection and repair of the pipe. It is quite evident that either pipe or culvert should be laid on an unyielding foundation. To admit the possibility of sinking in either case would be absurd. There have been a few cases where pipes have been care- lessly laid in this respect, but they have been condemned as bad construction. If we take first the principle of laying a bare pipe under the bank, it will be seen that an element of weakness presents itself in the liability of the water to follow the line of the pipe between its surface and the material adjoining it. To prevent this it is enclosed in clay puddle, and obstructions to this action of the water are placed at right angles round the pipe. The rims of the sockets themselves form a considerable obstruction to the passage of water, but an additional precaution is sometimes taken to place wider flanges, projecting say, six inches all round the pipe. The discharging pipes are laid not from the lowest level PIPES ACROSS THE PUDDLE TRENCH. 33 of the reservoir, but at a level some feet above the bottom, and it is of advantage to lay another pipe from the bottom itself, which shall have its outlet in the stream below, so that the reservoir may be completely emptied when necessary. Crossing the puddle trench is the great difficulty of the line of discharge pipe. The puddle will not carry weight, and the pipe has to be made to carry itself and all above it from side to side of the puddle trench, unless it be very wide, when a solid pier of masonry is brought up from the bottom of the trench in the centre, to afford a central bearing to the pipe. The transverse strength of this pipe is capable of estimation as well as any other cast-iron girder, for it becomes a cylindrical cast-iron girder, of such strength as to carry the load due to it, with, of course, in such a situation, a very large margin for contingencies. Mr. Bateman directed this difficulty to be met, in the case of the Halifax Waterworks, by bringing up a solid ashlar pier of the full width of the puddle trench, dressing down the sides of the trench where the masonry abuts against them, and filling the joint with cement. In the middle of this pier, lengthwise of the trench, an iron plate is brought up, projecting 12in. beyond each face into the puddle, and standing up 18in. above the pipe, the joints between the iron plate and the masonry being filled in with cement, and other precautions were taken in passing the discharge pipe through the iron plate. There are not wanting on this subject, as on some others, differences of opinion as to the desirability of. placing bare pipes under embankments. Culverts of masonry, it is said, are preferable, through which the water may be discharged either openly or through a pipe which can be gut at for examination and repairs, and there are some very successful examples of this mode of construction on the Bradford Waterworks, designed and carried out by the late Mr. John W. Leather, of Leeds ; as good, perhaps, in design and execution as any in the country. 34 DISCHARGE OF WATER FROM THE RESERVOIR. After the failure of the embankment of the Bradfield Reservoir of Sheffield, where the discharge pipes had been laid on the principle of trusting to the pipe, but where several precautions usually considered necessary had been omitted, it was very much the opinion of Mr. (now Sir) Eobert Bawlinson, who, with Mr. Beardmore, investigated the case on the part of the Government, that the bank failed because of defects in the discharging pipes, and Mr. Rawlinson went so far, in some general remarks on reservoirs, as to condemn in toto the principle of laying a bare pipe under an embankment, and urged strongly the necessity of enclosing the pipes in culverts of masonry large enough to admit of workmen passing up them. One ought, however, to consider whether the larger culvert does not invite strains, requiring enormous resis- tance, which the comparatively small pipe does not, and which is therefore so far preferable. The joints of a large culvert are no doubt a source of weakness, and it is to this point chiefly, and to that of the possibility of crushing the materials, that attention is drawn when considering whether a large culvert or a small pipe is preferable. ( 35 ) SECTION V. APPROXIMATE COST OF A STORAGE BESERVOIR. To estimate approximately the cost of a reservoir for im- pounding water by an earthen embankment, the following work would have to be taken into consideration : Before depositing any earth, the seat of the embankment would have to be examined, and the top soil and all boggy earth removed outside and reserved for spreading upon the outer slope. The depth of the puddle trench could not be exactly ascertained before the work is commenced ; but it would probably allow a considerable margin for contingencies if the depth were assumed to be, at the deepest part, equal to the height of the bank, and 10ft. at each end. Inasmuch as the depth to which the puddle trench would have to be excavated would not be known in beginning the work, the sides should be carried down vertically as far as the ground is of uncertain character, and until the ground below can be proved to be strong and suitable for the commencement of the puddling. In almost very case close-planking the sides of the trench would be necessary. When this is done by driving the planking vertically behind horizontal walings,the depth to which the trench can be carried down of the full width is limited to the length of the runners used, for at the bottom of each set the new set of timbering must be com- menced Gin. or Sin. on each side within it, and when the depth of the trench is great, this continual narrowing does not leave sufficient width in the bottom, unless the width at the top be made greater than is required for the thick- D 2 36 APPROXIMATE COST OF A STORAGE RESERVOIR. ness of the puddle. It is, therefore, better in these trenches of uncertain depth to lay the planking horizontally. In going down with the trench, water may be found to come in through fissures in the sides, on one side, or the bottom. As long as it comes through the bottom, the trench would be carried further down, so as to get com- pletely under the water, if possible ; but if it come through a fissure in the side only, that fissure would have been passed through, and may be caulked with cotton-waste or tow, or plugged with dry wood. If the water running into the trench can be stopped in this way, and the bottom is strong and likely to continue so, the clay may be got in and worked for puddle in thin layers all along the trench, doing the puddling more by labour than by water, enough of this only to soak the clay being allowed to run on to it ; the bulk of the water being conducted to the sump-hole from which it is to be pumped. The bottom of the trench for this reason should be inclined sufficient to carry off" the water quickly. Strong springs of water met with in excavating a puddle trench can only be dealt with by special means ; but in nearly every case there will be water naturally soaking out of the adjacent ground when its balanced pressure is relieved, and it is necessary to lay the bottom dry by pumping before the puddling can be commenced. Nothing could be a worse beginning of the work than to throw a mass of puddled clay into a wet bottom ; it could not be united with the sides of the trench by treading, as it can be in the absence of water, and it might well be expected that the water in the ground on the upper side of the puddle would, in that case, rise on its outer side between the puddle and the outer side of the trench; whereas, when once the puddle has been well worked of a stiff consistence, water cannot pass it or act upon it ; but if, in the first instance, water is in excess, a way is prepared for a future run which would carry with it small portions of the clay continually. If the trench cannot be kept free from water while the WORK TO BE DONE. 37 puddling is being done, it is necessary to protect it from future contact with water by a facing of concrete and a concrete bed although, as to the bed, the motion of the water in the bottom carries with it the cement or lime, and leaves little but a mass of loose materials, unless, in the first instance, a drain-pipe be laid under the concrete bed to take the water to the purnping-engine. In order to estimate approximately beforehand to what depth the puddle trench will require to be excavated, borings should be made along the centre line of the em- bankment down to and 12ft. into retentive ground; this latter because it would not do to rest the puddle on merely a thin stratum of retentive ground, which might have immediately under it a pervious stratum through which water might pass out under the puddle. The borings having indicated the surface of the retentive ground, the excavation is to be carried 6ft. into it ; and if the borings have truly proved the surface there will then be an assurance of at least 6ft. of sound ground under the puddle. Notwithstanding the borings, however, which are only useful as indicating beforehand the quantity of work to be done, the excavation itself must prove whether it is necessary to carry it still lower than had been approxi- mately estimated. It is not the bottom at the middle of the bank only that has to be carefully examined the hill-sides on which the embankment abuts require examination far into them, or at least on that side where the strata are faulty. One of the Manchester reservoirs is said never to have been filled, because, as is supposed, the water, after rising to a certain level, passes round the end of the bank, behind the puddle, through loose strata. It is necessary, therefore, to carry the puddle trench far into the hill- side, where such ground exists at the site of the embankment. As an example from which to estimate approximately the cost per million cubic feet of storage-room and that is, perhaps, the most convenient form in which a general estimate can be attempted one may be taken which $8 APPROXIMATE COST OF A STORAGE RESERVOIR. would be sufficient to equalise the flow of the streams from an area of 2,000 acres during three consecutive years of least rainfall in a locality where 33in. is the average annual fall of a long series of years ; and where, also, the character of the rainfall and the ground are such that 180 would be the proper number of days' storage of the average daily yield of those three years, the site being understood to have the proportions already stated as being approxi- mate to an average of many examples. In such a case the available depth of a year's rainfall would be 13in., if from 14in. to 15in. be allowed for evaporation and other forms of loss, and from 5in. to Gin. of the 33in. as being in excess of the average of the three years to be reckoned upon. The area from which the water would proceed being 2,000 acres, the yearly amount would be 94,380,000 cubic feet, and the daily average yield 258,575 cubic feet. To contain 180 days' supply, therefore, of this quantity, the capacity of the reservoir would be 46J million cubic feet. This would be impounded by an embankment 600ft. long and 60ft. high at the middle of its length. If the top width be made 20ft., the inner slope 3 to 1 and the outer slope 2 to 1, the extreme width of the seat of the bank would be 320ft. nearly (rather less, because the level of the ground at the toe of the inner slope is somewhat higher than at the toe of the outer slope, and because the inner slope is flatter than the outer one) ; and the area to be cleared of objectionable material, to a depth of, say, Sin. vertically, would be about 12,000 sq. yds. If the thickness of the puddle wall at the top be made 7ft., and the batter of the two sides 1 in 8, the width of the puddle trench at the lowest part of the ground would be 15ft. nearly, and 7ft. at the ends. The depth in different parts of the trench would vary according to the ground met with, but would be, in general, deepest near the middle, and if at the middle point the depth be assumed to be equal to the height of the bank 60ft. in the present example and 10ft. at the ends of the bank, WORK TO BE DONE. 39 a line drawn straight between these lowest points would probably equalise the steps in which, practically, the bottom would be cut, and would represent the average depth. The excavation of the puddle trench would then be, if the sides were carried down vertically, about 8,000 cubic yards. The quantity of puddle below the ground would be the same. Above the ground the puddle wall would be about 6,000 cubic yards, and the total quantity of puddle 14,000 cubic yards. The embankment would be 80,000 cubic yards including the puddle wall, and deducting that the quantity would be 74,000 cubic yards. The embankment, less the puddle wall, is taken in one, because, although the material con- sists of three kinds viz., a toe of rough stone at the foot of each slope, selected material on each side of the puddle wall, and the remainder of the earth, each of which would be estimated at its own price when it had been ascertained from what part of the site each kind of material would be procured yet in a general estimate the distinction can hardly be made. There would be, however, in this example 8,000 cubic yards of rough stone, 24,000 cubic yards of selected material, and the remainder would be 42,000 cubic yards. If there are to be two discharges from the same reser- voir viz., one for supply and the other for compensation to the stream the supply pipe would be laid through the discharge culvert, up to the valve tower at its inner end, whether it be situated in the reservoir, clear of the embankment, or built within the embankment itself. The former is the better plan. The best position of the discharge pipe or culvert, or the line along which it should be laid, demands the most serious consideration in every case, in order to hit the happy medium which combines security with economy. The level at which it must necessarily be laid being near the bottopa of the reservoir, and the puddle trench being almost as necessarily sunk much below that level, the pipe or culvert, when laid near the middle of the 4 APPROXIMATE COST OF A STORAGE RESERVOIR. bank, must cross the puddle trench at a considerable height above the bottom, and right through the mass of puddle. This is the plan which was formeily adopted, whether the discharge pipe was inclosed in a culvert of masonry or was laid bare in the ground ; but as it was necessary to support the pipe or culvert across the trench upon a more solid foundation than the puddle itself afforded, the unequal settlements which took place when the bank had been made to its full height tended to fracture the work. To obviate this, straight vertical joints completely across the whole structure of the culvert were sometimes provided at the points where the unequal settlements would be likely to occur slip joints so that the portion of the culvert between the slip joints might settle bodily and evenly. In the same way the brickwork of railway and other tunnels driven through yielding ground is made with a straight joint at the end of every length, instead of leaving toothing for the next length, which is proper enough, and more sightly when finished, where the ground is in unyielding rock. This provision of a straight joint, however, in the case of reservoir embankments, has sometimes not had the ex- pected effect, owing to the uncertainty of the direction in which the settlements take place, there being hori- zontal as well as vertical movements of the earth above the culvert. The culvert, therefore, should not cross the puddle trench at any great height, if at all, above the bottom of the trench. This consideration drives the position a long way from the middle of the bank, as is shown in Fig. 7, in order to lay the culvert in the solid ground. The bottom of the reservoir, to a height of 14ft. or 15ft. above the lowest point, contains but little water say in this case half a million cubic feet. It is not necessary, therefore, to lay the discharge pipe lower than is sufficient to draw off the water to this level, s the constant multiplier for these measurements. It is less than is sometimes adopted, but is as much as it is safe to adopt without taking into account all those particulars of a weir which bear upon the obstructions or facilities to the flow of water over it. This constant 4*81 is applicable to what may be called the normal condition of a weir, in which the water falls over the weir or notch from a still head, and when the height h is the whole height from the sill of the weir to the surface of still water above it say four or five feet above it and when there is no velocity of approach. When the water arrives within a few feet of the weir in a stream with some sensible velocity it must be taken into account ; it is equivalent to an increase of head forcing the water over the weir, and this head is one sixty- fourth part of the square of the velocity in feet per second with which the water flows, at its surface, towards the weir. The condition which most influences the quantity of water passing over a weir, when calculated from the whole height (7i), is the thickness of the lip or sill over which the water flows. It is only when the thickness is reduced to a minimum, and eliminated altogether from calculation, that even an approximation to the true quan- tity of water flowing over a weir can be arrived at by the application of any constant, such as 4*8, or perhaps more 62 STREAM GAUGES. commonly 5 or 5-1 ; and indeed for accuracy every weir requires a careful study of its circumstances. The influence of thickness of lip or sill, over which the water flows, is shown clearly by some trials made by the author, the results of which were communicated to the Institution of Civil Engineers, and published in the Minutes of Proceedings, vol. xc. p. 305. One set of ex- periments was made over a Jin.-plate weir, another set over a Sin. -plank weir. The whole depth (ti) varied from lin. to Tin. The diminution of depth on the outer edge is produced by the retardation of the flow over the sill of the weir, the thicker sill retarding the flow of water more than the thinner one, and a thin plate, say T Vrn. thick, would, if tried in a similar way, pro- bably show still less retardation than the Jin. plate. Some few experiments were made by the author with sills Gin. and 12in. thick, and these showed much greater reductions of depth than those with the Sin. plank, but they were not made with sufficient accuracy to warrant their insertion along with the others in the paper com- municated to the Institution. Such as they were, how- ever, they showed a greater diminution of depth than the weirs of less thickness. The fact, however, which is the most evident upon an examination of every experiment, with whatever thickness of sill, is that there is no simple ratio between the whole depth (h) and the depth on the outer edge (d), but that varies with every depth, in such manner that with the Jin. plate d = -72 h + -025 A 2 and with the Sin. plank d = -33 h + -05 A a These are in some measure confirmed by a few experiments on the outer edge of 2in. plank-weirs, made by the late Mr. T. E. Blackwell. These show that the curve which would most nearly traverse the points determined by the experiments is one of which the following would be the equation, viz., d = '60 h + -025 7i 2 . DEPTH ON 1 THE OUTER EDGE OF A WEIR. The following diagram, Fig. 13, shows all three curves. The scale is one-third of the full 'size. By plotting the dimensions to the full size, and drawing the curve through the points determined by the rules just given, the depth on the outer edge resulting from every whole depth may be accurately measured. / in. 2 in. 3 in. 4 in. 5 in. 6 in. 7 in. WHOLE DEPTHS SECTION YIIT. RAINFALL. THE chief source of the rainfall of this country is the Atlantic Ocean. The heat rays of the sun convert water into vapour ; and as the vapour of water is lighter than air, being about five-eighths of the weight of air, bulk for bulk at the same temperature and pressure, it rises into the atmosphere and collects together in clouds, which are blown about by the wind, and chiefly by the prevailing westerly and south-westerly winds, moving laterally and rising up against the hill-sides into a colder region, where it contracts and unites in rain drops, for as it is heat which changes the particles of water on the surface of the ocean into vapour, so it is the loss of heat which changes the vapour into water again. The vapour itself is invisible ; what is seen as clouds is partially condensed into water, but not yet into globules heavy enough to fall through the resisting medium of air. Bain is precipitated in large quantities on the high ground of the chain of hills which range in a generally north and south direction through England, which shed the water east and west eastwards into the great basins of the Thames, the Great Ouse, the Trent, the Humber, the Yorkshire Ouse, the Tees, the Tyne, the Tweed, the Forth and the Tay, and westwards into those of the Clyde, the Eden, the Kibble, the Mersey, the Dee, and the Severn, with other (minor) river-basins ; while on the south there are the Avon, the Parret, the Exe, and the Tamar. This dividing ridge begins in the neighbourhood of Devizes, and upon or near it are situated Wootton Basset, Thames MAIN RANGE OF HILLS. 65 Head, Cheltenham, Daventry, Naseby, Coventry, Birming- ham, Wolverhampton, Newcastle-under-Lyme, Buxton, Chapel-en-le-Frith, Saddleworth, Eochdale, Colne, Settle, Kibble Head, Swaledale Head, Tindale Tarn, Tyne Head, Tweed Head, and Clyde Head; and so into the rocky formations of Scotland. These hills intercept the clouds of vapour and condense a portion of them which is not able to rise over their tops, precipitating a large amount of rain, the fall being generally from 30in. to 40in. in a year, and as much as 70in. or 80in. in particular situations; while other por- tions of vapour follow the western slopes until they come to a gap or break in the range of hills, through which they pour and are condensed on the eastern side, giving at these particular places as much rain as on the western side. If the rainfall on the western coast be compared with that further inland, it will be seen to increase as these hills are approached. Mr. Bateman drew attention to this in his evidence before the Water Supply Commission, to the effect that if in any particular year the rain on the westerly coast, say, at Liverpool, is 36in., and going right across the country to the east coast, it increases as the range of hills is approached, where it is at the foot, say, 40in., on the summit of the hills it is from 50in. to 60in. ; further east it is 30in., and further east still it is 20in. In an investigation he had made across England from Liverpool over the Manchester Waterworks drainage- ground and over that of Halifax, it was observed that the winds impinge upon the westerly slope of the mountains which form the eastern side of the Kivington (Liverpool) Waterworks drainage-ground, where in a certain year the rainfall was 48Jin. Over the ridge, in the first trough to the east, are the Bolton Waterworks, the trough running pretty nearly north and south ; and at Belmont, in the Bolton Water- works district, the rain was 53in. The next trough is the F 66 RAINFALL. valley from which the Blackburn Waterworks are supplied, and there it was 42in. ; and over the mountains right down in the east it was 30in. The Manchester Waterworks are formed in a mountain range, the Pennine chain of hills, lying between Man- chester and Sheffield, commonly called the backbone of England. Rain at Manchester in 1859 was 38in., in round numbers. Going eastward, the rain at the Denton Reser- voir, which is 300ft. above the sea, was 34in ; at Newton it was 35in., and a little further east it was 33in. All these places are upon the plain, or nearly the plain. Then at the foot of the hills the depth of rain was 46^ in. Higher up at the head of the valley, on the west side of the hills, it was 53^in., then 57*64in. ; a little further towards the head, on the east side, just over the summit, it was 58Jin. At the reservoir of the Sheffield Waterworks, which is on the hills more to the east, it was 46in., at Penistone 39in., and at Sheffield 25in., showing an increase as the hills are ascended, and, over them, rapidly diminishes towards the east. On the line of the Rochdale Canal, which also crosses the backbone of England, in tlie same way, in another year, the rainfall at Rochdale, which is at the foot of the hills, was 39'7in. At Whiteholme, on the top of the hills, 66-7in. ; at Blackstone Edge tollbar, 67'5in. ; and, on the east side, 66* Gin. ; but these last three places are almost entirely upon the summits of hills not more than, 1,200ft. high. Then at Sowerby Bridge, which is at the easterly foot, though comparatively in the hills, it was 32'27in., and at Halifax less than that. It was observed by Dr. Miller, in the Lake district, that the rainfall increases up to a height of about 2,000ft. above the sea, but decreases on mountains of higher elevation. If the elevation of the country lies within the region of the rain-clouds, which may be said to extend to about WEST TO EAST. 67 3,000 or 4,000ft., the greatest portion of deposit within that range takes place at from 700 to 2,000, or 2,30ft If the greater portion of the gathering-ground lies within that zone, setting aside local circumstances, that will be the elevation which will give the greatest quantity of rain. Supposing a continuous ridge exceeding 2,000ft. high to range north and south, there would be comparatively little rain on the east side ; it would stop nearly all the rain-clouds from the west, and the water would be pre- cipitated on the westerly slopes : but, where there is a range of mountains, the summits of which measure up- wards of 3,000ft. with depressions in the ridge, the largest amount of rain falls in the valleys to the east of those depressions. These westerly and south-westerly winds prevail over the greater part of England and Wales ; but in the north of England, in Northumberland, a westerly wind is a dry wind, and a wet wind on the coast of North- umberland is a dry wind in the west. Mr. Symons began in the year 1858 to collect and arrange the observations which had then been -made of the depths of rain fallen in previous years, and to extend the observations, and since 1860 has published them an- nually through Mr. Stanford, of Charing Cross. There are more than two thousand places in this country where the rainfall is observed daily and sent to Mr. Symons at Camden Square. The observations are examined, collated, and put into form to be useful both in the localities whence they originate and for comparison with the observations of other localities, the whole forming a yearly record of great value. The rainfall map of the 6th Keport of the Rivers Com- mission, 1874, shows the average annual fall at various places in most of the river-basins. Taking first those on the western coast, which have the heads of the valleys towards the east, the rainfall is seen to increase upwards from the coast as the watersheds are approached, thus : F 2 68 RAINFALL. Liverpool Manchester .. Marple Chapel-en-le-Frith Eibble basin : Preston Settle Lune basin : Lancaster Garsdale Lake district : Whitebaven Kendal Inches. 35 36 36 40 39 50 44 52 52 61 Taking next, from the same records of rainfall, those river basins in which the heads of the valleys are towards the west, it is seen that in general, but not without excep- tions, the depth decreases from the watersheds towards the middle and lower portions of the basins, thus : Inches. Thames basin : Cirencester 31 Oxford 25 Greenwich 24 Severn basin : Hengoed . . 36 Shrewsbury 27 Worcester 28 Wye basin : Rhayader .. 46 Hereford .. 30 Ross .. .. 27 Trent basin : Birmingham 31 Derby 26 Retford .. 23 Calder basin : Halifax .. 31 Pontefract 25 Aire basin : Head of the val ey 35 Leeds 23 Yorks. Ouse basin : Richmond . . 31 Thirsk .. 24 York .. .. 23 Tyne basin : Alendale . . 50 Tynemouth 27 On the " Map of the Eivers and Catchment Basins " of the Ordnance Survey Office a series of rainfall depths are given which, although not the average rainfalls, are comparable one with another, and, for this purpose, are perhaps better than averages would be. These show the following reductions of depth of rainfall from west to east : COMPARATIVE RAINFALLS. 69 Iirchep. Thames basin : Head of the valley . 31-8 Oxford 27-1 Beading 24-8 Windsor . 23-6 Kingston 24-2 Croydon . 24-2 Greenwich 28-5 Sheerness . 22-5 Severn basin : Head of the alley 68'4 Shrewsbury 23-5 Worcester . 26-0 Cheltenham . 25-7 Gloucester . 21-8 Wye basin : Khayader . 41-0 Hav 32-7 Hereford 28-3 Trent basin : Birmingham 31-0 Leicester 27-6 Derbys. Wye and Loughborough .. . 26 -3 Derwent basin : Head of the valley . . 65-1 Cromford 37'3 Helper 29-9 Derby 29-4 Don basin : Head of the valley . . 54-8 Barnsley 27*4 Sheffield 32-5 Doncaster 33-1 Calder basin . 49-7,31-1, and 27'2 Aire basin . 39-0,27-7, 24-2 Wharfe basin . 54-7,30-9, 25-2 Yorks. Ouse basin . 27-0,25-0, 25-5 Wear basin . 31-3,25-8, 24-2 Tyne basin . 45-5,28-5, 24-2 It is only by a patient attention to and collection of observations on the rainfall in various parts of the country that data can be arrived at upon which to base calculations of what quantity of water may be expected to be derived from any particular source in any given locality. All atmospheric phenomena are most intricate in their rela- tions to and effect upon the land, and nothing but the most patient study of observed facts, extending over long periods of time, can determine anything worthy of being relied upon in practice. The rain-gauge is the instrument by which the quantity of rain falling to the earth is measured. There are various 7 RAINFALL. forms of it, from the rude quart bottle with a funnel in- serted in the neck, to the most delicate instrument of the scientific professor. Some are made to carry a float in the body of the gauge, to which is attached a graduated rod projecting from the mouth of the funnel, which by its rise indicates the depth of rain fallen. Others have a gradu- ated glass tube attached to the body of the gauge, with a communication between them at the bottom, the water rising to the same level in both. Others, again, are made with a loose funnel inserted into a vessel which is to be emptied into a separate gradu- ated glass tube when it is desired to know the depth of rain fallen. There are also various modifications of each of these kinds of gauges by the various makers of such instruments. The best size of the mouth of the funnel is not very well determined, but a common size is Sin. dia- meter; others, again, are lOin. diameter, but Mr. Symons, who has under his control a great number of rain-gauges in the kingdom, and who has paid a great deal of attention to the niceties of measurement, said that a funnel of Sin. diameter is as good as any other, and sufficiently accurate. The height at which a rain-gauge is fixed above the ground is important to be attended to. It has long been known, but apparently not generally known, that the nearer the ground the gauge is set, the more rain it regis- ters, but it was not until Mr. Symons's comparative expe- riments had been made, that anything like a definite conclusion on this point had been arrived at. Gauges were fixed at all heights from the surface of the ground to a height of 20ft. At the ground-level itself the cause of the greatest register of quantity was proved to be because of the rebounding into it of rain-drops falling on the surround- ing soil or grass. When, however, a trench was dug round the gauge so as to prevent this, the register ceased to show excess. On the whole, Mr. Symons recommends the mouth of the rain-gauge to be not less than Gin. or more than 12in. above the ground, except when a greater ele- RAIN-GAUGES. 71 vation is necessary to obtain a proper exposure, for this is important. Gauges sheltered by buildings, or trees, or shrubs, or tall flowers, are not in the best situations. The distance from any building should be at the very least as great as its height. The gauge must be fixed perfectly level. If it be impossible to fix the gauge unless near some build- ings, those are to be preferred which stand north-west, north, and north-east of the gauge ; those standing south and south-east will be in the next least objectionable quarter, and those standing south-west of the gauge are in the most objectionable positions. Observations should be made daily, and at the same hour of the day. In snow, that which is caught in the funnel should be taken out and melted and measured as rain. As a check upon this, select a place where the snow is of a fair depth, not drifted, invert the funnel and take up a funnel full, or whatever can be taken up in this way, and melt it. As a second check, measure the average depth of snow and take a twelfth of it as the equivalent depth of water. Strike an average of the three processes and enter that as the depth of rain. But it is to be observed that in respect of the first of these methods the snow is liable to be blown out of the funnel if the weather be at all windy, and allow- ance, therefore, should be made for this. Snow, measured in depth within a few hours after it has ceased to fall, has often been found to yield, by melting, a depth of water equal to one-twelfth of its depth, not unfrequently one- tenth, and sometimes one-eighth; it depends upon the state of the atmosphere at the time of the fall. SECTION IX. AREAS OF KIVER-BASINS. THE areas of the river basins of England and Wales, prepared by the Ordnance Department and published by Mr. Stanford, of Charing Cross, may be divided into sections, as follows, beginning at the Land's End, and proceeding along the south-east and north-east coasts, and along the north-west and west coasts back to Land's End. From Land's End to Fowey, a distance of 85 miles along the coast not following every indent of the sea, but a general line 12 rivers or streams have basins of 47, 40, 29, 33, 10, 33, 12, 40, 66, 50, and 80 square miles respectively, and the river Fowey itself of 120 square miles. Proceeding in like manner, a further distance of 88 miles from Fowey to Dawlish, there are 12 rivers having basins of the following areas : Name. Lynher Tamar Tavy .. .. Plymouth Leat Plym Area. 71} 100/ 385 85 23 59 Name. Yealme Ernie .. Aune .. Dart .. Teign .. Area 36) 43 54) 73\ 200J 203 From Dawlish to St. Alban's Head, a distance of 90 miles, there are nine rivers, the areas of the basins of which are, in square miles, as follows : Name Exe Otter Axe Area. 11) 584J 821 2IJ 165 Name. Char .. .. Brit . . Bredy.. .. (Weymouth) Area. 39) 52 1 21) 87 SOUTH AND EAST. 73 From St. Alban's Head to Littlehampton, 95 miles, Area. 231) 35 85) 235 26\ 370 f The Isle of W ght is not included ; it has a coast-line of about 55 miles, and 5 rivers. From Littlehampton to Dover, 95 miles, there are 8 rivers- Name. Area. Name. Area. __,, . . 75 Adur .. (Brighton) . . there are 13 rivers Name. Area. Name. Frome 187 Itchen Piddle 119 Hamble Stour .. . 459 ft Avon .. 673 (Portsmout ) Lymington Beaulieu . 9tt 52) Arun .. Test .. . 477 Ouse Area. 35 160 56 205 Name. Cuckmar . Old Haven Rother 312\ 881 From Dover round by the North Foreland and Whit- stable and outside the Isle of Sheppey to Sheerness and up to Chatham, and down the Medway again to Sheerness, and up the Thames to Greenwich to meet the basins of the Thames proper and the Lea, and, crossing over and going down the north shore round by the mouth of the river Crouch to Brad well, the distance is about 185 miles, and there are the following rivers : Name. Stour The Swale . . . Medway Cray and others Area. 373 157 680 314 Name. Thames and Lea Roding Crouch Area. .. 4,613 .. 317 181 Proceeding along the east coast to Great Yarmouth, and about 20 miles beyond, to the division of the watersheds of the Bure and Waveney, a distance of 100 miles or there- abouts, the following rivers discharge I- Name. Blackwater Colne .. Stour .. Orwell Deben . . Area. 434 24) 192} 53) 407 171 153 Name. Area 321 Aide Minsmore .. Blyth Yare & Waveney Bure .. .. 109J 34 1 79} 53 880 348 74 AREAS OF RIVER-BASINS. Again, to and a little beyond the Withern Eau, at Saltfleet, a distance of about 130 miles Name. Glaven Nar Ouse .. Nene .. Area. 293 131 243 2,607 1,077 Name. Welland .. Witham .. Steeping . . Withern Eau Area. .. 760 .. 1,079 .. 101 189 Passing the mouth of the small river Ludd, and enter- ing the Huinber, and proceeding along the south shore past Grimsby, New Holland, and Winteringham, we come to the mouth of the Trent, then the Don, the Aire, and the Yorkshire Ouse ; and, on the left bank of the Ouse, the Derwent, and lower down, the Foulness and the river Hull; then, passing round Spurn Point, we come to Hornsea, having traversed the tideway for a distance of 135 miles or so, although the coast-line from Saltfleet to Hornsea is not more than 40 miles ; yet we are bound to go so far up the Humber to meet those great rivers the Trent, the Don, the Aire, the Wharfe (the area of which is here included in that of the Ouse), and the Ouse itself. The areas of these river-basins are as' follow : Area. 815 1842 794 133 364 206 Kesuming, there are, from Hornsea to Kedcar, a distance of about 80 miles Name. (Scarborough) .. .. Name. Ludd Ancholme .. Trent Area. .. .. 139 .. .. 39 .. .. 122 . . . . 244 .. .. 4,052 Name. Aire .. Ouse .. Derwent Foulness Hull .. Don .. .. 682 Area. 157 Name. Esk Area. 147 100 From Kedcar to Tynemouth, 44 miles, there are Name. Tees .. Area. 708 \ 77/ Name. Wear .. Tyne .. Area. .. 456 .. 1,130 From Tynemouth to Berwick-on-Tweed, 60 miles EAST, NORTH-EAST, AND NORTH-WEST. 75 Name Blyth '. Wansbeck . Area. 31\ 131) 126 37 18 Name. Coquet Aln Till Area. 240 104 129\ 37/ 231 The object we have in view in making these tabular statements is to show, at a glance almost, what a large number of small river-basins adjoin the sea-coast of Eng- land and Wales ; but without further remark at present upon that point, we proceed to the north-west coast, and follow it and the west coast to Land's End, whence we started. From the river Line, in Cumberland, to the mouth of the Kent, at the head of Morecambe Bay, there are the outfalls of the rivers of the Lake district of Cumberland and Westmoreland, the distance being about 125 miles to the southern watershed of the river Kent. Name. Line . . Eden .. Warn pool Waver Ellen .. Derwent Elien ., Area. Name 21\ Calder 104) Irt 915 Esk 78) Duddo 70 72 262) Leven 11 Kent 72J [ Area- 28) 61 64) 46 1 28V 56 1 202 255 These rivers convey into the sea the surplus waters from Ulleswater, Haweswater, Bassenthwaite lake, Der- wentwater, Thirlmere, Crummockwater, Buttermere, Loweswater, Ennerdalewater, Wastwater, Conistonwater, and Windermere. From the watershed of the Kent, round by Blackpool and up the Kibble nearly to Preston, and back by South- port to Formby, near the mouth of the Mersey, is about 50 miles, along which the following rivers discharge : Name. Lune .. Wyre .. Kibble Area. 418 208 585 Name. Douglas Area 168 1 55 1 AREAS OF RIVER-BASINS. Going from Formby up the Mersey about 10 miles above Liverpool, and crossing over to the mouth of the river Weaver, back by Birkenhead to the mouth of the Mersey and round by Hoose and West Kirby to the head of the Dee estuary, and back round Air Point to the coast at Prestatyn, the distance is about 85 miles, and it includes the outfalls of the basins of the following rivers, viz. : Name. Alt .. Mersey Area. 126\ 885/ Name. Weaver Dee Area. 711 813 Thence along the northern shore of Wales, round by Great Orme's Head and through the Menai Strait along the western coast of Carnarvon and round to Aberdaron, is 90 miles, and the following rivers fall in : Name. Clwyd Conway Area. 319 39 222 78 Name. Seiont.. Soch .. Erch .. Dwyfach Area- 143) 33 1 55 1 48 The Isle of Anglesey has a coast-line of 100 miles, and 5 rivers Name. Braint Cefni .. Area. 53 41 47 Name. Alaw .. Area. 69 58 Area. 23) 31 52 48j 386 From Aberdaron, along the Ashore of Cardigan Bay to Cardigan Head is 100 miles, including Name. Prysor Artro .. Mawddach Dysynni Afon Dyfi Lery .. Eheidof Ystwyth From Cardigan Head round by St. David Head, and St. Govens Head, to the mouth of the Bristol Channel at Worms Head, is a distance of 160 miles, in which are Area Name 141 Wvrai 45 Arth q Aeron 151 64 Teifi 217 34) 24 70, 75 WEST. 77 Name. Nevern (St. Bride's Bay) Cleddau . . (Pembroke) Taff ! Area. 94J 65/ 212\ 114/ 611 183f Name. Towy .. Gwendraeth Llwchwr . . Area. 514 73 \ 156f From Worms Head along the South Wales shore by Swansea, Cardiff, Tredegar, and Newport, to the water- shed dividing the Wye from the Severn basins, is 100 miles or thereabouts; and there are 12 rivers, viz.: Name. Tawe " Neath Afon Ogmore Ely Taff Taking the Severn basin properly to terminate where it meets that of the Wye on one side of the Channel and that of the Bristol Avon on the other, near Aust Passage, and returning down the Channel on the Somerset and Devon shore to its mouth at Hartland Point, west of Bide- ford Bay, there are, in 120 miles, 15 river-basins, in- cluding that of the Severn, viz. : Area Name. Area. 66 Kumney . . . . 94V 106 Ebbw.. .. . 94J 118 Usk .. . . 540\ 87 . , . 55} 114 Wye .. . . . 1,609 67 81] 198J Name. Severn Avon Yeo Axe Brae Parret Area .. 4,350 . 891 . 106 . 101 . 197 .: so . 562 . 82 Name East Lj Taw . Torridg nn e Area 24 29 41 47 455 336 10 On the Devonshire and Cornwall coast, from Hart! Point to Land's End, there are river-basins of the follow- ing areas, in a distance of 110 miles, viz. : 108, 8, 149 r 154, and 43 square miles; and another, in which St. Ives- is situated, of about 10 square miles. SECTION X. CONDUITS. WATER may be very well conveyed along a hill-side in an earthenware pipe, in moderate quantities. A 24in. pipe running half full, with an inclination of 5ft. in a mile, will carry a million-and-a-half gallons a day, and 2J millions when running two-thirds full. But to go to a smaller size, a 12in. pipe with the same inclination would carry 300,000 gallons a day, half full, and 450,000 gallons if running two-thirds full. A 2 Tin. pipe will carry, at the two degrees of fulness mentioned, 2,300,000 gallons, and 3,400,000 gallons, respectively. A 30in. pipe, nearly 3 million gallons a day half full, and 4J millions if running two-thirds full. The carrying capacity of any circular pipe may be found for any degree of fulness from the following considerations. If full, or half full, the hydraulic mean depth is half the radius. This is evident, because the cross-sectional area of the pipe is equal to that of a triangle, the base of which is equal in length to the circumference of the circle, and the height to the radius, half of which, multiplied into its base, is the area. The hydraulic mean depth is, the area divided by the whole circumference when the pipe is running full of water, and is, therefore, half the radius ; and it is the same when the pipe is running half full, for in that case it is half the area divided by half the circum- ference ; but at any height, H, above or below the centre of the pipe, it is as follows D representing the diameter, and K the radius : The width at the surface of the water (see Fig. 14) is W = VR 2 -H 2 x 2. DEGREE OF FULNESS. 79 The width V is P "" W . From H and V find the 2 length of that part of the circumference in contact with the water above the centre of the pipe, and add it to the lower half of the cir- cumference, thus procuring the wetted border of the section. The length of the two arcs above the centre is the same as that of a single arc the chord of which is 2 H. Find the chord of half the arc = VH 2 + V 2 = C. Then 8 Q ~ 2H = tjie i en gth of o the two arcs above the centre, to be added to that of the lower half of the pipe, to find the wetted border, which, being multiplied into half the radius, gives an area, to TT which is to be added W x for the whole sectional 2 area of the stream, and this divided by the wetted border gives its hydraulic mean depth. For example, in a pipe 24in. diameter running two- thirds full, the height H, is 4in., and the width W = V12 2 - 4 2 X 2 = 22-62. The width Y is 24 - 22 ' 62 = 69. The chord of an arc above the centre is C = V^ 2 + * 69 2 4-05. The length of the two arcs is 8 X 4 05 - 2 x 4 _ g . 13< 3 The lower half of the circumference of the pipe is 3-,1416 X 24 . 2 3 &2ft., the wetted border. 99fi9 v 4- The sectional area is 45-83 x 6 + n * o CONDUITS. 320 sq. in. = 2-22 sq. ft., and the hydraulic depth, or 2 22 mean radius, is r = -58ft. y * 82 If Eytelwein's rule be adopted, in which li represents the hydraulic mean depth, and / twice the fall per mile, the mean velocity of the stream of water would be ~ J~hf = ^ ^-58 X 10 = 2 -18ft. per second, or 130ft. per minute, and the area being 2*22 sq. ft., the quantity is 288 cubic feet per minute, or 2,592,000 gallons per day as before stated. Larger pipes than those of about 24in. diameter are difficult to handle, require heavy tackle to lift about, and are liable to split longitudinally with external pressure, unless the pipes are evenly bedded all round the lower half, and the haunches of the top solidly filled in between the pipe and the sides of the trench. At what diameter, exactly, a brick or stone conduit becomes cheaper than a pipe, depends upon the local materials ; but, usually, about 20in. becomes the turning- point, in respect of expense, between an earthenware pipe and a culvert of masonry. The pipe has some advantage in being glazed, but for clear water this is not of much importance. A circular conduit, 2ft. diameter and half a brick thick, would usually be laid at less expense than a pipe of the same size. Yery excellent conduits are made of square shape, with flag bottom and covers, and sides of clean bedded stones with squared joints. A larger quantity of materials is required for this form than for a circular one, because to carry the same volume of water at the same inclination, a larger sectional area is required, and the walls, being straight, need to be thicker. The question arises, when considering the advisability of adopting a square or a circular form, what are the comparative carrying capacities of the two forms, the more immediate question being what dimensions of the square form carry the same quantity of water per day or per minute, as a circular conduit of given diameter. This FORM OF CHANNEL. 81 may be seen from the following considerations : In rectangular channels the best proportion of width to depth of the stream of water is width 2, depth 1. That proportion is the best which gives the greatest hydraulic mean depth with a given quantity of materials used in the construction of the channel, because, the greater that depth, the less need be the sectional area of the stream, the carrying capacity of all conduits having the same inclination being as the area multiplied into the square root of the hydraulic mean depth. A rectangular conduit may be compared with a circular one in the following manner : Let them both run half full; then if the height of xj the rectangular con- M |\~ ' duit be the same as _v ^ its width, the width < -f D > of the stream will Fig. 15. be twice its depth. Let h represent the hydraulic mean depth, as before, W the width, and D the depth of the stream (see Fig. 15). If the width be twice the depth, the area is 2 D 2 , and h = 2 D 2 2 D 2 yy , 2 D = |~j) = * 5 D ; that is, in a rectangular stream in which the width is twice the depth, the hydraulic mean depth is half the simple depth, as, in the circular form, it is half the radius. Then fh = *J -o 1) = 707 The sectional area multiplied into the square root of the hydraulic mean depth thus becomes 2 D 2 x *707 fj D = 1 * 41 fj D 5 , and this quantity must be the same in the square as in the circular form, to satisfy the con- ditions. For example, in the case of a rectangular stream, in which the width is twice the depth, what would be the dimensions to make the carrying capacity equal to that of a circular conduit 3ft. diameter running half full? In a 82 CONDUITS. this latter form the hydraulic mean depth or mean radius is -75ft. The area of the lower half of the conduit is 3-1416 x 3 x '75 - - = 3-53 sq. ft., and the area multi- plied into the square root of the hydraulic mean depth is A x \/~h = 3-53 x ^866 = 3-05. _Then in the rectan- gular channel Ax V ^ = 1*4:1 */~T) 5 =3-05. D 5 = /3 * 05\ 2 VFH/ = 4 ' 66 ' and D = V4-66 = l'36ft., the depth, and the width is 2 72ft., the area being 3 70 sq. ft. The border is W + 2 D = 5 44f t., and the hydraulic mean q . 70 depth is -|r = ' 68ft ' bein S lialf t]be de P th > as before o * 44 stated. If the quantities of water carried by the two- conduits be calculated from these data, they should be the same. Small conduits are more liable to freeze than large ones, and should be covered, to protect them from freezing as well as from dirt. Snow is troublesome in an open conduit whether large or small ; it clogs the run of water ; but the freezing over of the surface of a large body of water is not of so much importance as in a small one. In either case it reduces the sectional area of the stream, and at the same time increases the solid surface with which the water runs in contact, but the effect of this in reducing the quantity of water carried is but little in a large conduit, while it is very considerable -in a small one. In respect of protection from dirt, fencing may be sufficient in the open country, but the expense of fencing bears a greater proportion to the whole expense in a small than in a large conduit, and is almost as much as that of covering a small conduit. If the line of conduit is not subject to contamination by dirt it may be open, though it be not large, if the inclination is sufficient to cause a velocity of about 3ft. per second. This would wash away earth if not protected by a facing. OPEN CONDUITS. 83 In an open conduit cut with side slopes at which the ground will stand without slipping, so that the facing is for the purpose of protecting the earth from the wash of water rather than for keeping it up by its weight or lateral resistance, the side slopes would usually be flatter than those which coincide with the best form in respect of carrying capacity. They would usually be 1 J to 1 or more, but side slopes of 1 J to 1 are best in respect of carrying capacity, which, with these slopes, is the same as that of a rectangular channel of a width equal to twice its depth, and of the same sectional area. The peculiarity of this slope is that the length of the two slopes and bottom is the same as the length of the two sides and bottom of a rectangular channel of the propor- tions mentioned, the area of the two forms being the same ; consequently the hydraulic mean depth is the same, and, therefore, the discharging capacity. If the slope be drawn through the point M in Fig. 15, it will leave the area of the section the same as that of the rect- angular channel, whatever the slope be, but there is only one slope which will leave the length of border the same as that of the rectangular channel ; that slope is 1^ to 1, and the length of the two slopes is equal to the top width, being 3^ times the depth, the bottom width being f- of the depth. Keferring to the figure, the area is 3_ 1 D + D x D = 2 D 2 , and the border is If D+f D + 2i If D = 4 D. Hence, the hydraulic mean depth is 9 T) 2 -= *5 D, the same as that of the rectangular channel, 4 D and also of the circular one. But sometimes practical considerations have greater weight than the best deductions, and the sides of an open channel would generally be less troublesome to keep up with slopes of 1J to 1 or more. Frost is the great dis- turber of the upper part of open channels, whether large or small, although the covering of water prevents it from reaching the bottom. The sides above the water should G 2 CONDUITS. be porous the facing, that is to say, should not be close- jointed so that water may not accumulate behind it, for when it does so, it swells when frozen and disturbs the facing. But when the facing is thus open-jointed it would be the means of introducing mud into the conduit from behind it in long-continued rains upon clayey ground ; to prevent this, the facing should be laid upon a bed of sand. Through loose ground the making of the conduit water- tight must always be one of the chief difficulties a difficulty of course to be overcome. For this purpose puddle, to be used with all materials except concrete, is perhaps the least expensive material, and gravel puddle is better for the purpose than clay puddle. A foot is an abundant thickness for small conduits for the bottom and slopes of the ground, and 2ft. above-ground in the em- banked portions of the line of conduit. In these the hardest of the excavated earth will be placed along the central portion, and brought up to the level of the under- side of the puddling, as far as the height above-ground is but a few feet. A material which may be used for conduits is concrete, made with Portland cement of good quality. It forms at once a water- tight channel and one which needs but little protection of the surface, a facing of cement being sufficient for all that part under water, but above the water, in an open conduit, it would be preferable to face the concrete with brick or stone, and indeed for some little depth below the water surface. A covered conduit may equally well be made with concrete, both bottom and top, and the thickness COVERED CONDUIT Fig. 16. COVERED CONDUITS. 85 need not be more than about half as much more as would be the proper thickness of brickwork. Beyond the several points in a long line of conduit at which slight cutting should end, or the height above- ground would be but a few feet, and where it would be economical to cross straight over low ground rather than extend the line far up the hollow and back again on, the other side, the aqueduct is best carried on piers and arches; but economy points to girders, which can be made to carry the water between them on a floor laid upon the lower flanges, or in the form of a wide box-girder ; but if the water runs in contact with the iron the con- ducting property of the metal quickly draws heat from the water in winter. If it be lined with a non-con- ducting material, which is at the same time brittle, the difference in the rate of expansion by heat of the metal and the lining tends to destroy the adhesion. This may in some measure be prevented, and perhaps entirely, by sinking the aqueduct bodily as far as is necessary to completely immerse it, so that it may preserve a nearly uniform temperature both top and bottom; but this, of course, somewhat adds to the retardation of the flow by increasing the wetted border. To prevent contact with the metal altogether, by substituting an independent carrier for the water within and clear of the girders, would be expensive, but such a carrier might very well be made in earthenware, either rec- tangular or circular, and of any size by being jointed crosswise. The least expensive aqueduct would be an earthenware pipe of stoneware or fireclay carried on a single girder in saddles upon the top flange. An open girder, continuous over the piers, with wide flanges both top and bottom, would resist the wind, and as the pipe and the water together would be of considerable weight, it would not be likely to be blown off the girder, especially if tied down with a strap over all, every 10ft. or so. However desirable it may be to follow the contour of 86 CONDUITS. the ground, there will occur, in any conduit of considerable length, breaks in the continuity of such a line, caused by an intervening valley, or by a range of hills, through which a tunnel may be necessary, in order to continue the conduit. In the case of a valley to be crossed, cast-iron pipes are used, laid underground at such a depth that they may have a sufficient covering for their protection (say 2ft.), and rising again on the opposite side to within so much of the level of the conduit from which they depart as will give a sufficient head to the water to force its way through them. The following formulas by which the necessary difference of level of the two ends of the pipe, or the head, is ascertained, are based on the experiments of Dubuat, Bossut and Couplet. Taking a number of their experiments made with pipes of from lin. to 5in. in diameter, and from 30 to 1,700ft. in length, M. Prony found that, taking English measures and putting h = the head of water in feet, I = the length of the pipe in feet, d = the diameter of the pipe in feet, v = the velocity in feet per second = 48-49 A/ $h and by substituting a fall in feet per mile, which call , , 2-24 v 2 Eytelwein, taking the same set of experiments, found that v = 50 A / 7 , d g AJ . This correction 50d is for short v i -- 50rf pipes, but in case of actual waterworks practice it may be neglected, and then Eytelwein's expression may be translated into v = A / 4L. and / = 2 ' llv \ v Z * 11 d In using these and similar rules for practical purposes, engineers have, in exercising a wise precaution in under- estimating rather than over-estimating the capacity of a pipe to deliver water, had a tendency to increase these co- CROSSING RA VINES. 8 7 efficients of 2*24 or 2*11, for the purpose of allowing for the obstruction of bends and other irregularities in a long length of pipe,, and Mr. Blackwell proposed 2*3 in all cases; but a few of the more eminent water engineers, who have had large experience in gravitation works, have been able to ascertain from actual examples the quantity of water passing through long and large conduit pipes, and Mr. Bateman has said that the very general, method of coating pipes inside and out with the pitch of coal-tar, to preserve them from oxidation, has had the effect of diminishing the friction of the water to a considerable degree; so that it is probable that when pipes are so coated the effect of it is to facilitate the passage of the water to quite as great an extent as the bends and other irregularities retard it. Roundly, 10 ft. per mile may be named as the allowance for the difference of level of the two ends of a pipe thus laid across a valley ; but where the pipe is large, less than that is sufficient. Ten feet per mile will induce a velocity of 3ft. per second through a 2ft. pipe. It frequently happens that in a length of several miles of conduit pipe one or more streams of water, or ravines, or other such places, have to be crossed, and instead of passing under them, the pipes are sometimes carried over them, as shown in the illustration (Fig. 17). Large pipes are now commonly cast in 12ft. lengths, so Fig. 17. that a stretch of 36ft. can be had from side to side, and if a greater length be required, one or more intermediate 88 CONDUITS. piers can be built. It is not usual to carry more than three pipes in one stretch; but three are safely thus carried across such places by means of flange joints strongly bolted, the flanges themselves being also of more than the ordinary strength. As to the strength of cast-iron pipes laid across a valley, it is necessary to consider that concussions may occur if stop valves be placed on the line, and also that concussions may occur if the pipe be so laid as to be liable to air locks, although no concussion would occur from either cause, if in the one the valves were made with a pitch of screw so small as to prevent the valve door being shut down sud- denly, and, in the other case, if one or more self-acting air valves were placed on the summit of every rise. The most trying time to a pipe of this kind is when it is first charged with water ; but it is easy to admit the water for the first time gradually, and not recklessly to open the valve at the head of the pipe, as if it were already full of water. When these precautions are taken, there is no need to make the strength of a pipe equal to more than six times the strain it is subject to from the head of water upon it ; and if we take the low estimate of six tons per square inch as the utmost tensile strength of the iron, we shall have a working strain of one ton per square inch of metal. At the head of a line of conduit pipe there should be a sluice valve, and a provision made for turning the water sideways into some proper watercourse. The mouth of the pipe should be some feet below the head of water 10ft. is not too much to prevent air being drawn i* to the pipe during the ordinary working. When this Talve is shut down, the body of water shut into the pipe will pro- ceed on its course at first with the momentum it had acquired, leaving a vacuum between its head and the sluice valve, which will cause it to partially return, and to oscillate backwards and forwards until the forces within the pipe are balanced. At every low point a washing-out pipe should be placed^ AIR IN PIPES. 89 with a valve upon it, so that the conduit pipe may be emptied when necessary. It is well to have these outlets of limited size, so that carelessness in opening them sud- denly may not cause damage to property on the brook course below, if it be a mere brook into which the water is turned. It will not unfrequently happen that in the course of a long conduit pipe a railway will have to be crossed, and here the pipes should be unusually thick capable, say, of withstanding ten times the strain they will be sub- ject to. In cutting the trench for the pipes, air locks should be as much as possible guarded against by cutting through many small elevations of ground, so that long reaches of rise and fall may be obtained. The desirability or otherwise of this certainly depends on the perfection of action of the air valves ; for if this action be perfect the more ups and downs the better, for the air has then shorter distances to travel before it can escape ; but, considering that a large quantity of air is contained in the water itself which is constantly seeking a higher level, it is perhaps better to afford it as few points of accumulation as possible. The best known air valves are those with a ball of gutta percha falling down from its seat as long as it has nothing but air to support it, the air meanwhile escaping, when pressed by water, but rises to its seat by floating on the water when it reaches it, and as long as no fresh supply of air accumulates about it it is held up tightly to the india- rubber seat provided for it. These valves are made by Messrs. Guest and Chrimes, of Eotherham. In a discussion on a paper on the Melbourne Water- works, Mr. Hawksley stated that concussions in mains are caused by the sudden escape of air at the air valves, causing two columns of water to meet each other and give a blow to the pipe, and in one case he ordered the air outlet to be no more than fin. diameter, so that the air could escape only gradually. SECTION XL TUNNELS. ON the Bristol Waterworks there are three tunnels one at Harp tree, about 1 J mile in length ; another at North Hill, about half a mile, and another at Winford of one mile, all on the main conduit, and another on a branch conduit. The first-named of these tunnels was driven through an intensely hard and difficult conglomerate rock, without beds or joints. There were nine shafts, and at some of the faces of the tunnel the driving alone cost 6 per lineal yard ; although at others it was only 3. The average cost of powder alone was 10s. per lineal yard. The size of the hole blown out was about 6ft. square, and the very rough bottom and sides were afterwards lined with masonry. The contractor who undertook this tunnel was. obliged to give it up before it was half driven, and the driving of it was re-let at 3 14s. per lineal yard, being at the rate of 18s. Qd. per cubic yard, and the masonry at about 30s. per lineal yard, being together 5 4s., but there were extras which brought up the cost to 5 10s. per yard. The driving of the North Hill tunnel, through mag- nesian limestone, was estimated to cost 3 5s. per lineal yard in rock, being at the rate of 16s. per cubic yard, and at the loose ends 1 15s. per lineal yard, being at the rate of 7s. per cubic yard. At the Winford tunnel, through blue lias beds and shale, and some marl, the contractor was paid for the driving of the tunnel in rock 2 10s. per lineal yard, being at the rate of 12s. Qd. per cubic yard; and in clay A FEW EXAMPLES OF COST. 91 at 1 15s. per lineal yard, being at the rate of 7s. per cubic yard. At a water tunnel in Dorsetshire, through the Kim- meridge clay, 5ft. high, and 3ft. Gin. wide in the clear of the masonry, which was 12in. thick, the tunnel being about half a mile in length and 300ft. below the summit of the hill, the driving was estimated to cost, at the loose ends, 1 15s. per lineal yard, and in the main portion of the tunnel 2 10s. It is worth noting that this tunnel gave out so much foul air that the men could not work. The Alwoodley tunnel of the Leeds Waterworks is said to have cost 6 per lineal yard complete. The Mottram tunnel, on the Manchester Waterworks, 2,770 yards in length, with four shafts, of which the deepest was 150ft., and with bore holes for air, the ground consisting of clay at one end and sandstone and shale at the other, was estimated to cost per lineal yard : s. d. 6 cubic yards excavation, at 5s 1 10 Brickwork, 1 cubic yards at 25s 1 17 6 Centres 10 Proportion of shafts 060 Pumping, &c 16 6 Total 500 The tunnels on the Bradford Waterworks were esti- mated to cost per lineal yard, where lining was required and also timbering : s. d. 4^ cubic yards excavation, at 18s 3 15 1^ cubic yard masonry, at 24s 160 12 cubic feet ashlar in springers and keyl A , n stones, at Is. 6d .. ./ Total 5 19 9 and where no timbering was required : s. d. 3^ cubic yards excavation, at 18s 215 9 Masonry as above 249 Total 506 SECTION XII. SERVICE RESERVOIRS. THE greatest difficulty usually met with in the construc- tion of service reservoirs is that of site and elevation. The remark made by somebody that it was curious how rivers mostly ran through towns must have had its origin in a forgetfulness of the circumstances under which towns have grown up. Towns have begun to be formed on the banks of rivers more or less navigable, but it was the navigability of the river that first induced settlement on its banks for the purpose of commerce ; and then, up to the time that steam became known to be so powerful an agent, and as roads began to be made, waterfalls were sought for power for manufactures, as well as for manu- facturing uses. So that we find the "centres" of all manufacturing towns close to the rivers running through them; but presently people build their houses outside and away from their factories and warehouses, and there- fore on higher ground, and it is this tendency to get to higher ground on which to build houses, that renders the choice of a sufficiently elevated site for a service reservoir difficult to find within a moderate distance of the town. The service reservoirs of Manchester are five miles off; those of Liverpool eight miles ; and those of the most feasible scheme once proposed for the supply of water to the metropolis were to be ten miles off. However, those of most other towns are nearer. When the service reser- voir is made near the town it is recommended that it be covered, to protect the water from the impurities of the atmosphere ; and in all cases a service reservoir should be POSITION. 93 covered if it is less than 15ft. deep, for if still water be exposed at a less depth than that, vegetation is promoted, and when that dies animalcules are formed. The size of a service reservoir, unlike that of an im- pounding or storage reservoir, depends upon circumstances within the immediate control of the engineer that is to say, it depends upon the character of the supply. If the supply be through a conduit from a storage reservoir, and the conduit be a short one, one or two days' supply may be sufficient, because anything happening on such a con- duit to prevent the delivery of water can soon be put right ; while the longer the conduit, or the more complex in character, the greater should be the contents of the reservoir. The service reservoir of the scheme already mentioned as designed for the supply of the metropolis, the conduit of which was to be 180 miles in length, was intended to hold three weeks' supply. Also where a service reservoir is supplied by pumping engines, it should hold a considerable quantity of water, to allow of stoppages of the machinery or part of it. Generally, perhaps from three to seven days' supply may be said to be the ordinary practice. Eeservoirs not requiring to be covered are usually formed by excavating the ground and embanking the earth round it, adjusting the level of the bottom of the excavation so that the quantities of cutting and embank- ment are equalised. To render the reservoir watertight, it is usual to lay down a flooring of clay puddle, 18in. to 2ft. in thickness, worked in layers in the manner described for the puddle of the storage reservoir. The slopes of the excavation should be not less than 2 horizontal to 1 vertical, and should be cut down in steps, so as to hold up the puddle placed on them. From the top of the slope of the excavation the puddle is continued on the surface of the ground (the bed-puddle) to the centre of the bank, and up through the centre of the bank the puddle is carried as a wall. In reservoirs of considerable size it is necessary to lay down this bed-puddle, or over a part of 94 SERVICE RESERVOIRS. its area, before the floor-puddle and that on the slopes can be completed, in order to provide a place of deposit for the excavated material, but a margin of it, of not less than 3ft. wide, should be left uncovered, so that the slope puddle may afterwards be joined up to it; and this margin should be formed thus : ,_J- J BED.PUDDLE. Fig. 18. So that when the joining up is to be done the layers may overlap and be re-worked into each other. This part of the work requires the greatest watchfulness to ensure soundness. It is often the case that the thickness of the puddle wall of service reservoirs is made less than that of storage reservoirs proportionally to the height, but it is not very obvious that this is sound practice. It may be said that in the higher bank there are more risks of disturbance ; yes, but then the puddle is made thicker in proportion to the height. Of course, if the larger reservoir burst, more damage will be done than if the smaller one were to fail ; but this hardly forms a good reason, for the damage done by the bursting of even the smaller reservoir would be sufficiently serious to prevent any risk being incurred on that score. As long as the puddle wall of the larger bank is held up in its place, it has no more force to resist, proportionally to its height, than that of a smaller bank, and the possibility of its not being constantly held up in its place cannot be admitted in the case of the smaller any more than in the larger bank. The only reason of PUDDLING. 95 any value why the puddle wall of a large reservoir should be proportionally thicker than that of a smaller one admits a deficiency of practice. It is that in works of magnitude, where large numbers of workmen are employed, it is more difficult to ensure sound work than where the attention of the inspector can be more concentrated ; but that only admits the insufficiency of the number of inspectors. And if it be said that there is a difference between the two cases, inasmuch as the service reservoir is generally kept full, while the storage reservoir is subject to fluctuation of level, and therefore of pressure on the puddle wall, this does not seem to touch the question, but rather to be a consideration in the formation of the inner slope of th& bank which is to protect the puddle wall. The bottom should be formed with an inclination from the sides to the centre, and along the centre there should be a channel with an inclination towards the lower end, and from the lower end of this channel there should be a pipe laid to lay dry the bottom of the reservoir the drain pipe. The level to which the water is drawn off for use is the foot of the slope, some feet above the bottom of the reservoir. The water is drawn off through copper-wire gauze strainers of from 40 to 60 strands to the inch. For smaller reservoirs, covered over when finished, vertical walls are built, and the excavated material embanked around them. Sometimes these reservoirs are made circular, but they are difficult to cover economi- cally, although the form itself is economical in respect of wall material, the circle containing a greater area than any other form having the same length of wall. The best way of covering service reservoirs is by running 14in. walls lengthwise at distances of from 15 to 20ft. apart, and turning 9in. brick arcnes over the spaces, having a rise of one-fifth of the span, filling up the spandrels with concrete, and covering over the whole with earth 18in. or 2ft. in depth. Openings may be made in the walls, either altogether circular, or in the form of vertical spaces arched over, so that the wall consists of a 9 6 SERVICE RESERVOIRS. series of piers supporting a continuous depth of wall say 2ft. from which the main arches spring. One or more openings in the arches should be made for the escape of air, and a man-hole should be provided, with ladder bars built into the wall, or, which is perhaps pre- ferable, an iron ladder should be provided by which access may be had to the bottom. Ladder bars built into the wall have sometimes been made of cast iron, but at least one serious accident has happened to a workman by the sudden breakage of one of these bars on receiving a blow, and they ought to be of wrought iron. An overflow weir, capable of passing over the quantity of water that the conduit or the pumping main will de- liver into the reservoir, should be placed at the top-water level, and, having fixed upon the greatest height to which the water is to be allowed to rise above this level say Gin. the length of the weir may be found (without going into the particulars of the exact form of the weir) by the general equation I = where q = the quantity of water in cubic feet per minute, d = the depth in inches measured from a still head, and Z = the length required, in feet. The sluice valve, by which the water is discharged from the service reservoir, belongs to the main, which forms the first feature in the means of distribution. ( 97 ) SECTION XIII. PRESSURE, AND ITS EFFECT IN PIPES. THE force and mode of action of water under pressure along and at the end of a main pipe may be worth con- sidering in connection with its storage in reservoirs such as have been described. The pressure of still water is the weight of a vertical column of it above the place where the pressure is measured ; but still water does no work, and when the column is in motion the pressure is less. The weight of water is as follows, the foundation being the Troy grain, 5,760 of which used to make a pound weight ; but this pound not being satisfactory for general purposes in England, the pound weight was increased to 7,000 of those grains. An Act of Parliament made a gallon of distilled water at the temperature 62 F. to weigh lOlb., or 70,000 grains, in air of the density pro- duced by a pressure equal to the weight of a column of mercury 30in. high ; and established also, from experi- ments which had been made by a commission, that a cubic inch of distilled water at the temperature and pressure above mentioned weighs 252 '458 grains. A cubic foot therefore weighs 252-458 x 1,728 = 346,247 grains, or ^^! = 62-3211b. In half a dozen different 7,UUU tables of the weight of mercury compared with that of water, six different values may be seen viz., 13*56, 13-568, 13-57, 13-58, 13-596, and 13-6. When tables differ, what is the proper weight? The difference seems to arise from comparing the weight of mercury at one temperature with that of water at another, in some H 98 PRESSURE, AND ITS EFFECT IN PIPES. cases, and in other cases in taking water sometimes at the temperature 39-2 F., when it is at its greatest density, and at other times taking it at the common temperature of 62 F. This latter is the more useful for ordinary purposes. At 62 F. mercury is 13*596 times heavier than water. The pressure of the atmosphere then is the same as a column of water - - = 33 -99ft. high, or 34ft., and the corresponding pressure per square inch is 34X12 7 ^ 52 ' 458 = 14-711b. When the mercury rises to 30-5in. the pressure is 151b. nearly per square inch. But as the weight of the atmosphere is often less than 30in. of mercury, and sometimes only 28*5in., it is the minimum pressure which should be reckoned upon in practice in order to guard against failure of action at all 9ft f\ v 1 ^ PiQA times. This is * * = 32 -29ft. of water, and \2t the corresponding pressure per square inch is 13-97lb. or 14lb. As the head of the column of water is open to the atmosphere equally with the point at which the pressure is applied, this pressure is " above the atmosphere," and although there may be a little difference between the pressures of the atmosphere at the two ends of the column, measured at the same instant, if the pressure reckoned upon be that of the minimum there will be no failure of effect. The weights above mentioned relate to water without admixture of other matter; common water contains in solution heavier matter than water itself, derived from the ground through or over which it runs, and in practice a cubic foot is taken to weigh 62Jlb. and to contain 6 \ gallons. In the case of a pipe conveying water from a reservoir to the place where it is to be used, the column of water divides itself into two portions, and the pressure at the lower end of the column is according to the height of the lower portion. The upper portion, being that part of the HEAD OF WATER. 99 whole column between the top of the virtual column and the level of the water where it meets the atmosphere, is the head of water, which feeds the column as fast as it descends by the force of gravity. In a pipe of any given diameter, as 1ft., the resistance of the sides of the pipe to the motion of the water is proportionate to its length, for it is proportionate to the area of surface with Avhich the water runs in contact ; secondly, it is proportionate to the velocity of the water, for it is proportionate to the number of particles of water in contact with a given length of pipe, as 1ft., during any given time, as one second. But the head of water required to supply the force of which the column of water is robbed in overcoming this re- sistance must be as the square of the velocity, for not only is it thus simply proportionate to the velocity with which the water moves, but it must be replenished as fast as it runs away. If the length of pipe in contact with the water during one second be twice as great in one case as in another, then there will be twice the resistance due to that cause, requiring twice the head to overcome it, and at the same time the water will run away from the head twice as fast, and require twice the length of pipe full of water to replenish it in the same time. The head, therefore, is as the square of the velocity. Now as the altitude of the proper head cannot be in- creased, but remains at the same level, nearly, whatever the velocity in the pipe may be, the only way in which the head can be increased is by taking from the length of the real column the height which may be necessary to give the required velocity increasing the head at the expense of the real column, and thereby reducing its effective pressure. The same effect may be shown by substituting actual pressures for heads of water in a horizontal pipe, such as a pumping main. At a point on a line of main let three sections of it be marked off, of equal length, say 1ft., in the direction in which the water flows, and let these sections be numbered 1, 2, and 3 from the point of observation. From the same point let three H 2 too PRESSURE, AND ITS EFFECT IN PIPES. other sections be marked off, of the same length, in the direction from which the water comes, and let these be called A, B, and C, and let them be bodies of water. Let the diameter of the pipe be such that each body of water requires a pressure of lib. to be given to it to overcome the resistance of each of the sections 1, 2, and 3. Then let three operations be performed : 1. A moves through section 1, requiring a pressure ofllb 1 2. A and B move through sections 1 and 2, A requiring 21b. andB21b 4 3. A B and C move through sections 1, 2, and 3, A re- quiring 31b., B 31b., and C 31b 9 Then if each operation is performed in the same time, as one second, the pressure required is as the square of the velocity. If feet vertical of water be substituted for pounds pres- sure, the illustration serves equally for a head of water. In respect of diameter : in pipes of different diameters the resistance is inversely as the diameter. The resistance is, indeed, directly as the area with which the water runs in contact, which in the same length of pipe is as the circumference, and therefore as the diameter, and a diameter of two offers twice as much resistance as a diameter of one ; but the distance at which it acts the radius of the pipe is twice as far removed from the axis (the point in which there is no resistance), and this, be it remarked, in two opposite directions, so that the effect of distance is as the square of the radius, and therefore of the diameter ; the resistance being direct in its action, and the distance at which it acts inverse, the result is that the resistance is inversely as the diameter. These several forces and resistances are formulated thus : Let v velocity per second. I - length of pipe. d = diameter. h = head of water. HYDRAULIC GRADIENT. IOI in which c is a constant multiplier deduced from experi- ments to be 2,500 when all dimensions are taken in feet. This is the value of c according to Eytelwein's deduction for long pipes. The velocity, then, in feet per second is / 2,500 d h /~dh v = /Y/ j = oO/v/ =-; and the diameter is If v 02 I d = - . This is the usual requirement in the case of a pipe to convey water from a reservoir to the place where it is to be used, for in such case the height and length are fixed, and the velocity must be limited so that at its maximum it may do no harm to the pipe by its violence, and so that branches ^derived from it may be duly filled, and so that a sufficient working pressure be given. When the pipe is several miles in length the rule is converted into a form expressing the head of water in feet per mile by dividing 5,280 by 2,500, in which I is 2*11 Z7 2 eliminated, and Ji = - . If the velocity be made 3ft. 19 per second, li = , and the pressure of water running with that velocity would be, at the distance of one mile from the reservoir, less than that due to the whole height 19 of the column by . d It might seem that the pressure would be that due to the whole height less such a head as is required to produce the velocity considered as falling water merely, which would be ; but although that is so in open streams, which are in train, it is not so in pipes under pressure. In this case, as in the other, there is a certain gradient line, which, if drawn straight between the head of water in the reservoir and the height due to the pressure at the end of the pipe, is the gradient which that pipe would necessarily take if it ran full, but only full, that is with- 102 PRESSURE, AND ITS EFFECT IN PIPES. out pressure on the highest part of its circumference ; and the pressure at any part of the length of a pipe is that due to the vertical height between the actual position of the pipe and that gradient, which is the " hydraulic gradient." There being thus a gradient line in all conduit pipes, there must be a length at which there would be no pressure, supposing the pipe to be prolonged so far from the reservoir, and there the water would simply run out of the end of the pipe with the velocity due to the gradient. This length is found as follows : Substituting H, the whole head, for h, the head which is due to the velocity v, ,2,500 dli v 2 For example, let d = 2ft., H = 100, v = 3, then Z = 2,500 x 2 x 100 = 5 5 } 5 55ft> Thus at the distance of t/ 10 miles or so there would be no pressure in a pipe 2ft. diameter and 100ft. below the reservoir, and it could not carry the water farther than 55,555ft. with a velocity of 3ft. per second; beyond that distance the velocity would diminish, unless an actual gradient were immediately given to the pipe equal to the hydraulic gradient ; but that being done, the same velocity would continue to any distance, if the diameter remain the same ; the stream of water through the pipe would then be " in train," the forces acting upon it being balanced by the resistances, and it would flow under the same conditions as a river. But if pressure were required, there would need to be either a greater head, a shorter length, or a larger pipe. The conditions to be determined beforehand are (1) the quantity of water required, (2) the pressure required, (3) the height at which it is t j be supplied above a fixed datum level; and (4) the height of the reservoir above the same datum. In one of the examples previously referred to, the quantity of water for supply was found to be 3,000,000 gal- lons a day, after leaving to the stream one-third of the total EXTREME LENGTH OF A PIPE. 103 available quantity. If the distance at which this quantity were required to be delivered were 5 miles, and the height of the storage reservoir above the service reservoir in which the water would be delivered were 150ft., the following conditions would ensue. The quantity per second corre- . 3,000,000 sponding to 3,000,000 gallons a day is 5 ^.Q QQQ = 5' 55 cubic feet. If the velocity be limited to 2Jft. per second, the /' K . K JX diameter would be d - 0-5 v -7854 21in. The head would be A = 5 ' l'~6?" = 39 ' 29ft " eay 40ft. The effective head would be 150-40 = 110 fr., and the pressure per square inch - . . 2 = 47 7lb. at the end of a 21 in. main 5 miles long. Upon a line of conduit pipe such as this there may be- taken off one or two branches. Say that one-sixth of the water is wanted at three miles distance from the reservoir, and another sixth at four miles, leaving 2,000,000 gallons per day to go to the far end. If the same velocity were preserved throughout, the square of the diameter of the pipe would be reduced one-sixth at the first branch, and one-third at the second. Thus the first length of three miles being 21in. diameter, the second length of one mile would be 19-18, or, say, 20in. ; and the third length of one mile 17-14, or, say, 18in. Each branch takes off 500,000 gallons a day, and, preserving the same velocity, /(21) 2 the diameter of each would be \/ Q~ - 8-51in., say, 9in. The effective head in the main conduit pipe at the point where the first branch is derived would be found by deducting the loss of head due to its distance from the 3 x 40 reservoir, three miles, which would be -= =24ft., from the difference of altitudes of the reservoir and the branch above the datum. For the second branch the deduction or 104 PRESSURE, AND ITS EFFECT IN PIPES. would be rather greater per mile, the diameter being less, while the velocity is the same, for the head is inversely proportionate to the diameter, according to the formula c h d = v 2 I. Thus if the loss of head due to a velocity of 2jft. per second in the 21in. pipe be 8ft. per mile, it would o-i y Q be in the 20in. pipe ^Q" = 8 ' 4ft - P er mi * e an(i in tlie 0-1 y, Q 18in. pipe -^ = 9 '4ft, per mile. Adding together the losses of these three lengths viz., for the first three miles, 24ft., for the fourth mile, 8Jft., and for the fifth mile, 9 Jfr, the total loss at the end of the five miles would be 42ft., instead of 40ft, as it would be if the full diameter were continued to the end, and the quantity delivered were 3,000,000 gallons a day. Cast iron is the material for water-pipes, from 3in. to 3ft. Gin. diameter. They have been cast as large as 44in. and 48in., but there are several reasons of convenience and economy which make it desirable to limit the diameter of cast pipes to about 40in. or 42in. If the quantity of water to be conveyed is such as to require a larger dia- meter, it would probably be found that either two cast pipes, or one pipe built up of rolled plates, would be pre- ferable. They are sometimes made smaller than 3 in. ; but the expense of laying constitutes a considerable part of the whole expense of small pipes, and it is not much more for 3in. than for 2in. pipes. The metal of which pipes are cast is not so strong as that put into girders and some other structures. The tensile strength of this metal is about eight tons per square inch ; but that put into pipes is probably not more than seven tons per square inch for many of the pipes of every set, and it is the strength of these upon which the success of the work depends. Whatever the quality and ultimate strength of the metal may be, the working strain should not exceed a determinate part of it, arrived at in two stages of the process of calculation. In the first place, every pipe is subjected to an actual STRENGTH OF CAST-IRON PIPES. 105 water pressure before it is laid, If the pressure be applied steadily to represent the effect of a head of water, it may be as much as one-half of that which the metal would bear before breaking ; but if, while under pressure in the proving press, the pipes be struck with a hammer to represent the jarring and blows to which they are sub- ject in the ground, the pressure applied should not be more than one-third of the ultimate strength of the metal. The proof strain of the pipes in the press should not, on the one hand, be so great as to injure the strength of the metal, which would probably happen if more than half the pressure due to the ultimate strength were applied ; but, on the other hand, the actual strain produced in the metal should be sufficient to prove the soundness of the casting, and the quality of the workmanship. But between the time of proving and being laid in the ground the pipes are subject, to a variety of accidents which tend to produce defects, some of which may be undiscoverable ; and, moreover, the arrest of the motion of the water passing through them produces a greater strain than that due merely to the height of the column of water. A complete stoppage of the motion could not be suddenly effected, but there is no doubt that the shut- ting of stop-cocks, in a system of piping, throws addi- tional pressure on some parts of it; and the working pressure, due to the head of water, should not be more than some determinate part of that applied in proving the pipes say one-third of the pressure applied in the first- named manner, or one-half applied in the manner secondly named ; so that, in calculating the thickness of metal, the steady pressure due to the head of water should not ex- ceed one-sixth of the ultimate strength of the metal. If this be seven tons, or, perhaps, not more than 15,0001b. per square inch, the strain produced by the head of water should not exceed ^ = 2,5001b. per inch. If H = the height of the column of water in feet, the ic6 PRESSURE, AND ITS EFFECT IN PIPES. pressure per square inch, on the internal surface of the = '434 H. This is a radial pressure acting on the whole circum- ference of the pipe equally all round, except that it is less on the top of the pipe than the bottom, by the pressure due to the diameter ; but this may be neglected, and its consideration may, in fact, be done away with, by measur- ing the height of the column of water from the bottom of the pipe. But, although the pressure is radial, and the circumference receives a nearly equal pressure per square inch all round, the component part of the pressure which constitutes the force tending to tear the metal asunder, acts in a direction tangential to the circumference at any point, and at right angles to the radius ; and as all the radii are alike in a circular pipe, the force tending to burst the pipe is proportionate to the radius, and is mea- sured by it multiplied into the pressure due to the head of water. For calculation of the thickness of metal, it answers all purposes to take one inch of the length of the pipe. The whole outward pressure in pounds, tending to separate one-half of the ring from the opposite half, is 434 H multiplied into the diameter in inches, and this force is restrained by the two sides of the pipe. As it is only necessary to take into account one side, the strength may be calculated from the radius instead of the diameter. Let *434 H = p = the pressure of the water in pounds per square inch ; r = the internal radius of the pipe in inches ; t =the thickness of the metal, and s = the strain per square inch of the metal acted upon, to which it is subject under the pressure p and radius r, then the following quantities should be equal to each other, viz : p r = st, and t = S But here is an anomaly ; for the part of the metal which the pressure acts upon with the force p r is infinitely thin. Beyond the face, the metal is strained less and less as the radius increases. STRENGTH OF CAST-IRON PIPES. 107 The following remarks depend upon the truth of the law that the extension of a material per unit of its length, strained by an elongating force, is proportional to the force applied. The extension of cast iron, under all strains up to that which breaks it completely, is not exactly proportional to the force applied; but it is so within the limits of the smaller strains to which the metal is subject in water-pipes. The strength with which any portion of the metal re- strains the force which tends to tear it asunder, is measured by the extension of the metal per unit of its length with- in the limits of its proper elasticity, and both the force and that extension diminish as the radius increases. The metal at the back of the pipe can only assist the strength of that at the internal face, in proportion to the rate of extension which the force within the pipe produces in it ; and the rate of extension at any part of the thickness of the metal is inversely proportionate to its distance from the centre of the pipe. The magnitude of the bursting force is itself proportional to the internal radius, and is confined to it, and its pro- portional stress at any part of the thickness is inversely as the distance at which it acts ; and as the rate of ex- tension is also inversely as the same distance, therefore the metal, at any part of its thickness, restrains the burst- ing pressure with a force which is inversely proportionate to the square of the radius at that part. With an internal radius of 1, a thickness of 1, and a force of 1, the back of the pipe is strained with a force of J, and as the length of its circumference is twice that of the internal circumference, the extension due to a force of 1 would there be J ; but as the force is only , the strain there is ^ of ^, or \\ that is, it is inversely as the square of the radius. In a lOin. pipe, lin. thick, the internal radius is 5in. and the external radius Gin., and with any given pressure of water the back of the pipe is strained less than the face in the ratio 5 2 : 6 2 = 25 : 36. io8 PKESSUKE, AND ITS EFFECT IN PIPES. For the sake of showing the effects in an extreme case, we may take the metal to be still thicker. The dis- tance at which the force acts directly on the metal is limited to a radius of 5in. As the force does not act directly upon the metal beyond the face, but indirectly through the interposing metal, it is diminished as the radius increases. At 6in. radius the force is ths of whatever it is at 5in. ; at Sin. radius it is -f ths, and so on ; and the effect of this diminishing force is further reduced in the same ratio by the distance at which it acts, so that at Gin. from the centre of the pipe there is a force of ths acting at a distance of 1 ^th; at 7in. a force of ths acting at a distance of 1 fths, and so on. Whatever strain per square inch it may be thought proper to subject the metal to at the interior of the pipe, that at the back will be in the following proportion. Let the maximum strain be assumed to be 2,500lb. per square inch, then, 9 ^oft v ^ At Sin. radius (face of the metal) z ' ou " = 2,5001b. 5 r- 2.500 x 5 , ^ Gin. = l,7 7Jin. (middle of the thickness) '-- X . 5 = l,0611b. 7f X Ij Sin 2,500 X 5 _ Q7fllh 8m. iTSTr- 9/61b. o X lj 9in 2,500 X 5 _ 7721h Jin. ______ t /21b. TA' ^ 1 0uU X i) rncrii 10in - n -Vxa- The mean strain (M) of the whole thickness is not 2,500 + 625 2 multiplied into the square of the internal radius, and divided by the mean of the squares of the internal radius (r) and the external radius (E). STRENGTH OF CAST-IRON PIPES. 109 In the case above stated it is 2 X 25 x 2,500 100 -J 2iO per square inch. The force producing these strains is pr = the pressure per square inch, multiplied into the internal radius of the pipe in inches. In order that the inner portion of the metal be not overstrained, it is necessary to extend the thick- ness far enough to comprehend a restraining force equal to that exerted on the inner portion of the metal, and its limit is found at a radius the square of which bears the vsame relation to the square of the internal radius as the force exerted at the face of the metal bears to that ex- erted at the back, and in very thick pipes the mean strain per square inch of the whole thickness differs widely from the arithmetical mean between the strains at the internal and external radii, because the strain at every part of the thickness is as the square, inversely, of its distance from the centre of the pipe, but at all distances which lie within the thickness of ordinary cast-iron pipes the mean strain would not differ much from the arithmetical mean between the inner and outer strains. In the diagram Fig. 19, A B represents the strain per square inch at the face of the metal, and C D, E F, &c., the strains at the several distances C, E, &c., from the centre of the pipe, the corresponding strains being inversely as the squares of those distances, in pounds per square inch, produced by the Fi g . force p r. There are many short rules for the thickness of metal in cast-iron water-pipes, and they vary much in the results obtained from them. They may be compared with the principles above stated. Mr. Molesworth, in the well- known * Pocket-book of Engineering Formulae,' gives the rule, t = -000125 p d + -37 for pipes less than 12in. diameter, or, l io PRESSURE, AND ITS EFFECT IN PIPES. t = the same + '50 for pipes from 12in. to 30in. dia- meter, t being the thickness of metal, p the pressure of water per square inch, and d the diameter in inches. To adopt a uniform notation, let the radius (r) be taken instead of the diameter, then t = -00025 pr 4- -37 for pipes less than 12in. diameter, or, t = the same -f *50 for pipes from 12in. to 30in. dia- meter. Mr. Neville, in * Hydraulic Tables, Co-efficients, and Formulae,' gives the rule for pipes cast vertically, t = -0016 nd 4- -32, and for pipes cast horizontally, t = '0024 n d 4- -33, in which n is the number of atmospheres of pressure, = the head of water in feet divided by 33. Adopting, like- wise, r instead of d, and converting n into pounds per square in. (jp), the rule would be, for pipes cast vertically, J i t = -0002234 pr + -32, and for pipes cast horizontally, t = -000335 p r + -33. But Mr. Neville remarks that, in practically applying these formulae, the value of n should always have ten added to it. He mentions fa formula adopted by M. Dupuis, the engineer of the Paris Waterworks, which is t = (-0016 n 4- -013) d + '32. Taking in this case also the radius instead of the dia- meter, and converting n into pound per square in. the rule would be t = (-0002234 p -f -026) r 4- '32. Professor Eankine, in his Manual of Civil Engineer- . TT ing, 9 gives the rule = , in which H is the head of water in feet. This would be equivalent to t = -000192 pd or, t = -000384 p r. But Dr. Eankine remarks that shocks from without STRENGTH OF CAST-IRON PIPES. Ill cause the thickness of cast-iron pipes to be often made considerably greater than that given by the above rule. The following empirical rule, he says, expresses very accurately the limit to the thinness of cast-iron pipes in ordinary practice viz., that the thickness is never to be less than a mean proportional between the internal dia- meter and Vth in. Mr. Thomas Box, in 'Practical Hydraulics,' gives as an empirical rule, t, d, and H being the same expressions as those before stated, and in the same terms. ; It is to the investigation of Professor Peter Barlow that we are indebted for a solution of the difficulty of apportioning to cast-iron pipes a thickness properly pro- portionate to the strain upon them from internal pressure. Barlow's rule is t = **, , in which t, p, and r are the same c-p expressions as those used above, and c = the cohesive strength of the metal per square inch, which is assumed above to be 15,0001b. before it breaks, but only 2,500 as a maximum working strain on the inner portion of the metal, and it is only metal of good quality which it would be safe to subject to even this degree of strain in metal, that is to say, produced from " mine " or native ironstone ; with any considerable admixture of inferior metal the pipes would probably not bear straining nearly so much. Professor Barlow's investigation did not extend to the minutiae of foundry necessities, such as increase of thick- ness for unavoidable defects in casting, or the difficulty of making very thin castings ; but it established a true basis around which these practical requirements gather, and to which they are more or less wisely added. To compare these various rules, let each of four pipes viz., lOin., 14in., 20in., and 30in. diameter be subject to the same pressure, viz., 1741b. per square inch (400ft. head). 112 PRESSURE, AND ITS EFFECT IN PIPES. Diameter. lOin. Min. 20in. 3Gin. pr 87011). l,2181b. l,740lb. 2,610lb. t 374 t 520 t 748 t 1-12 334 468 668 1-00 588 804 935 1-15 Neville 674 815 1-02 1-38 644 774 969 1-29 Box 569 673 805 986 According to Professor Kankine's rule to lynit the thin- ness of pipes to a mean proportional between the internal diameter and V n - that would make the least thickness t= */ -0208d, and for lOin. pipes would be '456 14in. -539 20in. -645 30in. -790 The thicknesses above stated by Mr. Neville's rule are those of pipes cast vertically. The increased thickness required by his rule for pipes cast horizontally is due to remediable defects, and we must allow to all the other formulas that they demand strictly proper workmanship, and make no allowance for defects which are not abso- lutely unavoidable ; moreover, casting pipes vertically, of nearly all sizes, is becoming more and more the custom. It may be remarked upon Mr. Neville's rule that it is not necessary to add 10 to the value of n (although this is done in the above table) unless it be for very small pressures. For facility of application, and near agreement with actual practice, Box's rule is preferable to any of the others given above. SECTION XIV. AQUEDUCTS. OF the form and construction of large conduits, or aque- ducts, there are no better examples than those proposed for bringing water to London from the Lake district by Mr. Hemans * and Mr. Hassard, j and from Wales by Mr. Bateman. Neglecting altogether the merits of either of these projects as a water supply for London, in respect of the source whence it was to be derived, the form and construction of the aqueducts may be usefully examined in connection with the present subject, especially as these were nearly alike in both the cases named, and were such as almost any large conduits or aqueducts must probably have been in this country ; nor need the same form and construction be confined to particularly large conduits, for, in any one of considerable length, whether of large size or not, the same features would be met with. Unlike a railway, which may go up a hill or down a valley, and also a canal, which, with locks, may be made in a similar manner, a conduit for conveying water by gravitation must have its regular inclination, not necessarily the same in all parts of its length, but the falling gradient must be continuous. In each of these aqueducts there were six chief feature!?, viz.: (1) tunnels, (2) open watercourses, (3) "cut and cover," that is, where the ground is cut open and the con- duit constructed and arched over, and the earth filled in over the top; (4) raised aqueducts over ground lying * The late George Willoughby Hemans, M.Inst.C.E. t Richard Hassard, Esq., M.Inst.C.E. I 114 AQUEDUCTS. below the general gradient of the conduit; (5) the por- tions connecting the two forms of construction, 2 and 4, or 3 and 4 ; (6) pipes laid underground across valleys too wide and deep to be crossed at the gradient height, rising again 011 the other side to the proper level, and the con- duit being continued in one or other of the ways indicated by 1, 2, or 3. It was not the first time the engineers above-named had had to consider how best to convey a large quantity of water a long distance. Mr. Bateman had then recently made the works which supply Glasgow with water from Loch Katrine, and Mr. Hassard had laid down the plan for supplying Dublin from the river Yartry. The aque- duct to convey water to London from Ulleswater was to carry 250,000,000 gallons per day. The gradient was to have been Gin. per mile in some parts, and less than that in others, the principle laid down on the score of economy being that the greater fall, and therefore the smaller sec- tional area, should be given to the tunnels and aqueducts, which are the most expensive portions, and the lesser fall and larger dimensions to those parts which are of com- paratively cheap construction, viz., the open watercourses and those where the ground is cut open and filled in again, and where useful material would be got from the excavations. In most conduits of considerable length it will be advantageous to save head, so as to deliver the water at the far end at as high an elevation as possible, and the value of this may often be greater than additional expen- diture required for a larger conduit. The value of each can be strictly calculated. With 4in. fall per mile in the open aqueduct shown in Fig. 20 (see next page), which is reduced from the sections given in the Appendix F of the Eeport of the Metropolitan Water Supply Commission, 1869, the mean velocity was calculated at 109ft. per minute, and the quantity of water discharged at 28,340 cubic feet per minute, the width of the stream being 30ft. at the surface LARGE CONDUITS. and 20ft. at the bottom. Depth, in the middle of the stream, 10ft. Gin. Side slopes J to 1. Bottom, at the centre, Gin. lower than at the sides. With a fall of Gin. per mile the surface width would be reduced to 26ft., and Fig. 20. Fig. 21. Fig. 22. Fig. 23. Fig. 24. Fig. 25. Fig. 26. the bottom width to 16ft., the depth being 10ft. Gin. at the middle. With these dimensions and fall the mean velocity was calculated at 128ft. per minute, and the discharge at 27,702 cubic feet per minute. These are the sections and form of construction in rock, which is for the most part the Silurian slate formation. In ordinary ground the form was to have been as shown in Fig. 21. With this form, and a fall of '4ft. per mile, the velocity, it was said, would be 119ft. per minute, and the discharge 28,760 cubic feet, the width at the surface OF THE r UNIVERSITY Ii6 AQUEDUCTS. of the water being 28ft. and the depth 12ft. The curved bottom extends to about half the height, at which point the straight sides touch the circle tangentially. With a fall of Gin. per mile the dimensions would be reduced to a width of 26ft. at the surface, and a depth of lift. Gin. With these dimensions and fall the velocity would be 131ft. per minute, and the discharge 28,361 cubic feet. In the covered aqueduct shown in Fig. 22, with a fall of 4in. per mile, the velocity would be 106ft. per minute and the discharge 28,514 cubic feet. The width at the bottom is 22ft. and at the springing of the arch, 7ft. above the bottom, it is 24ft. The depth of water is 12ft., or 5ft. above the springing. Where the fall would be in- creased to 6in. per mile, the bottom and middle widths would be reduced to 18ft. and 20ft. respectively, the depth remaining 12ft. With these dimensions and fall the velocity was calculated at 127ft. per minute, and the discharge at 28,575 cubic feet per minute. In the tunnels shown in Fig. 23, with a fall of Gin. per mile, the velocity would be 125ft. per minute, and the discharge 28,240 cubic feet, the width at the bottom being 18ft., the middle width 20ft. at a height of 5ft. above the bottom, the arch semicircular, and the surface of the water 7ft. Gin. above the springing, the depth of water being 12ft. Gin. No puddle was proposed to be used in any part of this aqueduct, but the excavations were to be lined with concrete, about 18in. thick, faced with rubble stone where the ground is rock, and in ordinary ground the concrete would in some parts be faced with brick on edge, and in others rendered with Portland cement. With respect to the water-tightness of the aqueduct, Mr. Hassard said that in the construction of a great portion of the open aqueduct, it was probable that no lining would be required. This evidence is similar in effect to that of Mr. Bateman, who, having then recently made the aqueduct bringing water from Loch Katrine to Glasgow, said that the ground there consists chiefly of the mica-slate and clay -slate formations, and that very little LARGE CONDUITS. 117 lining was required; it is almost impervious to water. There was no clay along that line, and no means of transporting materials, and, knowing the geological for- mations of the country, Mr. Bateman had adopted tunnels instead of looking for a line along the surface, which had been done by others without success when turning their attention to that source for the supply of the city. There are on this line of aqueduct as many as seventy different tunnels, of comparatively short length ; no long tunnel, except the first one, of 2325 yards, on leaving Loch Katrine. Tunnelling, he said, where short tunnels can be made, and where the materials can be brought to daylight at short intervals, is perhaps the cheapest and the best and the quickest way of getting through a country of that sort. After passing through the first tunnel, the water is conveyed for six or seven miles along the hillsides, not, in this case, in an open aqueduct, but in the manner called " cut and cover." Where the conduit passes through an agricultural country it may be open ; there is rather an advantage than otherwise in its being exposed ; but near towns or through a thickly-wooded country, or on slopes of mountains liable to snow-drifts, the conduit should be covered. In any case the drainage of the hillsides must not be interfered with, and proper culverts must be provided for passing it either under or over the conduit. In connection with the question of lining an open watercourse is that of the velocity of the stream, and it was said that the proposed velocity of neither one nor the other of these aqueducts was such as would be inconsistent with a simple clay bottom ; it would not disturb a clay bottom, and would have no effect at all on a gravel bottom ; but, nevertheless, an aqueduct for the supply of water to a city should be lined throughout. Fig. 24, reduced from the sections given in the Appendix A Q of the report, shows the form of the open watercourses of Mr. Bateman's main aqueduct. The fall is Gin. per mile. The width at the surface of the water is 26ft. 4 Jin., and the depth 10ft., the form being circular throughout. The sectional area of the stream is 193 '4 sq. ft., and the Il8 AQUEDUCTS. wetted sides 35ft. in length. The hydraulic mean depth 193 -4 (H.M.D.) therefore is, _- = 5-526, and V5-526 x 1 DO X - = 2 -143ft. mean velocity, per second. Then 193-4 x 2-143 X 540,000 = 224,000,000 gallons per day carried. Fig. 25 shows the form of section of the covered water- courses and tunnels. The width is 16ft. 6in. at a height of 3ft. 9in. from the bottom, with a semicircular arch. The depth of the invert is 1ft. 6in., and the depth of water 10ft., the surface of the stream running within a height of 2ft. of the soffit of the arch at the crown. The fall is 14in. per mile, the sectional area 146-25 sq. ft., the wetted sides 34- 866ft. H.M.D. = J__ = 4-195, and 34-866 >v/4*195 X 2-333 X = 2 -844ft. per second mean velocity. Then 146-25 x 2-844 = 415-935 c. ft. per second, which gives 224,604,900 gallons per day. During the sitting of this Commission, which extended over thirty-six days, the examination of witnesses took somewhat the form of a discussion, between the members and the principal witnesses, on the question of the quan- tity of water necessary to bo supplied for the growing wants of London, and both Mr. Bateman and Messrs. Hemans and Hassard had to consider whether the aque- ducts would carry as much as 300,000,000 gallons per day. It was found that this could be done with but slight addi- tions to the capacity of the aqueducts already proposed. In the case of the Welsh project, an increase of 2ft. in the depth of water in the open watercourses, that is, from 10ft. to 12ft., would accomplish it, and the width at the water surface would then be 27ft. 9in., the fall remaining the same, viz., 6in. per mile. In the covered portions and the tunnels the section would be enlarged, as shown in the Appendix A E of the report, of which Fig. 26 is a reduction. This section is drawn in Fig. 26 on a larger scale than LARGE CONDUITS. IIQ the other figures, to show iis peculiarities, the chief one of which is the depth of the invert, which is 3ft. If the dis- position of the materials be examined, it will be seen that they are placed so as to make the form a very strong one, and at the same time it is one which] affords a great hydraulic mean depth. There remains a question whether, for an open aqueduct which must for a long time after its construction carry much less water than it is ultimately designed to carry, the circular form of section of the waterbed is as good as one with straight slopes and a nearly straight bottom. When the section of the stream at r its greatest flow occu- pies nearly half the circular bed, the sides are pretty steep ; but in the mean time, and while the quantity of water being carried is much less, the sides of the stream are shallow. That is not so in the angular form. At the time these conduits were proposed, the quantity of water supplied to London was about 108 million gallons per day. The open watercourse of Mr. Bateman's main aqueduct is 13ft. Gin. radius, and, as shown above, would run 10ft. deep when supplying 224 million gallons a day, but at the first, and for some time after its construction, the depth corresponding to this quantity would have been only 6ft. 9in. in the centre of the stream. To carry the quantity supplied to London, taking it at 15,000 cubic feet per minute, the depth would be 7ft. Sin. Thus in about fifteen years the increase in depth would have been llin. In the open watercourse of Mr. Hassard's main aque- duct, with the same inclination viz., Gin. per mile, the depth at the first for the same quantity of water would have been 6ft. 3in. in the middle and 5ft. 9in. at the sides. For 15,000 cubic feet per minute the depth would be 7ft. 2in. in the middle and 6ft. 8in. at the sides. Thus either of these streams would have increased in depth about llin. between that time and this, but the angular form would from the first have had considerable depth at the sides. SECTION XY. KJVERS AND WATERCOURSES. THE quantity of water flowing down a river channel may be calculated by the following rules : they range, in point of accuracy and attention to details, from the simplest and most general to the nicest refinements of correction for varying conditions of a flow of water ; but they all depend essentially upon the two conditions of hydraulic mean depth and inclination of the surface of the water, which together govern the velocity. The volume is the product of the cross sectional area of the stream and the mean velocity of the whole section, and while the former is a matter of simple measurement, the latter is more difficult to arrive at with any degree of accuracy ; and it is only after an investigation of the im- mense number of experiments which have been made, that the authorities in the science of hydraulics have been able to arrive at formulae which represent the true velocity approximately. With certain precautions, the velocity may, in some cases, be actually measured, as well as the cross sectional area, and when that can be done the volume may be found more satisfactorily in that way. The cross sectional area of the stream may be measured by selecting a part of the river which is of tolerably uniform section for a considerable distance say 200 yards dividing the distance into equal lengths, and measuring the cross section of each division by means of ropes preferably of wire strung across the river, taking the depths at short intervals along the ropes, and where the difference of level of the surface of the water at the two ends of the length of river THE MEAN VELOCITY. 12 1 experimented upon can be ascertained with accuracy, the mean velocity of the whole stream in ordinary cases and in tolerably uniform channels may be found by the formula deduced by Eytelwein, or that by Du Buat. The funda- mental conditions are that the velocity varies as the square root of the hydraulic mean depth, the fall being constant, or as the square root of the fall when the hydraulic mean depth is constant ; or, neither being constant, as the square root of the hydraulic mean depth and fall multiplied into each other ; and to bring this abstract rule into conformity with observed actual velocities a coefficient is applied, of such magnitude as to bring the abstract numbers into coincidence with the actual numbers observed. Eytelwein's 10 _ rule for the mean velocity per second is v= */ A/, where Ji the hydraulic mean depth, and / = twice the fall per mile ; h, /, and v being all in feet or all in inches. Du Buat's rule is, for inches, \/ s hyp. log. */ s -\- I'6 and for feet, g= 88-51 (V d - -03)^ _ tj s hyp. log. *J s -f- 1 " ti d being the hydraulic mean depth, and s the length in which the surface of the water falls one unit, as 2,640 when the fall is 2ft. in a mile. The fractional deductions are made from the fundamental formula v = c \ / -, in /d . -v = c \/ -, i] which c is the coefficient 307 or 88-51, in order to make it agree more nearly with the results of experiments under varying conditions, and are applicable in cases of moderate velocity of 2ft. or 3ft. per second. Other authorities make corrections for similar effects of increasing velocity. Thus, Mr. John Neville, in his " Co-efficients and Formulae," published by Messrs. Crosby Lockwood and Son, gives, from experiments made by various persons, the increasing coefficient as follows, when 122 RIVERS AND WATERCOURSES. applied to the abstract rule */rs, r being tlie mean radius or hydraulic mean depth, and s the sine of the angle of inclination, or the fall in any length divided by that length ; thus being when the fall is 2ft. in a mile. For a velocity of about 1ft. per second the coefficient is 91*3; for about IJft. per second it increases to 95 '5; for l|ft. per second, 98 6 ; for 2ft., 100 5 ; for 2 ft., 100 6 ; for 2|ft., 103 ; for 3jft., 106-6 ; for 5ft., 109-3 ; for 6ft., Ill ; for 7*ft., 112-3; for 14Jft., 117-9; for 15ft., 118-4; and for a velocity of about 21ft. per second, the coefficient is 120. As the velocity thus does not strictly follow the rule of */rs, Mr. Neville has found a more exact formula, which is v = 140 /Jr% 11 tyrs, and this seems to agree nearly with observed velocities under all circum- stances. Mr. Neville has found that Du Buat's formula may be pretty safely relied on when applied to general practical purposes, and says that much of the valuable information presented by Prony and Eytelwein is but a modification of what Du Buat had previously given, and to whom we are primarily indebted for much that is attributed to the two former. None of these found any difference in the velocity of a stream which could be attributed to the kind of surface over which it ran; but a later authority, Kutter, has introduced into his formula, as translated by Mr. Lowis D'A. Jackson, a term of correction according to the kind of surface, as brickwork, earth, gravel, &c. Kutter's formula is, for English feet 1-811 . . -00281 N rs 0028l\N_ IS JJr in which v = mean velocity in feet per second, r - mean radius or hydraulic mean depth in feet, S = sine of the hydraulic slope of the surface, N = coefficient of rough- ness and irregularity ; and the values given to N are for THE MEAN VELOCITY. 123 brickwork and ashlar in good order, -013; for channels in earth in good average order, *020 ; and for rivers and brooks, from '020 to *035 ; but this formula is not so well adapted to rivers as the three preceding. It may be useful to compare the results of the first three rules. In a river of 100ft. mean width, 6ft. deep, and of such a contour of bed as to give 5ft. hydraulic mean depth, the fall of the surface of the water being 1ft. per mile, or 1 in 5,280, the mean velocity in feet per second by Du Buat's rule is, 88.51 U/5--03) _ _ = V 2(540 -hyp. log. V 2641 -6 and 2-67 X 600 = 1,602 cubic feet per second. By Eytelwein's rule it is, V 5 X 2 = 2-87 and 2-87 X 600 = 1,722 cubic feet per second. By Mr. Neville's rule it is, and 3-23 x 600 = 1,938 cubic feet per second. And if we take the coefficient for velocities about as much as this to be 103, as found by others, the mean velocity would be 103 Jra = 103 \/ 5 X ^Q = 3 ' 17ft P er second or, nearly the same as by Mr. Neville's own rule ; and it illustrates what is found to be a general tendency in all the hydraulic formulae derived from experiments necessarily made on a comparatively small scale viz., that the action of large masses of water is sensibly greater than these formulas indicate, so that in applying them to rivers of large volume they rather understate the actual quantities, which, indeed, is no fault, but the contrary. The truth of Eytelwein's and Du Buat's formulae has been confirmed by Mr. Bateman, for rivers and open watercourses where the section is tolerably uniform. When he laid out the Manchester Waterworks he con- 1 2 4 RIVERS A ND WA TER CO URSES. structed the works in many parts with special reference to taking such observations as would determine a great many points which were then somewhat in doubt, and he tested upon the watercourses there the calculations of almost everybody. (Vide Evidence, Water Supply Commission, 1868.) But where the fall of the surface of a river is very small in any length that could be experimented upon, as it is in many cases, the inclination cannot be ascertained with sufficient accuracy to enable these formulae to be applied for finding the velocity, and in those cases the volume of water is best ascertained by actual measure- ments of the velocity with floats, and for that purpose no better proceeding can be taken than that adopted on the river Thames. The length of the river experimented upon was divided into six measured distances, and the time was taken in which the floats traversed the six divi- sions at five or six different places in the width of the river. The mean velocity was not computed from the observed surface velocity, but was actually ascertained by floats so adjusted that whilst one all but dragged upon the bottom, and therefore travelled with the bottom velo- city, another floated at the surface, and the two floats being tied together, one acted upon the other, in quicken- ing and retarding their respective paces. Gutta-percha was used for the floats ; it is very nearly of the same specific gravity as water, being 0-96 of water, and there- fore it floats. A gutta-percha ball will float almost wholly immersed, so that the wind can have no effect upon it. The balls were so adjusted that one was heavier than the other, and sank to the bottom, but did not touch it, and thus by finding the mean velocity in all parts of the stream, the mean of the whole stream was found. To estimate the mean velocity roughly by one observa- tion, Prony's rule may be taken 783 + -(. 345 + in which V = the maximum surface velocity in feet per BOTTOM VELOCITY. 125 second in the centre of the river, or in its axis, whether that be in the centre or not, and this gives for velocities similar to those in the above examples, the same results as in Mr. Neville's shorter rule v = 835 V, which would 4* 73 indicate a maximum surface velocity of ^ K 5* 66ft. * 8o5 per second, but for velocities about half these the mean is more nearly 8 Y. Eeferring to the examples above worked out, it must l)e confessed that there is no very near agreement between 2-67 as found by the first, and 3-23 by the last ; but this velocity is greater than necessarily occurs in rivers, and the best judgment would probably be shown in using Eytelwein's or Du Buat's formula in cases of ordinary flow, and Neville's or Prony's in floods. As to the velocity of water at the bottom of a river, or anywhere along its bed, it is very difficult to ascertain it by actual measurement, apart from that in other portions of the body, but from the experiments of Du Buat it is found to be, for mean velocities of about 3 ft. per second, u = (V V - I) 2 When Y = the mean surface velocity from side to side of the stream, which is always less than that in the centre or axis of the stream. In this case u and Y are the velo- cities in inches per second. Mr. Beardmore adopted this rule in his hydraulic tables for velocities of from 1 to 15ft. per second. Experiments which have of late been made upon the large American rivers show a different relation between the surface and bottom velocities. In a discussion at the Institution of Civil Engineers in 1879, Mr. George Higgin said that in the experiments carried out under the direction of Mr. Bate-man, Past- President of the Institution, on the great rivers of South America, certain new laws were discovered in the move- ment of large masses of water. One of these was that the surface velocity of water at a given inclination varied directly as the depth of the channel, and another was that 126 RIVERS AND WA TERCO URSES. the bottom velocity of water varied directly as the square of the depth. With a given volume of water passing at increasing rates of inclination, and, therefore with diminishing depth, it was calculated that at a depth of 27ft., and with a surface velocity of 176ft. per minute, the bottom velocity would be 69ft. per minute, at a depth of 21ft. and with a surface velocity of 241ft. per minute, the bottom velocity would be 72ft., and at a depth of 18ft., and with a surface velocity of 290ft. per minute, the bottom velocity would be 75ft. ; thus while the surface velocity increased 65 per cent., the bottom velocity in- creased only 10 per cent. But the question arises whether the rules derived from the motion of masses of water so vast as those of the American rivers are more applicable to the English, Irish, Scotch, and Welsh rivers, than the old formulae are, confirmed as they have been by experi- ments on a scale of very considerable magnitude. Investigations by Professor Osborne Kej nolds, F.E.S., and Professor W. C. Unwin, F.K.S., have thrown much light upon the motion of water in open channels and in pipes, explaining in a great measure the phenomena observed by the older hydraulicians. SECTION XVI. COMPENSATION TO MILLS. IT is hardly possible to divert water from one district to another without injury to the interests of persons already having rights in its use, and where mills driven by water power exist below the point of diversion it is incumbent on the party proposing to divert water for use elsewhere to compensate the millowners for its abstraction. Unless this be proposed to be done in a full and adequate measure, no interference with existing rights will be sanctioned by law. Millowners are very tenacious of their water rights, and sometimes have spent enormous sums of money in opposing waterworks schemes. They have often overrated the value of water power to them- selves, not only in corn-mills, where water power is by prejudice presumed to be superior to steam power because of its steadiness, but in woollen and cotton mills, and even in fulling and in rolling mills, where the inequality of the work done during various parts of the day causes a waste of water on the wheels. To give a money compensation to millowners where the number is considerable, cannot come into question for a moment. Attention must therefore be directed to provide reservoirs to regulate and economise the water, so that the quantity which previously passed the mills in floods and was useless, indeed injurious, may be stored and made use of. Where mills are compensated from the same ground that supplies the town, it is well to have separate re- servoirs for the two purposes, so that the turbid flood 128 COMPENSATION TO MILLS. LEAPING WEIR Fisr. 27. waters are made to overleap the channel which conveys the clear water into the reservoir for the supply of the town, and the portion due to the mills to enter that from which they are to be supplied. This may be done by making the two flood weirs at the same level, and proportioning the length of each to their respective quantities, or better by a separating or leaping weir of which this diagram is a sketch. The principle on which the leaping-weir acts is to separate the maximum flow of water required for the town, and to keep it at as high a level as possible, from the greater volume cf flood - water, which is not required to be kept at so high a level. The smaller flow is continuous, and, up to the maximum flow required, is comparatively clear, while the flood- waters come down intermittently with a rush. The position of the lip, which separates the clear water from the flood- water, may be fixed on the following principles. For any given 4 depth of water D in the diagram, Fig. 27, let h = - D, y and the parabolic curve a b c the line of flow of the particles which have the mean velocity of the whole sheet of water. Then, inasmuch as the height h governs this velocity, which would be, say, 7*5 V/& if taken in feet per second, the width W, for any height H, would be = V4/&H. If the water arrives at the edge of the weir with any pre-impressed velocity, the head necessary to give it the velocity must be added to that measured 4 as D. If d be this head, then h must be taken = - (D + d). SEP A RA TION OF FLOW. 129 This would be the case where the water runs over a wide- crested weir before arriving at the edge over which it Fig. 28. falls; and as this velocity of approach increases, so will the width W increase, which would then be d being = when v = the velocity, in feet per second, of the water approaching the edge of the weir. Mills generally are so constructed as to be capable of using water at the rate of not more than one-third of the average yield of a district ; whether from design or from the long experience of the millwrights of the most economical extent to which water can be applied to mills without large reservoirs, is immaterial, the fact being so; and one-third of the available yield has generally been given to them in compensation, whereby they are abundantly benefited, for they get this third regularly day by day, whereas before they had it very irregularly. In 1868, as well as in some other years, this allowance has had to be stopped in some cases, in order to furnish a sufficient quantity for the more urgent necessities of the towns, but money compensation has had to be sub- stituted. A reservoir, therefore, constructed solely for the use of the mills, must have a capacity equal to one K 13 COMPENSA TION TO MILLS. half that of the reservoir for the town, plus about 5 ? 000,000 cubic feet per 1000 acres of drainage ground, to com- pensate for its being deprived of the dry weather flow, which, as has been said, is received into, the reservoir for the town. Where it is desirable to take the whole of the water of a district for the supply of the town, whether because of its superior elevation or its purity, and where the mills can be compensated from a reservoir in a separate district, the area to be appropriated to the use of the mills should be of such extent that two-thirds of the yield from it shall be equal to one-third of the area appropriated to the town, because, in addition to one-third of the yield from the latter which is due to the mills, one-third of the waters from whatever area may be appropriated to the mills in the other district is already enjoyed by them ; therefore two-thirds of its yield should be equal to one- third of the yield of the district appropriated to the town ; or, in other words, the area appropriated to the mills must be one-half as large as that appropriated to the town, the amount of rainfall being the same in both districts ; and if the rainfalls be unequal, the compensation area must be more or less than one-half of that appropriated to the town accordingly as the rainfall may be less or more respectively in the one district than in the other. It may be observed that although a given volume of water falling through a given height produces a certain number of horses power on the basis already stated, viz., that 8-8 cubic feet of water per second falling 1ft. is equal to 1 horse power, and that, likewise, the same quantity falling 10ft. is equal to 10 horse power the stream of water exerts its power not for 8 hours a day only, as the horse does, but for the whole 24 hours, and is, therefore, in some cases, of the value of three times as many horses work as its nominal power represents, if the flow of water, while the mill is standing, be stored in a dam close at hand. This, no doubt, causes a certain amount of inconvenience to mills lower down the stream, MILLOWNERS? RESERVOIR. 131 in respect of the quantity so withheld, which may not come down until a late hour in the day ; and on some streams regulations are established whereby a tolerably equable flow is maintained during reasonable working hours ; and taking the circumstances of a large number of mills, and comparing the work done with the power which passes them, they appear to do an amount of work, with the assistance of the night water impounded in dams, which is equal to about one-third of the power of the available quantity of water. But with a storage reservoir to control the whole available quantity and deal it out day by day during say 12 or 14 hours each day, the velocity of the stream is increased, and the mills get the water at earlier hours all the way down. The benefit to be derived from the construction of a storage reservoir is in respect of two-thirds of the available quantity of water. Thus, with a storage reservoir, about three times the quantity of work may be done, but the benefit derived is in respect of twice the quantity only. The following is an instance in point. There are fifteen mills in a district above which there is a suitable site for a reservoir which commands a watershed area of 1,000 acres or thereabouts. The average annual rainfall for 14 years has been 33 inches. The loss by evaporation and absorption has not been ascertained in this particular area, but comparing its position and general circumstances with other districts in which actual measurements have been made, it may be estimated with great probability at 13in. We say we lose these 13in. by evaporation and absorption, but it means the whole loss from whatever cause. Of course a good deal must be evaporated, and another portion absorbed by vegetation this however being mostly evaporated from the leaves and by sinking into the ground, from which it does not again issue within the watershed area belonging to the reservoir ; but also it is very probable that over a large area the rainfall is not uni- form, and that parts of it will receive more rain than other parts, and if the rain gauge bo situated in one of these K 2 132 COMPENSATION TO MILLS. wetter portions of the district, it will show a result greater than the true one. This is more especially likely to be the case where the rainfall is estimated not from a gauge planted within the district itself from which the water is to be derived, but from one at some distance from it. So that when it is said that so much is lost by evaporation, it is meant to say that the whole quantity due to the watershed area and the rainfall as shewn by the gauge does not come into the reservoir. The loss varies from 10 to 18 inches as determined by different gaugings, and a part of this great variation may perhaps be due to the situation of the rain-gauge with reference to the actual watershed area to which its register is applied. The question may arise, how it is known that either 10, 13, or 18in. of lainfall are evaporated and absorbed? The result is arrived at by labour and patience in gauging the quantity of water actually flowing off the ground, by which it is found that the actual quantity falls short of the whole quantity due to the rainfall by certain quantities which vary between those limits, and comparing these various quantities with the character of the ground upon which the rain has fallen in each case, engineers exercise their judgment as to what allowance to make in any particular district. If 33in., as in this case, be the average annual rainfall, and 13in. the loss there would be 20in. available if all of it could be stored, but as that is not practicable, a deduction of about 5 inches should be made for excessive floods, leaving a practically available depth of 15 in. A depth of 15in. over 1,000 acres would give the following quantity : There are in 1,000 acres 43,560,000 square feet, which at 15in. deep would yield 54,450,000 cubic feet. If we take 312 working days in a year, and supply the mills with water for 12 hours a day, we should be able to give out of this reservoir year by year (3^2 J 12 ~/ 14 ,540 cubic feet per hour, or 242 cubic feet per minute. But as VALUE OF WATER POWER. 133 the mills are supposed to be capable of beneficially using one-third of this already, the benefit to be derived would be in respect of 1 60 cubic feet per minute only. Will it, then, pay to make this reservoir to give out this quantity for 12 hours a day all the year round, and year by year? Seeing what many other reservoirs have cost, and not going to either extreme, this one might cost 12,000, the bank being made as perfectly as possible, by raising it in thin layers with barrows and dobbin carts, the puddle being particularly well worked, the waste weir of good length, to that on the occurrence of a rare flood, when the reservoir might be nearly full, the overflow could not attain to such a height as to endanger the bank by over-topping it, a bye channel being provided for the ordinary flow of the stream, and a substantial cottage built for the reservoir keeper. The falls at these 15 mills vary from 10ft. to 30ft., the aggregate being 326ft. The wheels are all either overshot or breast wheels, of good construction, and in good working order. Then, although we estimated 13-2 cubic feet of water per second per foot of fall to be, perhaps, an average of all wheels to give an effective horse-power, we shall be warranted in taking 12 cubic feet per second in this case. This is the quantity that Sir Wm. Fair- bairn frequently gave as the proper quantity in such cases. The aggregate amount of power, therefore, to accrue to the mills from the construction of this reservoir will be (^[2 x go =J 72 horse-power. In the district we are considering an effective horse-power is worth 12 per annum, and if each mill contribute its quota according to the benefit it would receive (we will not now go into the more minute subdivision of benefits by considering that those mills nearest the reservoir would receive more benefit than those farther off) there will be an income of 864 a year. Deducting the wages of the reservoir keeper, and setting aside 40 a year to provide a fund for repairs, there would be a net income 720 a year. The 134 COMPENSATION TO MILLS. outlay being 12,000, the percentage return would be 6 per annum. But this does not represent the whole gain to the mill. The gain is chiefly in having a constant stream of water, and an absence of floods. Nothing is more annoying to a miller than to see water pass him which he can make no use of, and which at the same time hinders his work by backing up against the tail of his wheel. By storing the flood waters he can always reckon upon a certain power of doing work, and can enter into contracts with a certainty of being able to fulfil them. Herein lies the chief gain in constructing storage reservoirs. ( 135 ) SECTION XVII. OF WATER POWER IN GENERAL. A CUBIC foot of water, or 6J gallons, weighs 62Jlb. The gallon weighs 10 Ib. It is commonly taken from Watt's experiments that a horse of average power does work equivalent to that of raising 33,0001b. 1ft. high per minute, or 5501b. 1ft. high per second, if not worked more than 8 hours a day. This would be equivalent to raising 8*8 cubic feet of water 1ft. high per second, or 528 cubic feet per minute. But that quantity of water could not practically be raised to that height in that time by that power. To put everything into the simplest form, the horse might draw water out of a well by means of a barrel attached to a rope passing over a pulley at the head of the well, the horse walking away from it at the speed of 220ft. per minute, or at the rate of 2J miles an hour, which is taken to be the best working pace during 8 hours a day ; and the horse would raise at this speed a weight of 150lb. But the weight which would be thus drawn out of the well would include that of the barrel and the rope, and ihe hindrance caused by the friction of the pulley on its bearings. The friction of the pulley would be so small that it might be neglected, but the weight of the barrel and the rope would probably be 20 per cent, of the whole weight. The weight of the water raised would be 80 per cent, of the 1501b., or 1201b., which would be 12 gallons. But it would not be an economical way of applying the horse's power, that the load should thus be drawn up by a straight run away from the well, because the quantity of water is small, 136 ON WA TER PO WER IN GENERAL. and time would be wasted in emptying the barrel and replacing it so often. A more economical arrangement would be to wind the rope round a horizontal drum at a little distance from the well, supported on a vertical shaft, and to attach to the shaft a beam or pole, the end of which the horse could draw in a continuous round, and if the circumference of the path be made 5 times the circumference of the drum the horse would move 5 times as much weight with one- fifth as much speed : that is, 7501b. at the speed of 44ft. per minute. The weight of the barrel and rope in this case would not be more than about 15 per cent, of the whole load, but the resistance of the drum to being turned would be about 5 per cent., so that the whole resistance would be the .same, viz., 750 -f- 5 = 1501b. at the speed with which the horse moves ; and 150 X 220 = 33,0001b. per foot high per minute = 1 horse- power. The actual weight of water raised would be 80 per cent, of the 750lb., or GOOlb., which would be 60 gallons each turn. If the well is large enough to allow two barrels to pass up and down, and the end of the horse beam be fitted with a swivel, so that at the end of the motion in one direction the horse can reverse the motion and draw up another full barrel while the empty one is being lowered, the 15 per cent, loss due to the weight of the barrel and rope would be most of it saved, but about as much would be lost in the time required by the horse to reverse the motion at the end of each draw, so that in either case it comes to about the same thing ; and in this way the horse can work 8 hours a day. If a horse has a single run out and returns unloaded, the time of working might be 10 hours a day, but the amount of work done in the day would be no more than in the other case. A horse-power then being 33,0001b. raised 1ft. high per minute, or its equivalent, 33,000lb. falling 1ft. per minute, or 550lb. falling 1ft. per second, the volume of water falling 1ft. is 550 -f- 62 5 = 8-8 cubic feet per second, to produce 1 horse-power. There are few, if any, THE STEA DY FLOW OF A RIVER. 1 3 7 mechanical means by which more than 80 per cent, of this power can be transmitted to the working point, or by which more than 7 cubic feet of water per second can be raised back again to the height of 1ft. by the fall of 8 8 cubic feet through that height in that time. When a river or other stream of water flows in the condition called in train, the water can do no more work than it is doing; it gravitates, indeed, with the same power per foot of its fall as if it fell over a precipice ; but while it is flowing in train, the whole power with which it is endowed by the force of gravity is expended in over- coming the resistance of the bed to its transfer from place to place, with the rate of motion which it acquires by virtue of the inclination of its volume ; but if, at the end of this inclination it fall vertically, it is no longer in train, there being no longer the resistance of the bed, and the force of gravity accelerates its motion, acceleration before being prevented by the continued resistance of the bed, the motion of the water being thereby made uniform, or at least not accelerated. When the same water falls vertically it may be again put in train by interposing a resistance such as will prevent the acceleration of its velocity, and its power may be developed and used by transferring the accelerating force to a uniformly-moving body, the weight of the water and the height of its descent being the measure of its power. The resistance of the bed of the channel being suddenly removed, and that of the unloaded wheel or turbine substituted, the measure of useful effect of the water is the difference between these two resistances per foot of fall in each case. In the latter case a portion the greater portion of the power is liberated. Wheels and turbines, according to the perfec- tion of their construction, take more or less power to turn them before they are brought to the point of doing useful work, and this is so much taken from the power of the water, the remainder only being the useful effect of the motor. To compare the power of one force with another, the assumed power of a horse is established at 33,000 foot- 138 ON WATER POWER IN GENERAL. pounds per minute, however that may vary from the actual power of different horses. A horse-power is that resistance viz., loOlb., which custom has established that a horse can overcome when moving along a level road at the speed of 220ft. per minute, during eight hours a day ; and 150x220 = 33,000 foot-pounds per minute, including all friction and resistance of the vehicle or machinery by which the load is moved. It is probably more than most horses can do ; but that is of little or no importance, the object being to establish a standard power by which one force may be compared with another; and as to the dura- tion of eight hours a day, that is essential in the question of the power of a horse, but not of a horse-power. ( 139 ) SECTION XVIII. WATER-WHEELS. As a cubic foot of water weighs 6 2 Jib., a quantity equal to 528 cubic feet per minute is equal to a horse-power per foot of fall of the water, when the motor intervening between the power and the work is acted upon by the steady pressure of the water, as when it is delivered into buckets of such form as to lower it down gradually from the upper level to the lower one. In unloaded motors, driven by a steady pressure with the speed required when doing work, the quantities of water required to move them vary with their construction between -|th and fths of the power of the water. The usual portion of the power of the water liberated by such a wheel is about two-thirds, the remainder being absorbed in moving the wheel itself, and the gearing through which it moves the machinery. When the stream of water is constant in volume, the construction of the motor can be adapted so as to derive from it 80 per cent, of its power, and transfer that portion to the work to be done to the resistance to be overcome ; but when the volume of water varies much from time to time, the motor works at a disadvantage with the smaller quantities, for the strength and consequent weight of the motor, must be sufficient for the largest volume, and the power required to drive it when unloaded bears a larger proportion to the whole power than when the larger quantities of water are being used. When the construction of the wheel or other motor is such that it yields two-thirds of the power expended upon it, half as much more water 140 WA TER- WHEELS. is required to produce an effective horse-power upon the work done that is, 792 cubic feet per minute per foot of fall. It is not unusual to reckon that 12 cubic feet of water per second, or 720 cubic feet per minute, falling upon a well-constructed bucket-wheel, is equal to an effective horse-power per foot of fall. This is at the rate of 73 per cent, of the power expended. The buckets are best made of sheet-iron, where the water is not of such character as to cause an unusual amount of corrosion or deterioration, in the form, or some similar form, to that shown in Fig. 29 ; but they may be made of wood, which has, in some situations, an advantage over iron (Fig. 30). The width of the entrance B C in Fie. 29. Figf. 30. Fig. 29 is about a third of the depth of shrouding A C, which is about the same as the distance of the buckets apart, C C. This varies from 1ft. to Ijft., which deter- mines the number of buckets, according to the diameter of the wheel. The term " overshot " is usually applied to a wheel which receives the water near the top. Formerly the water was carried over the wheel and delivered upon it on the opposite side to that from which it approached, the wheel thus at the top revolving in the same direction as the stream of water, and at the bottom against it ; thus BUCKET WHEELS AND RACE WHEELS. 141 the water overshot the wheel ; but the back-lash of the water in the stream below caused a serious hindrance to the motion of the wheel, and the form was there- fore changed to the pitch-back, in which the water is delivered upon the wheel on that side from which it approaches it, and consequently at the bottom revolves in the same direction as the stream passing under it. The old term, however, is still retained for wheels upon which the water is delivered near the top, to distinguish them from those which receive the water nearer the centre, called high breast, or low breast, according as they receive the water above or below the centre. High-breast and overshot wheels may be classed together as being wheels with buckets, and having about the same degree of efficiency, while those which receive the water below the centre have straight float-boards to which the action of the water is confined by a close-fitting breast of masonry. A high-breast wheel has the water laid on at a point not exceeding about 30 above the horizontal centre ; above that it may be called overshot. A water-wheel may be likened to a clock-face ; it is an eleven o'clock wheel when the water is laid on at 30 from the vertical centre, half-past ten o'clock when laid on at 45, and a ten o'clock wheel when laid on at 60 below the vertex. The farther from the vertical centre the bulk of the water acts upon the wheel the greater must be its effect, for it has then the greater leverage, and less dead- weight upon the bearings ; but then the size and weight of the wheel must be increased, so that the most economical point of application has to be sought between these two conditions, in each particular case in practice. In every case a small portion of the head of water is taken up in giving a sufficient velocity to the water entering the buckets to fill them to the required degree generally about two-thirds full and to prevent the buckets striking against the stream of water; there- fore, the entering water should have a velocity rather greater than that of the circumference of the wheel. 142 WA TER- WHEELS. This varies from 3ft. to 6ft. per second; 3ft. or 3Jft. is the best for effective power; -but sometimes the arrangement of the machinery makes it advisable to give to the circumference of the wheel a velocity as much as 6ft. per second, or even a little more in some cases ; and up to 6ft. the increased velocity is not found in practice to much diminish the effective power ; but perhaps the best velocity on the whole is 4ft. or 4Jft. per second. The co-efficient of the velocity of the entering water would, in most cases, be properly taken at '94, in which case the head of water to produce a velocity of 6ft. per second 6 2 would be (54 x r-94) 2 = ' ^ ^'' or ^ n ' J an ^ a ^ ow i n g f r tne construction, the loss of head would be about 1ft. The effect of the separate quantities of water lying in the buckets round the wheel between the point of application and that of the discharge near the bottom is the same as the quantity contained in each bucket multiplied into the sum of the horizontal distances of all the buckets from the centre of the wheel. As the velocity of the circumference of the wheel is supposed to be uniform, all the buckets will be filled to the same degree, the sluice- opening and the head remaining the same ; therefore, the water may be supposed to form a continuous ring round that part of the circumference of the wheel upon which the water acts, as between A and B in Fig. 31; A being the point of application, and B the point of discharge ; and the effect of the weight of water in all the buckets is the same as that of a continuous ring of the same weight multiplied into the distance C of the centre of gravity of the ring from the centre of the wheel, which is, according to the rule made and provided in such case, that the distance of the centre of gravity of a circular arc from its centre is a fourth proportional to the length of the arc, the radius, and the Fi-,31, WATER ACTING BY ITS WEIGHT. 143 chord of the arc. If, for instance, the water be laid on at "11 o'clock," or at 30 from the vertex, and be retained in the buckets until it arrives within 30 of the vertical through the axis of the wheel, the arc will be 120, or two-thirds of the semi-circumference of the wheel. If E be the radius, the length of the arc will be 2 X % 1416R = 2-0944 R. The chord is 2 cosin 30 = 2 X '866 E = 1-732 E; and according to the rule the distance of the centre of gravity of the ring of water from the centre of the wheel is 2-0944 E : E :: 1-732 E: the distance required 1 7 QO T?2 = o.o944 K = * 82 E. If the radius be 1 5ft. to the centre of gravity of the water in the buckets, the whole weight of water would act at a distance of 15 X 82 = 12 3ft. If the buckets be of such dimensions, and be filled to such degree that the quantity of water poured into them would form a continuous ring Gin. deep, the radius 15ft. passing through the centre of it ; then the length of the ring of water would be 2 0944 x 15 = 31 -41ft., and the quantity of water would be 31 -41 x ' 5 = 15 70 cubit feet per foot in width of the wheel, acting at the distance 12 30ft. from the centre. This is, in effect, the same as a vertical column of the height A B, and of the same sectional area as the ring, acting at the distance 15ft. The height of the column is 1-732 E = 1-732 x 15 = 25-98, or say, 26ft. Let the quantity of water to be expended be 20 cubic feet per second, or 1,200 cubic feet per minute. If the velocity of the wheel at the centre of gravity of the water in the buckets be 5ft. per second, the quantity would be 2^ cubic feet per second per foot in width of the wheel. The width, therefore, would require to be 20 ^Tr = 8ft. Such a wheel might be made to give at the working point from 75. per cent, to 80 per cent, of the power of the water. This power is - "Too"" ~ = ^9 horse 144 WA TER- WHEELS. power, and the. effective power would be, probably, 45 horse power, and the wheel would allow of the power being increased to 60 horse power at times when one- third more water than usual might be at command ; that is, when it would be sufficient to fill the buckets to the degree which would be equal to a continuous ring 8in. deep, 8ft. wide, and having a clear vertical fall of 26ft. UNDERSHOT WHEELS. The undershot wheel is an improved form of current wheel ; both depend for their efficiency on the impulse of water, as distinguished from its gravity. But instead of being placed in an open current, the wheel is fixed in a close channel, or race, of masonry, very little wider than SECTION PLAN Fig. 32. the wheel itself, and the water is penned up by a sluice- gate, moving in grooves in the side walls, issuing beneath it when raised by means of a rack and pinion. Fig. 32 represents such a wheel. Because the efficiency of this UNDERSHOT. 145 form of wheel depends upon the velocity which can be induced in the jet of water, the approach to the opening through which it issues is differently formed from other openings through which merely quantity of water is required ; the side walls being made to converge towards the opening, and the sluice-gate being placed in a sloping position ; at least, this should be the form. Sometimes the sluice-gate is placed vertically; but the effect of placing it in a sloping direction is to increase the velocity ef the water issuing from under it, as compared with that through an abrupt opening, and as the effect of water acting on an undershot wheel is in respect of its velocity and actually as the square of its velocity any increase of that element which can be obtained by arrangement of sluices is to be desired. Water issues from openings into the air with the velocity due to heavy bodies falling from a height equal to the head of water, or the vertical height from the centre of the opening to the surface of the pent- up water (with however some abatement, to be hereafter referred to), and when the opening is so formed as not to impede the flow of water, the quantity issuing is nearly that due to the area of the opening multiplied into this velocity. Many openings from which water is made to issue are so abruptly formed that the actual quantity is much less than the quantity so found, because, although the water attains the velocity due to its head in the axis of the vein, or jet, at some short distance outside the opening that is, at the point of contraction of the vein yet it does not do so equally throughout its cross-section, the friction against the sides of the opening retarding the flow of the outer portions. When water flows out of an opening into the atmosphere it approaches it from all sides, as shown in Fig. 33, and, in issuing, its viscidity causes its particles to shoot across towards and meet in the section of contraction (A A in the figure). The cross- sectional area of this part of the jt cannot be measured in practical works, but on a smaller scale it has been L 146 IV A TER- WHEELS. measured and compared with the area of the opening. Experiments made on the flow of water through holes in thin plates and, therefore, under circumstances where the water issues abruptly show the sectional area of the vena wntracta to vary from about one-half to about Wo- thirds of the area of the orifice from which the water issues. In constructing the sluices of undershot water-wheels they should therefore be made so that the water may have an easy approach to the opening through which it is to issue, for then the retarding influence of the edges of an abrupt opening being reduced, the mean velocity of all the filaments of water passing through an opening will be much increased, if the opening be placed in such a position as to occupy the place of the contracted vein. This question of increased velocity must always be taken in conjunction with the area of the opening, for it is not an absolute increase, but a relative one relative, that is, to the area of the actual opening. If an abrupt opening be placed at a distance in front of the point where the issuing jet is to take effect, equal to the length FLOW FROM ABRUPT OPENINGS. 147 of the contracted vein, the velocity at the point of con- traction would be the same as through an opening with converging sides; practically the same, although there are minor influences which affect it slightly. It is on these considerations also that the mouth of a pipe into which water enters from a reservoir is made bell-mouthed, or trumpet shaped, so that immediately after entry the pipe may run full bore. The damage done by floods in Italy some years ago might lead one to suppose that in that and neighbouring countries hydraulic laws are not understood. Sir John Eennie, in a letter to the Times, showed how floods might there be prevented, or at least how damage from them might be obviated ; and yet it is chiefly from continental experimentalists that English engineers have received their elementary knowledge of hydraulics. On that part of the subject now under notice the phenomena of spouting fluids the following are the original authorities, and the results of their experiments. Du Buat (Principes d* Hydraulique) gives the relation between the diameter of the jet at the point of contrac- tion and that of the orifice as 6 to 9, from which are deduced the relative areas 4 to 9 ; the Abbe Bossut (Hydrodynamique) as 41 to 50, or in area as 16*8 to 25; Daniel Bernoulli (Hydrodynamique) as 5 to 7, or in area as 25 to 49 ; J. B. Venturi (of Modena) as 4 to 5, or in area as sixteen to 25 ; Michelotti (of Turin) as 4 to 5, or in area as 16 to 25 ; MM. Poncelet and Lebros, French engineers, from a number of experiments on a larger scale, found the relative areas to be as -62 to 1, or nearly as 5 to 8. It will be found useful to compare these latter relative areas with the co-efficients of actual discharge to be presently mentioned. The first practical step to be taken in constructing any work in which water is to be used for power must be to ascertain what quantity of it will issue from any opening of given dimensions under a given head of water, and, therefore, it is worth while to go to the root of the matter L 2 148 WA TER- WHEELS. before proceeding to particulars of construction. Although the experiments made on the form which water assumes when issuing from an opening, and to which we have before referred, have necessarily been made on a smaller scale than that of general practice, yet they are very useful guides to the comprehension of the reasoning on larger affairs, and help to account for anomalies between that which we find to be the result by experiment, and that which we should expect on theoretical grounds alone. But it is always so in constructive works; the best and only true results are to be arrived at by comparing theoretical knowledge with experimental knowledge, and ultimately uniting them in practice. Experiments on the actual quantities of water issuing from openings of known areas and forms show that those quantities are in all cases less than those which are due to the areas of the openings multiplied into the velocities due to the several heads of water, calculated upon the known effects of the power of gravity, which give in any particular case the quantity or the velocity which is called the theoretical quantity or the theoretical velocity. But taking the velocity so found in feet per second viz., eight times the square root of the head of water in feet, as a standard, co-efficients of diminution have been found for various forms of opening, which show the ratio between the theoretical velocity and that which may be called the mean velocity of all the filaments of water issuing through any actual opening. The more abrupt the outlet the less is the co-efficient of actual velocity, or, as some say, the co- efficient of contraction. Whether one or the other of these expressions is the more proper depends upon the form of the opening, the area of which is measured and multiplied into the co-efficient to find the actual discharge. With abrupt openings the diminution may more properly be attributed to the contraction of the vein outside the opening, and with openings which have converging side walls the diminution should be attributed to the reduction of velocity caused by the friction of the particles of water EXPERIMENTS ON FLOW OF WATER. 149 amongst themselves and against the side walls. Gene- rally, the velocity is found by measuring the actual quantity of water discharged in a given time, and dividing it by the area of the opening through which it issues. In making these experiments the water is dis- charged into a tank of known capacity, and the time of filling is accurately noted. From experiments conducted in this manner co-efficients are found which make theo- retical deductions accord with observations of facts. There is another method of ascertaining the velocity by actual measurement. It is known that a heavy body issuing into the atmosphere with an initial velocity at some height above the ground describes in its descent a parabolic curve nearly, and would do so exactly if the air were removed. If an experimental vessel with a hole in its side near the bottom be set up at some height above the ground, and if a vertical line be let fall from the mouth of the orifice to a horizontal plane at any depth below it, and if horizontal lines be measured out from the vertical line to the jet at several points, then these ordinates, measured at the points of corresponding abscissa, show the jet to describe a parabolic curve nearly. If h be put for the head of water above the centre of the orifice, which is due according to the theory of falling bodies to the initial velocity of the issuing jet, and if x = the length of any abscissa and y its corresponding ordinate, then y 2 = 4hx. By measurements in this way Bossut found at three different heights the value of h to be nearly that of the actual head of water. Calling the actual head H, the heads calculated from the range of jet at these several heights were as follow : WhenH= 7 511ft., h= 7 -404ft. H = 12 -890ft, h = 12 -564ft. H = 23 -583ft., h = 22 -720ft. The differences are due partly to the resistance of the air at high velocities, and partly to the viscidity of the water and consequent friction of its particles. 150 WA TER- WHEELS. If we state the theoretical discharge or the theoretical velocity as = 1, the limits between which actual dis- charges and actual velocities vary are 625 and 1 of those determined by the theory of falling bodies. By no form of construction can the actual discharge or the actual velocity reach the theoretical discharge or the theoretical velocity, because the theory assumes the falling body to fall in vacuoj and although the very great difference between the density of the atmosphere and any heavy body falling in it, or issuing into it, reduces its retarding influence to a very small opposing force, yet it has a degree of density, and its opposing force is inversely pro- portionate to the difference of density between itself and the body issuing into it. The quantity of water, therefore, or its velocity, issuing from any opening of whatever form, can never quite reach that found by theoretical calculation. Dr. Downing, Professor of Civil Engineering in the University of Dub- lin, in his 'Prac- tical Hydraulics/ gives a table of ex- periments appa- rently those made <>j " ~~-^-~ fry Castel and ___^: -""" D'Aubuisson to determine the co- efficient of dis- charge and that of velocity through short-truncated Fig. 34. tubes, the sides of which converge at various angles. The length of the experimental tube was 2J times the diameter at the outer end. See Fig. 34. The angle that gave the maximum discharge was between 13 and 14, 'the ratio between the actual and the theoretical discharge being then as *95 to 1, but it UTMOST PRACTICABLE VELOCITY. IS 1 does not vary nmcli on either side of this ratio within a range of about 5 ; thus at 8 it is -93, and the same at 18, so that for quickness of discharge the angle may vary from 8 to 18, with a mean co-efficient of '94 or there- abouts ; but as the angle increases beyond about 18 the co-efficient of discharge diminishes more rapidly, until at 48 it is but 84, and if continued to the extremest angle of 180 would be about *5. The co-efficient of velocity, however, continues to increase with the angle, even beyond the angle of maximum discharge, where it is *96, to 48, where these experiments show it to be *98. These experiments were made on the small scale, but three ex- periments made at a mill on the canal of Languedoc show similar results, as to discharge, through a truncated pyra- midal tube of considerable dimensions. The length was 9 -59ft., dimensions at larger end 3 -2ft. by 2 -4ft., at the smaller end '623ft. by -443ft. The opposite faces made angles of 11 38' and 15 18'. The head of water was 9 69ft. The co-efficients of discharge deduced from these three experiments on the large scale were '987, -976, and 979 respectively, or very nearly the full theoretical quantity. Eytelwein ('Handbuch der Mechanik und der Hy- draulik '), translated by Dr. Thomas Young, and quoted in Tredgold's ' Tracts on Hydraulics,' gives the constant multiplier 7 8 for an orifice of the form of the contracted stream, that is when the internal edges of an orifice in a thick plank or a short tube are rounded off to that form, from which we deduce the co-efficient *97. When the internal edges are not rounded the co-efficient is *92. The late Mr. Beardmore, in his ' Tables to Facilitate Hydraulic and other Calculations,' gives the constant 7 '5 to be multiplied into the square root of the head of water, for the mean velocity in feet per second for openings such as these. The theoretical value is 8*03^, so that the co-efficient in this case would be '934. From the results of his own practice, which was con- siderable in this respect, Mr. Beardmore considered that 1 5 2 WA TER- WHEELS. the constant 7'5 was to be preferred for openings con- structed as nearly as may be of the form of the issuing jet. Adopting this constant, we may apply it to an example. If an undershot wheel be applied to utilise a fall of water of 4ft. that is 4ft. head irom the surface down to the centre of the opening of the sluice ; and if the width of the sluice be 6ft., and the vertical height to which it is found necessary to raise the sluice-gate, in order to do the work required, be 6 in. ; the area of the opening would be 3 sq. ft., which call A ; let h = the head of water in feet, then the mean velocity of all the filaments of water through that opening, supposing the side walls to be splayed, and the head of the sluice-gate sloped up-stream, would be 7'5^/h, and the quantity of water discharged would be 7-5VA xA = 7'5x2x3 = 45 cubic feet per second. As to the best diameter of an undershot wheel and its speed, Sir W. Fairbairn states, in his ' Treatise on Mill Work,' that assuming 2'4*/h to be the velocity of the extremity of the float-boards to give a maximum effect, and let N = the number of revolutions per minute, then the diameter, expressed in terms of the velocity and height of fall, will be 19-1 x 2 ' 4 J ^ V/A = 46 ^ A nearly. For instance, if the fall be 4ft., and the number of revo- lutions 8 per minute, then the diameter = -- x fj ^ ll^ft. nearly. The number 19 ! appears to be arrived at thus : N, the number of revolutions, is taken in respect of a minute, while the velocity 2 '4 ^h is taken at per second. The number of seconds in a minute (60) divided by 3*1416, the ratio of the circumference of a circle to its diameter, = 19-1. Other authorities give the best speed of an undershot wheel as half that of the water ; others again as '57 of that the water. Now there is an apparent discrepancy here, and it probably arises from the different values SPEED OF AN UNDERSHOT WHEEL. 153 given to the co-efficient of velocity of the issuing jet. According to the form of the opening, that velocity varies from 5 A/h to 7 * 5 */h, being least with abrupt openings and greatest with openings of the form of the vena contract^ or with trained walls and sluices. If the co- efficient 5 be adopted, and the proper speed of the wheel be taken at half the velocity of the water, then the speed of the wheel would be 2'5 */h, agreeing nearly with Sir W. Fairbairn's statement above given ; but with openings of the form to which it would be proper to apply the co-efficient 7*5, the speed of the wheel (sup- posing it be likewise half that of the water) would be 3*75 */h. On the whole, it will probably be near the truth for ordinary cases to make the speed of the wheel in feet per second from 3 */h, to 3'5 */h, accordingly as the form of the opening varies either way from a form which would be a mean between an abrupt opening and one of the best form ; the co-efficient, or rather constant multiplier, being taken at from 6 to 7 for the velocity of the water, and the speed of the wheel at half that velocity. The ratio of the useful effect, or work done, to the power expended on an undershot wheel is usually reckoned as but little more than 1 : 3. Thus, if the head of water be 4ft., the width of the opening 8ft., and its vertical height 6in., the area would be 4 sq. ft. The velocity of the water through the opening (supposing there to be converging side walls and sloping gate) would be 7-5- v //t = 7'5x2 = 15ft. per second, and the area being 4 sq. ft. there would be 60 cubic feet of water expended per second, or 3,600 cubic feet per minute, falling 4ft., which is the same power as (3,600 x 4 = ) 14,400 cubic feet falling 1ft. in a minute. But as the ratio of the useful effect and the power is as 1 : 3 the /14 400 \ effective force of this expenditure of water is ( - = ) v / 4,800 cubic feet raised 1ft. high per minute. A horse- power being 33,0001b., raised 1ft. high per minute is also 154 WA TER- WHEELS. (oo AAA \ ,' = j 528 cubic feet of water raised 1ft. high per minute. Therefore the effective power of an undershot wheel applied to utilise this quantity of water with this fall would be 1,800 l328~ = 9 horse-power. Sir William Fairbairn states that the usual range of diameters for undershot wheels is from 12ft. to 25ft., and that from 12ft. to 16ft. is considered to be most effective. In his own practice he found from 14ft. to 18ft. diameter to give the best duty. The float-boards, instead of being set in a radial direction on the wheel, are sometimes set in an inclined direction, but this does not seem to in- crease the useful effect. The number of floats is usually 4d - -f- 12, d being the diameter of the wheel in feet. Thus, for a wheel 15ft. diameter the number of floats 4 x 15 + 12 = 32. The thickness of the vein of fluid may be from 6in. to 9in., and the depth of the float-boards from 18in. to 24in. The greatest improvement on the undershot wheel has been made by M. Pon- celet. His form of wheel is shown in Fig. 35. It has curved floats of sheet iron ; in- deed, the whole framework is of iron, and very light. It is well Fig. 35. suited for low falls and large quantities of water, and can be driven at a greater speed than a low-breast wheel, with which its performance is to be compared. Its useful effect is from 50 to 60 per cent, of the power of the water PONCELETS WHEEL. 155 expended, and its speed from half to three-fifths of the velocity of the water. M. de Bergue exhibited at the Institution of Civil Engineers a drawing of one of these wheels erected by him 16ft. Sin. diameter and very wide, the fall of water being 6ft. 6in. The following is a method of describing the curve of the floats of M. Pon- celet's wheel. Let a b c, Fig. 36, be a horizontal line, and b d the perpendicular to it. Let b r be the radius of the wheel, the divergence from the vertical being from Fig. 3G. 24 to 28. Take be = from one-third to a quarter of the fall of water, and draw the inner circumference //, and the outer circumference g g. Take on b d, h i = one-sixth of b h, and from the centre i, with radius i &, describe the curve of the float. The number of floats is greater in this than in ordinary undershot wheels, and therefore the motion is more equable and continuous. Let d = the diameter of the wheel in feet, then for wheels from 10ft. to 20ft. diameter, the number of floats = + 16; 1 5 6 WA TER- WHEELS. thus for a wheel 15ft. diameter, the number of floats BREAST WHEELS. The essential difference in the actions of water on under- shot wheels, and on overshot and breast wheels, is that in the undershot form the wheel is driven by the impulse of the water on the float-boards, and in the other two forms it is turned by the weight of the water. For equal quan- tities of water expended the action by weight is about twice as effective as by impulse. An ordinary "under- shot" will raise back again to the height from which it falls about one-third of the quantity of water expended ; Poncelet's wheel fully one-half; while an ordinary " over- shot " will raise three-fifths ; an overshot wheel of good construction will raise from two-thirds to seven-tenths ; and a high-breast wheel of the best construction will raise three-fourths of the quantity of water expended, back again to the height from which it falls. A high- breast wheel is formed with buckets, similar to those of an overshot, which retain the water poured into them above the axis of the wheel, acting upon it by the force of gravity. In a low-breast wheel the water is applied below the level of the axis, and is made also to act by its weight by making the wheel to move in a close-fitting race of masonry, which holds up the water to the breast of the wheel. In order that the water may act upon the wheel by weight through the greatest fall it is made to run over the top of the gate in the form of a weir, the gate being lowered sufficiently to allow the proper quantity to flow over it, and raised to shut off the water ; called the sliding hatch. To ascertain the velocity and quantity of water flowing over such a sluice-gate in a given time, reference must be made to experiments on the flow of water over weirs. The flow over weirs follows the same general law as that which governs the flow through openings below BREAST WHEELS. 157 the surface ; that is to say, the velocity is proportional to the square root of the head of water, or the depth in the case of weirs. The theoretical velocity in both complete orifices and weirs is 8*03 sJh,Ji being the height in feet from which the water falls, or the head of water (reduced from the theorem of Torricelli, v = *J 2 g Ji) in which v = the velocity in feet per second, and g = the force of gravitj-, or the velocity acquired by a heavy body at the end of the first second of its time of falling, = 32* 2ft. per second ; but the practical velocity is_less ; under the most favourable circumstances it is 7 8 J h, but in general the value of the co-efficient may be taken to be 7 5. The quantity discharged is diminished in practice in both kinds of openings by the same influences ; viz., by the contraction of the stream caused by projections into it, which diminish its sectional area, and of the friction on the border of the stream, which diminishes the mean velocity. The speed of the wheel should be somewhat less than the velocity of the water in order that the float-boards may not strike against it and retard the motion of the wheel. As to the depth or head of water, it is to be re- marked that it is not the depth measured immediately over the gate or hatch itself, but from the level of still water a few feet away from it ; and the depth from which the velocity is to be calculated is the whole depth from the surface of still water to the top of the gate. The actual depth measured on the gate is, on an average of all depths, about four-fifths of the full depth, approximately. The mean velocity of the stream going over the gate, calculated from the depth between the still water of the head and the top of the gate, is two-thirds the velocity due to the lowermost thread of particles, which is 7 5 ^~h. That thread of particles which has the mean velocity of the whole is at a depth below the surface of four-ninths of the whole depth, and is /4 2 V 9 * = 7 ' 5 * 3^= 7 ' 5 158 WA TER- WHEELS. If, for instance, the depth were Gin., or -5ft., the mean velocity would be 5 *J 5 = 3 54ft. per second. But the actual velocity of the sheet of water passing over 1he gate would be greater in the ratio of 5 to 4, for the depth of water on the gate would be approximately four- fifths of the whole depth. Thus the actual velocity would be 7 = 4* 42ft. per second; and the speed of the wheel might be 4ft. per second, so that the spaces between the float-boards which are successively presented to the flow of water may be fully supplied. The speed, however, may be required to be greater than 4ft. per second, according to the kind of work it has to do, and according to the intermediate gearing. Sir William Fairbairn usually made the speed of breast wheels from 4 to 6ft. per second at the periphery. If the water does not flow immediately on to the wheel from a still head, but arrives in a channel of no great width, and therefore with a perceptible velocity, let that velocity be ascertained with floats and reduced to feet per second ; or if not by direct observation with floats, let the known approximate quantity of water coming down the channel be divided by its sectional area, which will give the mean velocity of the stream, and that velocity increased by one- fourth will in most cases give the velocity at the surface, which is that to be ascertained, and if it be called w, then ;, the mean velocity due to the whole depth of water above the gate, will be 5 */h -f- *035 2 , and that of the sheet of water passing over the gate will be greater than this in the ratio 5 : 4. The . parts of a low-breast wheel are, besides the axle and the arms, the rim, the starts, the sole-boards, and the float-boards. The sole-boards should not close up the spaces between the float-boards, but at the top of each a horizontal slit of an inch or so in width should be left for the escape of air when the water flows in, and for its admission when the water is discharged after passing the SPEED OF BREAST WHEELS. 159 vertical centre of the wheel, otherwise the water will neither enter freely nor be discharged freely. The axle, arms, and starts, are usually of oak or elm; the float- boards of fir. Another form of sluice gate is the double hatch, the opening being wholly below the surface, and the upper and lower parts of the gate being brought within the required distance of each other by racks and pinions. This form is adopted to ensure a greater velocity in the issuing stream of water than it can attain when it passes over the top of the gate, with the same expenditure of water. The quantity of water discharged in a given time by either form of gate may be calculated on the same basis. It is proportional to the square root of the height from which it falls and to the area of the opening through which it issues to the velocity and sectional area combined. Water falling over a weir takes the form of a parabolic curve, and there issues in any given time two-thirds of the quantity which would issue in the same time from an opening of the same dimensions placed horizontally at a depth below the surface equal to the whole depth of water flowing over the weir. Through an opening wholly below the surface the quantity is proportional to the area multiplied into the velocity. The causes of diminution of the flow in either case are (1) contraction of the stream, and (2) friction, or that retardation of the particles of water next the bottom and sides which ensues upon their being rolled over each other, by reason of the contact of some of them with the confines of the channel, while those in the axis of the stream pursue a straighter course. CURRENT WHEELS. The original form in which use was made of water in motion to do mechanical work was that of opposing to the force of the current of a river a series of float-boards placed round a wheel. In EwbanVs historical account of ma- 160 WATER-WHEELS. chines for raising water he describes the tympanum (Fig. 37) used by the Romans, and so called by them from Fig. 37. its resemblance to a drum ; but a similar form of wheel had been used in more ancient times. It had a hollow shaft, or axle, and the arms proceeding from it to the circumference of the drum were bent up at their ends, and formed so many scoops, which, when the wheel was turned round, gathered up each its portion of water, and as each arm came to a horizontal position the water was shot inwards and entered the hollow shaft, and, one end only being open, the water was discharged from it and led away. This machine was greatly improved in the early part of last century by M. De La Faye, a member of the French Academy of Sciences, who " developed by geo- metrical reasoning a beautiful and truly philosophical improvement." Quoting from Belidor's description of De La Faye's reasoning, Ewbank gives it thus : " When the circumference of a circle is developed a curve is described (the involute), of which all the radii are so many tangents to the circle, and are likewise all respectively perpen- dicular to the several points of the curve described, which has for its greatest radius a line equal to the periphery of the circle developed. Hence, having an axle whose circumference a little exceeds the height which the water is proposed to be elevated, let the circumference of the axle be evolved, and make a curved canal, whose curvature shall coincide throughout exactly with that of the involute ANCIENT WHEELS. 161 just formed. If the further extremity of this canal be made to enter the water that is to be elevated, and the other extremity abut upon the shaft which is turned, then in the course of rotation the water will rise in a vertical direction, tangential to the shaft and perpendicular to the canal, in whatsoever position it may be." As given by Belidor ( (Fig. 38) it has four arms, but Ewbank says that is frequently constructed with double that number. Fig. 38. Dr. Olinthus Gregory, in his treatise on Mechanics, after describing this same machine, says: "Thus the action of the weight, answering always to the extremity of a horizontal radius, will be as though it acted upon the invariable arm of a lever, and the power which raises the weight will be always the same ; and if the radius of the wheel, of which this hollow channel serves as a bent spoke, is equal to the height that the water is to be raised, and consequently equal to the circumference of the axle or shaft, the power will be to the load of water recipro- cally as the radius of a circle to its circumference, or directly as 1 to 6J nearly." The wheel being turned by the impulse of the stream acting upon the float-boards, the orifices, A, B, C, D, &c., of the curved arms dip, one after another, in the water, which runs into the channels so formed, and as the wheel revolves the fluid rises in them vertically and enters the hollow shaft, from which it runs out in a stream at either end. This form of wheel can only raise water to the height M 162 WATER- WHEELS, of half its diameter, but the " Persian Wheel " (Fig. 39) takes it up nearly to the full height of its diameter. Buckets are hung upon pins projecting from one or both sides of the wheel, and when they arrive at the top they are emptied by coming in contact with the trough, which conveys the water away. For this purpose they are furnished with bowed springs, which come in contact with a fender at the side of the trough into which the water is discharged, and so the bucket is tilted up and emptied, and swings down again to its vertical position. The power of such wheels as these is measured by the area of the float-board and the velocity of the current combined. The velocity is most easily ascertained by Fig. 39. means of floats, which are sometimes of wood, painted white and loaded with lead until the upper surface stands nearly level with the surface of smooth water ; but, per- haps, spheres are better, of some material which displaces nearly, but not quite, its own bulk of water, as offering less obstruction to the action of wind. Oranges are sometimes used. Having ascertained the surface velocity of the stream,, the inquiry would be What produces this velocity ? It is the force of gravity acting on a mass of matter which possesses the quality of fluidity ; and water is drawn to the ocean from its source by that power, and is interrupted in its course thither by being employed to turn wheels, or otherwise to transmit the force inherent in it to the work . SURFACE VELOCITY OF A STREAM. 163 to be done. The surface of a stream of water may be considered as an inclined plane, reversed, down which, moves the body of water. When water enters a river or stream, time must elapse before that portion of the river or stream below the point at which the water enters becomes in train. A river is in train when the inclination of its surface does not vary while its hydraulic mean depth remains constant ; and it may be said to be in pro- gressive train and in retrogressive train when the inclina- tion and hydraulic mean depth increase gradually and decrease gradually, respectively. For instance, after the flood waters of the upper part of a river had ceased to flow into it, it would not become in train until all that water had spread its influence over the lower part of the river ; but after that it would continue in train until it should be again influenced by additional water. When- ever that might occur, if the quantity were to run in gradually until it were exhausted, the river would be put into a state of progressive train, and if, by reason of no more water running into the river until that which had run in had run out, the river would be in the meantime in a state of retrogressive train ; and so the regimen of the liver might fluctuate gradually in this way ; but it is seldom that this regular influx and efflux take place. The regimen is usually interrupted by intermediate additions of water, so that, except in dry weather, it is not easy to ascertain when a river is or is not in train, and the alternative is to observe to what level the surface marks in summer, excluding excessive droughts, and to call that the summer level. The river is at those times " in train." Taking the surface of the river, then, when it is in train, the water drawn along it by the force of gravity may be said to move along the inclined path of its surface reversely, for the same reason that a solid moves down and upon an inclined path ; and that, of the laws governing the two cases, some are applicable to both, while others are applicable to each respectively. If an inclined path down which a solid body might M 2 1 64 WATER-WHEELS. move were perfectly smooth, there would be no. sliding friction, and as soon as the limiting angle of resistance to the friction of stability should be attained, the solid would shoot down the incline with an accelerating velocity. In a river the water is not perfectly fluid, but has some viscidity. If it were a perfect fluid it could not be retained in its channel, and no state of the river such as that we call in train could be maintained. It is sometimes said that it is " fortunate " that water decreasing in temperature below about 40 degrees Fahr., expands, and that when it is converted into ice the specific gravity is so much less than that of water that it floats upon it, otherwise that the whole would become a solid mass of ice. It may be said to be equally "fortunate" that water is not a perfect fluid, otherwise it would all run out of the river in a glut, and no permanent stream could be maintained. When water is gathered together in a stream and descends towards the sea, it does so with a velocity the square of which is proportionate to the inclination of its surface, combined with its hydraulic mean depth, the mean velocity of the whole body being in general 8 or 9 tenths (according to the roughness of the bed) of a mean proportional between its hydraulic mean depth and twice the fall of its surface per mile. Water flowing in the axis of a stream goes down with greater velocity than that near the sides, which shows that, although we say water is a perfect fluid for all practical purposes, it yet possesses some viscidity, for its outer portions hang to the ground over which it runs, and the velocity increases from the bottom upwards and from the sides inwards, until the maximum velocity is attained in the axis of the river; and it is even observed in parts of some rivers that there is a reverse current near the shore, running up the river. Between this upward current and the main down- ward current there are eddies. There are also eddies at some distance upwards from the point of observation of the shore water, at which point it turns downwards again THE FLUIDITY OF WATER NOT PERFECT. 165 and gets into the main stream. The velocity is greatest in the axis because the channel is there the deepest. The axis need not be in the centre of the river, for it is its main channel, wherever that may be ; and the velocity is there the greatest, because at any point of the depth whether at the point where the mean velocity takes place or whether at the surface it is further removed from the retarding influence of the bed. The motion is due to the attraction of the mass of the earth, and it finds the readiest way to the lowest point continually. The velocity it acquires in falling is the measure of its force. It rolls with an involved motion, the moving particles at the surface being .continually replaced by those from below and from the sides. All these things show that water is not a perfect fluid, but that it has in some degree the quality of viscidity, or viscosity, if that word more exactly explains the meaning. The wheels last described are current wheels, and there are many situations where they may be usefully employed, especially in new countries, and where other forms could not be readily adopted. The power of such wheels may be determined on the following considerations : If the wheel be fixed, and the current of water impinge against the float-boards it will do no work, but the effort of the water, tending to turn the wheel round, will be the greatest possible will be the maximum effort that the water is capable of when running with its actual velocity. On the other hand, if the wheel be freed, and it offer so little resistance to the current of water as to move with it that is, with the same velocity then again no work will be done, there being no resistance. Between these two states there is one which produces the maximum effect, or greatest amount of work. When the water is at liberty to escape sideways as fast as it impinges on the float-boards, as it does in current wheels, it can be shown by a process of reasoning that the effect is a maximum when the float-boards move with a velocity equal to one-third of the velocity with which they would 1 66 WA TER- WHEELS. move if there were no resistance, or one-third of that of the current of water; and also that the most effective force with which the water can act on the wheel is four- ninths of its utmost force when its head accumulates against the float-board when the wheel is held still. This force is equal to the weight of a column of water whose base is the area of the immersed float-board, and whose height is that due to the velocity of the current. That height is found thus. The force of gravity constantly adds a certain quantity of motion, second by second, to a body falling freely, whatever actual velocity it may have attained at the end of any previous second, and this quantity is 32^ft., and is usually represented by the letter g. In the first second, after falling from a state of rest, it falls a distance of IG^ft., being the mean between zero when at rest and 32ift., the velocity it has acquired at the end of the first second. For practical purposes such as these we are considering, it is sufficiently accurate to take #=32, and h, the height fallen through in the first second, = 16. The velocity will then be for any height, v = fjl g Ji, = Jl&h = 8 fj h ; and conversely, the height corresponding to any given velocity, v, will be h = jj-, v being the velocity in feet per second. Supposing, then, the velocity of any stream employed to turn a current wheel to be found by experiment to be 8ft. per second, the height from which it must have fallen to produce this velocity is =lft. Supposing the immersed area of the float-board to be 10 square feet, the force of this current on this immersed area of float-board would be 10 x 1 X 62i = 625lb. But this is the whole force due to the stream of water, and can only take effect when the wheel is held still and therefore, of course, is doing no work. When let go it will move with a velocity, compared with that of the stream, which will be due to the extent to which it may be loaded, and the maximum effect, or greatest amount of work done, will take place when the FORCE OF A WATER CURRENT. 167 force acting on the float-board is - of the whole force of 9 the stream, or ( 4 X 625 = \ 2 77-7lb., and when the velocity ^8 \ of the wheel is J of that of the water, or ( - = \ 2f f t. per second, the work done will be that of falling (277-7 x 2|- = ) 7401b. 1ft. per second, which is about 1 horse-power. This takes account of only one float-board, but it has been found by experiment that by making the number of float- boards greater than is strictly required in order to keep one float-board always fully immersed, a greater effect is produced, and taking this practical increase of effect into account we may say this wheel would be, at least, 1^ horse-power. Where a stream can be confined in its channel so as to make all the water that impinges on the float-boards continue to act upon them until the wheel releases it, the best relative velocity of the wheel to that of the stream is one-half, instead of one-third when unconfined. But when the circumstances of the situation are such that an artificial channel can be made to bring the water to the site of the work the wheel is taken out of the category of current wheels and becomes a prop' 31 ' " undershot " wheel ; as, for instance, where a stream, being small, may be wholly dammed up for the purpose of gaining a few feet head of water without causing it to overflow the banks of the stream above, or do other damage ; or where part of the water of a larger river may be diverted from a point at some distance above the site of the intended wheel and brought to it in an artificial channel having a less rate of inclination than the river itself, so that a few feet head of water can be accumulated, then a proper undershot wheel may be applied. 168 SECTION XIX, CORN-MILLS. THE cases to be presently mentioned are such as admit of the quantity of water expended being ascertained, which is usually the whole volume of the stream, and whether that be so or not in particular cases the quantity ex- pended can be ascertained from the two measurements of the fall and the opening of the sluice-gate ; but current wheels such as those last mentioned are sometimes applicable. The quantity of water which actually strikes the wheel is always less than the whole quantity which comes against it ; it bears the same relation to the whole quan- tity as the difference between the velocity of the water and that of the wheel bears to the absolute velocity of the water. The force with which this quantity strikes the wheel is as the square of the relative velocity, or the difference between the two velocities, for the force is as the relative velocity multiplied into the quantity striking the wheel with that velocity, and the quantity is as the relative velocity, therefore the force is as the square of the relative velocity. If, for instance, the stream move at the rate of 9ft. per second, and the wheel at the rate of 3ft. per second, 36, the square of the differ- ence, represents the force acting upon the wheel ; but if in the same stream the wheel move at the rate of 6ft. per second, the force is only 9, the square of 3, the difference between the two velocities. But when a close race is fitted to the lower portion of the wheel, which is the usual mode of construction, so that the water does not all VELOCITY OF WATER AND OF WHEEL. 169 escape immediately after striking the float-board with which it comes in contact, but continues to act until it finally leaves the wheel at or near the bottom, the case is different, and under these circumstances the best velocity for the wheel is found to be nearer one-half than one-third of that of the water. In general, the largest bodies of water are found in the lowest positions, with small or but moderate falls, and although the application of water to turn the wheels is better effected with a steady pressure and uniform motion that is by its weight yet when the quantity is large, and the fall but little, it cannot be so well applied in that way as by means of undershot wheels. The water acts upon these by impact, in contradistinction to weight, and the power of water acting in this manner is derived from a force different in its nature from that which produces a steady pressure. Taking the quantity of water expended to be the same in the two cases, it would be discharged in the former through a small opening with great velocity, and in the latter case through a large opening with but little velocity ; in the one case it is discharged near the bottom of the fall, in the other near the top. At a depth of 5-7 6ft. the velocity through a sluice is 7-5 V 5 '76 = 18ft. per second. The constant 7*5 is thus derived. In the discharge of water through holes in thin plates the stream is found to be contracted in sectional area at a short distance outside the opening. With round holes the diameter at the contracted part can be measured, and its sectional area ascertained, and it has been found by hydraulicians who have made these measurements that the area at the contracted part of the stream is about two- thirds of that of the hole. If the velocity at this part suffered no diminution, which is sometimes assumed, the discharge would be a x 8 */ A, a being the sectional area of the stream at its smallest part, and h the height of the surface of the water above the centre of the opening ; and if A be the area of the opening, the quantity 17 CORN-MILLS. issuing would be f A X 8 \fh. But the cubic quantities actually measured do not amount to so much as this represents ; they amount to only f A x 8 ^1T; the differ- ence, therefore, must be caused by a diminution of the Telocity in the ratio f to f , or 8 to 7*5, in the contracted part of the stream ; and in the opening itself in the ratio 1 to f or 8 to 5 ; and the diminution of velocity in the contracted part is probably the same in all forms of opening, although the degree of contraction varies much with the forms ; thus the actual velocity of a stream issuing from under a sluice-gate, taken at that part where it is greatest, is 7*5 */h, h being measured in feet, and the velocity in feet per second. The most general pro- portions of velocities between the water and the wheel found in twenty-seven experiments by Smeaton was 10 to 4, the extremes being 10 to 3-4 and 10 to 5-2 ; and the most general proportion between the power and effect was 10 to 3, the extremes being 10 to 3-25 and 10 to 2-82 ; but as the former is that which obtained when the power exerted was greatest, the proportion in large works may properly be taken at 3 to 1 for ordinary undershot wheels with straight float-boards, where the water is confined to them by a close race. Amongst the trials I have made of the quantity of water expended in doing various kinds of work may be selected, first, either those in respect of different kinds of work on the same kind of wheel, or those in respect of the same kind of work on different kinds of wheel : the latter method seems preferable, and the following are selected from some trials of the quantity of water expended in grinding corn with undershot wheels. These, as will be seen, are much less effective, in proportion to the quantity of water expended, than either overshot or breast wheels; but there are many of them, and notwithstanding their less effectiveness, they are more appropriate for large quan- tities of water and low falls than the other kinds of wheel. In a corn-mill driven by an undershot wheel 16 -80ft. VELOCITY OF WATER AND OF WHEEL. 17* diameter, 8 50ft. wide, which has 24 straight float-boards 2 25ft. wide, without soling, there are two pairs of French burr wheat-stones, 4ft. lOin. diameter, and one pair 4ft. Sin. diameter ; also one pair of grey stones 5ft. diameter, one pair of shelling-stones, one corn-screen, and two flour- dressing machines. The centre of the wheel is 2* 20ft. above the level of a full head of water. The bottom of the sluice-opening is 3 40ft. below full head. When the wheel is standing, the tail- water is 6 '20ft. below full head. On the occasion of the following trial, No. 1, the water was 56ft. below full head, the height above the bottom of the sluice-opening being 2 '84ft. Two pairs of 4ft. lOin., and one pair of 4ft. Sin. wheat-stones, and one flour-dressing machine, are running. The sluice-gate is drawn '81ft The surface of the water in the tail-race is 5* 20ft. below the full head, or 4 '64ft. below the present head. The head above the centre of the sluice-opening is 2-84 - *-?r - 2 -44ft. So far, these are matters of ob- 2 servation and measurement, but the next is one of calcula- tion ; that is, the quantity of water discharged through the sluice-opening, which is 8 70ft. wide, and formed as in the diagram. There are side walls, as in Fig. 32, and the bottom is level with the sill. The side walls are not of the best form for facilitating the passage of the water, but they conduce to it in some degree. Under the circumstances, the proper co-efficient of discharge would probably be 75, and the quantity of water 8-70 X '81 X 8 V 2 '44 X '75 = 65 cubic feet per second, or 3,900 cubic feet per minute, which, multiplied into the fall, 4 -64ft. = 18,096. There being three pairs of stones running, the quantity of water per minute per foot of fall per pair of stones is 6,032 cubic feet, including the dressing machineiy. The next trial, No. 2, was with a full head of water, with the same wheel, the machinery running being two pairs 4ft. 8in. and one pair 4ft. lOin. wheat-stones, one pair 5ft. grey stones, and one flour-dressing machine. The sluice-gate was drawn -76ft. There being a full head of I7 2 CORN-MILLS. water the surface water was 3 40 - = 3 -02ft. above the centre of the opening. The area of the opening is 8-70 x '76 = 6-60 sq. ft., and the discharge would "be 8 -70 x *76 X 8 V3'02 X -75 = 68 cubic feet per second, or 4,080 cubic feet per minute. There being a full head, the fall was 5 -20ft., and 4,080 x 5-20 = 21,216. If the driving of the meal-stones requires as much power as a pair of wheat-stones, so that the number might be reckoned as four pairs, then the quantity of water ex- pended per minute per foot of fall per pair of stones is 5,304 cubic feet ; but if the number be taken at 3 5 pairs, then 6,060 cubic feet. On the third trial with this wheel the water was 14ft. below full head, and the sluice-gate was drawn *80ft., the machinery running being the same as on the last [trial. The height of the water above the bottom of the sluice was 3-40 - -14 = 3 -26ft. The height above the centre of the opening 3*26 '40 2 -86ft., and the discharge 8-70 X '80 X 8 V2'86 X '75 = 70 cubic feet per second, or 4,300 cubic feet per minute. The fall was 5ft., and 4,300 X 5 = 21,500. If the work done be reckoned as four pairs of stones, the quantity per pair is 5,375 cubic feet; but if as only 3=L pairs, then 6,143 cubic feet per minute per foot of fall, the dressing machinery being included. The speed of this wheel is ten revolutions per minute. On the fourth trial the grey stones and the dressing machine were thrown off, and the three pairs of wheat-stones run. The water was 1 50ft. below full-head, and the sluice-gate was drawn -98ft. The height of the water above the bottom of the sluice was 3-40 1-50 = 1-90, and above the centre of the opening 1-90 - -49 = 1-41. The discharge 8-70 X *98 X 8 fj I -41 x * 75 = 61 cubic feet per second, or 3,660 cubic feet per minute. The fall was 5-20 - 1-50 = 3 -70ft., and 3,660 X 3- 70 = 13,542. There being three pairs of stones running, the quantity of water expended per pair of stones would be 4,514 cubic feet per minute per foot of fall. TRIALS OF QUANTITY OF WATER USED. 173 At another corn-mill there are three wheels, the trials with one of which only are selected. It is 16 '30ft. dia- meter, 6 -20ft. wide, with 24 straight float-boards 2 -25ft. deep. The centre of the wheel is 56ft. above the level of a full head of water. The bottom of the sluice-opening is 5 -61ft. below full head. On the occasion of the following trial, No. 1, the water was 1'lSft. below the level of full head. The sluice was drawn 98ft. The head above the bottom was, therefore, 5 -61 _ 1-15 = 4 -46 ft., and above the centre of the open- . QQ ing 4-46 - = 3 -97ft. The width of the sluice-gate 2i is 6 70ft. The discharge, therefore, would be 6 70 X '98 X 8 A/ 3-97 X * 75 = 76 cubic feet per second, or 4,560 cubic feet per minute. The fall from present head to tail- water is 5 -46ft, and 4,560 x 5-46 = 24,897. There were four pairs of stones running at the time, and the quantity per foot of fall per minute per pair of stones would be 6,224 cubic feet. The speed of this wheel is eight revolutions per minute. On the next trial, No. 2, with the same wheel, the water was l-35ft. below full head, the sluice was drawn l-26ft., the head above the bottom was 5*61 1*35 = 4*26, and 1-26 above the centre of the opening 4 '26 = 3* 63ft. The discharge would be 6*70 X 1-26 x 8 V 3 ' 63 X '75 = 95 cubic feet per second, or 5,700 cubic feet per minute. The fall was 5ft., and 5,700 x 5 = 28,500. There being four pairs of stones, the quantity is at the rate of 7,125 cubic feet per pair. The next trial was with a wheel where the sluice-open- ing is 10* 50ft. wide. The depth of water to the bottom of the sluice was 5 '45ft. The gate was drawn '68ft. The head upon the centre of the opening was, therefore, 5.45 I2 = 5 -lift., and the quantity discharged 10*50 2 X '68 x 8 A/ 5- II X -75 = 96 cubic feet per second, or 5,760 cubic feet per minute. The fall was 5 -32ft. at the 174 CORN- MILLS. time of the trial, and 5,760 x 5-32 = 30,043. The number of pairs of stones being five, the quantity per pair was 6,128 cubic feet. All these wheels are undershot, and of rather rude construction, but not, perhaps, unusually so. The next trial was with two low-breast wheels 14ft. diameter, each 10ft. 6in. wide, where the water falls over the top of the gates. The combined length of the opening is 19ft., and the depth of water going over 6|in. The form of the tops of the gates is such as to make it probable that five would be very nearly the proper con- stant to apply for the quantity of water in cubic feet per minute, and 5 *jW~x I = 5 VC 6 !) 3 X 19 = 1,700. 1,700 X 5ft. fall = 8,500. There were running three pairs of wheat-stones 4ft. diameter, with the dressing machinery, which would make, per pair of stones, 2,833 cubic feet per minute per foot of fall. The useful effect of the weight of a given quantity of water acting during a long time, the velocity being con- sequently small, is much greater than that of the same quantity acting by the impulse of a great velocity. If the quantity per second or per minute be multiplied into the vertical height of the fall, and called M, this divided by 528 exhibits the horse-power of the water when applied by its weight upon the wheel ; but when it acts by impulse, M must be divided by 1056 for the horse- power of the water, and if it acts through part of the fall by impulse, and through the remainder by weight, these parts must be taken separately. The horse-power of a waterfall, therefore, cannot be stated, even when the quantity and fall are known, without taking into account its mode of action, for it requires twice as much water to produce a given power by way of impulse, as that which is required to produce the same power by its weight, moving with slower speed. If, for instance, Q be the quantity of water in cubic feet per minute, and Ji the height of fall in feet, the horse-power is when its 528 TRIALS OF QUANTITY OF WATER USED. 175 weight is brought to bear upon a wheel which has a velocity of its circumference sufficient only to give the water room to fall freely; and the slower the speed the greater the useful effect, according to the following reasoning. (Eobison's l Mechanical Philosophy.') Putting the work to be done into the form of a weight to be raised, "if K be the radius of the wheel to the centre of gravity of the water in the bucket, and w be the weight of the column of water acting at that distance from the centre of the wheel, and if r be the radius of the axle, or the distance from the centre at which the weight W reacts upon the falling water, then the forces are in a state of equilibrium when R w = r W, and this is so whether the acting and reacting forces be at rest or move with any velocity whatever, so that it be uniform ; for gravity would accelerate the falling water if it were not completely balanced by some reaction, and in this balance, gravity and the weight raised exert equal and opposite pressures, and thus produce uniform motion. Now as to the speed, both the falling water and the weight raised maybe taken for comparison in cubic feet of water, and if A be the cross-sectional area of the falling column of water, and h its height, its weight may be represented by A Ji. " If Y be the velocity of the descending weight w, in feet per second, and v that of the ascending weight W, then Wr = AAR ; but R : r : : V : v, therefore Wv = AAV. The work done is measured by the weight and the height to which it is raised per second, or by Wv ; therefore, the greatest amount of work is done when AAV is a maximum. But AV is a constant quantity, being the quantity of water descending per second; if the wheel moves fast A is small ; when V is small A is great, but AV remains the same; therefore, Ji should be the greatest possible that is, the water should be applied upon the wheel as high up as possible ; but this diminishes the head necessary to give the water its velocity of entry into the buckets, which must be such as to prevent them striking it in 176 CORN-MILLS. passing the entering stream of water ; and a diminution of this head diminishes the velocity of the entering water, while, at the same time, the less the speed of the wheel the less need this velocity be. As the diminution has no limit, the reasoning shows that an overshot wheel does more work as it moves with slower speed." But practical considerations and experiments have shown that a velocity of at least 3ft. per second should be given to the circum- ference of a water-wheel, and that it may be as much as 6ft. per second without much loss of effect. With overshot wheels it is very desirable to keep the water up to the same head at all times ; but this cannot Fig. 40. be done without wide reservoirs. The small reservoirs or dams for the storage of the night water, or at most, for the 36 or 40 hours from Saturday to Monday, are not of sufficient capacity to do this, and the head consequently varies considerably between morning and night, as well as at different times of the year. There are two ways of applying the water under these circumstances; one by means of a sliding gate or roll of leather over which the water flows upon the wheel at various heights, but always with the same velocity, and therefore without unneces- sary loss of head (Fig. 40), and the other by means of VARIOUS FORMS OF WATER- WHEEL. 177 a pentrough above the wheel to contain a considerable depth of water (Fig. 41), whereby a sacrifice of power is made when the water is at a high level, the diameter of the wheel and the application of the water being accom- modated to the lowest working head. The following case is one of this sort: The former method is much the better, but in water questions it is not always what is best that can be insisted upon, but what exists which must be dealt with. A corn-mill has an overshot wheel 1 5ft. diameter, 7 Jft. wide. The wheel works close under Fig. 41. the pentrough, as in Fig. 40, and the water is, therefore, laid on at the highest possible point, which is about 25 deg. from the vertex. At the time the following observations were made there was a depth of water in the pentrough of 4ft., the sluice-opening being in the bottom, which consists of Sin. planking. The length of the opening is 6 -40ft., and the width, when all the machinery of the mill is running, is 3in. ; the area of the opening is, therefore, 1 60 sq. ft. The coefficient of discharge through such an opening would be about 60, and the J 7 CORN-MILLS. quantity of water passing through the sluice would be A/64 x 4 x 1-60 x -60 = 15-36 cubic feet per second, or 920 cubic feet per minute. The water is laid on to the wheel 1ft. below the bottom of the pentrough, and about 1 Jffc, is lost at the bottom of the wheel, the effective fall being 15 2-5 +| = 15ft. The power of the water 2i applied through this wheel is, therefore, that of 920 cubic feet per minute falling 15ft., or 13,800 cubic feet per minute falling 1ft. The machinery in the mill, all of which can be run at the same time with the before-named quantity of water, is : Four pairs of French burr wheat-stones, 4ft. 4in. diameter ; one pair of Derbyshire grit meal-stones ; one pair of shelling-stones ; one bean-splitter; one corn- dressing machine; one flour-dressing machine, 20in. diameter, 6ft. long. If the other pairs of stones be sup- posed to require the same power as the wheat-stones, and 13 800 that there are in all six pairs, = 2,300 cubic feet 6 of water per minute per foot of fall for each pair ; and 2>3 = 4 -35 horse-power. 528 The quantity of wheat ground per hour is about four bushels by each pair of stones, when in good condition ; or 3J bushels at other times. The second example is that of a flour-mill. There is a slight difference, it may be said parenthetically, between a flour-mill and a corn-mill. In country places, such as that where the mill first mentioned is situated, other grain besides wheat is ground for the convenience of the neigh- bourhood, and for these the term corn-mill is more appro- priate ; but mills near large towns are often fully occupied in grinding wheat, except that they may have a pair of meal-stones for occasional use, and these are more properly called flour-mills. In the following case there are two breast- wheels,, each 16ft. diameter, one 12ft. wide, WATER USED PER PAIR OF STONES. I./9 the other 8ft., with cast-iron hollow shafts, and cast-iron arms and rings, into which oak starts are fitted. The larger, or No. 1 wheel, has fonr sets of arms and rings, and forty oak starts in each ring ; the smaller, or No. 2 wheel, has three sets of arms and rings, and the same number of starts in each ring as the other wheel has ; and there are 40 float-boards of elm in each wheel, 18in. in depth, and 40 back-boards, also of elm. The circumference of the wheels being 50ft., the floats are 15in. apart from centre to centre. When the following observations were made, the total fall of water was 6ft, between the head and the surface of the water in the tail-race when the mill was running, and as the tail-race is carried up to the centre of the wheel or nearly so at a good depth, about 2ft., there is no drag on the wheels by running in backwater. The wheels have cast-iron breasts, which confine the water closely to the edges of the float-boards, and curved water- gates of elm, worked by racks and pinions. The water- gate of the large wheel is double, the combined width of the two openings being 11 -30ft.; the width of that of the smaller wheel is 7 90ft., and the water runs over the top of the gate, and under a fixed head-beam, as shown in Fig. 42. There are ten pairs of stones in this mill, nine pairs of French burr wheat-stones, 4ft. 2in. diameter, and one pair of Derbyshire grit meal-stones, with all the necessary -wheat-dressing and flour-dressing machinery. But at the time of the experiments there were only seven pairs of wheat-stones running, together with the dressing-machi- nery, or as much of it as was required to keep in work the seven pairs of stones. The quantity of water is cal- culated in the following manner, which, for small heads above the openings, is more accurate than that of mea- suring the head of water from the surface to the centre of the opening. The gate being lowered by the miller to the depth which he finds sufficient to do the work, the heights H and Ji in Fig. 42 are measured, after a suffi- cient time has elapsed to allow the water to settle to a N 2 i8o CORN-MILLS. steady head, and after the miller has finally adjusted the height of the gate. As the thickness of the water- gate is 6in., and the side and division-posts are square in form, the proper co-efficient of discharge would be about -63. The quantity of water passing through such an opening is taken to be the difference between those which would pass over two weirs, the one having the depth H, and the other the depth A, both below the surface of still water. In this way, on the first experi- ment of No. 1 wheel, the depth H was ll^in., and h 4in. r the combined length of the two openings being 1 1 30fL HEAD BEAM Fig. 42. The fundamental condition is that at the depth H or h,. the velocity of the water is proportional to ^QA H or V 64 A, and the mean velocity of the whole sheet of water is two-thirds of that which it is at the depth H or Ji t the quantity actually discharged being corrected by the co-efficient 63, which embraces the corrections for both retardation of velocity and contraction of the sectional area of the stream, caused by its passing through the square form of opening, as in this case. Generally, if Z ba WHEEL WITH SLIDING GATE. 181 the length of opening in feet, the quantity discharged in cubic feet per second would be I H x 1 V64~H x -63 - Z h x | */Wk X '63 which is more conveniently stated as 5-33Z VH 3 X '63 - 5-33Z JW x '63; or, finally, as when H and li are measured in feet, and the quantity discharged is measured in cubic feet per second; but when, as in the present instance, H and h are measured in inches, and the quantity is desired to be stated in cubic feet per minute, 3-35 must be multiplied into 60, and divided by the square root of the cube of 12, which is 41*56. Under these circumstances, therefore, the quan- tity discharged in cubic feet per minute is stated as Q = 4-83Z(, v /H 3 - ./A 3 ). The depth H, then, in the first experiment with the wheel No 1, being 11 Jin., and the depth h being 4in., Q = 4-83 x 11-30 x (V(ll-25) 3 - V*" 3 ) = 1,621. In the same experiment, with No. 2 wheel, the depth H was 12 Jin., and h 4J in. Q = 4-83 X 7-90 X (V(12'25) 3 - V(4'25) 3 = 1,301. The two quantities together are 2,922 cubic feet per minute, having a total fall of 6ft., and 2,922 x 6 = 17,532 cubic feet per minute falling 1ft. There being seven pairs of stones running, with the wheat -dressing and flour-dressing machines, and the elevator and hoisting tackle, the quantity of water ex- pended per minute per foot of fall was 2,505 cubic feet per pair of stones driven. If this be represented in liorse-power it would be .1 - = 4-74. In the second experiment with No. 1 wheel, the height H was 10 Jin., and h 3in. Q = 4-83 x 11-30 (V(10-50) 3 - V^ 5 ) = 1,572. In the same experiment, with No 2 wheel, H was 12Jin., and li 3jin 1 82 CORN- MILLS. Q = 4-83 x 7 90 (V (12- 50)^- ^(3~'~50f = 1,437. These together are 3,009 cubic feet per minute, falling" Oft., equivalent to 18,054 cubic feet falling 1ft., and - = 2,579 cubic feet of water expended per minute per foot of fall per pair of stones driven. In the third experiment with No. 1 wheel, H was 11 Jin., and Ji 3 J in. Q = 4-83 x 11-30 (V(11'25) 3 - V(3'50) 3 = 1,700. Jn the same experiment with No. 2 wheel, H was 12in., and h 3jin. Q = 4-83 x 7-90 (V(12) 3 - /(^Wj 3 ) = 1,339. Together, these are 3,039 cubic feet per minute falling 6ft., or 18,234 falling 1ft., and 18>234: = 2,605 cubic feet of water per minute per foot of fall per pair of stones. The mean quantity falling 6ft., derived from the three experiments, is 2.922+3.009 + 3,039 = 2)990 ^c feet O per minute for seven pairs of stones, or 2,563 cubic feet O X A ^ per minute per foot of fall for each pair, and -^ ^ = 4*85 o^o horse-power. With regard to the large quantity of water shown to be used per pair of stones with those undershot wheels, viz., 6,032, 6,060, 6,143, 6,224, 7,125, 6,128, cubic feet per minute per foot of fall, including the dressing machinery, the average being 6,285, if this be put into the form of 6 285 horse-power it would be * =12 horse-power nearly, 528 per foot of fall per pair of stones. Every miller knows, or at least millers often say, that a pair of French burr wheat-stones of medium size can be driven by 4 horse- power, which would be 528 x 4 = 2,112 cubic feet of water per minute per foot of fall ; and that is so when the water is used by way of its weight on overshot or high-breast wheels; and taking this as a standard the- HORSE-POWER PER PAIR OF STONES. 183 undershot wheels on which the above-named experiments were made do effective work only about one-third of the 2112 power expended, or more accurately ' =33*6 per \)2i ' oo cent. The owners of all those undershot wheels would be amply compensated for the expense of substituting for them the wheels called "Poncelet," which give an effective power of 55 per cent., and would use under the o 119 ' same circumstances * = 3,840 cubic feet of water only, oo to do the same work, or with the same quantity of water would do more work in the ratio of 1*63 to 1, or 5 to 3. With regard to the diameter of the wheat-stones named, such as 4ft. lOin., 4ft. 8in., &c., these are rather larger than the medium size, which is perhaps 4ft. 4in. or so, but on the other hand the quantity of water named in each case was measured as fully as was consistent with my duty. The experiments with breast wheels show a much less quantity of water required per foot of fall per pair of stones driven, including the dressing machinery as before, viz., 2,833, 2,505, 2,579, 2,605, the average being 2,631 cubic feet per minute; and applying the same standard of 4 horse-power, or 2,112 cubic feet of water O 119 per minute falling 1ft., the effective power is * = 80 2b' ol per cent, nearly. SECTION XX. WORK DONE BY WATER-WHEELS. THE most direct measure of the work done by a water- wheel is the quantity of water pumped to a certain height by another quantity falling through a certain other height. The following instance affords such a measure. When I was an assistant to the late Mr. James Simpson (past President Inst.C.E.), I made the following trials for him with two low-breast wheels, each 19ft. diameter, No. 1 being 12ft. wide ; and No. 2, 10ft. The fall of water was 6ft. Each wheel works three pumps. A cast- iron pipe, lOin. diameter, and 10,890ft. long, delivers the water into a service reservoir at a height of 148ft. above the level of the source from which the water is pumped. This reservoir, for a few feet in height at the top, has vertical walls, inclosing an area of 40,804 sq. ft. The trial consisted first of the quantity of water expended on the wheels, and secondly of the increase of the depth of water in the reservoir in a certain time, when the outlet valve was closed. The gate of the wheel No. 1 is lift, wide, and it had a depth of water of l-21ft. ; the gate of No. 2 wheel is 9 75ft. wide, and it had a depth of water of 96ft. According to the construction and arrangement of these gates the proper co-efficient of discharge would probably be 62. Without allowance for contraction of area or for diminution of velocity, the quantity would be 8 '02 /J h x lh X 1 r = 5 '35 lh A/ A, and if this be reduced, for the effects of contraction, &c., by the co-efficient 62, the actual quantity would be 3J Hi *J h = 3J I A/ h 3 . Accord- ingly the quantity in cubic feet per second would be PUMPING WATER BY WATER-POWER. 185 3J- (11 V (1'21) 3 + 9-75 V (-96) 3 = 80, or 4,800 cubic feet per minute. This would be the quantity falling from a still head of water ; but the form of the channel is such that the water approaches the wheels with a velocity of 1 Jft. per second, as observed by floats, and the height h must be increased by a height which is sufficient to produce this velocity, which is ^ a = 035 v 2 . The formula, therefore, is 3^ Ik X 1-21 V 1'21 +0-35 x 2-25 + 9-75 X '96 J -95+ -035 x 2-25) = 83 cubic feet per second, or 4,980 cubic feet per minute, which, multiplied into the fall, 6ft., and divided by 528, is equal to 56 horse-power. To compare this with the effect produced in 11 hours' pumping, the water surface of the reservoir was raised 19in., the quantity in that time amounting to 64,606 cubic feet, or at the rate of 1-63 cubic feet per second. The area of the lOin. pipe is -545 sq. ft., and the velocity through it must, therefore, have been 3ft. per second. The head of water required to produce this velocity is which the pumps lift, is, therefore, 148 -f 47 = 195ft. If this be multiplied into the number of cubic feet per minute, 98, and divided by 528, the effect is that of 36 horse-power, or 64 per cent, of the power expended. This is the utmost quantity of water the wheels would carry, purposely tried, and the velocity of the water through the pumping main was greater than it should have been for economical working. If a less quantity of water had been expended on the wheels, such as would have produced a velocity in the lOin. main of 2ft. per second, or thereabouts, the result would probably have been a greater effect than the percentage above named. In the neighbourhood of Sheffield water power is much used for grinding saws and cutlery, and saw-grinding is very heavy work ; but still heavier work is that of forging and grinding anvils, and for this kind of work water power 1 8 6 WORK DONE BY WA TER- WHEELS. is preferred to steam ; the work is not very regular, and in the intervals the water accumulates and the great power required is exerted during short periods of time. A grind- ing establishment is called a wheel. On some of the streams there is a succession of very considerable falls of water, and, although the quantity is not large, a great deal of work is done by the same stream. One of them, for instance, has an ordinary flow of about 600 cubic feet per minute where it begins to be used, increasing to 1,000 or more where it falls into a larger river, and in this distance of a few miles there are twenty grinding wheels, mills and forges. The fall at No. 1 wheel is ISJft. The wheel is overshot, 14ft. diameter, 5ft. wide, with 5ft. head of water in the pentrough over it. There are 16 grindstones for table knives and files ; but it is the trough in which the stone runs that the grinder claims as his possession ; and this is a wheel of 16 troughs. When 14 of these are occupied, the sluice-gate or " shuttle " is drawn 2 Jin. The length of the opening being 4ft. 4in., its area is 91 sq. ft. The form of the opening is such that probably *63 would be the proper co-efficient of discharge when the sectional area of the stream is taken to be that of the sluice-opening, and 8 V h X *63 = 5-04, or say, 5 J h y for the mean velocity of all the particles of water passing through the opening, when resolved in a direction at right angles to it, or in the direction which the successive central particles take ; and the quantity discharged would, there- fore, be -91 x 5 V~5 X 60 = 606 cubic feet per minute. Wheel No. 2 is loft, diameter, 6 -58ft. wide, with 4ft. head of water in the pentrough. There are 8 grindstones for table knives, and 10 for "light" work. All these being occupied, the shuttle is drawn 2in. The length of opening is 6 *17ft., and the quantity of water discharged would be 2 6-17Xj2 x5 V 4 x60 = 618 cubic feet per minute. The fall is 18ft. No. 3 is an overshot-wheel, 11* 75ft. diameter, 7* 25ft. SAW-GRINDING, ETC. 187 wide, with a head of 3ft. in the pentrough at the time of the trial to ascertain the quantity of water. There are 9 table-knife and 4 razor stones. With these running, the shuttle is drawn 2Jin. The length of opening is 6 85ft., and the area 1 * 42 sq. ft. The quantity of water is 1-42 x 5 V^> X 60 = 736 cubic feet per minute. The fall is 14ft. No. 4 has two water-wheels, each lift, diameter, one of them 5ft. wide, the other 4 -67ft. The fall is 15ft. When the trial was made there were running 10 table-knife stones, and 4 razor stones. The sluice-openings are re- spectively 4* 75ft. drawn IJin., and 4* 50ft., drawn IJin., discharging together 656 cubic feet per minute. These are all over shot- wheels, with pentroughs, from near the bottom of which the water is discharged upon the wheel, and in which the head varies from time to time, according to the season, or according to the work being done ; whether it is more or less than the power of the stream for the time being. The next one is a wheel of a different kind. No. 5 is a high-breast wheel, 15^ft. diameter, 8Jft. wide. The fall is 13ft. with a full head of water; but it varies- at different times, for the same reasons as those before stated. For this wheel, however, the whole fall of water, whatever it be at various times, is made use of without loss of head by letting the water fall over the top of a movable lip, which is raised or lowered at pleasure, so as to discharge the water into the buckets of the wheel at the highest possible level. The circumference of the wheel moves closely under a series of cast-iron bars arranged across the face of the wheel, l^in. apart, the clear length of waterway of the openings being 6ft. 9in. (see Fig. 39 r p. 176). When the trial was made, there were 11 saw-grind- ing stones running, and five of these openings were ex- posed, the head upon each successive bar from the top increasing by 2in. Thus, upon the first opening the head was 2in. ; upon 1 88 WORK DONE B Y WA TER- WHEELS. the second, 4in. ; upon the third, Gin. ; fourth, 8in. : and fifth, lOin. The quantity of water passing through these openings may be estimated by the velocity due to the head upon each, which will be proportional to the square root of the head in each case. The passages between the bars partake of the character of a tube projecting inwards through the side of a tank into the body of water a form which does not facilitate the passage of the water through it, but retards it, as com- pared with a tube having a rounded mouth, or even with a tube having sharp arrises, if they form part of the side of the vessel. On the other hand, the length of each passage is short, being about 4in. On the whole, it is considered that a proper co-efficient of discharge is ?, and that the quantity in cubic feet per second would be expressed by Q^A x 8 J~h x '7. The expression *J h must be the sum of the square roots of all the heights, in feet, thus : V '17 + V" 7 ^ + V" 7 ^ + V '66 + */~83 = 3-41 and Q = 6-75 X i^r* x 5 ' 6 x 3 ' 41 X 60 = 798 cubic feet \2i per minute. This method of applying water to a wheel may be either by means of a gate sliding in the arc of a circle by means of rack and pinion, or it may be by means of a roll of leather or other web, covering the openings and folding downwards, its position at any time corre- sponding with the top of the sliding gate in the other method. The roll has less friction, and is in some other respects preferable ; but the gate is, perhaps, the more lasting. The same kind of work on another kind of wheel will exhibit the difference in effect between a high-breast wheel upon which the water is laid without loss of head, and upon which it acts with its full weight, or nearly so, and a wheel of less diameter than the fall of water, working under a pentrough. HIGH AND LOW FA LLS. 189 No 6 has two water-wheels, one 9ft. diameter, 7ft. wide, with a head of water in the pentrough of 2 42ft. ; the other wheel is 8*67 diameter, 6 50ft. wide, with the same head of water. The sluice-opening in the first-named wheel is 6* 75ft., and in the other 6 '25ft., and the shuttle was drawn 2in. in the one and 2Jin. in the other, and the quantity of water expended on both wheels was 1,080 cubic feet per minute. The fall is lift. There were running 6 saw-grinding stones, and 2 scythe-stones. If the quantity of water expended on the high-breast wheel viz. 798 cubic feet per minute be multiplied into its fall, 13ft., and divided by the number of stones running, 11, the result is 943 cubic feet per minute per stone. If the same process be followed in the second case, the quantity of water is 1,080 cubic feet per minute, the fall lift., the number of stones running, 8, and the result is - = 1,485 cubic feet per minute o per foot of fall per stone running. The tilt-hammer is almost an indispensable piece of machinery. One of the water-wheels works two of these (one at once), and a blowing-machine. The wheel is 9ft. diameter, 7ft. wide. The sluice-opening is 6 '25 x '18ft. = 1 12 sq. ft. The head upon it is 1 92ft. The quantity of water discharged when one tilt-hammer and the blowing-machine are in work may be estimated at 1-12 x 5 V 1*92 = 7-78 cubic feet per second, or 467 cubic feet per minute. The fall is lift., and 467 x 11 = 5,137 cubic feet per foot of fall per minute. The hammer is 2Jcwt., with a fall of 7in., and makes 250 strokes per minute. At an anvil-forge the grin ding-wheel is 9ft. diameter, 5 85ft. wide, overshot ; head of water in pentrough, 3ft., sluice opened IJin. Total fall of water, 12ft. The wheel for the iron forge is 10ft. diameter, 4ft. wide,, buckets 11 in. deep, works one hammer with a sluice- opening of 4in., 4ft. in length, with a head of 3 10ft. The shear-steel forge, which works one hammer, is a 190 WORK DONE B Y WA TER- II HEELS. breast- wheel 12ft. diameter, 3jft. wide, having buckets 12in. deep. The sluice-opening is 3* 40ft. long, and Gin. wide, with a head of 3 10ft. The shearing scrap wheel is overshot, 9Jft. diameter, 4ft. 4in. wide. The sluice-opening is 3in. wide, 4ft. long, with a head of 3 -10ft. Another anvil forge has a breast-wheel 20ft. diameter, 7 -17ft. wide. The fall is 13ft. When the following ma- chinery is working, the sluice-opening is 1 Jin., the length being 7ft., and the head of water 3ft. viz. blowing cylin- ders which supply 18 anvil hearths, 6 smiths' fires, 1 shear- steel furnace, and 1 iron furnace. With the folio wing- machinery added, the opening of the sluice is 2in. viz. 2 slide lathes, 1 planing machine, and 1 drilling machine. The anvil-grinding wheel is overshot, 11 -50ft. diameter, 6ft. wide. The sluice-opening 5 60ft. long, 1 Jin. wide, the head of water being 3ft. Coming lower down the streams into the main rivers, the wheels become undershot with larger quantities of water and less height of fall. The first example of a forge with this kind of wheel that is undershot, with the water confined in a close-fitting race is a wheel 14ft. diameter, 6ft. wide, the centre of which is 42ft. above the level of a full head of water. The head at the time the following trial was made was 1ft. below the full head. There are two forge- hammers, one 5cwt. with 16in. fall, the other 4cwt. with 14in, fall. The present fall of water is 5ft. The sluice is 6ft. wide, and when the 4cwt. hammer is working it is drawn lOin. Another wheel works two tilt-hammers of 2Jcwt. (one at once), with a fall of 7in., and one forge-hammer of 4cwt., with a fall of 12in. The diameter of the wheel is 14ft., width 5ft. 9in. With the present head of water, 1ft. below full head, the sluice-gate is drawn 9in. to work one tilt-hammer. The wheel of another tilting forge is 13ft. diameter, 5ft. 9in. wide, the centre being -42ft. above the level of a full head of water. There are two tilt- FORGE HAMMERS. 191 hammers of 2jcwt., with a fall of 7 in., making 300 strokes per minute. At the next works of this kind the wheel is 13Jft. dia- meter, 4ft. wide, the bottom of the sluice 1 42 feet below the present head ; sluice-opening 4* 50ft. wide ; gate drawn 8 Jin. for one tilt, and 16 Jin. for the forge-hammer, which is SJcwt., with 16in. fall, the tilts being each 2cwt., with 7in. fall. Another kind of work is that of a wire-mill. The ma- chinery consists of two wire-blocks 20in. diameter, and one 24in., and two fans ; also of six grinding-stones for hackle-pins, 2ft. 9in. diameter. The wheel is overshot, 10 % 68ft. diameter, 4 -5ft. wide. The sluice-opening is 4ft., and is drawn 3in., under a head in the pen trough of 3* 75ft. The quantity of water expended would be 4 x *25 x 5 fj (3-75) x 60 = 582 cubic feet per minute. The fall of water is 15ft. SECTION XXI. TURBINES. WHEN the height from which water falls exceeds about 40ft. it cannot be economically applied by way of it& weight acting with a moderately slow motion on a single vertical wheel of ordinary construction, although a fall of 80ft. or 90ft. may be utilised on two vertical wheels placed one above the other; not so well, however, directly the- one above the other, as when placed sideways in the manner shown in Figs. 43 and 44. In this arrangement, both wheels move in the same direction ; but if one be directly over the other, they move in opposite directions. Moreover, it is sometimes desirable to work one wheel without the other, and in that case also this arrangement is convenient, and especially so when there is a side stream, high enough to be conducted into a tank over the lower wheel, but not into the higher one. The upper wheel shown in the diagram is 50ft. diameter, and 6ft. wide, the lower one 48ft. diameter and 7jft. wide, both of wrought iron. In t-his instance the upper wheel is supplied by an 18in. pipe from a reservoir on the main stream, and by an arrangement of the sluices and stop-cocks the water is turned on to either wheel from the main source. But when the fall of water exceeds about 30ft., it is- more economically applied by way of its free velocity on a smaller wheel, usually placed horizontally, whereby the force of the water is diffused over the whole circum- ference, requiring, therefore, a smaller diameter ; and this kind of wheel is suitable to any height of fall, say, from 3ft. to 300ft., and to various heights in the same place, for PRESSURE AND REACTION. 193 it works in backwater as well as free, and makes effective whatever fall there may be for the time being. This is an advantage where the quantity of water varies greatly TANK Fig. 43. Fig. 44. at different times, as upon a stream where the flood- waters are not impounded. The force brought to bear upon these wheels is of two kinds direct pressure and reaction, the o 194 TURBINES. reaction being obtained by the liberation of pressure on one side of an arm, or of a cell or bucket. The fundamental principle of the reaction-wheel is the release of pressure on one side of a revolving arm, whereby it is driven in the opposite direction with a pressure equal to that taken away. Fluid pressure acts in opposite directions at the same time, with equal intensity in both directions; and when the resistances arc less than its pressure, it also moves in opposite directions at the same time, the velocity in either direction being inversely as the resistance ; and if the abstraction of the quantity of water, due to the motion in one or both directions, be replenished at the head, the motion will be continuous under the same head. Fipr. 45. If the vertical pipe or chamber A, in Fig. 45, communi- cate with the head-water, and an arm, or two or more arms, project from it ; or if passages be made between it and a wheel revolving round it, one of the cells or buckets of which may be represented by the two opposite vanes, B C and D E, with the closed end, C D, the water presses with equal force on the two sides, they being of equal area, and there is no motion. Neither would there be any motion if the end were closed between C and g, instead of between C and D, for the pressure upon the end C g in the direction of the tangents at every point between the two vanes is equal to the pressure upon D g only ; and the pressures would equally be balanced whatever form, whether straight or curved, be given to the vane C g E. But if an opening be made in one side, as from C to /, ELEMENTAR Y FORM. 195 that side of the cell would he relieved of the amount of pressure due to the area of the opening, the pressure which it had before being now transferred to the issuing water, and forcing it out with the velocity due to the head, and the obstructions to its flow. If there were no such obstructions the velocity in feet per second would be */ bli = 8 V ^> ^ being the head of water in feet; but as there are obstructions in every form of channel, and how- ever they may be lessened by good forms, the velocity of issue from turbine-orifices will probably in no case exceed 7 * 5 V h, considered as that of water issuing from an orifice which has no motion of its own. Such an opening being made, the vane opposite to it has upon it the pres- sure due to the head of water, and would have to be held by an external force equal to that which presses out the water with the velocity 7 5 >J h. If, at the same time, an opening were made from D to J 2 gJi = v is adopted, and it is called loss of head. By the same standard 7-2^/h would imply a loss of head of 19 per cent., or 14 per cent, more than the " loss " in the first instance, which, however, hardly seems properly to be called a loss, if it never existed. But by the usual standard the loss of head due to the hydraulic resistances of ontward-flow turbines seems to vary from 14 to 20 per cent., and in taking 19 per cent, it would seem that a sufficient allowance is made for all the hydraulic resistances combined ; and in this is included also the leakage between the fixed and movable parts of the turbine. The turbine consists essentially of a wheel with a hollow rim, across which are placed, at certain distances apart, curved vanes to receive the pressure of the w^ater on their concave sides, and the angle at which they are placed across the rim varies accordingly as the water acts chiefly by direct pressure or by the pressure of reaction. In the outward-flow turbine the water issues horizontally all round the bottom of a cast-iron pipe or chamber, in which guide-blades are set, so as to conduct the water into the rim of the wheel at the proper angle, and it escapes through the outer circumference of the wheel. The rim is connected across underneath to the central upright shaft, which drives the machinery, by a strong disc of cast iron, the supply-pipe, or chamber, and the fixed guide-blades being suspended from a frame above, and hanging within the revolving wheel, and clear of the disc beneath, by which means (the method of M. Fontaine) the weight of the water and the chamber is taken off the bearings, and the shaft-friction much reduced. The revolving upright shaft is kept from the water through which it passes by being inclosed in a pipe, which supports the whole machine. For low falls of water the top of the supply-chamber is open, but for high falls 202 TURBINES. the top is closed, and the shaft passes through it. In one case the water is delivered into an open reservoir or chamber immediately above the turbine, in the other the turbine works at the end of a closed pipe, which is under pressure all the way from the head-water, which may be at a considerable distance from the position of the turbine. The available head of water, however, which produces the velocity before mentioned, is almost as easily ascer- tained as if it were immediately above the turbine. With the reservations named above, nothing can alter the velocity with which water issues from an opening under a given head. If the area of the opening be too large in proportion to the quantity of water, the head will fall ; if it be not proportionately large enough, the head will rise, until an equality is established ; it will rise, that is to say, if confined in a pipe, and it will of necessity either rise or spread out laterally. The main object is to transmit to the wheel as much as possible of the motion obtained. The driving power of the turbine is measured by the difference between the pressure of the water due to the head and its pressure at the point of egress. The motion of the water is an absolute quantity, to which that of egress and that of the wheel are together equal. If pressure on the egress orifices of the wheel be wholl}' taken away, as it is when the orifices move with a velocity twice that due to the head of water, considered as the velocity due to that head when the orifice is at rest, then the whole motion is transferred to the wheel ; but if the water issue from the wheel with any velocity that is, if the velocity of the water be greater than that of the wheel the pressure causing that velocity of issue is to be deducted from the pressure due to the head, before the useful effect of the power can be found. Jf for instance, the velocity of egress were one-fourth of that due to the head, or 1 8y^, the loss of head on this account would be 6 j per cent. If the velocity of egress be a little less than one-fourth, so that the loss of head be exactly 6 per cent., there would be, with the 19 per cent, before mentioned, OUTWARD FLOW. 203 25 per cent, of the power expended before any work was done. But there is yet another source of loss of power, viz., the friction of the upright shaft in its bearings, for which, perhaps, 2 per cent, may be added, making in all 27 per cent, of the power expended, the useful effect of the turbine being in this case 73 per cent. But this is not so much as has been found to be the useful effect of many outward flow turbines, both in this country and abroad. In one of the " Abstracts of Papers in Foreign Trans- actions, &c.," of the Institution of Civil Engineers, is an abstract of an investigation into the maximum efficiency practically attainable in the three chief kinds of turbines viz., outward flow, parallel flow, and inward flow, by J. C. Bernhard Lehmann, from experiments with thirty- six turbines of all sizes, from 1 to 500 h.p., made in order to ascertain the shaft friction, from which it appears that the percentage of total available power lost by hydraulic resistances was 14 per cent. ; by unutilised energy carried away in the issuing water, 7 per cent. ; shaft friction, both in the foot- step and bearings, 2 per cent., or a total loss of 23 per cent., and therefore a possible efficiency of 77 per cent. In another " abstract " of a paper by Prof. Kichelmy, it is estimated, from many experiments, that the actual amount of the loss of head in the supply cham- ber, before the water has issued into the wheel, is between five hundredths and eight hundredths of the head, accord- ing to circumstances in different cases. It is assumed that the form of the opening leading from the central supply chamber to the wheel revolving around it is the most favourable for the free issue of the water, and that it issues from the supply chamber into the wheel cells without contraction ; and, therefore, the diminution ought to be attributed to a lesser velocity of efflux, due no longer to the head, but only to this multiplied by the square of 92 or of -95, or by the square of a number intermediate between these two, which is a loss in the supply pipe or chamber of from 10 to 15 per cent, of the head and of the 204 TURBINES. energy of the water, and is the same form of loss as that which has been stated as 12 per cent, of the head, the actual velocity being 7*5 */h. Fig. 47 is a plan, and Fig. 48 a section of the essential parts of an outward-flow turbine. One of the principal points to be considered is the working velocity of the wheel. Mr. Cullen, an Irish millwright and engineer, states in his treatise on the turbine that he has found by experience that the most effective speed of the inner cir- cumference of the wheel is 4' 4 Jh, when the head does not exceed 38ft. For high falls his ex- perience is that the cube root of the height should be taken and multiplied by 8-1. Thus, the velocity of the inner circumference of the running wheel for high falls is S'l^^. These velocities, Mr. Cullen says, produce the greatest amount of moving power, Fig. 47. and are about two- thirds of the velocity of the water on its entering the wheel. According to Mr. Cullen's rules, the diameter A B in the sketch should be = /s-yr + 1, where Q = the quantity of water in / ^v \ h cubic feet per second, and li the head in feet. Thus, if Q = 40, and h = 30, the inner diameter of the wheel would be 3fr. Sin. The number of buckets he gives as N = 3 d + 28, d being the inner diameter as already found. Then the width of the buckets, B D on the sketch, should be -^r OUTWARD FLOW. 205 Applying these rules to the case stated, the number of buckets would be 39, and the width 5in., so that, adding lOin. to 3ft. 8in., the outer diameter would be 4ft. 6in. The height of the buckets would be 4in. The velocity at the inner circumference would be 24ft. per second, and at the outer circumference nearly 30ft. per second. Com- paring these with the rules in Molesworth's pocket-book of engineering formulae, there is a little difference. The inner diameter would be about the same, but the outer diameter would be 5ft., and the velocity at the outer circumfer- ence would be 36ft. per second. Mr. D.K.Clark, in his ' Rules, Tables, and Data,' gives rules (p. 941) for the dimensions of out- ward-flow tur- bines, which agree nearly with Mr. Cullen's, except in the diameters, inner and outer. By Mr. Clark's rule for the " exterior diameter," it would be, in the instance men- / P tioned, D = 4* 85 / as stated, P being the " actual horse-power of the turbine." Now, if in the above in- stance we take the actual horse-power of the turbine to be 75 per cent, of the power of the water, that is, 40 cubic feet per second falling 30ft., P would 102, for 4Q X 3(> 8 * 8 = 3 -82ft. for the X '75 = 102, and 4-85 206 TURBINES. 11 exterior diameter," which is only about 2in. more than the interior diameter should be, by Mr. Cullen's rule, and also Mr. Moles worth's. But if in Mr. Clark's rule we read D = interior diameter of wheel, instead of " exterior," the rule would agree nearly with the other two men- tioned. It is evident that water descending in a vertical pipe, or chamber, need not necessarily flow out of it horizon- tally, as in the outward-flow turbine, but that by placing the wheel across the upright pipe, or chamber, the water may continue to have its general direction vertical, and parallel with the axis, its direction for part of its descent only that is, the part occupied by the depth of the wheel being horizontal, or partaking of a horizontal and vertical motion combined, the water being finally de- livered into the tail-race in a nearly vertical direction, on the underside of the wheel, being received into the buckets or cells on the top side of the wheel, and being guided into them by blades fixed in the bottom of the pipe or cylinder, and bent in a direction tangential to the circumference of the wheel. Thus the guide-blades at the bottom of the fixed cylinder occupy an annular space beneath which the buckets of the wheel revolve. This kind of wheel is perhaps not quite properly to be called a turbine at all, but simply a horizontal wheel ; nevertheless, it is convenient to classify it as a turbine, and to distinguish it as having a parallel flow. It is the principle on which are constructed those called Jonval, Fontaine, Henschel, Koecklin. Fig. 49 repre- sents a development of part of the circle through the middle of the buckets of the wheel, vertically. On this line, the angle which the direction of the water, on its leaving the guide passages, makes with the horizontal face of the wheel is between 14 and 20, varying accord- ingly as the water acts on the vanes by pressure or by reaction. In the former case the proper angle for the guiding passages of an axial turbine is stated to be 14 30' in a paper on the theory and construction of tur- bines, by Professor Fink, translated in the " Abstracts of PARALLEL FLOW. 207 Papers in Foreign Transactions, &c.," of the " Minutes of Proceedings of the Institution of Civil Engineers, 1878." That ano-le is taken at the mean radius of the wheel, or at 7, a Fig. 49. the distance from the axis which is a mean between the inner and outer radii ; but at the circumference the angle is to be reduced to 12 20'. In a reaction turbine the angle of the guide passages is 20 at the line of mean radius, and 17 10' at the outer circumference. In the diagram, the distance a b is the distance apart of the vanes of the wheel, which depends upon the number of buckets for any given diameter. According to, the instructions of Prof. Fink, the number of buckets ARROWS, 10 - Bed-puddle, 94 Blackwell's experiments, 53, 59 Bottom velocity, 125, 126 Bradfield Reservoir, 13, 30 Branch mains, 103 Breast wheels, 156, 158, 175, 179- 183 Buckets of wheels, 140 Bye-wash, 43 CAPACITIES of reservoirs, 24, ^ 283 Carts, 10 Cast-iron pipes, 104-112 Clay puddle, 2, 3 Co-efficients of discharge, 59-61 Concrete, 47-50 Conduits, 79-87 large, or aqueducts, 113- 119 Conical tube, 150 Conservancy of rivers, 287-294 Consolidation of embankments, 10-12 Contraction of jet, 146-148 Cornish engine, 244 Cost of a reservoir (approximate), 44, 267-269 Current wheels, 160-162, 166, 167 DAYS' storage (number of), 18, 20 Depth of water on the outer edge of a weir, 62 Detection of waste of water, 237 Discharge pipes, 5, 31, 32, 40, 41 Dobbin carts, 10 Domestic water-supply, 217-221 Du Buat's formula, 121, 123 INDEX. AFFECTIVE fall on wheel, 142 Efflux of water from a hole, 146 Embankments, 8-13 Excavating puddle-trench, 35 Eytelwein's formula, 101 TjlLOOBS, 247-286 *- Flow of water off ground, 253-258 * Freezing of open channels, 82 the r\ AUGES (rain), 70, 71 (water), 51-63 Gravel puddle, 3, 4 Grimwith Compensation Reser- voir, 29 Grindstones driven by water- power, 186-191 TTEAD of water, 99 ** High -breast wheels, 141, 177-179 High falls of water, 192 Holmfirth Reservoir, 13 Horse-power, basis of, 136 Hydraulic gradient, 102 mean depth, 81 Hydraulicians (the older), 147 TNTERSTICES of concrete ma- X terials, 48-50 Irwell, river, 291 TZUTTER'S formula, 122 T AND, relief of, from floods, ^ 271-277 Llanwyddyn Reservoir, 305. 1Y/TETERS, 234-236 1U Mills, 127-216 Motion of water in pipes, 100 SEVILLE'S formula, 122, 125 pIPE across puddle trench, 33 Pit sand, 46 Plank gauges, 51-58 Poncelet's wheel, 154 Pressure in pipes, 106-109 of the atmosphere, 97, 98 Prony's formula, 124 Puddle lining, 227 trench, 4, 36, 37 wall, 1 . Puddled clay, 2, 3 Pumping main, 241 water by water-power, 184, 185 T) AIL waggons, 10 Xi Rainfall, 17, 64-69 Rain gauges, 70. 71 INDEX. 309 Eegulation of flood waters, 278- 286 Belief of land from floods, 271- 277 River in train, 137, 163, 164 River sand, 46 Irwell, 291 Severn, 259 Thames, 259 Witham, 289 Rivers as county boundaries, 298 conservancy, 287-294 , lowering the water-level of, 248 , yearly neglect of, 248 Road watering, 233 Rotative beam-engine, 245 q EPARATING the clear water, 128 Service reservoirs, 93-95, 222-229 Severn and Thames contrasted, 260 Slip-joints, 40 Standpipes, 243 Storage per acre of gathering ground, 21 Strainers, 95 Stream gauges, 51-63 Strength of cast-iron pipes, 104- 112 Surface velocity, 124 rpHAMES and Severn compared, 1 259 Thickness of cast-iron pipes, 110- 112 Tittesworth Reservoir, 30 Top-bank above top-water, 8, 23 Trials of coal consumed in pump- ing water, 245, 246 of water required to work mills, 171, 174 Tunnels, 90, 91 Turbines, 192-216 TTNDERSHOT water - wheels, U 152, 167, 170, 174 yALVEpit, 30 tower, 42 Velocity in open channels at the surface, 120-127 in open channels, the mean, 120-126 in open channels at the bottom, 120-126 of approach to weirs, 158 of water, 165 of water hi pipes, 99-101 "WASTE of water, 237 " Watering roads, 233 Weight of water, 98, 135 Weirs of reservoirs, 28-30 on rivers, 251 Witham, river, 289 LONDON: PRINTED BY WILLIAM CLOWES AND SONS, LIMITED, STAMFOBD STREET AND CHASING CBOSS. 7, STATIONERS' HALL COURT, LONDON, E.G. February, 1892. CATALOGUE OF BOOKS INCLUDING NEW AND STANDARD WORKS IN ENGINEERING: CIVIL, MECHANICAL, AND MARINE, MINING AND METALLURGY, ELECTRICITY AND ELECTRICAL ENGINEERING, ARCHITECTURE AND BUILDING, INDUSTRIAL AND DECORATIVE ARTS, SCIENCE, TRADE AGRICULTURE, GARDENING, LAND AND ESTATE MANAGEMENT, LAW, &c. PUBLISHED BY CROSBY LOCKWOOD & SON. MEGHANICAL ENGINEERING, etc. New Pocket-Book for Mechanical Engineers. THE MECHANICAL ENGINEER'S POCKET-BOOK OF TABLES, FORMULA, RULES AND DATA. A Handy Book of Reference for Daily Use in Engineering Practice. By D. KINNEAR CLARK, M.Inst.C.E., Author of " Railway Machinery," " Tramways," &c. &c. Small 8vo, nearly 700 pages. With Illustrations. Rounded edges, cloth limp, ?s. 6d.-, or leather, gilt edges, gs. [Just published. Neiv Manual for Practical Engineers. THE PRACTICAL ENGINEER'S HAND-BOOK. Comprising a Treatise on Modern Engines and Boilers : Marine, Locomotive and Sta- tionary. And containing a large collection of Rules and Practical Data relating to recent Practice in Designing and Constructing all kinds of Engines, Boilers, and other Engineering work. The whole constituting a comprehensive Key to the Board of Trade and other Examinations for Certi- ficates of Competency in Modern Mechanical Engineering. By WALTER S. HUTTON, Civil and Mechanical Engineer, Author of "The Works' Manager's Handbook for Engineers," &c. With upwards of 370 Illustrations. Fourth Edition, Revised, with Additions. Medium 8vo, nearly 500 pp., price i8s. Strongly bound. [Just published. K3" This work is designed as a companion to the Author's "WORKS' MANAGER'S HAND-BOOK." It possesses many new and original features, and con' tains, like its predecessor, a quantity of matter not originally intended for publica- tion, but collected by the author for his own use in the construction of a great variety of modern engineering work. *** OPINIONS OF THE PRESS. " A thoroughly good practical handbook, which no engineer can go through without learning something that will be of service to him." Marine Engineer. " An excellent book of reference for engineers, and a valuable text-book for students of engineering." Scotsman. " This valuab'e manual embodies the results and experience of the leading authorities en mechanical engineering." Building- News. " The author has collected together a surprising quantity 01 rules and practical data, and has shown much judgment in the selections he has made. . . . There is no doubt that this book is one of the most useful of its kind published, and will be a very popular compendium." Engineer. " A mass of information, set down in simple language, and in such a form that it can be easily referred to at any time. The matter is uniformly good and well chosen, and is greatly elucidated by the illustrations. The book will find its way on to most engineers' shelves, where it will rank as one of the most useful books of reference." Practical Engineer. "Should bJ found on the office shelf of all practical engineers." English Mediae's. B 2 CROSBY LOCKWOOD & SON'S CATALOGUE. Handbook for Works' Managers. THE WORKS' MANAGER'S HANDBOOK OF MODERN RULES, TABLES, AND DATA. For Engineers, Millwrights, and Boile? Makers; Tool Makers, Machinists, and Metal Workers; Iron and Brass Founders, &c. By W. S. HUTTON, C.E., Author of " The Practical Engineer's Handbook." Fourth Edition, carefully Revised, and partly Re-written. In One handsome Volume, medium 8vo, 155. strongly bound. [Just published* fc3" The Author having compiled Rules and Data for his own use in a great variety of modern engineering work, and having found his notes extremely useful, decided to publish them revised to date believing that a practical work, suited to the DAILY REQUIREMENTS OF MODERN ENGINEERS, would be favourably received. In the Third Edition, the following among other additions have been made, viz.: Rules for the Proportions of Riveted Joints in Soft Steel Plates, the Results of Experi- ments by PROFESSOR KENNEDY for the Institution of Mechanical Engineers Rules. for the Proportions of Turbines Rules for the Strength of Hollow Shafts of Whi$~ worth's Compressed Steel, &c. %.* OPINIONS OF THE PRESS. "The author treats every subject from the point of view of one who has collected workshop notes for application in workshop practice, rather than from the theoretical or literary aspect. The volume contains a great deal of that kind of information which is gained only by practical experi- ence, and is seldom written in books." Engineer. "The volume is an exceedingly useful one, brimful with engineers' notes, memoranda, and' rules, and well worthy of being on every mechanical engineer's bookshelf." Mechanical World. " The information is precisely that likely to be required in practice. . . . 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By WILLIAM TEMPLE- TON, Author of "The Engineer's Practical Assistant," &c. &c. Sixteenth Edition, Revised, Modernised, and considerably Enlarged by WALTER S. HUTTON, C.E., Author of "The Works' Manager's Handbook," "The Practical Engineer's Handbook," &c. Fcap. 8vo, nearly 500 pp., with Eighi Plates and upwards of 250 Illustrative Diagrams, 6s., strongly bound for workshop or pocket wear and tear. [Just fublished > \* OPINIONS OF THE PRESS. "In Its modernised form Hutton's ' Templeton ' should have a wide sale, for It contains much valuable information which the mechanic will often find of use, and not a few tables and notes which he might look for in vain in other works. This modernised edition wi be appreciated by all who have learned to value the original editions of ' Templeton.' ' English Mechanic. 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" Written with sufficient technical detail to enable the principle and relative connection ol the various parts of each particular brake to be readily grasped." Mechanical World. Engine-Driving Life. ENGINE-DRIVING LIFE : Stirring Adventures and Incidents in the Lives of Locomotive-Engine Drivers. By MICHAEL REYNOLDS. Second Edition, with Additional Chapters. Crown 8vo, zs. cloth. "From first to last perfectly fascinating". Wilkie Collins's most thrilling conceptions are thrown nto the shade by true incidents, endless in their variety, related in every page." North British Mail, "Anyone who wishes to get a real Insight into railway life, cannot do better than read ' Engine- Driving Life' for himself ; and if he once take it up he will find that the author's enthusiasm and real ove of the engine-driving profession will carry him on till he has read every page." Saturday Review. Pocket Companion for Enginemen. THE ENGINEMAN'S POCKET COMPANION AND PR AC- TICAL EDUCATOR FOR ENGINEMEN, BOILER ATTENDANTS, AND MECHANICS. By MICHAEL REYNOLDS. With Forty-five Illustra- tions and numerous Diagrams. Second Edition, Revised. Royal i8mo, 35. 6d. t strongly bound for pocket wear. " This admirable work is well suited to accomplish its object, being the honest workmanship of a competent engineer." Glasgow Herald. " A most meritorious work, giving in a succinct and practical form all the Information an engine- minder desirous of mastering the scientific principles of his daily calling would require." Miller. " A boon to those who are striving to become efficient mechanics." Daily Chronicle. CIVIL ENGINEERING, SURVEYING, etc. 7 French-English Glossary for- Engineers, etc. A POCKET GLOSSARY of TECHNICAL TERMS: ENGLISH- FRENCH, FRENCH-ENGLISH; with Tables suitable for the Architectural, Engineering, Manufacturing and Nautical Professions. By JOHN JAMES FLETCHER, Engineer and Surveyor. 200 pp. Waistcoat-pocket size, is, 6d., limp leather. " It ought certainly to be In the waistcoat-pocket of every professional man." Iron. "It is a very great advantage for readers and correspondents in France and England to have so large a number of the words relating to engineering and manufacturers collected in a liliputian volume. The little book will be useful both to students and travellers/ Architect. " The glossary of terms is very complete, and many of the tables are new and well arranged. We cordially commend the book.' Mechanical World. Portable Engines. THE PORTABLE ENGINE; ITS CONSTRUCTION AND MANAGEMENT. A Practical Manual for Owners and Users of Steam Engines generally. By WILLIAM DYSON WANSBROUGH. With 90 Illustra- tions. Crown 8vo, 35. 6d. cloth. " This is a work of value to those who use steam machinery. . . . Should be read by every- one who has a steam engine, on a farm or elsewhere." Mark Lane Exp " We cordially commend this work to buyers and owners of stean have to do with their construction or use." Timber Trades Journal. d owners of steam engines, and to those who Trades Journal. : as Mr. Wansbrough furnishes to the reader _ ; who use the steam engine." Building Ne-ws. " An excellent text-book of this useful form of engine, which describes with all necessary minuteness the details of the various devices. . . ' The Hints to Purchasers contain a good deal of. commonsense and practical wisdom." English Mechanic. " Such a general knowledge of the steam engine as Mr. Wansbrough furnishes to the reader should be acquired by all intelligent owners and others who use the steam engine." Building Ne-ws. CIVIL ENGINEERING, SURVEYING, etc. MR, HUMBER'S IMPORTANT ENGINEERING BOOKS. The Water Supply of Cities and Towns. A COMPREHENSIVE TREATISE on the WATER-SUPPLY OF CITIES AND TOWNS. By WILLIAM HUMBER, A-M.Inst.C.E., and M. Inst. M.E., Author of "Cast and Wrought Iron Bridge Construction," &c. &c. Illustrated with 50 Double Plates, i Single Plate, Coloured Frontispiece, and upwards of 250 Woodcuts, and containing 400 pages of Text. Imp. 4to, 6 6s. elegantly and substantially half-bound in morocco, I. Historical Sketch of some of the means that have been adopted for the Supply of Water to Cities and Towns. II. Water and the Fo- reign Matter usually associated with it. III. Rainfall and Evaporation. IV. Springs and the water-bearing formations of various dis- tricts. V. Measurement and Estimation of the flow of Water VI. On the Selection of the Source of Su voi List of Contents. urce of Supply. VII. Wells. VIII. Reser. irs. IX. The Purification of Water. X. Pumps^ XI. Pumping Machinery. XII. and valuable work Conduits.-XIII. Distribution of Water.-XIV. Meters, Service Pipes, and House Fittings. XV. The Law and Economy of Water Works. XVI. Constant and Intermittent Supply. XVII. Description of Plates. Appendices, giving Tables of Rates of Supply, Velocities, &c. &c., together with Specifications of several Works illustrated, among which will be found : Canterb Aberdeen, Bideford, Canterbury, Dundee. Halifax, Lambeth, Rotherham, Dublin, and others. ' The most systematic and valuable work upon water supply hitherto produced In English, or n any other language. . . . Mr. Humber's work is characterised almost throughout by an exhaustiveness much more distinctive of French and German than of English technical treatises." Engineer. " We can congratulate Mr. Humber on having been able to give so large an amount of Infor- mation on a subject so important as the water supply of cities and towns. The plates, fifty in number, are mostly drawings of executed works, and alone would have commanded the attention of every engineer whose practice may lie in this branch of the profession." Builder. Cast and WrouyJit Iron Bridge Construction. A COMPLETE AND PRACTICAL TREATISE ON CAST AND WROUGHT IRON BRIDGE CONSTRUCTION, including Iron Foundations. In Three Parts Theoretical, Practical, and Descriptive. By WILLIAM HUMBER, A.M.Inst.C.E., and M.InstM.E. Third Edition, Re- vised and much improved, with 115 Double Plates (20 of which now first appear in this edition), and numerous Additions to the Text. In Two Vols., imp. 4to, 6 i6s. 6d. half-bound in morocco. "A very valuable contribution to the standard literature of civil engineering. In addition to elevations, plans and sections, large scale details are given which very much enhance the instruc- tive worth of those illustrations." Civil Engineer and Architect's Journal, "Mr. Humber's stately volumes, lately issued in which the most important bridges erected during the last five years, under the direction of the late Mr. Brunei, Sir W. Cubitt, Mr. Hawk- shaw, Mr. Page, Mr. Fowler, Mr. Hemans, and others among our most eminent engineers, are drawn and specified in great detail." Engineer, CROSBY LOCK WOOD & SON'S CATALOGUE. MR. H UMBER'S GREAT WORK ON MODERN ENGINEERING. Complete in Four Volumes, imperial 4to, price 12 izs., half-morocco. Each Volume sold separately as follows : A RECORD OF THE PROGRESS OF MODERN ENGINEER- ING. FIRST SERIES. Comprising Civil, Mechanical, Marine, Hydraulic, Railway, Bridge, and other Engineering Works, &c. By WILLIAM HUMBER, A-M.Inst.C.E., &c. Imp. 4to, with 36 Double Plates, drawn to a large scale, Photographic Portrait of John Hawkshaw, C.E., F.R.S., &c., and copious descriptive Letterpress, Specifications, &c., 3 35. half-morocco. List of the Plates and Diagrams. Victoria Station and Roof, L. B. & S. C. R. (8 plates) ; Southport Pier (2 plates) ; Victoria Station and Roof, L. C. & D. and G. W. R. (6 plates) ; Roof of Cremorne Music Hall ; Bridge over G. N. Railway ; Roof of Station, Dutch Rhenish Rail (2 plates) ; Bridge over the Thames, West London Extension Railway ($ plates); Armour Plates: Suspension Bridge, Thames (4 platesl ; The Allen Engine ; Sus- pension Bridge, Avon (3 plates) ; Underground Railway (3 plates). " Handsomely lithographed and printed. It will find favour with many who desire to preserve In a permanent form copies of the pjans and specifications prepared for the guidance of the coa- tractors for many important engineering works." Engineer, HUMBERTS RECORD OF MODERN ENGINEERING. SECOND SERIES. Imp. 4to, with 36 Double Plates, Photographic Portrait of Robert Stephensqn, C.E., M.P., F.R.S., &c., and copious descriptive Letterpress, Specifications, &c., 3 35. half-morocco. List of the Plates and Diagrams. Birkenhead Docks, Low Water Basin (15 plates); Charing Cross Station Roof, C. C. Railway k Cross Station Roof, C. ailway (3 plates); Digswell Viaduct, Great Northern Railway ; Robbery Wood Viaduct, Great Northern Railway ; Iron Permanent Way; Clydach Viaduct, Merthyr, Tredegar, and Abergavenny Railway ; Ebbw Viaduct, Merthyr, Tredegar, and Abergavenny Rail- way ; College Wood Viaduct, Cornwall Rail- way; Dublin Winter Palace Roof (3 plates); Bndge over the Thames, L. C. & D. Railway (6 plates) ; Albert Harbour, Greenock (4 plates), ' Mr. Humber has done the profession good and true service, by the fine collection of examples he has here brought before the profession and the public." Practical Mechanic's Journal. HUMBERTS RECORD OF MODERN ENGINEERING. THIRD SERIES. Imp. 410, with 40 Double Plates, Photographic Portrait of J. R. M'Clean, late Pres. Inst. C.E., and copious descriptive Letterpress, Speci- fications, &c., 3 35. half-morocco. List of the Plates and Diagrams. MAIN DRAINAGE, METROPOLIS. North Side. Map showing Interception of Sewers ; Middle Level Sewer (2 plates) ; Outfall Sewer, Bridge over River Lea (3 plates) ; Outfall Sewer, Bridge over Marsh Lane, North Woolwich Railway, and Bow and Barking Railway Junc- tion ; Outfall Sewer, Bridge over Bow and Barking Railway (3 plates); Outfall Sewer. Bridge over East London Waterworks' Feeder (2 plates) ; Outfall Sewer, Reservoir (2 plates) ; Outfall Sewer, Tumbling Bay and Outlet ; Out- fall Sewer, Penstocks. South Side. Outfall Sewer, Bermondsey Branch (2 plates) ; Outfall Sewer, Reservoir and Outlet (4 plates) ; Outfall Sewer, Filth Hoist ; Sections of Sewers (North? and South Sides). THAMES EMBANKMENT. Section of River Wall ; Steamboat Pier, Westminster (2 plates) ; Landing Stairs between Charing Cross and Waterloo Bridges ; York Gate (2 plates) ; Over- flow and Outlet at Savoy Street Sewer (3 plates) ; Steamboat Pier, Waterloo Bridge (3 plates) ; Junction of Sewers, Plans and Sections r Gullies, Plans and Sections ; Rolling Stock ; Granite and Iron Forts. " The drawings have a constantly increasing value, and whoever desires to possess clear repre- sentations of the two great works carried out by our Metropolitan Board will obtain Mr. Humber's volume." Engineer. HUMBER'S RECORD OF MODERN ENGINEERING. FOURTH SERIES. Imp. 4to, with 36 Double Plates, Photographic Portrait of John Fowler, late Pres. Inst. C.E., and copious descriptive Letterpress, Speci- fications, &c., 3 33. half-morocco. List of the Plates and Diagrams. Mesopotamia ; Viaduct over the River Wye, Midland Railway (3 plates) ; St. Germans Via- Abbey Mills Pumping Station, Main Drain- age, Metropolis (4 plates) ; Barrow Docks (5 plates) ; Manquis Viaduct, Santiago and Val- paraiso Railway (2 plates) ; Adam's Locomo- tive, St. Helen's Canal Railway (2 plates) ; Cannon Street Station Roof, Charing Cross aring Cr Railway (3 plates) ; Road Bridge over the Ri Moka (2 plates) ; Telegraphic Apparatus for nlway (3 pi duct, Cornwall Railway Iron Cylinder for Diving (2 plates); Wrought- ell ; Millwall Docks (6 plates); Milroy's Patent Excavator; Metro- politan District Railway (6 plates); Harbours, Ports, and Breakwaters (3 plates). We gladly welcome another year's issue of this valuable publication from the able pen o? Mr. Humber. The accuracy and general excellence of this work are well known, while its useful- ness in giving the measurements and details of some of the latest examples of engineering, as carried out by the most eminent men in the profession, cannot be too highly prized." Artisan. CIVIL ENGINEERING, SURVEYING, etc. 9 MR. HUMBER'S ENGINEERING BOOKS continued. Strains, Calculation of. A HANDY BOOK FOR THE CALCULATION OF STRAINS IN GIRDERS ANDSIMILARSTRUCTURES,AND THEIR STRENGTH. Consisting of Formulae and Corresponding Diagrams, with numerous details for Practical Application, &c. By WILLIAM HUMBER, A-M.Inst.C.E., &c. Fifth Edition. Crown 8vo, nearly 100 Woodcuts and 3 Plates, 75. 6d. cloth " The formulae are neatly expressed, and the diagrams good." Athenaeum. " We heartily commend this really handy book to our engineer and architect readers." Eng- lish Mechanic. Barlow's Strength of Materials, enlarged byHuntber A TREATISE ON THE STRENGTH OF MATERIALS; with Rules for Application in Architecture, the Construction of Suspension Bridges, Railways, &c. By PETER BARLOW, F.R.S. A New Edition, revised by his Sons, P. W. BARLOW, F.R.S., and W. H. BARLOW, F.R.S. ; to which are added, Experiments by HODGKINSON, FAIRBAIRN, and KIRKALDY ; and Formulae for Calculating Girders, &c. Arranged and Edited by W. HUMBER, A-M.Inst.C.E. Demy 8vo, 400 pp., with 19 large Plates and numerous Wood- cuts, 1 8s. cloth. " Valuable alike to the student, tyro, and the experienced practitioner, It will always rank in future, as it has hitherto done, as the standard treatise on that particular subject." Engineer. " There is no greater authority than Barlow." Building- News. " As a scientific work of the first class, it deserves a foremost place on the bookshelves of every civil engineer and practical mechanic." English Mechanic. Trigonometrical Surveying. AN OUTLINE OF THE METHOD OF CONDUCTING A TRIGONOMETRICAL SURVEY, for the Formation of Geographical and Topographical Maps and Plans, Military Reconnaissance, Levelling, &c., with Useful Problems, Formulas, and Tables. By Lieut.-General FROME, R.E. Fourth Edition, Revised and partly Re- written by Major General Sir CHARLES WARREN, G.C.M.G., R.E. With 19 Plates and 115 Woodcuts, royal 8vo, i6s. cloth. "The simple fact that a fourth edition has been called for Is the best testimony to its merits. No words of praise from us can strengthen the position so well and so steadily maintained by this work. Sir Charles Warren has revised the entire work, and made such additions as were necessary to bring every portion of the contents up to the present date." Broad Arrow. Field Fortification. A TREATISE ON FIELD FORTIFICATION, THE ATTACK OF FORTRESSES, MILITARY MINING, AND RECONNOITRING. By Colonel I. S. MACAULAY, late Professor of Fortification in the R.M.A., Wool- wich. Sixth Edition, crown 8vo, cloth, with separate Atlas of 12 Plates, ias, Oblique Bridges. A PRACTICAL AND THEORETICAL ESSAY ON OBLIQUE BRIDGES. With 13 large Plates. By the late GEORGE WATSON BUCK, M.I.C.E. Third Edition, revised by his Son, J. H. WATSON BUCK, M.I.C.E. ; and with the addition of Description to Diagrams for Facilitating the Con- struction of Oblique Bridges, by W. H. BARLOW, M.I.C.E. Royal 8vo, 12$. cloth. " The standard text-book for all engineers regarding skew arches Is Mr. Buck's treatise, and it would be impossible to consult a better." Engineer. "Mr. Buck's treatise is recognised as a standard text-book, and his treatment has divested the subject of many of the intricacies supposed to belong to it. As a guide to the engineer and archi- tect, on a confessedly difficult subject, Mr. Buck's work is unsurpassed." Building News. Water Storage, Conveyance and Utilisation. WATER ENGINEERING : A Practical Treatise on the Measure- ment, Storage, Conveyance and Utilisation of Water for the Supply of Towns, for Mill Power, and for other Purposes. By CHARLES SLAGG, Water and Drainage Engineer, A.M.Inst.C.E., Author of "Sanitary Work in the Smaller Towns, and in Villages," &c. With numerous Illusts. Cr. 8vo. 75. 6d. cloth. " As a small practical treatise on the water supply of towns, and on some applications of water-power, the work is in many respects excellent." Engineering. " The author has collated the results deduced from the experiments of the most eminent authorities, and has presented them in a compact and practical form, accompanied by very clear and detailed explanations. . . . The application of water as a motive power is treated very carefully and exhaustively." Builder. "For anyone who desires to begin the study of hydraulics with a consideration of the practical applications of the science there is no better guide." Architect. io CROSBY LOCK WOOD &> SON'S CATALOGUE. Statics, Graphic and Analytic. GRAPHIC AND ANALYTIC STATICS, in their Practical Appli. cation to the Treatment cf Stresses in Roofs, Selid Girders, Lattice, Bowstring and Suspension Bridges, Braced Iron Arches and Piers, and other Frameworks. By R. HUDSON GRAHAM, C.E. Containing Diagrams and Plates to Scale. With numerous Examples, many taken from existing Structures. Specially arranged for Class- work in Colleges and Universities. Second Edition, Re- vised and Enlarged. 8vo, i6s. cloth. "Mr. Graham's book will find a place wherever graphic and analytic statics are used or studied." Engineer. "The work is excellent from a practical point of view, and has evidently been prepared with much care. The directions for working are ample, and are illustrated by an abundance of well- selected examples. It is an excellent text-book for the practical draughtsman." Athenaum. Student's Text-Book on Surveying. PRACTICAL SURVEYING : A Text-Book for Students pre- paring for Examination or for Survey-work in the Colonies. By GEORGE W. USILL, A.M.I.C.E., Author of "The Statistics of the Water Supply of Great Britain." With Four Lithographic Plates and upwards of 330 Illustra- tions. Second Edition, Revised. Crown 8vo, 75. 6d. cloth. " The best forms of instruments are described as to their construction, uses and modes of employment, and there are innumerable hints on work and equipment such as the author, in his experience as surveyor, draughtsman and teacher, has found necessary, and which the student in his inexperience will find most serviceable." Engineer. " The latest treatise in the English language on surveying, and we have no hesitation in say- ing that the student will find it a better guide than any of its predecessors .... Deserves to be recognised as the first book which should be put in the hands of a pupil of Civil Engineering, and every gentleman of education who sets out for the Colonies would find it well t J have a copy." Architect. "A very useful, practical handbook on field practice. Clear, accurate and not too con- densed." Journal of Education. Survey Practice. AID TO SURVEY PRACTICE, for Reference in Surveying, Level- ling, and Setting-out ; and in Route Surveys of Travellers by Land and Sea. With Tables, Illustrations, and Records. By Lowis D'A. JACKSON, A.M.I.C.E., Author of " Hydraulic Manual," "Modern Metrology," &c. Second Edition, Enlarged. Large crown 8vo, I2S. 6d. cloth. "Mr. Jackson has produced a valuable vade-mecum for the surveyor. \Ve can recommend this book as containing an admirable supplement to the teaching of the accomplished surveyor." Athenceum. " As a text-book we should advise all surveyors to place It In their libraries, and study well the matured instructions afforded in its pages." Colliery Guardian, " The author brings to his work a fortunate union of theory and practical experience which, eided by a dear and lucid style of writing, renders the book a very useful one." Builder. Surveying, Land and Marine. LAND AND MARINE SURVEYING, in Reference to the Pre- paration of Plans f jr Roads and Railways ; Canals, Rivers, Towns' Water Supplies; Docks and Harbours. With Description and Use of Surveying Instruments. By W. D. HASKOLL, C.E., Author of " Bridge and Viaduct Con- struction," &c. Second Edition, Revised, with Additions. Large cr. 8vo, gs. cl. ' This book must prove of great value to the student. We have no hesitation in recommend- ' 'ill me ranged boo it as a carefully-written and valuable text-book. It enjoys a well-deserved repute among surveyors." ing it, feeling assured that it will more than repay a careful study." Mechanical World. sful and well arranged book for the aid of a student. We can strongly i Builder. " This volume cannot fail to prove of the utmost practical utility. It may be safely recommended to all students who aspire to become clean and expert surveyors." Mining Journal. Tunnelling. PRACTICAL TUNNELLING. Explaining in detail the Setting, out of the works, Shaft-sinking and Heading-driving, Ranging the Lines and Levelling underground, Sub-Excavating, Timbering, and the Construction of the Brickwork of Tunnels, with the amount of Labour required for, and the Cost of, the various portions of the work. By FREDERICK W. SIMMS, F.G.S., M.InstC.E. Third Edition, Revised and Extended by D. KINNEAR CLARK, M.Inst.C.E. Imperial 8vo, with 21 Folding Plates and numerous Wood Engravings, 305. cloth. "The estimation in which Mr. Slmms's book on tunnelling has been held for over thirty years cannot be more truly expressed than in the words of the late Prof. Rankine : ' The best source of in- formation on the subject of tunnels is Mr.F.W.Simms's work on Practical Tunnelling.' "Architect. " It has been regarded from the first as a text book of the subject. . . . Mr. Clarke has added immensely to the value of the book." Engineer. CI VIL ENGINEERING, S UR VE YING, etc. 1 1 Levelling. A TREATISE ON THE PRINCIPLES AND PRACTICE OF LEVELLING. Showing its Application to purposes of Railway and Civil Engineering, in the Construction of Roads ; with Mr.TELFORD's Rules for the same. By FREDERICK W. SIMMS, F.G.S., M.Inst.C.E. Seventh Edition, with the additionof LAW'S Practical Examples for Setting-out Railway Curves, and TRAUTWINE'S Field Practice of Laying-out Circular Curves. With 7 Plates and numerous Woodcuts, 8vo, 8s. 6d. cloth, *** TRAUIWINE on Curves may be had separate, 55. " The text-book on levelling in most of our engineering schook and colleges." Engineer. " The publishers have rendered a substantial service to the profession, especially to the younj members, by bringing out the present edition of Mr. Simms's useful work." Engineering. Heat, Expansion by. EXPANSION OF STRUCTURES BY HEAT. By JOHN KEILY, C.E., late of the Indian Public Works and Victorian Railway Depart- ments, Crown Svo, 35. 6d. cloth. SUMMARY OF CONTENTS. Section I. FORMULAS AND DATA, Section II. METAL BARS. Section III. SIMPLE FRAMES. Section IV. COMPLEX FRAMES AND PLATES. Section V. THERMAL CONDUCTIVITY. Section VI. MECHANICAL FORCE OF HEAT. Section VII. WORK OF EXPANSION AND CONTRACTION. Section VIII. SUSPENSION BRIDGES. Section IX. MASONRY STRUCTURES. " The aim the author has set before him, viz., to show the effects of heat upon metallic and other structures, is a laudable one, for this is a branch of physics upon which the engineer or archi- tect can find but little reliable and comprehensive data in books." Builder. " Whoever is concerned to know the effect of changes of temperature on such structures as suspension bridges and the like, could not do better than consult Mr. Keily's valuable and handy exposition of the geometrical principles involved in these changes." Scotsman. Practical Mathematics. MATHEMATICS FOR PRACTICAL MEN: Being a Common- place Book of Pure and Mixed Mathematics. Designed chiefly for the use of Civil Engineers, Architects and Surveyors. By OLINTHUS GREGORY, LL.D., F.R.A.S., Enlarged by HENRY LAW, C.E. 4th Edition, carefully Revised by J. R. YOUNG, formerly Professor of Mathematics, Belfast College. With 13 Plates, 8vp, i is. cloth. " The engineer or architect will here find ready to his hand rules for solving nearly every mathe- matical difficulty that may arise in his practice The rules are in all cases explained by means of examples, in which every step of the process is clearly worked out." Builder. " Ons of the most serviceable books for practical mechanics. . . It is an instructive book for the student, and a text-book for mm who, having once mastered the subjects it treats of, needs occasionally to refresh his memory upon them." Building Neius, Hydraulic Tables. HYDRAULIC TABLES, CO-EFFICIENTS, and FORMULAE for finding the Discharge of Water from Orifices, Notches, Weirs, Pipes, and Rivers. With New Formulas, Tables, and General Information on Rainfall, Catchment-Basins, Drainage, Sewerage, Water Supply for Towns and Mill Power. By JOHN NEVILLE, Civil Engineer, M.R.I.A. Third Ed., carefully Revised, with considerable Additions. Numerous Illusts. Cr. Svo, 14$. cloth. " Alike valuable to students and engineers in practice ; its study will prevent the annoyance of avoidable failures, and assist them to select the readiest means of successfully carrying out any given work connected with hydraulic engineering." Mining- Journal. " It is, of all English books on the subject, the one nearest to completeness. . . . From the good arrangement of the matter, the clear expl.anations, and abundance of formulae, the carefully calculated tables, and, above all, the thorough, acquaintance with both theory and construction, which is displayed from first to last, the book w be found to be an acquisition." Architect, Hydraulics. HYDRA ULIC MANUAL. Consisting of Working Tables and Explanatory Text. Intended as a Guide in Hydraulic Calculations and Field Operations. By Lowis D'A. JACKSON, Author of "Aid to Survey Practice," " Modern Metrology," &c. Fourth Edition, Enlarged. Large cr. Svo, i6s. cl. " The author has had a wide experience in hydraulic engineering and has been a careful ob- server of the facts which have come under his notice, and from the gjeat mass of material at his command he has constructed a manual which may be accepted as a trustworthy guide to this branch of the engineer's profession. \Ve can heartily recommend this volume to all who desire to be acquainted with the latest development of this important subject." Engineering, " The standard- work in this department of mechnnics.' Scotsman. " The most useful feature of this work is its freedom from what is superannuated, and Its thorough adoption of recent exneriments ; the text is, in fact, in great part a short account of the great modern experiments." Nature, 12 CROSBY LOCK WOOD & SON'S CATALOGUE. Drainage. ON THE DRAINAGE OF LANDS, TOWNS AND BUILD- INGS. By G. D. DEMPSEY, C.E., Author of " The Practical Rulway En- S'neer," &c. Revised, with large Additions on RECENT PR \CTICE IN RAINAGE ENGINEERING, by D. KINNEAR CLARK, M.Inst.C.E. Author of "Tramways," "A Manual of Rules, Tables, and Data for Enginaers," &c. Second Edition, izmo, 55. cloth. "The new matter added to Mr. Dempsey's excellent work is characterised by the comprehen- sive grasp and accuracy of detail for which the name of Mr. D. K. Clark is a sufficient voucher." Athenctum. " As a work on recent practice in drainage engineering, the book is to be commended to all who are making that branch of engineering science their special study." Iron. " A comprehensive manual on drainage engineering, and a useful introduction to the student." Building News, Tramways and their Wording. TRAMWAYS: THEIR CONSTRUCTION AND WORKING. Embracing a Comprehensive History of the System ; with an exhaustive Analysis of the various Modes of Traction, including Horse-Power, Steam, Heated Water, and Compressed Air ; a Description of the Varieties of Rolling Stock: and ample Details of Cost and Working Expenses: the Progress recently made in Tramway Construction, &c. &c. By D. KINNEAR CLARK. M.Inst.C.E. With over 200 Wood Engravings, and 13 Folding Plates. Two Vols., large crown 8vo, 305. cloth. 11 All interested in tramways must refer to it, as all railway engineers have turned to the author's work ' Railway Machinery.'" Engineer. "An exhaustive and practical work on tramways, in which the history of this kind of locomo- tion, and a description and cost of the various modes of laying tramways, are to be found." Building News. " The best form of rails, the best mode of construction, and the best mechanical appliances are so fairly indicated in the work under review, that any engineer about to construct a tramway will be enabled at once to obtain the practical information which will be of most service to him.' Athenczutn. Oblique Arches. A PRACTICAL TREATISE ON THE CONSTRUCTION OF OBLIQUE ARCHES. By JOHN HART. Third Edition, with Plates. Im- perial ovo, 8s. cicth. Curves, Tables for Setting-out. TABLES OF TANGENTIAL ANGLES AND MULTIPLES for Setting-out Curves from 5 to zoo Radius. By ALEXANDER BEAZELEY, M.Inst.C.E. Third Edition. Printed on 48 Cards, and sold in a cloth box, waistcoat-pocket size, 35. 6d. " Each table is printed on a small card, which, being placed on the theodolite, leaves the hands free to manipulate the instrument no small advantage as regards the rapidity of work." Engineer. "Very handy ; a man may know that all his day's work must fa on two of these cards, which he puts into his own card-case, and leaves the rest behind." Athenautn. Earthwork. EARTHWORK TABLES. Showing the Contents in Cubic Yards of Embankments, Cuttings, &c., of Heights or Depths up to an average of 80 feet. By JOSEPH BROADBENT, C.E., and FRANCIS CAMPIN, C.E. Crown 8vo, 55. cloth. "The way in which accuracy is attained, by a simple division of each cross section into three elements, two in which are constant and one variable, is ingenious." Athenaeum, Tunnel Shafts. THE CONSTRUCTION OF LARGE TUNNEL SHAFTS : A Practical and Theoretical Essay. By J. H. WATSON BUCK, M.Inst.C.E. Resident Engineer, London and North- Western Railway. Illustrated with Folding Plates, royal 8vo, izs. cloth. " Many of the methods given are of extreme practical value to the mason ; and the observations on the form of arch, the rules for ordering the stone, and the construction of the templates will be found of considerable use. We commend the book to the engineering profession." Building News, "Will be regarded by civil engineers as of the utmost value, and calculated to save much time and obviate many mistakes." Colliery Guardian, Girders, Strength of. GRAPHIC TABLE FOR FACILITATING THE COMPUTA. TION OF THE WEIGHTS OF WROUGHT IRON AND STEEL GIRDERS, etc., for Parliamentary and other Estimates. By J. H. WATSON. BUCK, M.Inst.C.E. On a Sheet, zs.6d. CIVIL ENGINEERING, SURVEYING, etc. 13 River Engineering. RIVER BARS: The Causes of their Formation, and their Treat- ment^ by " Induced Tidal Scour; " with a Description of the Successful Re- duction by this Method of the Bar at Dublin. By I. J. MANN, Assist. Eng. to the Dublin Port and Docks Board. Royal 8vo, ~s. 6d. cloth. " We recommend all interested in harbour works and, indeed, those concerned in the im- provements of rivers generally to read Mr. Mann's interesting work on the treatment of river bars." Engineer. Trusses. TRUSSES OF WOOD AND IRON. Practical Applications of Science in Determining the Stresses, Breaking Weights, Safe Loads, Scantlings, and Details of Construction, with Complete Working Drawings. By WILLIAM GRIFFITHS, Surveyor, Assistant Master, Tranrnere School of Science and Art. Oblong Svo, 45. 6d, cloth. " This handy little book enters so minutely into every detail connected with the construction of roof trusses, that no student need be ignorant of these matters." Practical Engineer. Railway Working . SAFE RAILWAY WORKING. A Treatise on Railway Acci- dents: Theit Cause and Prevention ; with a Description of Modern Appliances and Systems. By CLEMENT E. STRETTON, C.E., Vice-President and Con- sulting Engineer, Amalgamated Society of Railway Servants. With Illus- trations and Coloured Plates. Second Edition, Enlarged. Crown Svo, 3$. 6d. cloth. [Just published. " A book for the engineer, the directors, the managers ; and, in short, all who wish for informa- tion on railway matters will find a perfect encyclopaedia in ' Safe Railway Working. " Rail-way . " We commend the remarks on railway signalling to all railway managers, especially where a uniform code and practice is advocated." Hercpath's Rail-way Journal. "The author may be congratulated on having collected, in a very convenient form, much valuable information on the principal quesiions affecting the safe workirg of railways." Rail- way Engineer. field-Book for Engineers. THE ENGINEER'S, MINING SURVEYOR'S, AND CON- TRA CTOR 'S FIELD-BOOK. Consisting of a Series of Tables, with Rules, Explanations of Systems, and use of Theodolite for Traverse Surveying and Plotting the Work with minute accuracy by means of Straight Edge and Set Square only ; Levelling with the Theodolite, Casting-out and Reducing Levels to Datum, and Plotting Sections in the ordinary manner; setting-out Curves with the Theodolite by Tangential Angles and Multiples, with Right and Left-hand Readings of the Instrument: Setting-out Curves without Theodolite, on the System of Tangential Angles by sets of Tangents and Off- sets ; and Earthwork Tables to 80 feet deep, calculated for every 6 inches in depth. By W. DAVIS HASKOLL, C.E. With numerous Woodcuts. Fourth Edition, Enlarged. Crown Svo, I2S. cloth. 1 ' The book is very handy ; the separate tables of sines and tangents to every minute will make it useful for many other purposes, the genuine traverse tables existing all the same." Athenceum. " Every person engaged in engineering field operations will e stimite the importance of such a work and the amount of valuable time which will be saved by reference to a set of reliable tables prepared with the accuracy and fulness of those given in this volume." Railway News. EarthivorJt, Measurement of. A MANUAL ON EARTHWORK. By ALEX. J. S. GRAHAM, C.E. With numerous Diagrams. Second Edition. i8mo, zs. 6d. cloth " A great amount of practical information, very admirably arranged, and available for rough estimates, as well as for the more exact calculations required in the engineer's and contractor's offices." Artizan. Strains in IromvorJe. THE STRAINS ON STRUCTURES OF IRONWORK; with Practical Remarks on Iron Construction. By F. W. SHEILDS, M.Inst.C.E, Second Edition, with 5 Plates. Royal 8vo, 5s. cloth. The student cannot find a better little book on this subject." Engineer. Cast Iron and other Metals, Strength of. A PRACTICAL ESSAY ON THE STRENGTH OF CAST IRON AND OTHER METALS. By THOMAS TREDGOLD, C.E. Fifth Edition, including HCDGKINSON'S Experimental Researches. Svo, izs. cloth. 14 CROSBY LOCK WOOD &- SON'S CATALOGUE. ARCHITECTURE, BUILDING, etc. Construction. THE SCIENCE OF BUILDING : An Elementary Treatise on the Principles of Construction. By E. WYNDHAM TARN, M.A., Architect. Third Edition, Enlarged, with 59 Engravings. Fcap. 8vo, 45. cloth, " A very valuable book, which we strongly recommend to all students." Builder. " No architectural student should be without this handbook.' Architect, Villa Architecture. A HANDY BOOK OF VILLA ARCHITECTURE: Being a Series of Designs for Villa Residences in various Styles. With Outline Specifications and Estimates. By C. WICKES, Author of "The Spires and Towers of England," &c. 61 Plates, 4to, i us. 6d. half-morocco, gilt edges. 1 " The whole of the designs bear evidence of their being the work of an artistic architect, and they will prove very valuable and suggestive." Building News. Text-Book for Architects. THE ARCHITECT'S GUIDE: Being a Text-Booh of Useful Information for Architects, Engineers, Surveyors, Contractors, Clerks of Works, &c. &c. By FREDERICK ROGERS, Architect, Author of " Specifica- tions for Practical Architecture," &c. Second Edition, Revised and Enlarged. With numerous Illustrations. Crown 8vo, 6s. cloth. " As a text-book of useful information for architects, engineers, surveyors, &c., it would be hard to find a handier or more complete little volume." Standard. "A young architect could hardly have a better guide-book." Timber Trades Journal, Taylor and Cresy's Rome. THE ARCHITECTURAL ANTIQUITIES OF ROME. By the late G. L. TAYLOR, Esq., F.R.I. B.A., and EDWARD CRESY, Esq. New Edition, thoroughly Revised by the Rev. ALEXANDER TAYLOR, M.A. (son of the late G. L. Taylor, Esq.), Fellow of Queen's College, Oxford, and Chap- lain of Gray's Inn. Large folio, with 130 Plates, half-bound, 3 35. " Taylor and Cresy's work has from its first publication been ranked among those professional books which cannot be bettered. ... It would be difficult to find examples of drawings, even among those of the rrost painstaking students of Gothic, more thoroughly worked out than are the one hundred and thirty plates in this volume." Architect. Linear Perspective. ARCHITECTURAL PERSPECTIVE : The whole Course and Operations of the Draughtsman in Drawing a Large House in Linear Per- spective. Illustrated by 39 Folding Plates. By F. O. FERGUSON. Demy 8vo, 35. 6d. boards. [Just published. Architectural Drawing. PRACTICAL RULES ON DRAWING, for the Operative Builder and Young Student in Architecture. By GEORGE PYNE. With 14 Plates, 4to, 75. 6d. boards. Sir Wm. Chambers on Civil Architecture. THE DECORATIVE PART OF CIVIL ARCHITECTURE. By Sir WILLIAM CHAMBERS, F.R.S. With Portrait, Illustrations, Notes, and an Examination of Grecian Architecture, by JOSEPH GWILT, F.S.A. Revised and Edited by W. H. LEEDS, with a Memoir of the Author. 66 Plates, 4to, 2is. cloth. House Building and Repairing. THE HOUSE-OWNER'S ESTIMATOR ; or, What will it Cost to Euili, Alter, or Repair? A Price Book adapted to the Use of Unpro- fessionil People, as well as for the Architectural Surveyor and Builder. By JAMES D. SIMON, A.R.I. B.A. Edited and Revised by FRANCIS T. W. MILLER, A.R.I.B.A. With numerous Illustrations. Fourth Edition, Revised. Crown 8vo, 35. 6d. cloth. "In two years it will repay its cost a hundred times over." Field, Cottages and Villas. COUNTRY AND SUBURBAN COTTAGES AND VILLAS: How to Plan and Build Them. Containing 33 Plates, with Introduction, General Explanations, and Description of each Plate. By JAMES W. BOGUE, Archite-t, Author of " Domestic Architecture," &c. 4to, los. 6d. cloth. ARCHITECTURE, BUILDING, etc. 15 The New Builder's Price Book, 1892. LOCK WOOD'S BUILDER'S PRICE BOOK FOR 1892. A Comprehensive Handbook of the Latest Prices and Data for Builders, Architects, Engineers and Contractors. Re-c obstructed, Re-written and Further Enlarged, By FRANCIS T. W. MILLER. ;oo closely-printed pages, crown 8vo, 45. cloth. ' [Just published. " This book is a very useful one, and should find a place in every English office connected with the building- and engineering professions." Industries. "This Price Book has been set up in new type. . . . Advantage has been taken of the transformation to add much additional information, and the volume is now an excellent book of reference." Architect. " In its new and revised form this Price Book is what a work of this kind should be compre- hensive, reliable, well arranged, legible and well bound.' British Architect. " A work of established reputation." Athenauin. " This very useful handbook is well written, exceedingly clear in its explanations and great care has evidently been taken to ensure accuracy." Morning Advtrtiser. Designing, Measuring, and Valuing. THE STUDENT'S GUIDE to the PRACTICE of MEASUR- ING AND VALUING ARTIFICERS' WORKS. Containing Directions for taking Dimensions, Abstracting the same, and bringing the Quantities into Bill, with Tables of Constants for Valuation of Labour, and for the Calcula- tion of Areas and Solidities, Originally edited by EDWARD DOBSON, Architect. With Additions on Mensuration and Construction, and a New Chapter on Dilapidations, Repairs, and Contract?, by E. WYNDHAM TARN, M.A. Sixth Edition, including a Complete Form of a Bill of Quantities. With 8 Plates and 63 Woodcuts. Crown 8vo, 75. 6d. cloth. " Well fulfils the promise of its title-page, and we can thoroughly recommend it to the class for whose use it has been compiled. Mr. Tarn's additions and revisions have much increased the usefulness of the work, and have especially augmented its value to students." Engineering. "This edition will be found the most complete treatise on the principles of measuring and valuing artificers' work that has yet been published." Building News. Pocket Estimator and Technical Guide. THE POCKET TECHNICAL GUIDE, MEASURER AND ESTIMATOR FOR BUILDERS AND SURVEYORS. Containing Tech- nical Directions for Measuring Work in all the Building Trades, Complete Specifications for Houses, Roads, and Drains, and an easy Method of Estimat- ing the parts of a Building collectively. By A. C. BEATON, Author of " Quantities and Measurements," &c. Sixth Edition, Revised. With. 53 Woodcuts, waistcoat-pocket size, is. 6d. gilt edges. [Just published, h.is ' Beaton." Building Ne y requisition in measuring i estimating. Its presence in the pocket will save valuable time and trouble." Building- World. Woodcuts, waistcoat-pocket size, is. 6d. gilt edges. [Just pul ' No builder, architect, surveyor, or valuer should be without his ' Beaton." Building News. 'Contains an extraordinary amount of information in daily requisition in measuring lating. Its presence in the pocket will save valuable time and trouble." Building Wi Donaldson on Specifications. THE HANDBOOK OF SPECIFICATIONS; or, Practical Guide to the Architect, Engineer, Surveyor, and Builder, in drawing up Specifications and Contracts for Works and Constructions. Illustrated by Precedents of Buildings actually executed by eminent Architects and En- g'neers. By Professor T. L. DONALDSON, P.R.I.B.A., &c. New Edition, in ne large Vol., 8vo, with upwards of 1,000 pages of Text, and 33 Plates, i ns.6d. cloth. "IE In this work forty-four specifications of executed works are given, Including the spedfica- sf the new Houses of Parliament, by Sir Charles Barry, and for the new Royal in :riptii book of precedents. . . . Suffice it to say that Donaldson's ' Handbook of Specifications tions for parts of the new Houses of Parliament, by Sir Charles Barry, and for the new Royal Exchange, by Mr. Tite, M.P. The latter, in particular, is a very complete and remarkable document. It embodies, to a great extent, as Mr. Donaldson mentions, 'the bill of quantities with the description of the works.' ... It is valuable as a record, and more valuable still as a must be bought by all architects." Builder. ^Bartholomew and Rogers 9 Specifications. SPECIFICATIONS FOR PRACTICAL ARCHITECTURE. A Guide to the Architect, Engineer, Surveyor, and Builder. With an Essay on the Structure and Science of Modern Buildings. Upon the Basis of the Work by ALFRED BARTHOLOMEW, tho^ughly Revised, Corrected, and greatly added to by FREDERICK ROGERS, Architect. Second Edition, Revised, with Additions. With numerous Illustrations, medium 8vo, 155. cloth. " The collection of specifications prepared by Mr. Rogers on the basis of Bartholomew's work Is too well known to need any recommendation from us. It is one of the books with which every young architect must be equipped ; for time has shown that the specification cannot be set aside through any defect in them." Architect. c6 ROSBY LOCKWOOD & SON'S CATALOGUE. Building ; Civil and Ecclesiastical. A BOOK ON BUILDING, Civil and Ecclesiastical, including Church Restoration ; with the Theory of Domes and the Great Pyramid, &c. By Sir EDMUND BECKETT, Bart., LL.D., F.R.A.S., Author of "Clocks and Watches, and Bells," &c. Second Edition, Enlarged. Fcap. Svo, 55. cloth. " A book which Is always amusing and nearly always instructive. The style throughout is in "the highest degree condensed and epigrammatic." Times. Ventilation of Huildings. VENTILATION. A Text Bock to the Practice of the Art oj Ventilating Buildings. With a Chapter upon Air Testing. By W. P. BUCHAN, R.P., Sanitary and Ventilating Engineer, Author of " Plumbing," &c. With 170 Illustrations. i2mo, 45. cloth boards. [Just published. The Art of Plumbing. PLUMBING. A Text Book to the Practice of the Art or Craft of the Plumber, with Supplementary Chapters on House Drainage, embodying the latest Improvements. By WJLLIAM PATON BUCHAN, R.P., Sanitary Engineer and Practical Plumber. Sixth Edition, Enlarged to 370 pages, and 380 Illustrations. i2mo, 45. cloth boards. " A text book which may be safely put in the hands of every young plumber, and which will also be found useful by architects and medical professors." Builder. " A valuable text book, and the only treatise which can be n garded as a really reliable manual of the plumber's art." Building Neu's. Geometry for the Architect, Engineer, etc. PRACTICAL GEOMETRY, for the Architect, Engineer and, Mechanic. Giving Rules for the Delineation and Application of various Geometrical Lines, Figures and Curves. By E. W. TARN, M.A., Architect, Author of "The Science of Building," &c. Second Edition. With 172 Illus- trations, demy Svo, gs. cloth. " No book with the same objects in view has ever been published In which the clearness of the rules laid down and the illustrative diagrams have been so satisfactory-" Scotsman. Tfie Science of Geometry. THE GEOMETRY OF COMPASSES; or, Problems Resolved by the mere Description of Circles, and the use of Coloured Diagrams and Symbols. By OLIVER BYRNE. Coloured Plates. Crown Svo, 35. 6d. cloth. " The treatise is a good one, and remarkable like all Mr. Byrne's contributions to the science of -geometry for the lucid character of its teaching." Building' News. DECORATIVE ARTS, etc. Woods and Marbles (Imitation of). SCHOOL OF PAINTING FOR THE IMITATION OF WOODS AND MARBLES, as Taught and Practised by A. R. VAN DER BURG and P. VAN DER BURG, Directors of the Rotterdam Painting Institution. Royal folio, iSi by 12$ in., Illustrated with 24 full-size Coloured Plates; also 12 plain Plates, comprising 154 Figures. Second and Cheaper Edition. Price i us. 6d. List of Plates. i. Various Tools required for Wood Painting a, 3. Walnut : Preliminary Stages of Graining and Finished Specimen 4. Tools used for Marble Painting and Method of Manipulation *,6. St. Remi Marble: Earlier Operations and finished Specimen 7. Methods of Sketching different Grains, Knots, &c. 8, 9. Ash: Pre- liminary Stages and Finished Specimen 10. Methods of Sketching Marble Grains n, xa. Breche Marble : Preliminary Stages of Working and Finished Specimen 13. Maple : Methods of Producing the different Grains 14, 15. Bird's- eye Maple: Preikninary Stages and Finished Specimen 16. Methods of Sketching the dif- ferent Species of White Marble 17, 18. White Marble: Preliminary Stages of Process and Finished Specimen of various Grains and 20, 2i. Mahogany: Earlier Stages and Finished Specimen 22, 23, 24. Sienna Marble : Varieties of Grain, Preliminary Stages and Finished Specimen 25, 26, 27. Juniper Wood : Methods 19. Mahogany : Specimens Methods of Manipulation Fi minary Stages 6, 27. Juniper Wo rain, &c.: Preli of producing Grain, &c.: Preliminary Stages and Finished Specimen 28, 29, 30. Vert de Mer Marble : Varieties of Grain and Methods of Working Unfinished and Finished Sped. mens 31. 32. 3?. Oak : Varieties of Grain, Tools Employed, and Methods of Manipulation, Pre- liminary Stages and Finished Specimen 34, 33, 36. Waulsort Marble: Varieties of Grain, Un- finished and Finished Specimens. *** OPINIONS OF THE PRESS. " Those who desire to attain skill in the art of painting woods and marbles will find advantage In consulting this book. . . . Some of the Working Men's Clubs should give their young men the opportunity to study It." /JwzV.fer. " A comprehensive guide to the art. The explanations of the processes, the manipulation and management of the colours, and the beautifully executed plates will not be the least valuable to the student who aims at making his work a faithful transcript of nature." Building News. DECORATIVE ARTS, etc. 17 House Decoration. ELEMENTARY DECORATION. A Guide to the Simpler Forms of Everyday Art, as applied to the Interior and Exterior Decoration of Dwelling Houses, &c. By JAMES W. FACEY, Jun. With 68 Cuts, izmo, zs. cloth limp. PRACTICAL HOUSE DECORATION : A Guide to the Art of Ornamental Painting, the Arrangement of Colours in Apartments, and the principles of Decorative Design. With some Remarks upon the Nature and Properties of Pigments. By JAMES WILLIAM FACEY, Author of " Elementary Decoration," &c. With numerous Illustrations. i2mo, zs, 6d. cloth limp. N.B.The above Two Works together in One Vol., strongly half-bound, 55. Colour. A GRAMMAR OF COLOURING. Applied to Decorative Painting and the Arts. By GEORGE FIELD. New Edition, Revised, Enlarged, and adapted to the use of the Ornamental Painter and Designer. By ELLIS A. DAVIDSON. With New Coloured Diagrams and Engravings, izmo, 35. 6d. cloth boards. "The book is a most useful resume of the properties of pigments." Builder. House Painting, Graining, etc. HOUSE PAINTING, GRAINING, MARBLING, AND SIGN WRITING, A Practical Manual of. By ELLIS A. DAVIDSON. Sixth Edition. With Coloured Plates and Wood Engravings. i2mo, 6s. cloth boards. " A mass of information, of use to the amateur and of value to the practical man." English Mechanic. "Simply invaluable to the youngster entering upon this particular calling, and highly service able to the man who is practising it.." Furniture Gazette. Decorators, Receipts for. THE DECORATOR'S ASSISTANT: A Modern Guide to De- corative Artists and Amateurs, Painters, Writers, Gilders, &c. Containing upwards of 600 Receipts, Rules and Instructions ; with a variety of Informa- tion for General Work connected with every Class of Interior and Exterior Decorations, &c. Fourth Edition, Revised. 152 pp., crown 8vo, is. in wrapper. " Full of receipts of value to decorators, painters, gilders, &c. The book contains the gist of larger treatises on colour and technical processes. It would be difficult to meet with a work so full of varied information on the painter's art." Building Ne-ws. " We recommend the work to all who, whether for pleasure or profit, require a guide to decora- tion." Plumber and Decorator. Moyr Smith on Interior Decoration. ORNAMENTAL INTERIORS, ANCIENT AND MODERN. By J. MOYR SMITH. Super-royal 8vo, with 32 full-page Plates and numerous- smaller Illustrations, handsomely bound in cloth, gilt top, price iSs. ' " The book is well illustrated and handsomely got up, and contains some true criticism and a- good many good examples of decorative treatment." The Builder. " This is the most elaborate and beautiful work on the artistic decoration of interiors that we have seen. . . . The scrolls, panels and other designs from the author's own pen are very beautiful and chaste ; but he takes care that the designs of other men shall figure even more than his own." Liverpool Albion. " To all who take an interest in elaborate domestic ornament this handsome volume will be welcome. " Graphic. British and Foreign Marbles. MARBLE DECORATION and the Terminology of British and Foreign Marbles. A Handbook for Students. By GEORGE H. BLAGROVE, Author of " Shoring and its Application," &c. With 28 Illustrations. Crown/ &vo, 3s. 6d. cloth. " This most useful and much wanted handbook should be in the hands of every architect and builder." Building World. " It is an excellent manual for students, and interesting to artistic readers generally." Sattirday " A' carefully and usefully written treatise ; the work is essentially practical." Scotsman. Marble Working, etc. MARBLE AND MARBLE WORKERS: A Handbook for Architects, Artists, Masons and Students. By ARTHUR LEE, Author of " A Visit to Carrara," "The Working of Marble," &c. Small crown 8vo, 25. cloth. " A really valuable addition to the technical literature of architects and masons. "Building 1 8 CROSBY LOCK WOOD &- SON'S CATALOGUE. DELAMOTTE'S WORKS ON ILLUMINATION AND ALPHABETS. A PRIMER OF THE ART OF ILLUMINATION, for the Use of Beginners : with a Rudimentary Treatise on the Art, Practical Directions for its exercise, and Examples taken from Illuminated MSS., printed in Gold and Colours. By F. DELAMOTTE. New and Cheaper Edition. Small 4to, 6s. orna- mental boards. " The examples of ancient MSS. recommended to the student, which, with much good sense, the author chooses from collections accessible to all, are selected with judgment and knowledge, as well as \a&te."Athenceum. ORNAMENTAL ALPHABETS, Ancient and Medieval, from the Eighth Century, with Numerals; including Gothic, Church-Text, large and small, German, Italian, Arabesque, Initials for Illumination, Monograms, Crosses, &c. &c., for the use of Architectural and Engineering Draughtsmen, Missal Painters, Masons, Decorative Painters, Lithographers, Engravers, Carvers, &c. &c. Collected and Engraved by F. DELAMOTTE, and printed in Colours. New and Cheaper Edition. Royal 8vo, oblong, zs. 6d. ornamental boards. "For those who Insert enamelled sentences round gilded chalices, who blazon shop legends over shop-doors, who letter church walls with pithy sentences from the Decalogue, this book will be use- ful. " Atlienceum. EXAMPLES OF MODERN ALPHABETS, Plain and Ornamental; including German, Old English, Saxon, Italic, Perspective, Greek, Hebrew, Court Hand, Engrossing, Tuscan, Riband, Gothic, Rustic, and Arabesque ; with several Original Designs, and an Analysis of the Roman and Old English Alphabets, large and small, and Numerals, for the use of Draughtsmen, Sur- veyors, Masons, Decorative Painters, Lithographers, Engravers, Carvers, &c. Collected and Engraved by F. DELAMOTTE, and printed in Colours. New and Cheaper Edition. Royal 8vo, oblong, zs. 6d. ornamental boards. "There is comprised in it ev-sry possible shape into which the letters of the alphabet and numerals can be formed, and the talent which has been expended in the conception of the various plain and ornamental letters is wonderful." Statidard. MEDIAEVAL ALPHABETS AND INITIALS FOR ILLUMI- NATORS. By F. G. DELAMOTTE. Containing 21 Plates and Illuminated Title, printed in Gold and Colours. With an Introduction by J. WILLIS BROOKS. Fourth and Cheaper Edition. Small 4to, 45. ornamental boards. " A volume in which the letters of the alphabet come forth glorified in gilding andali the colours of the prism interwoven and intertwined and intermingled." Sun. THE EMBROIDERER'S BOOK OF DESIGN. Containing Initials, Emblems, Cyphers, Monograms, Ornamental Borders, Ecclesiastical Devices, Mediaeval and Modern Alphabets, and National Emblems. Col- lected by F. DELAMOTTE, and printed in Colours. Oblong royal 8vo, is. 6d. ornamental wrapper. " The book will be of great assistance to ladles and young children who are endowed with the art of plying the needle in this most ornamental and useful pretty work." East Anglian Times. Wood Carving. INSTRUCTIONS IN WOOD-CARVING, for Amateurs; with Hints on Design. By A LADY. With Ten Plates. New and Cheaper Edition. Crown 8vo, zs. in emblematic wrapper. " The handicraft of the wood-carver, so well as a book can Impart It, may be learnt from ' A Lady's ' publication." Athenaum. " The directions given are plain and easily understood." English Mechanic. Glass Painting. GLASS STAINING AND THE ART OF PAINTING ON GLASS. From the German of Dr. GESSERT and EMANUEL OTTO FROMBERG, With an Appendix on THE ART OF ENAMELLING. i2mo, zs. 6d. cloth limp. Letter Painting. THE ART OF LETTER PAINTING MADE EASY. By JAMES GREIG BADENOCH. With 12 full-page Engravings of Examples, is. 6d. cloth limp. " The system is a simple one, but quite original, and well worth the careful attention of letter painters. It can be easily mastered and remembered." Building News. CARPENTRY, TIMBER, etc. ig CARPENTRY, TIMBER, etc. Tredgold's Carpentry, Revised & Enlarged by Tarn. THE ELEMENTARY PRINCIPLES OF CARPENTRY. A Treatise on the Pressure and Equilibrium of Timber Framing, the Resist- ance of Timber, and the Construction of Floors, Arches, Bridges, Roots, Uniting Iron and Stone with Timber, &c. To which is added an Essay on the Nature and Properties oi Timber, &c., with Descriptions of the kinds f Wood used in Building ; also numerous Tables of the Scantlings of Tim- ber for different purposes, the Specific Gravities of Materials, &c. By THOMAS TREDGOLD, C.E. With an Appendix of Specimens of Various Roofs of Iron and Stone, Illustrated. Seventh Edition, thoroughly revised and considerably enlarged by E. WYNDHAM TARN, M.A., Author of "The Science of Build- ing," &c. With 61 Plates, Portrait of the Author, and several Woodcuts. In one large vol., 4to, price i 55. cloth. "Ought to be in every architect's and every builder's library." BitUder. " A work whose monumental excellence must commend it wherever skilful carpentry Is con- cerned. The author's principles are rather confirmed than impaired by time. The additional plates are of great intrinsic value." Building News. Woodworking Machinery. WOODWORKING MACHINERY: Its Rise, Progress, and Construction. With Hints on the Management of Saw Mills and the Economi- cal Conversion of Timber. Illustratediwith Examples ot Recent Designs by leading English, French, and American Engineers. By M. Powis BALE, A.M.lnst.C.E., M.I.M.E. Large crown 8vo, 125. 6cl. cloth. " Mr. Bale is evidently an expert on the subject and he has collected so much information that <\is book is all-sufficient for builders and others engaged in the conversion of timber." Architect. "The most comprehensive compendium of wood- working machinery we have seen. The author is a thorough master of his subject." Building News. " The appearance of this book at the present time will, we should think, give a consid' rable impetus to the onward march of the machinist engaged in the designing and manufacti re of wood-working machines. It should be in the office of every wood-working factory." > glish (Mechanic. Saiv Mills. SA W MILLS : Their Arrangement and Management, and the Economical Conversion of Timber. (A Companion Volume to " Wood work- ing Machinery.") By M. Powis BALE. With numerous Illustrations. Crow 8vo, IDS. 6d. cloth. " The administration of a large sawing establishment is discussed, and the subject examine^. from a financial standpoint. We could not desire a more complete or practical treatise." Builder. " We highly recommend Mr. Bale's work to the attention and perusal of all those who are en- gaged in the art of wood conversion, or who are about building or remodelling saw-mills on im- proved principles." Building News. Carpentering. THE CARPENTER'S NEW GUIDE ; or, Book of Lines for Car- penters ; comprising all the Elementary Principles essential for acquiring a knowledge of Carpentry. Founded on the late PETER NICHOLSON'S Standard Work. A New Edition, Revised by ARTHUR ASHPITEL, F.S.A. Together with Practical Rules on Drawing, by GEORGE PYNB. With 74 Plates ( 4to, i is. cloth. Handrailinfj and Stairbuilding. A PRACTICAL TREATISE ON HANDRAILING : Showing New and Simple Methods for Finding the Pitch of the Plank, Drawing the Moulds, Bevelling, Jointing-up, and Squaring the Wreath. By GEORGE COLLINGS. Second Edition, Revised and Enlarged, to which is added A TREATISE ON STAIRBUILDING. With Plates and Diagrams. I2mo, zs. 6ci. cloth limp, ' ' Will be found of practical utility in the execution of this difficult branch of joinery." Builder. " Almobt every difficult phase of this somewhat intricate branch of joinery is elucidated by the .ld of plates and explanatory letterpress," Furniture Gazette. Circular Work. CIRCULAR WORK IN CARPENTRY AND JOINERY: A Practical Treatise on Circular Work of Single and Double Curvature. By GEORGE COLLINGS, Author of " A Practical Treatise on Handrailing." Illus- trated with numerous Diagrams. Second Edition, izmo, 2s. 6d. cloth limp. " An excellent example of what a book of this kind should be. Cheap in price, clear in defini- tion and practiced in the examples selected." Luildtr, 20 CROSBY LOCK WOOD 6- SON 'S CATALOGUE. Timber MercJiant's Companion. THE TIMBER MERCHANTS AND BUILDER'S COM- PANION. Containing New and Copious Tables of the Reduced Weight and Measurement of Deals and Battens, of all sizes, from One to a Thousand Pieces, and the relative Price that each size bears per Lineal Foot to any given Price per Petersburg Standard Hundred; the Price per Cube Foot of Square Timber to any given Price per Load of 50 Feet ; the proportionate Value of Deals and Battens by the Standard, to Square Timber by the Load We are glad to see a fourth edition of these admirable tables, which for correctness and simplicity of arrangement leave nothing to be desired." Timber Trades Journal. " An exceedingly well-arranged, clear, and concise manual of tables for the use of all who buy or sell timber." Journal of Forestry. Practical Timber MercJiant. THE PRACTICAL TIMBER MERCHANT. Being a Guide for the use of Building Contractors, Surveyors, Builders, &c., comprising useful Tables for all purposes connected with the Timber Trade, Mark's of Wood, Essay on the Strength of Timber, Remarks on the Growth of Timber, &c. By W. RICHARDSON. Fcap. 8vo, 35. 6d. cloth. "This handy manual contains much valuable information for the use of timber merchant?, builders, foresters, and all others connected with the growth, sale, and manufacture of timber." Journal of Forestry, Timber Freight Book. THE TIMBER MERCHANTS, SAW MILLER'S, AND IMPORTER'S FREIGHT BOOK AND ASSISTANT. Comprising Rules, Tables, and Memoranda relating to the Timber Trade. By WILLIAM RICHARDSON, Timber Broker; together with a Chapter on "SPEEDS OF SAW MILL MACHINERY," by M. Powis BALE, M.I.M.E., &c. i2mo, 35. 6d. cl. boards, "A very useful manual of rules, tables, and memoranda relating to the timber trade. We re- commend it as a compendium of calculation to all timber measurers and merchants, and as supply- Ing a real want in the trade." Building News, facking-Case Makers, Tables for. PACKING-CASE TABLES ; showing the number of Super- ficial Feet in Boxes or Packing-Cases, from six inches square and upwards. By W. RICHARDSON, Timber Broker. Third Edition. Oblong 4to, 35. 6d. cl, "Invaluable labour-saving tables." Ironmonger. "Will save much labour and calculation." Grocer, Superficial Measurement. THE TRADESMAN'S GUIDE TO SUPERFICIAL MEA- SUREMENT. Tables calculated from i to 200 inches in length, by i to 108 inches in breadth. For the use of Architects, Surveyors, Engineers, Timber Merchants, Builders, &c. By JAMES HAWKINGS. Third Edition. Fcap., 35. 6d. cloth. " A useful collection of tables to facilitate rapid calculation of surfaces. The exact area of any surface of which the limits have been ascertained can be instantly determined. The book will be found of the greatest utility to all engaged in building operations." Scotsman, " These tables will be found of great assistance to all who require to make calculations in super- ficial measurement." English Mechanic. Forestry. THE ELEMENTS OF FORESTRY. Designed to afford In- formation concerning the Planting and Care of Forest Trees for Ornament or Profit, with Suggestions upon the Creation and Care of Woodlands. By F.B. HOUGH. Large crown Svo, IDS. cloth. Timber Importer's Guide. THE TIMBER IMPORTER 'S, TIMBER MERCHANTS AND BUILDER'S STANDARD GUIDE. By RICHARD E. G RANDY. Compris- ing an Analysis of Deal Standards, Home and Foreign, with Comparative Values and Tabular Arrangements for fixing Nett Landed Cost on Baltic and North American Deals, including all intermediate Expenses, Freight, Insurance, &c. &c. Together with copious Information for the Retailer and Builder. Third Edition, Revised. I2mo, 2s. cloth limp. " Everything it pretends to be : built up gradually, it leads one from a forest to a treenail, and throws in, as a makeweight, a host of material concerning bricks, columns, cisterns, &c." English Mechanic. MARINE ENGINEERING, NAVIGATION, etc. 21 MARINE ENGINEERING, NAVIGATION, etc, Chain Cables. CHAIN CABLES AND CHAINS. Comprising Sizes and Curves of Links, Studs, &c., Iron for Cables and Chains, Chain Cable and Chain Making, Forming and Welding Links, Strength of Cables and Chains, Certificates for Cables, Marking Cables, Prices of Chain Cables and Chains, Historical Notes, Acts of Parliament, Statutory Tests, Charges for Testing, List of Manufacturers of Cables, &c. &c. By THOMAS W.TRAILL, F.E.R.N., M. Inst. C.E., Engineer Surveyor in Chief, Board of Trade, Inspector of Chain Cable and Anchor Proving Establishments, and General Superin- tendent, Lloyd's Committee on Proving Establishments. With numerous Tables, Illustrations and Lithographic Drawings. Folio, 3 zs. cloth, bevelled boards. "It contains a vast amount of valuable information. Nothing seems to be wanting to make it a complete and standard work of reference on the subject." Nautical Magazine. Marine Engineering. MARINE ENGINES AND STEAM VESSELS (A Treatise on). By ROBERT MURRAY, C.E. Eighth Edition, thoroughly Revised, with considerable Additions by the Author and by GEORGE CARLISLE, C.E., Senior Surveyor to the Board of Trade at Liverpool. I2mo, 55, cloth boards. " Well adapted to give the young steamship engineer or marine engine and boiler maker a general introduction into his practical work." Mechanical ll'orld. "We feel sure that this thoroughly revised edition will continue to be as popular in the future as it has been in the past, as, for its size, it contains more useful infoi motion than any similar treatise. ' ' /;: dm tries. The information given is both sound and sensible, and well qualified to direct young sea- going hands on the straight road to the extra chief's cert-ficate. Most useful to survej ors, inspectors, draughtsmen, and all young engineers who take an interest in their profession." Glasgow Herald. "An indispensable manual for the student of marine engineering." Liverpool Mercury. Pocket-Booh for Naval ArcJiitects and Shipbuilders. THE NAVAL ARCHITECT'S AND SHIPBUILDER'S POCKET-BOOK of Formula, Rules, and Tableland MARINE ENGINEER'S AND SURVEYOR'S Handy Book of Reference. By CLEMENT MACKROW, Member of the Institution of Naval Architects, Naval Draughtsman. Fourth Edition, Revised. With numerous Diagrams, &c. Fcap., 125. 6d. strongl> bound in leather. " Will be found to contain the most useful tables and formulae required by shipbuilders, carefully collected from the best authorities, and put together in a popular and simple form." Engineer. " The professional shipbuilder has now, in a convenient and accessible form, reliable data fo solving many of the numerous problems that present themselves in the course of his work." Iron. "There is scarcely a subject on which a naval architect or shipbuilder can require to refresh his memory which will not be found within the covers of Mr. Mackrow's book." English Mechanic, Pocket-BooJc for Marine Engineers. A POCKET-BOOK OF USEFUL TABLES AND FOR- MULAS FOR MARINE ENGINEERS. By FRANK PROCTOR, A.I.N.A, Third Edition. Royal 32010, leather, gilt edges, with strap, 45. "We recommend it to our readers as going far to supply a long-felt want." Naval Science, "A most useful companion to all marine engineers." United Service Gazette. Introduction to Marine Engineering. ELEMENTARY ENGINEERING : A Manual for Young Marine Engineers and Apprentices, In the Form of Questions and Answers on Metals, Alloys, Strength of Materials, Construction and Management of Marine Engines and Boilers, Geometry, &c. &c. With an Appendix of Useful Tables. By JOHN SHERREN BREWER, Government Marine Surveyor, Hong- kong. Small crown 8vo, zs. cloth. " Contains much valuable information for the class for whom it is intended, especially in the chapters on the management of boilers and eng'nes." Nautical Magazine. A useful introduction to the more elaborate text books." Scotsman. " To a student who has the requisite de-sire and resolve to attain a thorough knowledge, Mr. Brewer offers decidedly useful help." Attteuaunt. Navigation. PRACTICAL NAVIGATION. Consisting of THE SAILOR'S SEA-BOOK, by JAMES GREENWOOD and W. H. ROSSER ; together with the requisite Mathematical and Nautical Tables for the Working of the Problems, by HENRY LAW, C.E., and Professor J. R. YOUNG. Illustrated, i2mo, 75. st-ongly half-bound. 22 CROSBY LOCKWOOD & SON'S CATALOGUE. MINING AND METALLURGY. Metalliferous Mining in the United Kingdom. BRITISH MINING : A Treatise on the History, Discovery, Practical Development, and Future Prospects of Metalliferous Mines in the United King- dom. By ROBERT HUNT, F.R.S., Keeper of Mining Records ; Editor o5 " Ure's Dictionary of Arts, Manufactures, and Mines," &c. Upwards of 950 pp., with 230 Illustrations. Second Edition, Revised. Super-royal 8vo, f 2 2S. cloth. _! of the most valuable works of reference of modern times. Mr. Hunt, as keeper of mining records of the United Kingdom, has had opportunities for such a task not enjoyed by anyone else, and has evidently made the most of them. . . . The language and style adopted are good, and the treatment of the various subjects laborious, conscientious, and scientific." Engineering. "A mass of information not elsewhere available, and of the greatest value to those who may be interested in our great mineral industries." Engineer. "A sound, business-like collection of interesting facts. . . . The amount of Information Mr. Hunt has brought together is enormous. . . . The volume appears likely to convey more instruction upon the subject than any work hitherto published." Mining Journal. Colliery Management. THE COLLIERY MANAGER'S HANDBOOK: A Compre- hensive Treatise on the Laying-out and Working of Collieries, Designed as a Book of Reference for Colliery Managers, and for the Use of Coal-Mining Students preparing for First-class Certificates. By CALEB PAMELY, Mining Engineer and Surveyor; Member of the North cf England Institute of Mining and Mechanical Engineers ; and Member of the South Wales Insii- tute of Mining Engineers. With nearly 500 Plans, Diagrams, and other Illustrations. Medium 8vo, about Coo pages. Price i 55. strongly bound. [Just published Coal and Iron. THE COAL AND IRON INDUSTRIES OF THE UNITED KINGDOM. Comprising a Description of the Coal Fields, and of the Principal Seams of Coal, with Returns of their Produce and its Distribu- tion, and Analyses of Special Varieties. Also an Account of the occurrence of Iron Ores in Veins or Seams ; Analyses of each Variety ; and a History oi- the Rise and Progress of Pig Iron Manufacture. By RICHARD MEADE, Assistant Keeper of Mining Records. With Maps. 8vo, i 8s. cloth. "The book is one which must find a place on the shelves of all Interested In coal and iron production, and in the iron, steel, and other metallurgical industries." Engineer. " Of this book we may unreservedly say that it is the best of its class which we have ever met. . . A book of reference which no one engaged in the iron or coal trades should omit from his library. ' Iron and Coal Trades Review. Prospecting for Gold and other Metals. THE PROSPECTOR'S HANDBOOK: A Guide for the Pro- spector and Traveller in Search of Metal-Bearing or other Valuable Minerals, By J. W. ANDERSON, M.A. (Camb.), F.R.G.S., Author of "Fiji and New Caledonia." Fifth Edition, thoroughly Revised and Enlarged. SmaD crown 8vo, 35. 6d. cloth. " Will supply a much felt want, especially among Colonists, in whose way are so often thrown many mineralogical specimens the value of which it is difficult to determine. " Engineer. |'How_to find commercial minerals, and how to identify them when tliey are found, are the leading points to which attention is directed. The author has managed to pack as much practical detail into his pages as would supply material for a book three times its size." Mining Journal. Mining Notes and Formula?. NOTES AND FORMULAE FOR MINING STUDENTS. By JOHN HERMAN MERIVALE, M.A., Certificated Colliery Manager, Professor of Mining in the Durham College of Science, Newcastle-upon-Tyne. Third Edition, Revised and Enlarged. Small crown 8vo, zs. 6d. cloth. " Invaluable to anyone who is working up for an examination on mining subjects." Coal and Iron Trades Revww. " The author has done his work in an exceedingly creditable manner, and has produced a book that will be of service to students, and those who are practically engaged in mining operations.'' Engineer. " A vast amount of technical matter of the utmost value to mining engineers, and of consider able interest to students." Schoolmaster* MINING AND METALLURGY. 23 Explosives. A HANDBOOK ON MODERN EXPLOSIVES. Being a Practical Treatise on the Manufacture and Application of Dynamite, Gun- Cotton, Nitro-Glycerine and other Explosive Compounds. Including the Manufacture of Collodion-Cotton. By M. EISSLER, Mining Engineer and Metallurgical Chemist, Author of " The Metallurgy of Gold," &c. With about 100 Illustrations. Crown 8vo, IDS. 6d. cloth. " Useful not only to the miner, but also to officers of both services to whom blasting and the use of explosives generally may at any time become a necessary auxiliary." Nature. " A veritable mine of information on the subject of explosives employed for military, mining ay.d blasting- purposes." Army and Navy Gazette. " The book is clearly written. Taken as a whole, we consider it an excellent little book and ons that should be found of great service to miners and others who are engaged in work requiring the use of explosives." Athenaum. Gold, Metallurgy of, THE METALLURGY OF GOLD : A Practical Treatise on the Metallurgical Treatment of Gold-bearing Ores. Including the Processe s of Concentration and Chlorination, and the Assaying, Melting and Refining of Gold. By M. EISSLER, Mining Engineer and Metallurgical Chemist, formerly Assistant Assayer of the U. S. Mint, San Francisco. Third Edition, Revised and greatly Enlarged. With 187 Illustrations. Crown 8vo, I2S. 6d. cloth. "This book thoroughly deserves its title of a ' Practical Treatise. 1 The whole process of gold milling, from the breaking of the quartz to the assay of the bullion, is described in clear and orderly narrative and with much, but not too much, fulness of detail." Saturday Review. " The work is a storehouse of information and valuable data, and we strongly recommend it to all professional men engaged in the gold-mining industry." Mining Journal Silver f Metallurgy of. THE METALLURGY OF SILVER : A Practical Treatise on the Amalgamation, Roasting and Lixiviation of Silver Ores, Including the Assaying, Melting and Refining of Silver Bullion. By M. EISSLER, Author of " The Metallurgy of Gold.'' Second Edition, Enlarged. With 150 Illus- trations. Crown 8vo, zos. 6d. cloth. [Just published. " A practical treatise, and a technical work which we are convinced will supply a long-felt want amongst practical men, and at the same time be of value to students and others indirectly connected with tne industries." Mining Journal. " From first to last the book is thoroughly sound and reliable." Colliery Guardian. " For chemists, practical miners, assayers and investors alike, we do not know of any work on the subject so handy and yet so comprehensive." Glasgow Herald, Silver-Lead, Metallurgy of. THE METALLURGY OF ARGENTIFEROUS LEAD: A Practical Treatise en the Smelting of Silver-Lead Ores and the Refining of Lead Bullion. Including Reports on various Smelting Establishments and Descriptions of Modern Furnaces and Plants in Europe and America. By M. EISSLER, M.E., Author of "The Metallurgy of Gold," &c. Crown 8vo. 400 pp., with numerous Illustrations, i2s. 6d. cloth. [Just published. Metalliferous Minerals and Mining. TREATISE ON METALLIFEROUS MINERALS AND MINING. By D. C. DAVIES, F.G.S., Mining Engineer, &c., Author of "A Treatise on Slate and Slate Quarrying." Illustrated with numerous Wood Engravings. Fourth Edition, carefully Revised. Crown 8vo, izs. 6d. cloth. "Neither the practical miner nor the general reader interested in mines can have a better book for his companion and his guide." Mining Journal. IMinin^ World. "We are doing our readers a service in calling their attention to this valuable work." " As a history of the present state of mining throughout the world this book has a real value, and it supplies an actual wznt."Athen OTHER MINERALS AND MINING. By D. C. DAVIES, F.G.S. Uniform with, and forming a Com- panion Volume to, the same Author's " Metalliferous Minerals and Mining." With 76 Wood Engravings. Second Edition. Crown 8vo, izs. 6d. cloth. 1 ' AVe do not remember to have met with any English work on mining matters that contains the same amount of information packed in equally convenient form." Academy. " We should be inclined to rank it as among the very best of the handy technical and trades manuals which have recently appeared." British Quarterly Review. 24 CROSBY LOCK WOOD &> SON'S CATALOGUE. Mineral Surveying and Valuing. THE MINERAL SURVEYOR AND VALUER'S COMPLETE GUIDE, comprising a Treatise on Improved Mining Surveying and the Valua- tion of Mining Properties, with New Traverse Tables. By WM. LINTERN, Mining and Civil Engineer. Third Edition, with an Appendix on " Magnetic and Angular Surveying," with Records of the Peculiarities of Needle Dis- tuabances. With Four Plates of Diagrams, Plans, &c. i2mo, 45. cloth. " Mr. Lintem's book forms a valuable and thoroughly trustworthy guide." Iron and Coal Trades Review. '^This new edition must be of the highest value to colliery surveyors, proprietors and mana- gers." Colliery Guardian. Asbestos and its Uses. ASBESTOS: Its Properties, Occurrence and Uses. With some Account of the Mines of Italy and Canada. By ROBERT H.JONES. With Eight Collotype Plates and other Illustrations. Crown 8vo, I2S. 6d. cloth. "An interesting- and invaluable work." Collierv Guardian. " We counsel our readers to get this exceedingly interesting work for themselves ; they will find in it much that is suggestive, and a great deal that is of immediate and practical usefulness." Builder. " A valuable addition to the architect's and engineer's library." Building News. Underground Pumping Machinery. MINE DRAINAGE. Being a Complete and Practical Treatise on Direct-Acting Underground Steam Pumping Machinery, with a Descrip- tion of a large number of the best known Engines, their General Utility and the Special Sphere of their Action, the Mode of their Application, and their merits compared with other forms of Pumping Machinery. By STEPHEN MICHELL. 8vo, 155. cloth. "Will be highly esteemed by colliery owners and lessees, mining: engineers, and students generally who require to be acquainted with the best means of securing the drainage of mines. It Is a most valuable work, and stands almost alone in the literature of steam pumping machinery." Colliery Guardian. " Much valuable information Is given, so that the book is thoroughly worthy of an extensive circulation amongst practical men and purchasers of machinery." Mining Journal. Mining Tools. A MANUAL OF MINING TOOLS. For the Use of Mine Managers, Agents, Students, &c. By WILLIAM MORGANS, Lecturer on Prac- tical Mining at the Bristol School of Mines. i2mo, zs. 6d. cloth limp. ATLAS OF ENGRAVINGS to Illustrate the above, contain- ing 235 Illustrations of Mining Tools, drawn to scale. 4to, 45. 6d. cloth. " Students in the science of mining, and overmen, captains, managers, and viewers may gain practical knowledge and useful hints by the study of Mr. Morgans' manual." Colliery Guardian. " A valuable work, which will tend materially to improve our mining literature." Mining Journal. Coal Mining. COAL AND COAL MINING: A Rudimentary Treatise on. By the late Sir WARINGTON W. SMYTH, M.A., F.R.S., &c., Chief Inspector of the Mines of the Crown. Seventh Edition, Revised and Enlarged. With numerous Illustrations. I2mo, 45. cloth boajds. "As an outline is given of every known coal-field in this and other countries, as well as of the principal methods of working, the book will doubtless interest a very large number of readers." Mining Journal. Subterraneous Surveying. SUBTERRANEOUS SURVEYING, Elementary and Practical Treatise on, with and without the Magnetic Needle. By THOMAS FENWICK, Surveyor of Mines, and THOMAS BAKER, C.E. Illust. ismo, 35. cloth boards. Granite Quarrying. GRANITES AND OUR GRANITE INDUSTRIES. By GEORGE F. HARRIS, F.G.S., Membre de la Societe Beige de Geologic, Lec- turer on Economic Geology at the Birkbeck Institution, &c. With Illustra- tions. Crown 8vo, zs. 6d. cloth. "A clearly and well-written manual for persons engaged or interested in the granite industry.' ~ An interesting work, which will be deservedly esteemed." Colliery Guardian. An exceedingly interesting and valuable monograph on a subject which has hitherto received icuntably little attention in the shape of systematic literary treatment." Scottish Leader. " An exceed jnacccu ELECTRICITY, ELECTRICAL ENGINEERING, etc. 25 ELECTRICITY ELECTRICAL ENGINEERING, etc. Electrical Engineering. THE ELECTRICAL ENGINEER'S POCKET-BOOK OF MODERN RULES, FORMULA, TABLES AND DATA. By H. R. KEMPE, M.Inst.E.E., A.M.Inst C.E., Technical Officer Postal Telegraphs, Author of " A Handbook of Electrical Testing," &c. With numerous Illus- trations, royal i'zmo, oblong, 55. leather. \_Just published. " There is very little in the shape of formulae or data which the electrician is likely to want in a hurry which cannot be found in its pages." Practical Engineer. . "A very useful book cf reference for daily use in practical electrical engineering and its various applications to the industries of the present day." Iron. " It is the best bnok of its kind." Electrical Engineer. "The Electrical Engineer's Pocket- Book is a good one." Electrician. "Strongly recommended to those engaged in tne various electrical industries." Electrical Review. Electri c Liyli t ing. ELECTRIC LIGHT FITTING: A Handbook for Working Electrical Engineers, embodying Practical Notes on Installation _ Manage- ment. By JOHN W. URQUHART, Electrician, Author of " Electric Light," &c. With numerous Illustrations, crown 8vo, 55. cloth. [Just published. " This volume deals with what may be termed the mechanics of electric lighting, and is addressed to men who are already engaged in the work or are training for it. The work traverses a great deal of ground, and may be read as a sequel to the same author's useful work on ' Electric Light.' "Electrician. " This is an attempt to state in the simplest language the precautions which should be adopted in installing the electric light, and to give information, for the guidance of those who have to run the plant when installed. The book is well worth the perusal of the workmen for whom it is written." Electrical Revie-w. " Eminently practical and useful. . . . Ought to be in the hands of everyone in charge of an electric light plant." Electrical Engineer. " A really capital book, which we have no hesitation in recommending to the notice of working electricians and electrical engineers." Mechanical World. Electric Light. ELECTRIC LIGHT : Its Production and Use. Embodying Plain Directions for the Treatment cf Dynamo-Electric Machines, Batteries, Accumulators, and Electric Lamps. By J. W. URQUHART, C.E., Author of "Electric Light Fitting," &c. Fourth Edition, Revised, with Large Additions and 145 Illustrations. Crown 8vo, 75. 6d. cloth. [Just published. " The book is by far the best that we have yet met with on the subject." Athenaum. "It is the only work at present available which gives, in language intelligible for the most part to the ordinary reader, a general but concise history of the means which have been adopted up to the present time in producing the electric light." Metropolitan. ''The book contains a general account of th . . general account of the means adopted in producing the electric light, not ony as otane rom voltaic or galvanic batteries, but treats at length of the dynamo-electric machine in several of its forms." Colliery Guardian, Construction of Dynamos. DYNAMO CONSTRUCTION : A Practical Handbook for tJte Use of Engineer Constructors and Electricians in Charge. With Examples of leading English, American and Continental Dynamos and Motors. By J. W. URQUHART, Author of " Electric Light," &c. Crown 8vo, 75. 6d. cloth. \_Just published. 'The author has produced a book for which a demand has long existed. The subject is treated in a thoroughly practical manner." Mechanical Il'orld. Dynamic Electricity and Magnetism. THE ELEMENTS OF DYNAMIC ELECTRICITY AND MAGNETISM, By PHILIP ATKINSON, A.M., Ph.D. Crown 8vo. 400 pp. With 120 Illustrations, ics. 6d. cloth. [J list publish, d. Text Book of Electricity. THE STUDENT'S TEXT-BOOK OF ELECTRICITY. By HENRY M. NOAD, Ph.D., F.R.S., F.C.S. New Edition, carefully Revised. With an Introduction and Additional Chapters, by W. H. PREECE, M.I.C.E., Vice- President of the Society of Telegraph Engineers, &e. With 470 Illustra- tions. Crown 8vo, izs. 6d. cloth. 'We can recommend Dr. Noad's book for clear style, great range of subject, a good index <1 a plethora of woodcuts. Such collections as the present are indispensable. Athenaum. " An admirable text book for every student beginner or advanced of electricity." Engineering. 26 CROSBY LOCK WOOD 6- SON'S CATALOGUE. Electric Lighting. THE ELEMENTARY PRINCIPLES OF ELECTRIC LIGHT- ING. By ALAN A. CAMPBELL SWINTON, Associate I.E.E. Second Edition, Enlarged and Revised. With 16 Illustrations. Crown 8vo, is. 6d. cloth. "Anyone who desires a short and thoroughly clear exposition of the elementary principles oi electric-lighting cannot do better than read this little work." Bradford Observer. Electricity. A MANUAL OF ELECTRICITY: Including Galvanism, Mag- netism, Dia-Magnetisin, Electro-Dynamics, Magno-EIertricity, and the Electric Telegraph. By HENRY M. NOAD, Ph.D., F.R.S., F.C.S. Fourth Edition. With 500 Woodcuts. 8vo, i 45. cloth. " It is worthy of a place in the library of every public institution." Mining Journal. Dynamo Construction. HO W TO MAKE A DYNAMO : A Practical Treatise for Amateurs. Containing numerous Illustrations and Detailed Instructions for Construct- ing a Small Dynamo, to Produce the Electric Light. By ALFRED CROFTS. Third Edition, Revised and Enlarged. Crown 8vo, is. cloth. "The instructions given in this unpretentious little book are sufficiently clear and explicit to enable any amateur mechanic possessed of average skill and the usual tools to be found in an amateur's workshop, to build a practical dynamo machine." Electrician. NATURAL SCIENCE, etc. Pneumatics and Acoustics. PNEUMATICS : including Acoustics and the Phenomena of Wind Currents, for the Use of Beginners. By CHARLES TOMLINSON, F.R.S. F.C.S. , &c. Fourth Edition, Enlarged. i2mo, is. 6d. cloth. " Beginners in the study of this important application of science could not have a better manual " Scotsman. " A valuable and suitable text-book for students of Acoustics and the Pheno- mena of Wind Currents." Schoolmaster. Conchology. A MANUAL OF THE MOLLUSC A : Being a Treatise on Recent and Fossil Shells. By S. P. WOODWARD, A.L.S., F.G.S., late Assistant Palaeontologist in the British Museum. With an Appendix on Recent and Fossil Conchological Discoveries, by RALPH TATE, A.L.S., F.G.S. Illustrated by A. N. WATERHOUSE and JOSEPH WILSON LOWRY. With 23 Plates and upwards of 300 Woodcuts. Reprint of Fourth Ed., 1880. Cr. 8vo, 75. 6d. cl. " A most valuable storehouse of conchological and geological information.". Science Gossip. Geology. RUDIMENTARY TREATISE ON GEOLOGY, PHYSICAL AND HISTORICAL. Consisting of "Physical Geology," which sets forth the leading Principles of the Science ; and " Historical Geology," which treats of the Mineral and Organic Conditions of the Earth at each successive epoch, especial reference being made to the British Series of Rocks. By RALPH TATE, A.L.S., F.G.S., &c. With 250 Illustrations. i2mo, 55. cloth. " The fulness of the matter has elevated the book into a manual. Its information is exhaustive and well arranged." School Board Chronicle, Geology and Genesis. THE TWIN RECORDS OF CREATION; or, Geology and Genesis : their Perfect Harmony and Wonderful Concord. By GEORGE W. VICTOR LE VAUX. Numerous Illustrations. Fcap. 8vo, 5$. cloth. " A valuable contribution to the evidences of Revelation, and disposes very conclusively of the arguments of those who would set God's Works against God's Word.' The Rock, The Constellations. STAR GROUPS: A Student's Guide to the Constellations. By J. ELLARD GORE, F.R.A.S., M.R.I. A., &c., Author of "The Scenery of the Heavens." With 30 Maps. Small 4to, 55. cloth, silvered. [Just published. Astronomy. ASTRONOMY. By the late Rev. ROBERT MAIN, M.A. , F.R.S. , formerly Radcliffe Observer at Oxford. Third Edition, Revised and Cor- rected to the present time, by W. T. LYNN, B.A., F.R.A.S. izmo, zs. cloth. "A sound and simple treatise, very carefully edited, and a capital book for beginners." Knowledge [tional Times. !' Accurately brought down to the requirements of the present time by Mr. Lynn." Educa- NATURAL SCIENCE, etc. 27 DR. LARDNER'S COURSE OF NATURAL PHILOSOPHY. THE HANDBOOK OF MECHANICS. Enlarged and almost re- written by BENJAMIN LOEWY, F.R.A.S. With 378 Illustrations. Post 8vo, 6s. cloth. "The perspicuity of the original has been retained, and chapters which had become obsolete have been replaced by others of more modern character. The explanations throughout are studiously popular, and care has been taken to show the application of the various branches ol physics to the industrial arts, and to the practical business of life." Mining Journal. "Mr. Loewy has carefully revised the book, and brought it up to modern requirements." Nature. " Natural philosophy has had few exponents more able or better skilled In the art of popu- larising- the subject than Dr. Lardner ; and Mr. Loewy is doing good service in fitting this treatise, and the others of the series, for use at the present time." Scotsman. THE HANDBOOK OF HYDROSTATICS AND PNEUMATICS. New Edition, Revised and Enlarged, by BENJAMIN LOEWY, F.R.A.S. With 236 Illustrations. Post 8vo, 55. cloth. 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Engineering; "A most exhaustive book on the subject on which It treats, and is so arranged that it can be understood by all who desire to attain an accurate knowledge of physical science Mr. Loewy has included all the latest discoveries in the varied laws and effects of heat." Standard. "A complete and handy text-book for the use of students and general readers." English Mechanic. THE HANDBOOK OF OPTICS. ByDiONYSius LARDNER,D.C.L., formerly Professor of Natural Philosophy and Astronomy in University College, London. New Edition. Edited by T. OLVER HARDING, B.A. Lond., of University College, London. With 298 Illustrations. Small 8vo, 448 pages, 55. cloth. "Written by one of the ablest English scientific writers, beautifully and elaborately illustrated.'' Mechanic's Magazine. THE HANDBOOK OF ELECTRICITY, MAGNETISM, AND ACOUSTICS. By Dr. LARDNER. Ninth Thousand. Edit, by GEORGE CAREY FOSTER, B.A., F.C.S. With 400 Illustrations. Small 8vo, 55. cloth. " The book could not have been entrusted to anyone better calculated to preserve the terse and lucid style of Lardner, while correcting his errors and bringing up his work to the present state oi scientific knowledge." Popular Science Review. THE HANDBOOK OF ASTRONOMY. Forming a Companion to the " Handbook of Natural Philosophy.'' By DIONYSIUS LARDNER, D.C.L., formerly Professor of Natural Philosophy and Astronomy in University College, London. Fourth Edition. Revised and Edited by EDWIN DUNKIN, F.R.A.S., Royal Observatory, Greenwich. With 38 Plates and upwards of loo Woodcuts. In One Vol., small 8vo, 550 pages, gs. 6d. cloth. "Probably no other book contains the same amount of information in so compendious and well- arranged a form certainly none at the price at which this is offered to the public." Athenaum. "We can do no other than pronounce this work a most valuable manual of astronomy, and we strongly recommend it to all who wish to acquire a general but at the same time correct acquaint- ance with this sublime science." Quarterly Journal of Science. "One of the most deservedly popular books on the subject . . . We would recommend not only the student of the elementary principles of the science, but he who aims at mastering the higher and mathematical branches of astronomy, not to be without this work beside him." Practi- cal Magazine. Dr. Lardner's Electric Telegraph. THE ELECTRIC TELEGRAPH. By Dr. LARDNER. Re- vised and Re-written by E. B. BRIGHT, F.R.A.S. 140 Illustrations. Small 8vo, 2s. 6d. cloth. ' One of the most readable books extant on the Electric Telegraph." English Mechanic. 28 CROSBY LOCK WOOD & SON'S CATALOGUE. DR, LAKDNER'S MUSEUM OF SCIENCE AND ART. THE MUSEUM OF SCIENCE AND ART. Edited by DIONYSIUS LARDNER, D.C.L., formerly Professor of Natural Philosophy and Astronomy in University College, London. With upwards of 1,200 Engrav- ings on Wood. In 6 Double Volumes, i is., in a new and elegant cloth bind- ing ; or handsomely bound in half-morocco, 315. (id. V* OPINIONS OF THE PRESS. "This series, besides affording popular but sound instruction on scientific subjects, with which the humblest man in the country ought to be acquainted, also undertakes that teaching of ' Com- mon Things ' which every well-wisher of his kind is anxious to promote. Many thousand copies of this serviceable publication have been printed, in the belief and hope that the desire for instruction and improvement widely prevails ; and we have no fear that such enlightened faith will meet with disappointment." Times. " A cheap and interesting publication, alike Informing and attractive. 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Edited and Revised by JAMES GAULT, Professor of Commerce and Commercial Law in King's College, London. Crown 8vo, price about 35. 6d. [J the press. Accounts for Manufacturers. FACTORY ACCOUNTS: Their Principles and Practice. A Handbook for Accountants and Manufacturers, with Appendices oa the No- menclature of Machine Details ; the Income Tax Acts ; the Rating of Fac- tories ; Fire and Boiler Insurance ; the Factory and Workshop Acts, &c., including also a Glossary of Terms and a large number of Specimen Rulings, By EMILE GARCKE and J. M. FELLS. Third Edition. Demy 8vo, 250 pages, price 6s. strongly bound. " A very interesting description of the requirements of Factory Accounts. . . . the principle of assimilating the Factory Accounts to the general commercial books is one which we thoroughly agree with." Accountants' Journal. "There are few owners of Factories who would not derive great benefit from the perusal of this most admirable work." Local Government Chronicle, Foreign Commercial Correspondence. THE FOREIGN COMMERCIAL CORRESPONDENT: Being Aids to Commercial Correspondence in Five Languages English, French, German, Italian and Spanish. By CONRAD E. BAKER. Second Edition, Revised. Crown 8vo, 35. 6d. cloth. "Whoever wishes to correspond in all the languages mentioned by Mr. Baker cannot do better than study this work, the materials of which are excellent and conveniently arranged." Athemzunt, "A careful examination has convinced us that it is unusually complete, well arranged and reliable. The book is a thoroughly good one." Schoolmaster. Intuitive Calculations. THE COMPENDIOUS CALCULATOR; or, Easy and Con- cise Methods of Performing the various Arithmetical Operations required in Commercial and Business Transactions, together with Useful Tables. By D. O'GoRMAN. Corrected by Professor J. R. YOUNG. Twenty-seventh Ed., Revised by C. MORRIS. Fcap. 8vo, 2s. 6d. cloth ; or, 35. 6d. half-bound. " It would be difficult to exaggerate the usefulness of a book like this to everyone engaged in commerce or manufacturing industry." Knowledge. " Supplies special and rapid methods for all kinds of calculations. Of great utility to persons engaged in any kind of commercial transactions." Scotsman. Modern Metrical Units and Systems. MODERN METROLOGY: A Manual of the Metrical Units, and Systems of the Present Century. With an Appendix containing a proposed English System. By Lowis D'A. JACKSON, A.M.Inst.C.E., Author of "Aid to Survey Practice," &c. Large crown 8vo, las. 6d. cloth. "The author has brought together much valuable and interesting information. . . , We cannot but recommend the work." Nature. " For exhaustive tables of equivalent weights and measures of all sorts, and for clear demonstra- tions of the effects of the various systems that have been proposed or adopted, Mr. Jackson's treatise is without a rival." Academy. The Metric System and the British Standards. A SERIES OF METRIC TABLES, in which the British Stand- ard Measures and Weights are compared with those of the Metric System at present in Use on the Continent. By C. H. DOWLING, C.E. 8vo, los. 6d. strongly bound. "Their accuracy has been certified by Professor Airy, the Astronomer-Royal." Builder. "Mr. Bowling's Tables are well put together as a ready-reckoner for the conversion of one system into the other." Athenceum. Iron and Metal Trades 9 Calculator. THE IRON AND METAL TRADES' COMPANION. For expeditiously ascertaining the Value of any Goods bought or sold by Weight, irom is. per cwt. to ii2s. per cwt., and from one farthing per pound to one shilling per pound. Each Table extends from one pound to 100 tons. To which are appended Rules on Decimals, Square and Cube Root, Mensuration ot Superficies and Solids, &c. ; also Tables of Weights of Materials, and other Useful Memoranda. ByTnos. DOWNIE. Strongly bound in leather, 396 pp. ,95. " A most useful set of tables. . . . Nothing like them before existed." Building News. " Although specially adapted to the iron and metal trades, the tables will be found useful in every other business in which merchandise is bought and sold by weight." Rail-way News. 30 CROSBY LOCKWOOD & SON'S CATALOGUE. Calculator for Numbers and Weights Combined. THE NUMBER, WEIGHT AND FRACTIONAL CALCU- LATOR. Containing upwards of 250,000 Separate Calculations, showing at a glance the value at 422 different rates, ranging from ^th of a Penny to 2os. each, or per cwt., and 20 per ton, of any number or articles consecu- tively, from i to 470. Any number of cwts., qrs., and lbs v , from i cwt. to 470 cwts. Any number of tons, cwts., qrs., and Ibs., from i to 1,000 tons. By WILLIAM CHADWICK, Public Accountant. Third Edition, Revised and Im- proved. 8vo, price i8s., strongly bound for Office wear and tear. *** This work is specially adapted for the Apportionment of Mileage Charges for Railway Traffic. fS This comprehensive and entirely unique and original Calculator is adapted for the use of Accountants and Auditors, Railway Companies, Canal Companies, Shippers, Shipping Agents, General Carriers, etc. I ronf onnders, Brass founders, Metal Merchants, Iron Manufacturers, Ironmongers, Engineers, Machinists, Boiler Makers, Millwrights, Roofing, Bridge and Girder Makers, Colliery Proprietors, etc. Timber Merchants, Builders, Contractors, Architects, Surveyors, Auctioneers Valuers, Brokers, Mill Owners and Manufacturers, Mill Furnishers, Merchants and General Wholesale Tradesmen. *** OPINIONS OF THE PRESS. "The book contains the answers to questions, and not simply a set of Ingenious puzzle methods of arriving at results. It is as easy of reference for any answer or any number of answers as a dictionary, and the references are even more quickly made. For making up accounts or esti- mates, the book must prove _ invaluable to all who have any considerable quantity of calculations involving price and measure in any combination to do." Engineer. " The most perfect work of the kind yet prepared." Glasgow Herald. Comprehensive Weight Calculator. THE WEIGHT CALCULATOR. Being a Series of Tables upon a New and Comprehensive Plan, exhibiting at One Reference the exact Value of any Weight from i Ib. to 15 tons, at 300 Progressive Rates, from id. to i68s. per cwt., and containing 186,000 Direct Answers, which, with their Combinations, consisting of a single addition (mostly to be performed at sight), will afford an aggregate of 10,266,000 Answers ; the whole being calcu- lated and designed to ensure correctness and promote despatch. By HENRY HARBEN, Accountant. Fourth Edition, carefully Corrected. Royal 8vo, strongly half-bound, 1 55. " A practical and useful work of reference for men of business generally ; it is the best of the kind we have seen." Ironmonger. "Of priceless value to business men. It is a necessary book in all mercantile offices." Shef- field Independent. Comprehensive Discount Guide. THE DISCOUNT GUIDE. Comprising several Series of Tables for the use of Merchants, Manufacturers, Ironmongers, and others, by which may be ascertained the exact Profit arising from any mode of using Discounts, either in the Purchase or Sale of Goods, and the method of either Altering a Rate of Discount or Advancing a Price, so as to produce, by one operation, a sum that will realise any required profit after allowing one or more Discounts : to which are added Tables of Profit or Advance from i to go per cent., Tables of Discount from ij to g8f per cent., and Tables of Com- mission, &c., from | to 10 per cent. By HENRY HARBEN, Accountant, Author of" The Weight Calculator." New Edition, carefully Revised and Corrected. Demy 8vo, 544 pp. half-bound, i 55. " A book sudi as this can only be appreciated by business men, to whom the saving: of time means saving of money. We have the high authority of Professor J. R. Young that the tables throughout the work are constructed upon strictly accurate principles. The work is a mode of typographical clearness, and must prove of great value to merchants, manufacturers, and general traders." British Trade Journal, Iron Shipbuilders 9 and Merchants 9 Weight Tables. IRON- PL ATE WEIGHT TABLES: For Iron Shipbuilders, Engineers and Iron Merchants. Containing the Calculated Weights of up- wards of 150,000 different sizes of Iron Plates, from i foot by 6 in. by $ in. to 10 feet by 5 feet by i in. Worked out on the basis of 40 Ibs. to the square foot of Iron of i inch in thickness. Careiuily compiled and thoroughly Re- vised by H. BURLINSON and W. H. SIMPSON. Oblong 4to, 255. half-bound. "This work will be found of great utility. The authors have had much practical experience of what is wanting in making estimates; and the use of the book will save much time in making elaborate calculations." English Mechanic. INDUSTRIAL AND USEFUL ARTS. 31 INDUSTRIAL AND USEFUL ARTS. Soap-making. THE ART OF SOAP-MAKING : A Practical Handbook of the Manufacture of Hard and Soft Soaps, Toilet Soaps, etc. Including many New Processes, and a Chapter on the Recovery of Glycerine from Waste Leys. By ALEXANDER WATT, Author oi " Electro-Metallurgy Practically Treated," &c. With numerous Illustrations. Fourth Edition, Revised and Enlarged. Crown 8vo, 75. 6d . cloth. "The work will prove very useful, not merely to the technological student, but to the practical ^oap-boiler who wishes to understand the theory of his art." Chemical New s. "Mr. Watt's book is a thoroughly practical treatise on an art which has almost no literature In our language. We congratulate the author on the success of his endeavour to fill a void in English technical literature." Nature. Paper Malting. THE ART OF PAPER MAKING : A Practical Handbook of the Manufacture of Paper from Rags, Esparto, Straw and other Fibrous Materials, Including the Manufacture of Pulp trom Wood Fibre, with a Description of the Machinery and Appliances used. To which are added Details of Processes for Recovering Soda from Waste Liquors. By ALEXANDER WATT. With Illustrations. Crown 8vo, 75. 6d. cloth. "This book is succinct, lucid, thoroughly practical, and includes everything of interest to the modern paper maker. It is the latest, most practical and most complete work on the paper-making art before the British public." Paper Record. ' It may be regarded as the standard work on the subject. The book is full of valuable in- formation. The ' Art of Paper-making,' is in every respect a model of a text-book, either for a technical class or for the private student." Paper and Printing Trades Journal. " Admirably adapted for general as well as ordinary technical reference, and as a handbook for students in technical education may be warmly commended." The Paper Maker's Monthly Journal. Leather Manufacture. THE ART OF LEATHER MANUFACTURE. Being a Practical Handbook, in which the Operations of Tanning, Currying, and Leather Dressing are fully Described, the Principles of Tanning Explained and many Recent Processes introduced. By ALEXANDER WATT, Author of " Soap-Making," &c. With numerous Illustrations. Second Edition. Crown Svo, gs. cloth. "A sound, comprehensive treatise on tanning and its accessories. This book is an eminently valuable production, which redounds to the credit of both author and publishers." Chemical Review. "This volume is technical without being tedious, comprehensive and complete without being prosy, and it bears on every page the impress of a master hand. We have never come across a better trade treatise, nor one that so thoroughly supplied an absolute want." Shoe atid Leather Trades' Chronicle. Boot and Shoe Malting. THE ART OF BOOT AND SHOE-MAKING. A Practical Handbook, including Measurement, Last-Fitting, Cutting-Out, Closing and Making, with a Description of the most approved Machinery employed. By JOHN B. LENO, late Editor of St. Crispin, and The Boot and Shoe-Maker. With numerous Illustrations. Third Edition. i2mo, zs. cloth limp. " This excellent treatise is by far the best work ever written on the subject. A new work, embracing all modern improvements, was much wanted. This want is now satisfied. The chapter on clicking, which shows now waste may be prevented, will save fifty times the price of the book." Scottish Leather Trader. Dentistry. MECHANICAL DENTISTRY: A Practical Treatise on the Construction of the various kinds of Artificial Dentures. Comprising also Use- ful Formulae, Tables and Receipts for Gold Plate, Clasps, Solders, &c. &c. By CHARLES HUNTER. Third Edition, Revised. With upwards of 100 Wood Engravings. Crown Svo, 35. 6d. cloth. " The work is very practical." Monthly Review of Dental Surgery. " We can strongly recommend Mr. Hunter's treatise to all students preparing for the profession of dentistry, as well as to every mechanical dentist." Dublin Journal of Medical Science. Wood Engraving. WOOD ENGRA VING : A Practical and Easy Introduction to the Study of Vie Art. By WILLIAM NORMAN BROWN. Second Edition. With numerous Illustrations. 12010, is. 6d. cloth limp. " The book is clear and complete, and will be useful to anyone wanting to understand the first elements of the beautiful art of wood engraving." Graphic, 32 CROSBY LOCK WOOD & SON'S CATALOGUE. HANDYBOOKS FOR HANDICRAFTS. By PAUL N, HASLUCK. Metal Turning. THE MET A L TURNER'S HA ND YBOOK. A Practical Manual for Workers at the Foot-Lathe: Embracing Information on the Tools, Appliances and Processes employed in Metal Turning. By PAUL N. HAS- LUCK, Author of " Lathe-Work." With upwards of One Hundred Illustra- tions. Second Edition, Revised. Crown 8vo, zs. cloth. " Clearly and concisely written, excellent in every way." Mechanical World. Wood Turning. THE WOOD TURNER'S HANDYBOOK. A Practical Manual for Workers at the Lathe : Embracing Information on the Tools, Appliances and Processes Employed in Wood Turning. By PAUL N. HASLUCK. With upwards of One Hundred Illustrations. Crown 8vo, zs- cloth. "We recommend the book to young turners and amateurs. A multitude of workmen have hitherto sought in vain for a manual of this special industry." Mechanical World. WOOD AND METAL TURNING. By P. N. HASLUCK. (Being the Two preceding Vols. bound together.) 300 pp., with upwards of 200 Illustrations, crown 8vo, 35. 6d. cloth. Watch Repairing. THE WATCH JOBBER'S HANDYBOOK. A Practical Manual on Cleaning, Repairing and Adjusting. Embracing Information on the Tools, Materials, Appliances and Processes Employed in Watchwork. By PAUL N. HASLUCK. With upwards of One Hundred Illustrations. Cr. 8vo, zs. cloth. " All young persons connected with the trade should acquire and study this excellent, and at the same time, inexpensive \voik."CUrenweM Chronicle. Clock Repairing. THE CLOCK JOBBER'S HANDYBOOK: A Practical Manual on Cleaning, Repairing and Adjusting. Embracing Information on the Tools, Materials, Appliances and Processes Employed in Clockwork. By PAUL N. HASLUCK. With upwards of 100 Illustrations. Cr. 8vo,2s. cloth. " Of inestimable service to those commencing the trade." Coventry Standard, WATCH AND CLOCK JOBBING. By P. N. HASLUCK. (Being the Two preceding Vols. bound together.) 320 pp., with upwards of zoo Illustrations, crown 8vo, 33. 6d. cloth. Pattern Making. THE PATTERN MAKER'S HANDYBOOK. A Practical Manual, embracing Information on the Tools, Materials and Appliances em- ployed in Constructing Patterns for Founders. By PAUL N. HASLUCK. With One Hundred Illustrations. Crown 8vo, 2s. cloth. "This handy volume contains sound information of considerable value to students and artificers." Hardware Trades Journal. Mechanical Manipulation. THE ME CHA NIC'S WORKSHOP HA ND YBOOK. A Practical Manual on Mechanical Manipulation. Embracing Information on various Handicraft Processes, with Useful Notes and Miscellaneous Memoranda. By PAUL N. HASLUCK. Crown 8vo, 25. cloth. " It is a book which should be found in every workshop, as it is one which will be continually referred to for a very great amount of standard information." Saturday Re-view. Model Engineering. THE MODEL ENGINEER'S HANDYBOOK: A Practical Manual on Model Steam Engines. Embracing Information on the Tools, Materials and Processes Employed in their Construction. By PAUL N. HASLUCK. With upwards of 100 Illustrations. Crown 8vo, 2s. cloth. " By carefully going through the work, amateurs may pick up an excellent notion of the con- struction of full-sized steam engines." Telegraphic Journal. Cabinet Making. THE CABINET WORKER'S HANDYBOOK: A Practical Manual, embracing Information on the Tools, Materials, Appliances and Processes employed in Cabinet Work. By PAUL N. HASLUCK, Author of " Lathe Work," &c. With upwards of 100 Illustrations. Crown 8vo, zs. Cloth. {Glasgow Herald. " Thoroughly practical throughout. The amateur worker in wood will find it most useful." INDUSTRIAL AND USEFUL ARTS. 33 Electrolysis of Gold, Silver, Copper, etc. ELECTRO-DEPOSITION : A Practical Treatise on the Electrolysis of Gold, Silver, Copper, Nickel, and other Metals and Alloys. With descrip- tions of Voltaic Batteries, Magneto and Dynamo-Electric Machines, Ther- mopiles, and of the Materials and Processes used in every Department of the Art, and several Chapters on Electro- Metallurgy. By ALEXANDER WATT. Third Edition, Revised and Corrected. Crown 8vo, 95. cloth. "Eminently a book for the practical worker in electro-deposition. It contains practical descriptions of methods, processes and materials as actually pursued and used in the workshop." Engineer. Electro-Metallurgy \ ELECTRO-MET ALL URG Y ; Practically Treated. By ALEXANDER WATT. Author of "-Electro-Deposition," &c. Ninth Edition, Enlarged and Revised, with Additional Illustrations, and including the most recent Processes. lamo, 45. cloth boards. "From this book both amateur and artisan may learn everything necessary for the successfu prosecution of electroplating." Iron, Electroplating. ELECTROPLATING: A Practical Handbook on the Deposi- tion of Copper, Silver, Nickel, Gold, Aluminium, Brass, Platinum, &c. &c. With Descriptions of the Chemicals, Materials, Batteries and Dynamo Machines used in the Art. By J. W. URQUHART, C.E. Second Edition, with Additions. Numerous Illustrations. Crown 8vC; 55. cloth. " An excellent practical manual." Engineering; " An excellent work, giving the newest information." Horological Journal. Electrotyping. ELECTROTYPING : The Reproduction and Multiplication of Print- ing Surfaces and Works of Art by the Electro-deposition of Metals. By J. W. URQUHART, C.E. Crown 8vo, 55. cloth. " The book is thoroughly practical. The reader is, therefore, conducted through the leading aws of electricity, then through the metals used by electrotypers, the apparatus, and the depositing processes, up to the final preparation of the work." Art Journal. Horology. A TREATISE ON MODERN HOROLOGY, in Theory and Prac- tice. Translated from the French of CLAUDIUS SAUNIER, by JULIEN TRIP- PLIN, F.R.A.S., and EDWARD RIGG, M.A., Assayer in the Royal Mint. With 78 Woodcuts and 22 Coloured Plates. Second Edition. Royal 8vo, 2 2S. cloth ; 2 los. half-calf. " There is no horological work in the English language at all to be compared to this produc- tion of M. Saunier's for clearness and completeness. It is alike good as a guide for the student and as a reference for the experienced horologist and skilled workman." Horological Journal. " The latest, the most complete, and the most reliable of those literary productions to which continental watchmakers are indebted for the mechanical superiority over their English brethren in fact, the Book of Books, is M. Saunier's ' Treatise. 1 "Watchmaker, "Jeweller and Silversmith. Watchmaking. THE WATCHMAKERS HANDBOOK. A Workshop Com- panion for those engaged in Watchmaking and the Allied Mechanical Arts. From the French of CLAUDIUS SAUNIER. Enlarged by JULIEN TRIPPLIN, F.R.A.S., and EDWARD RIGG, M.A., Assayer in the Royal Mint. Woodcuts and Copper Plates. Third Edition, Revised. Crown 8vo, 95. cloth, " Each part is truly a treatise in itself. The arrangement is good and the language is clear and concise. It is an admirable guide for the young watchmaker." Engineering. " It is impossible to speak too highly of its excellence. It fulfils every requirement in a hand- book intended for the use of a worKman." IVatch and Clockmaker. ' This book contains an immense number of practical details bearing on the daily occupation of a watchmaker." Watchmaker and Metalworker (Chicago). Goldsmiths' Work. THE GOLDSMITH'S HANDBOOK. By GEORGE E. GEE, Jeweller, &c. Third Edition, considerably Enlarged. 12010, 35. 6d. cl. bds. "A good, sotnd educator, and will be accepted as an authority." Horological Journal. Silversmiths 9 Work. THE SILVERSMITH'S HANDBOOK. By GEORGE E. GEE, Jeweller, &c. Second Edition, Revised, with numerous Illustrations. i2mo, 35. 6d. cloth boards. "Workers in the trade will speedily discover its merits when they sit down to study it." English Mechanic. %* The above two works together, strongly half-bound, price 75. D 34 CROSBY LOCK WOOD & SON'S CATALOGUE. Bread and Biscuit Baking. THE BREAD AND BISCUIT BAKER'S AND SUGAR- BOILER'S ASSISTANT. Including a large variety of Modern Recipes. With Remarks on the Art of Bread-making. By ROBERT WELLS, Practical Baker. Second Edition, with Additional Recipes. Crown 8vo, zs. cloth. " A large number of wrinkles for the ordinary cook, as well as the baker." Saturday Review. Confectionery, THE PASTRYCOOK AND CONFECTIONER'S GUIDE. For Hotels, Restaurants and the Trade in general, adapted also for Family Use. By ROBERT WELLS, Author of " The Bread and Biscuit Baker's and Sugar Boiler's Assistant." Crown 8vo, 2s. cloth. " We cannot speak too highly of this really excellent work. In these days of keen competition our readers cannot do better than purchase this book." Bakers' Times. Ornamental Confectionery. ORNAMENTAL CONFECTIONERY : A Guide for Bakers, Confectioners and Pastrycooks ; including a variety of Modern Recipes, and Remarks on Decorative and Coloured Work. With 129 Original Designs. By ROBERT WELLS. Crown 8vo, 55. cloth. "A valuable work, and should be in the hands of every baker and pnfectioner. The illus- trative designs are alone worth treble the amount charged for the whole work." Bakers' Times. Flour Confectionery. THE MODERN FLOUR CONFECTIONER. Wholesale and Retail. Containing a large Collection of Recipes for Cheap Cakes, Biscuits, &c. With Remarks on the Ingredients used in their Manufacture, &c. By R. WELLS, Author of " Ornamental Confectionery," "The Bread and Biscuit Baker," " The Pastrycook's Guide," &c. Crown 8vo, 2s. cloth. Laundry Work. LA UN DRY MANAGEMENT. A Handbook for Use in Private and Public Laundries, Including Descriptive Accounts of Modern Machinery and Appliances for Laundry Work. By the EDITOR of " The Laundry Journal." With numerous Illustrations. Crown 8vo, zs. 6d. cloth. CHEMICAL MANUFACTURES & COMMERCE. New Manual of Engineering Chemistry. ENGINEERING CHEMISTRY: A Practical Treatise for the Use of Analytical Chemists, Engineers, Iron Masters, Iron Founders, Students, and others. Comprising Methods of Analysis and Valuation of the Principal Materials used in Engineering Work, with numerous Analyses, Examples, and Suggestions. By H. JOSHUA PHILLIPS, F.I.C., F.C.S., Analytical and Consulting Chemist to the Great Eastern Railway. Crown 8vo, 320 pp., with Illustrations, los. 6d. cloth. [Just published. " In this work the author has rendered no small service to a numerous body of practical men. . . . The analytical methods may be pronounced most satisfactory, being as accurate as the despatch required of engineering chemists permits." Chemical Neius. Analysis and Valuation of Fuels. FUELS: SOLID, LIQUID AND- GASEOUS, Their Analysis and Valuation. For the Use of Chemists and Engineers. By H. J. PHILLIPS, F.C.S., Analytical and Consulting Chemist to the Great Eastern Railway. Crown 8vo, 35. 6d. cloth. " Ought to have its place in the laboratory of every metallurgical establishment, and wherever fuel is used on a large scale." Chemical News. " Cannot fail to be of wide interest, especially at the present time." Railway News. Alkali Trade, Manufacture of Sulphuric Acid, etc. A MANUAL OF THE ALKALI TRADE, including the Manufacture of Sulphuric Acid, Sulphate of Soda, and Bleaching Powder. By JOHN LOMAS. 39 pages. With 232 Illustrations and Working Drawings. Second Edition. Royal 8vo, i IDS. cloth. "This book is written by a manufacturer for manufacturers. The working details of the most approved forms of apparatus are given, and these are accompanied by no less than 232 wood en- gravings, all of which may be used for the purposes of construction." Athenatum. AGRICULTURE, FARMING, GARDENING, etc. 35 The Blowpipe. THE BLOWPIPE IN CHEMISTRY, MINERALOGY, AND GEOLOGY. Containing all known Methods of Anhydrous Analysis, Work- ing Examples, and Instructions for Making Apparatus. By Lieut.-Col. W. A. Ross, R.A. With 120 Illustrations. New Edition. Crown 8vo, 55. cloth. "The student who goes through the course of experimentation here laid down will gain a better insight into inorganic chemistry and mineralogy than if he had 'got up' any of the best text-books ot the day, and passed any number of examinations in their contents. Chemical News. Commercial Chemical Analysis. THE COMMERCIAL HANDBOOK OF CHEMICAL ANA- LYSIS; or, Practical Instructions tor the determination of the Intrinsic or Commercial Value of Substances used in Manufactures.Trades, and the Arts. By A. NORMANDY. New Edition by H. M. NOAD, F.R.S. Cr. 8vo, 125. 6d. cl. "Essential to the analysts appointed under the new Act. The most recent results are given, and the work is well edited and carefully written." Nature. Brewing. A HANDBOOK FOR YOUNG BREWERS. By HERBERT EDWARDS WRIGHT, B.A. New Edition, much Enlarged. [In the press. Dye-Wares and Colours. THE MANUAL OF COLOURS AND DYE-WARES : Their Properties, Applications, Valuation, Impurities, and Sophistications. For the use of Dyers, Printers, Drysalters, Brokers, &c. By J. W. SLATER. Second Edition, Revised and greatly Enlarged. Crown 8vo, ys. 6d. cloth. "A complete encyclopaedia of the materia tinctoria. The information given respecting each article is full and precise, and the methods of determining the value of articles such as these, so liable to sophistication, are given with clearness, and are practical as well as valuable." Chemist and Druggist. " There is no other work which co_vers precisely the same ground. To students preparing for examinations in dyeing and printing it will prove exceedingly useful." Chemical News. figments. THE ARTIST'S MANUAL OF PIGMENTS. Showing their Composition, Conditions of Permanency, Non-Permanency, and Adul- terations; Effects in Combination with Each Other and with Vehicles ; and the most Reliable Tests of Purity. By H. C. STANDAGE. Second Edition. Crown 8vo, zs. 6d. cloth. " This work is indeed multum-in-parvo, and we can, with good conscience, recommend it to all who come in contact with pigments, whether as makers, dealers or users." Chemical Review. Gauging. Tables and Rules for Revenue Officers, Bretvers, etc. A POCKET BOOK OF MENSURATION AND GAUGING : Containing Tables, Rules and Memoranda for Revenue Officers, Brewers, Spirit Merchants, &c. By J. B. MANT (Inland Revenue). Second Edition Revised. Oblong i8mo, 4$. leather, with elastic band. " This handy and useful book is adapted to the requirements of the Inland Revenue Depart- ment, and will be a favourite book of reference." Civilian, " Should be in the hands of every practical bievrer."rewers' Journal, AGRICULTURE, FARMING, GARDENING, etc. Youatt and Burn's Complete Grazier. THE COMPLETE GRAZIER, and FARMER'S and CATTLE- BREEDER'S ASSISTANT. Including the Breeding, Rearing, and Feeding of Stock ; Management of the Dairy, Culture and Management of Grass Land, and of Grain and Root Crops, &c. By W. YOUATT and R. SCOTT BURN. An entirely New Edition, partly Re-written and greatly Enlarged, by W. FREAM, B.Sc.Lond., LL.D. In medium 8vo, about 1,000 pp. [/ the press, Agricultural Facts and Figures. NOTE-BOOK OF AGRICULTURAL FACTS AND FIGURES FOR FARMERS AND FARM STUDENTS. By PRIMROSE MCCONNELL, late Professor of Agriculture, Glasgow Veterinary College. Third Edition. Royal 32mo, 45. leather. "The most complete and comprehensive Note-book for Farmers and Farm Students that we have seen. It literally teems with information, and we can cordia llyrecommend it to all connected with agrcuilture." North British Agriculturist, 36 CROSBY LOCK WOOD <& SON'S CATALOGUE. Flour Manufacture, Milling, etc. FLOUR MANUFACTURE: A Treatise on Milling Science and Practice. By FRIEDRICH KICK, Imperial Regierungsrath, Professor of Mechanical Technology in the Imperial German Polytechnic Institute, Prague. Translated from the Second Enlarged and Revised Edition with Supplement. By H. H. P. POWLES, A.M.I.C.E. Nearly 400 pp. Illustrated with 28 Folding Plates, and 167 Woodcuts. Royal 8vo, 255. cloth. " This valuable work is, and will remain, the standard authority on the science of milling. , The miller who has read and digested this work will have laid the foundation, so to speak, of a suc- cessful career ; he will have acquired a number of general principles which he can proceed to apply. In this handsome volume we at last have the accepted text-book of modern milling in good, sound English, which has little, if any, trace of the German idiom." The Miller. " The appearance of this celebrated work in English is very opportune, and British millers will, we are sure, not be slow in availing themselves of its pages." Millers' Gazette. Small Farming. SYSTEMATIC SMALL FARMING; or, The Lessons of my Farm. Being an Introduction to Modern Farm Practice for Small Farmers in the Culture of Crops ; The Feeding of Cattle; The Management of the Dairy, Poultry and Pigs, &c. &c. By ROBERT SCOTT BURN, Author of " Out- lines of Landed Estates' Management." Numerous Illusts., cr. 8vo, 6s. cloth. "This is the completest book of its class we have seen, and one which every amateur farmer will read with pleasure and accept as a guide." field. "The volume contains a vast amount of useful information. No branch of farming is le(t untouched, from the labour to be done to the results achieved. It may be safely recommended to all who think they will be in paradise when they buy or rent a three-acre farm." Glasgow Herald. Modern Farming. OUTLINES OF MODERN FARMING. By R. SCOTT BURN. Soils, Manures, and Crops Farming and Farming Economy Cattle, Sheep, and Horses Management of Dairy, Pigs and Poultry Utilisation of Town-Sewage, Irrigation, &c. Sixth Edition. In One Vol., 1,250 pp., half- bound, profusely Illustrated, 125. " The aim of the author has been to make his work at once comprehensive and trustworthy, and in this aim he has succeeded to a degree which entitles him to much credit." Morning Advertiser. " No farmer should be without this book." Banbury Guardian. Agricultural Engineering. FARM ENGINEERING, THE COMPLETE TEXT-BOOK OF. Comprising Draining and Embanking ; Irrigation and Water Supply ; Farm Roads, Fences, and Gates ; Farm Buildings, their Arrangement and Con- struction, with Plans and Estimates; Barn Implements and Machines ; Field implements and Machines; Agricultural Surveying, Levelling, &c. By Prof. JOHN SCOTT, Editor of the " Farmers' Gazette," late Professor of Agriculture and Rural Economy at the Royal Agricultural College, Cirencester, &c. &c. In One Vol., 1,150 pages, half-bound, with over 600 Illustrations, izs, "Written with great care, as well as with knowledge and ability. The author has done his work well ; we have found him a very trustworthy guide wherever we have tested his statements. The volume will be of great value to agricultural students." Mark Lane Express. " For a young agriculturist we know ofino handy volume likely to be more usefully studied. Bell's Weekly Messenger. English Agriculture. THE FIELDS OF GREAT BRITAIN : A Text-Book of Agriculture, adapted to the Syllabus of the Science and Art Department. For Elementary and Advanced Students. By HUGH CLEMENTS (Board of Trade). Second Ed. .Revised, with Additions. i8mo, zs. 6d. cl. "A most comprehensive volume, giving a mass of information." Agricultural Economist. " It is a long time since we have seen a book which has pleased us more, or which contains such a vast and useful fund of knowledge." Educational Times. Tables for Farmers, etc. TABLES, MEMORANDA, AND CALCULATED RESULTS for Farmers, Graziers, Agricultural Students, Surveyors, Land Agents Auc- tioneers, etc. With a New System of Farm Book-keeping. Selected and Arranged by SIDNEY FRANCIS. Second Edition, Revised. 272 pp., waist- coat-pocket size, is. 6d. limp leather. " Weighing less than x oz., and occupying no more space than a match box, it contains a mass of facts and calculations which has never before, in such handy form, been obtainable. Every operation on the tarm is dealt with. The work may be taken as thoroughly accurate, the whole of the tables having been revised by Dr. Fream. We cordially recommend it." Bclfs Weekly Messenger. ' A marvellous little book. . . . The agriculturist who possesses himself of it will not be disappointed with his investment." The Farm. AGRICULTURE, FARMING, GARDENING, etc. 37 Farm and Estate Book-keeping. BOOK-KEEPING FOR FARMERS < ESTATE OWNERS. A Practical Treatise, presenting, in Three Plans, a System adapted for all Classes of Farms. By JOHNSON M. WOODMAN, Chartered Accountant. Second Edition, Revised. Cr. 8vo, 3$. 6d. cl. bds. ; or is. 6d. cl. limp. " The volume is a capital study of a most important s\&>]e.c\.."Agricnttttral Gazette. "Will be found of great assistance by those who intend to commence a system of book-keep- ing-, the author's examples being clear and explicit, and his explanations, while full and accurate, being to a large exteut free from technicalities." we Stock Journal. Farm Account Book. WOODMAN'S YEARLY FARM ACCOUNT BOOK. Giving a Weekly Labour Account and Diary, and showing the Income and Expen- diture under each Department of Crops, Live Stock, Dairy, &c. &c. With Valuation, Profit and Loss Account, and Balance Sheet at the end of the Year, and an Appendix of Forms. Ruled and Headed for Entering a Com- plete Record of the Farming Operations. By JOHNSON M. WOODMAN, Chartered Accountant. Folio, 75. 6d. half bound. [.culture. "Contains every requisite form for keeping farm accounts readily and accurately." Agri- Early Fruits, Flowers and Vegetables. THE FORCING GARDEN ; or, How to Grow Early Fruits, Flowers, and Vegetables. With Plans and Estimates for Building Glass- houses, Pits and Frames. By SAMUEL WOOD. Crown 8vo, 35. 6d. cloth. " A good book, and fairly fills a place that was in some degree vacant. The book is written with great care, and contains a great deal of valuable teaching." Gardeners' Magazine. " Mr. Wood's book is an original and exhaustive answer to the question ' How to Grow Early- Fruits, Flowers and Vegetables? ' "Land and Water. Good Gardening. A PLAIN GUIDE TO GOOD GARDENING ; or, How to Grow Vegetables, Fruits, and Flowers. With Practical Notes on Soils, Manures, Seeds, Planting, Laying-out of Gardens and Grounds, &c. By S. WOOD. Fourth Edition, with numerous Illustrations. Crown 8vo, 35. 6d. cloth. " A very good book, and one to be highly recommended as a practical guide. The practical directions are excellent." Athentzum. " May be recommended to young gardeners, cottagers, and specially to amateurs, for the plain, simple, and trustworthy information it gives on common matters too often neglected." Gardeners' Chronicle. Gainful Gardening. MULTUM-IN-PARVO GARDENING; cr, How to make One Acre of Land produce 620 a-year by the Cultivation of Fruits and Vegetables ; also, How to Grow Flowers in Three Glass Houses, so as to realise 176 per annum clear Profit. By S. WOOD. Fifth Edition. Crown 8vo, is. sewed. "We are bound to recommend it as not only suited to the case of the amateur and gentleman's gardener, but to the market grower." Gardeners' Magazine. Gardening for Ladies. THE LADIES' MULTUM-IN-PARVO FLOWER GARDEN, and Amateurs' Complete Guide. By S. WOOD. With Illusts. Cr.Svo, 35. 6d. cl. " This volume contains a good deal of sound, common sense instruction." Florist. "Full of shrewd hints and useful instructions, based on a lifetime of experience." Scotsman. Receipts for Gardeners. GARDEN RECEIPTS. By C. W. QUIN. lamo, is. 6d. cloth. "A useful and handy book, containing a good deal of valuable information." Athenceum. Market Gardening. MARKET AND KITCHEN GARDENING. By Contributors to " The Garden." Compiled by C. W. SHAW, late Editor of "Gardening Illustrated." i2mo, 35. 6d. cloth boards. " The most valuable compendium of kitchen and market-garden work published." Farmer. Cottage Gardening. COTTAGE GARDENING; or, Flowers, Fruits, and Vegetables for Small Gardens. By E. HOBDAY, ismo, is. 6d. cloth limp. Potato Culture. POTATOES : How to Grow and Show Them. A Practical Guide to the Cultivation and General Treatment of the Potato. By JAMES PINK. Second Edition. Crown 8vo, 2s. cloth. 38 CROSBY LOCK WOOD 6* SON '5 CATALOGUE. LAND AND ESTATE MANAGEMENT, LAW, etc. Hudson's Land Valuer's Pocket-Book. THE LAND VALUER'S BEST ASSISTANT: Being Tables on a very much Improved Plan, for Calculating the Value of Estates. With Tables for reducing Scotch, Irish, and Provincial Customary Acres to Statute Measure, &c. By R. HUDSON, C.E. New Edition. Royal 32010, leather, elastic band, 4$. "This new edition includes tables for ascertaining the value of leases for any term of years ; and for showing how to lay out plots of ground of certain acres in forms, square, round, &c., with valuable rules for ascertaining the probable worth of standing timber to any amount ; and is of incalculable value to the country gentleman and professional man." Farmers Journal. Ewart's Land Improver's Pocket-Book. THE LAND IMPROVER'S POCKET-BOOK OF FORMULA, TABLES and MEMORANDA required in any Computation relating to the Permanent Improvement of Landed Property. By JOHN EWART, Land Surveyor and Agricultural Engineer. Second Edition, Revised, Royal samo, oblong, leather, gilt edges, with elastic band, 4$. "A compendious and handy little volume." Spectator. Complete Agricultural Surveyor's Pocket-Boole. THE LAND VALUER'S AND LAND IMPROVER'S COM- PLETE POCKET-BOOK. Consisting of the above Two Works bound to- gether. Leather, gilt edges, with strap, 75. 6d. " Hudson's book is the best ready-reckoner on matters relating to the valuation of land and crops, and its combination with Mr. Ewart's work greatly enhances the value and usefulness of the latter-mentioned. . . . It is most useful as a manual for reference." North (if England Farmer. Auctioneer's Assistant. THE APPRAISER, A UCTIONEER, BROKER, HOUSE AND ESTA TE A GENT AND VALUER'S POCKE T A SSISTA NT, tor the Valua- tion for Purchase, Sale, or Renewal of Leases, Annuities and Reversions, and of property generally; with Prices for Inventories, &c. By JOHN WHEELER, Valuer, &c. Fifth Edition, re-written and greatly extended by C. NORRIS, Surveyor, Valuer, &c. Royal 32010, 5$. cloth. " A neat and concise book of reference, containing an admirable and clearly-arranged list of prices for inventories, and a very practical guide to determine the value of furniture.&c." Standard. " Contains a large quantity of varied and useful information as to the valuation for purchase, sale, or renewal of leases, annuities and reversions, and of property generally, with prices for Inventories, and a guide to determine the value of interior fittings and other effects." Builder. Auctioneering. AUCTIONEERS: THEIR DUTIES AND LIABILITIES. A Manual of Instruction and Counsel for the Young Auctioneer. By ROBERT SQUIBBS, Auctioneer. Second Edition, Revised and partly Re-written. Demy 8vo, 125. 6d. cloth. "The position and duties of auctioneers treated compendiously and clearly." Builder. "Every auctioneer ought to possess a copy of this excellent work." Ironmonger. " Of great value to the profession. . . . We readily welcome this book from the fact that It treats the subject in a manner somewhat new to the profession." Estates Gazette. Legal Guide for Pawnbrokers. THE PAWNBROKERS', FACTORS' AND MERCHANTS' GUIDE TO THE LAW OF LOANS AND PLEDGES. With the Statutes and a Digest of Cases on Rights and Liabilities, Civil and Criminal, as to Loans and Pledges of Goods, Debentures, Mercantile and other Se- curities. By H. C. FOLKARD, Esq., Barrister-at-Law, Author of " The Law of Slander and Libel," &c. With Additions and Corrections. Fcap. 8vo, 35. 6d. cloth. " This work contains simply everything that requires to be known concerning the department of the law of which it treats. We can safely commend the book as unique and very nearly perfect.' Iron. tie task undertaken bv Mr. Folkard has been verv satisfactorily oerf< . . . iue regard to brevity. ' "The task undertaken by Mr. Folkard has been very satisfactorily performed. . . . Such ex- planations as are needfut have been supplied with great clearness and with dv City Press. LAND AND ESTATE MANAGEMENT, LAW, etc. 39 Law of Patents. PATENTS FOR INVENTIONS, AND HOW TO PROCURE THEM. Compiled for the Use of Inventors, Patentees and others. By G. G. M. HARDINGHAM, Assoc.Mem.Inst.C.E., &c. Demy 8vo, cloth, price 25. 6d. Metropolitan Hating Appeals. REPORTS OF APPEALS HEARD BEFORE THE COURT OF GENERAL ASSESSMENT SESSIONS, from the Year 1871 to 1885. By EDWARD RYDE and ARTHUR LYON RYDE. Fourth Edition, brought down to the Present Date, with an Introduction to the Valuation (Metropolis) Act, 1869, and an Appendix by WALTER C. RYDE, of the Inner Temple, Barrister- at-Law. 8vo, i6s. cloth. " A useful work, occupying a place mid-way between a handbook for a lawyer and a guide to the surveyor. It is compiled by a gentleman eminent in his profession as a land agent, whose spe- cialty, it is acknowledged, lies i the direction of assessing property for rating purposes." Land Agents' Record. " It is an indispensable wo of reference for all engaged in assessment business." Journal of Gas Lighting. House Property. HANDBOOK OF HOUSE PROPERTY. A Popular and Practi- cal Guide to the Purchase, Mortgage, Tenancy, and Compulsory Sale of Houses and Land, including the Law of Dilapidations and Fixtures ; with Examples of all kinds of Valuations, Useful Information on Building, and Suggestive Elucidations of Fine Art. By E. L. TARBUCK, Architect and Surveyor. Fourth Edition, Enlarged. i2mo, 5$. cloth. " The advice is thoroughly practical." Law yournal. " For all who have dealings with house property, this is an indispensable guide." Decoration. "Carefully brought up to date, and much improved by the addition of a division on fine art. " A well-written and thoughtful work." Land Agents Record. Inwood's Estate Tables. TABLES FOR THE PURCHASING OF ESTATES, Freehold, Copyhold, or Leasehold; Annuities, Advowsons, etc., and for the Renewing of Leases held under Cathedral Churches, Colleges, or other Corporate bodies, for Terms oi Years certain, and for Lives ; also for Valuing Reversionary Estates, Deferred Annuities, Next Presentations, &c. ; together with SMART'S Five Tables of Compound Interest, and an Extension of the same to Lower and Intermediate Rates. By W. INWOOD. 23rd Edition, with considerable Additions, and new and valuable Tables of Logarithms for the more Difficult Computations of the Interest of Money, Discount, Annuities, &c., by M. FEDOR THOMAN, of the Societe Credit Mobilier of Paris. Crown 8vo, 8s. cloth. "Those interested in the purchase and sale of estates, and in the adjustment of compensation cases, as well as in transactions in annuities, life insurances, &c., will find the present edition of en. inent service. " Engineering. " ' Inwood's Tables ' still maintain a most enviable reputation. The new issue has been enriched by large additional contributions by M. Fedor Thoman, whose carefully arranged Tables cannot fail to be of the utmost utility." Mining yournal. Agricultural and Tenant-Right Valuation. THE AGRICULTURAL AND TENANT-RIGHT-VALUER'S ASSISTANT. A Practical Handbook on Measuring and Estimating the Contents, Weights and Values of Agricultural Produce and Timber, the Values of Estates and Agricultural Labour, Forms of Tenant-Right-Valua- tions, Scales ol Compensation under the Agricultural Holdings Act, 1883, &c. &c. By TOM BRIGHT, Agricultural Surveyor. Crown 8vo, 35. 6d. cloth. " Full of tables and examples in connection with the valuation of tenant-right, estates, labour, contents, and weights of timber, and farm produce of all kinds." Agricultural Gazette. " An eminently practical handbook, full of practical tables and data of undoubted interest and value to surveyors and auctioneers in preparing valuations of all kinds." Farmer. Plantations and Underwoods. POLE PLANTATIONS AND UNDERWOODS: A Practical Handbook on Estimating the Cost of Forming, Renovating, Improving and Grubbing Plantations and Underwoods, their Valuation for Purposes of Transfer, Rental, Sale or Assessment. By TOM BRIGHT, F.S.Sc., Author of " The Agricultural and Tenant-Right-Valuer's Assistant," &c. Crown 8vo, 35. 6d. cloth. [Just published. " Will be found very useful to those who are actually engaged in managing wood." Sell's Weekly Messenger. "To valuers, foresters and agents it will be a welcome aid." North British Agriculturist. "Well calculated to assist the valuer in the discharge of his duties, and of undoubted interest and use both to surveyors and auctioneers in preparing valuations of all kinds. "Kent Herald. 40 CROSBY LOCK WOOD &- SON'S CATALOGUE. A Complete Epitome of the Laws of this Country. EVERY MAN'S OWN LAWYER: A Handy-Book of the Principles of Law and Equity. By A BARRISTER. Twenty-ninth Edition. Revised and Enlarged. Including the Legislation of 1891, and including careful digests of The Tithe Act, 1891 ; the Mortmain and Charitable Uses Act, 1891; the Charitable Trusts (Recovery) Act, 1891 ; the Forged Transfers Act, 1891; the Custody of Children Act, 1891; the Slander of Women Act, 1891; the Public Health (London) Act, 1891; the Stamp Act, 1891; the Savings Bank Act, 1891 ; the Elementary Education (" Free Education") Act, 1891; the County Councils (Elections) Act, 1891; and the Land Registry (Middlesex Deeds) Act, 1891; while other new Acts have been duly noted. Crown 8vo, 688 pp., price 6s. 8rf. (saved at every consultation ! ), strongly bound in cloth. [Just published. \* THE BOOK WILL BE FOUND TO COMPRISE (AMONGST OTHER MATTER) THE RIGHTS AND WRONGS OF INDIVIDUALS LANDLORD AND TENANT VENDORS AND PURCHASERS PARTNERS AND AGENTS-COMPANIES AND ASSOCIATIONS MASTERS. SERVANTS AND WORKMEN LEASES AND MORTGAGES CHURCH AND CLERGY, RITUAL LIBEL AND SLANDER CONTRACTS AND AGREEMENTS BONDS AND BILLS OF SALE- CHEQUES, BILLS AND NOTES RAILWAY AND SHIPPING LAW BANKRUPTCY AND IN- SURANCEBORROWERS, LENDERS AND SURETIES CRIMINAL LAW PARLIAMENTARY ELECTIONS COUNTY COUNCILS MUNICIPAL CORPORATIONS PARISH LAW, CHURCH- WARDENS, ETC. PUBLIC HEALTH AND NUISANCES FRIENDLY AND BUILDING SOCIETIES COPYRIGHT AND PATENTS TRADE MARKS AND DESIGNS HUSBAND AND WIFE, DIVORCE, ETC. TRUSTEES AND EXECUTORS INTESTACY, LAW OF GUARDIAN AND WARD, INFANTS, ETC. GAME LAWS AND SPORTING HORSES, HORSE-DEALING AND DOGS INNKEEPERS, LICENSING, ETC. FORMS OF WILLS, AGREEMENTS, ETC. ETC. NOTE. The object of this work is to enable those who consult it to help them- selves to the law; and thereby to dispense, as far as possible, with professional assistance and advice. There are many wrongs and grievances which persons sub- mit to from time to time through not knowing how or where to apply for redress ; and many persons have as great a dread of a lawyer's office as of a lion's den. With this book at hand it is believed that many a SIX-AND-EIGHTPENCE may be saved ; many a wrong redressed many a right reclaimed ; many a law suit avoided ; and many an evil abated. The work has established itself as the standard legal adviser of all classes, and also made a reputation for itself as a useful book of reference for lawyers residing at a distance from law libraries, who are glad to have at hand a work em- bodying recent decisions and enactments. %* OPINIONS OF THE PRESS. " It is a complete code of English Law, written in plain language, which all can understand. . . 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PHILADELPHIA, 1876, THE PRIZE MEDAL Was awarded to the Publishers for Books : Rudimentary, Scientific, "WEALE'S SERIES," ETC. CROS3Y LOCKWOOD & SON, 7, STATIONERS' HALL COURT, LUDGATE HILL, LONDON, E.G. WEALE'S RUDIMENTARY SERIES. WEALE'S RUDIMENTARY SCIENTIFIC SERIES. V* The volumes of this Series are freely Illustrated with Woodcuts, or otherwise, where requisite. Throughout the fol- lowing List it must be understood that the books are bound in limp cloth, unless otherwise stated ; but the volumes marked with a \. may also be had strongly bound in cloth boards for 6d. extra, N.B. In ordering from this List it is recommended, as a rueans of facilitating business and obviating error, to quote the numbers affixed to the volumes, as well as the titles and prices. CIVIL ENGINEERING, SURVEYING, ETC. No. 31. WELLS AND WELL-SINKING. By JOHN GEO. SWINDELL, A.R.I.B.A., and G. R. BURNELL, C.E. Revised Edition. With a New Appendix on the Qualities of Water. Illustrated. 2S. 35. 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