CHEMICAL COMPOSITION OF WATER. PROFESSOR WAY, Consulting Chemist of the Royal Agricultural Society of England, delivered a lecture before the members, at their House, in Hanover-square, on Wednesday, the 19th of June, "On Variations in the Chemical Composition of Water, as affecting its Agricultural Uses." The Professor commenced his lecture by stating, that he intended on that occasion to call the attention of the members to three important heads of inquiry connected with water; more with a view to elicit from them practical illustrations founded on their individual experience, than to offer anything particularly novel or established. These heads of inquiry were the following, namely-1. On Water for Steam and other Boilers: the means of ascertaining its comparative suitableness for that purpose, and of counteracting its tendency to incrustation. 2. On Water for Irrigation; its chemical impregnation, and the theory of its action. 3. On the influence of Water, obtained under different circumstances, on the health of Cattle, Horses, and other live-stock on a farm. He remarked, that as the first head of inquiry related to the mechanical and chemical agency of inert matter, its details came within the range of analytical investigation; and he would be enabled to speak with much confidence on the facts he had to bring together under it; but as the other two heads included a reference to local circumstances, and to the influence of the vital operations of vegetation and animal physiology respectively, in the production of results, what he had to say on these points would be much less decisive, and advanced more for the purpose of seeking than for giving information. I. Water for Boilers.-The water from the clouds reaches the earth almost pure in a chemical sense, as a homogeneous liquid, composed of the elements oxygen and hydrogen. It was distilled from the sea and land, and from the leaves of vegetables in a state of purity, and formed clouds; from which it again fell at intervals to the earth through the atmosphere, bringing with it only very minute traces, varying according to circumstances, and frequently inappreciable by the chemist, of carbonic acid gas, ammonia, nitric acid, and the effluvia arising from animal perspiration and the decomposition of animal matter. On reaching the land, however, its solvent power immediately came into operation, and it became impregnated more or less with the soluble substances with which it came in contact; common salt and gypsum were always dissolved by it, while lime and other substances were taken up by it when there happened to be an excess of carbonic acid gas present, In order to illustrate this fact, the Professor exhibited to the members a simple and striking experiment. Three glass vessels were connected together by means of bent glass tubes; the first vessel contained fragments of marble (as a pure variety of native carbonate of lime); the second, distilled water; and the third and last, a clear solution of quick lime in pure water (or lime-water.) On adding dilute muriatic acid gradually to the marble in the first vessel, carbonic acid gas was disengaged in great abundance, which passing along the tubing into the middle vessel, was there washed and freed from impurity by its passage through the distilled water, and then proceeded, by means of a connecting glass tube, to the lower part of the inner surface, where it continued to bubble throughout the clear lime-water. After a few moments the limewater became turbid. The Professor remarked, that this effect resulted from the conversion of the lime into insoluble carbonate of lime (or chalk), by its combination with a first proportion of the carbonic acid gas passed through it. In a few moments afterwards, however, the liquid regained its original transparent appearance. This change, he explained, arose from the further supply of the same acid gas, constituting the insoluble carbonate of lime a soluble super-carbonate of that earth; the liquid, in fact, being then a solution, not of lime in water, as it was originally, but a solution of bi-carbonate of lime, or of chalk rendered soluble by excess of carbonic acid. To prove that this was the case, the Professor took the flask containing this solution, and having placed it over a spirit-lamp, caused ebullition to take place. After boiling for a short time, the liquid again became turbid, from the circumstance of the heat expelling the excess of carbonic acid, and again reducing the carbonate of lime to the state of insoluble chalk. He then proceeded to show how this experiment illustrated the change which was found to take place in the waters of limestone districts, which were naturally charged with carbonate as well as the sulphate of lime; and also how it happened that, while water, rendered hard by sulphate of lime only, did no injury to steamboilers, as that salt was not deposited on raising the water to a boiling temperature; hard water, on the contrary, holding a large amount of carbonate of lime dissolved in it by carbonic acid, did the greatest injury to them, by gradually depositing, on being boiled, such carbonate of lime at the bottom of the steam-boilers, until it amounted to a hard calcareous incrustation. Hard Water.-Water was always rendered hard by holding in solution either the carbonate or the sulphate of lime; and, accordingly, when obtained from wells in the chalk, oolitic, and limestone districts throughout the kingdom, was always hard; becoming turbid when boiled, and depositing its carbonate of lime on that part of the internal surface of the boiler nearest to the fire. As a familiar instance, he named the fur or crust in teakettles, in districts where such water was used; but in the case of steamboilers, this deposit was one of the greatest evils that could be imagined. The hard calcareous incrustation in immediate contact with the iron plating of the boiler, amounting in a few weeks to no less than from two to three inches in thickness. Professor Way explained how the injury arose in this case-namely, from the effect which the adhering crust had in preventing the transmission of the heat, received by the boiler from the fire, to the body of water within the boiler. He cited many curious instances of the cooling effect of this free transmission of heat on substances under other circumstances most fragile and combustible; and the contrary effect when the transmission of such heat was obstructed, as in the case of calcareous incrustation, when the heat was arrested by the solid slow-conducting body, and the temperature raised above that of boiling water. He stated that, however odd it might sound to make the statement, it was no less true, that water might be boiled in an orange-peel, in an egg-shell, or in a vessel made of thin wood, or even of common writing paper; the heat applied to the external surface being rapidly transmitted to the water, and the heat carried off in the steam generated, while the material employed for the boiler suffered no injurious effect from such application of heat. He related a singular instance of this kind, in the case of a person at Liverpool, who had frequently had his cotton-mill burnt down. The party in question imagined, that if he had a large reservoir for water placed at the top of his factory, constructed of wood instead of metal, the wood, in case of fire, would be immediately burnt to ashes, and the water would consequently be set at liberty and extinguish the fire. The fire unfortunately did break out again, as it was feared it would, but the wood, instead of being charred or burnt, remained entire, and, being encircled by the flames, the water continued to boil in its wooden reservoir as long as any remained. The furring of a boiler preventing this transmission of heat, and thus causing injury to the substance of the boiler, was the reason why, in some districts, where the water was charged with bi-carbonate of lime, the boilers were found to wear out sooner than in others; and why the railway companies had been led either to seek for soft water, or to soften the hard water they had been in the habit of using, by the addition of some substance that would prevent its furring their boilers. The London and South-Western Railway Company had used the substance known in commerce as sal-ammoniac, with great success; by dissolving one ounce of it in 90 gallons of water, in tanks kept specially for the purpose. This substance was the neutral salt, so long familiar to chemists as the muriate of ammonia, being a compound of muriatic acid and ammonia. Its action in removing the hardness of water arising from bi-carbonate of lime was explained by Professor Way in the following manner. When muriate of ammonia and carbonate of lime are brought together in solution, a double decomposition ensues, each of the four combining substances changes its relative position, and two new salts are the result-namely, carbonate of ammonia, which is volatile, and accordingly makes its escape into the atmosphere; and muriate of lime, one of the most deliquescent salts with which chemists are acquainted, and which consequently remains in the water in a state of complete and almost permanent solubility. It might, he remarked, be said, that the ammonia of the sal-ammoniac carried off the carbonic acid, while the muriatic acid dissolved the lime, thus liberating the water from the chemical conditions under which its hardness was occasioned. Softening Water-Professor Clark, of the University of Aberdeen, had, however, proposed a plan for softening water rendered hard by carbonate of lime, which Professor Way considered much better than the one just described, and which might be adapted to the uses of agriculturists. This plan consisted in adding to such water a certain quantity of quick lime, which would unite with the excess of carbonic acid, and become converted into carbonate of lime, at the same time that it would reduce by such abstraction the bi-carbonate also to a state of carbonate, and both being insoluble, they would, of course, fall as precipitates to the bottom of the vessel, or other enclosure in which the water was contained, leaving the water entirely free from the bi-carbonate of lime to which its hardness had in a great measure been owing. He then proceeded to describe Professor Clark's system of soap-tests, for ascertaining the relative degrees of hardness possessed by certain waters. He remarked that hard water, as was well known, curdled soap, which would not produce a lather until such hardness had been overcome. Professor Clark had recommended a solution of white curd-soap in spirit of wine of a certain strength to be employed in this testing. This solution would at once produce a lather with soft water, but not with hard water until a certain quantity of the solution had been added to it for the purpose of counteracting the hardness: when lather of a proper firmness had been gained, the amount of standard solution employed to produce the effect indicated the degrees of hardness of any particular water; thus a standard of comparison was established, by which the choice as to different sources from which it would be most advantageous to procure water could be satisfactorily determined. Professor Way then performed an experiment with this soap-test, on spring-water from the chalk at Croydon, in comparison with water from the Thames; the former indicating a hardness of about 18°, and the latter of about 15°. The operation consisted simply in adding to the water, from a graduated pipette or suction tube, successive measures of the solution, until the water when shaken up maintained a lather on its surface for five minutes. The number of measures then indicated the quality of the water, two soap measures being equal to one degree of hardness. The process was described as easy, exact, and simple; and one which might be practised by any gentleman who was interested in such subjects, without spoiling either his furniture or carpets. It would also indicate the hardness resulting from the presence of sulphate of lime, as well as that from the bi-carbonate; though, as he had previously remarked, water hardened by sulphate of lime offered no objection for use in steamboilers, as the sulphate by boiling did not become deposited, as was the case with the carbonate; in an economical and domestic sense, however, water rendered hard by either of those salts of lime was objectionable. Professor Way then observed, that Professor Clark, in recommending quick lime to soften water containing the bicarbonate, advised such quantities of lime to be added as a preliminary trial by the soap-test process should indicate as being requisite. Such water would, by this process, be rendered soft for domestic purposes, and for steam and other boilers. The only difficulty consisted in tanks being required for the due subsidence of the chalk thus brought into an insoluble state in the water; but that was an obstacle which would no doubt be surmounted, when it was considered how great the benefit of this plan would be found, not only in ordinary families but in union-houses and prisons; that it was estimated that in London alone 600,000l. every year was expended in the purchase of soap, one-half of which was wasted in the hardness of the water; and how important a point it was in the processes of bleaching, dyeing, and other staple manufactures carried on at Bolton, Manchester, Bradford, and other places, to have a soft water in which lime was absent; it would, he thought, be well worth the while of all parties interested in so important a question to make arrangements for the depositing tanks required. The Professor concluded this part of his subject by throwing out hints by which soft water might perhaps be artificially obtained on a large scale, and at little cost, where it did not occur naturally. He remarked, that water was found by experience to become softened by passing through the soil; water, only, however, which was rendered hard by the bi-carbonate of lime. Thames water filtered through clay made permeable by the admixture of sand, was found to become as soft as by Professor Clark's process. Drainage water through regularly permeable stiff soils was more suitable for steam-engines than spring-water. But whether water thrown over the land would by that means become soft, he was not prepared to say. When, however, it was considered that one acre of land received every year on an average 500,000 gallons of pure rain-water, sufficient for the wants of 35 people during that period, it might be a question whether poor sandy land or bad moor land might not be covered with flat tiles for the purpose of collecting the rain-water, which might be conveyed in earthen pipes to the places required for its use. He merely offered this suggestion for the consideration of parties more conversant than himself with the practical bearings of such an undertaking. II. Water for Irrigation.-Professor Way remarked that, for the purpose of irrigating, he thought that water should be hard, and not soft as for other purposes: that it should contain the sulphates and carbonates of potash, soda, and magnesia, including organic matter, as all these were substances that would be taken up and retained by the land. If this view of the subject were the correct one, it would follow that the water in granite districts would, from its softer nature, not be so useful in irrigation as that in other districts where lime and other earthy substances were dissolved by the water passing through them. On a former occasion Sir John Johnstone had named to the council the failure of some irrigation of his from the supposed circumstance of the absence of mineral and earthy matter in the water, from the water in fact being too pure for the purpose. Sir John Johnstone being thus appealed to, replied that, in the water to which Professor Way had alluded, there was no trace of lime whatever. The irrigation had been laid out by the late Dr. W. Smith on a thin moorland sandstone rock; there was no lime whatever. Professor Way then proceeded to say that, in Derbyshire, and at Bala Lake, in Wales, the water was exceedingly soft and pure, but considered as unfit for irrigation. He felt no doubt that irrigation would become much more general than it had been; and the subject was more interesting at the present time on account of the Society's ensuing country meeting being about to be held in Devonshire, where irrigating operations had been so successfully carried out. He should, on that occasion, select specimens of the different waters, under different circumstances, for the purpose of analysis, in order that he might report, as requested by the chemical committee of the Society, the result of his inquiries on that interesting branch of his researches. It had been found, by ascertaining from analysis the nutriment required by the hop-plant, that only those soils that contained phosphate of lime and potash, would be suitable for the cultivation of that plant-such soils as those on the green sandstone of Sussex, Kent and Surrey; and that what theory had thus prescribed as the condition, practice had actually proved to be the most advantageous in fact, the cultivation of hops having been most successfully carried out on the soils in question. He thought it would also be found, analogically, that successful irrigation would probably be found to be confined to certain districts-namely, to the limestone principally. He thought it might be a question how far the influence of that operation was due to the temperature of the water, or its chemical composition, or to both; he himself considered the chemical nature of the water to be the most essential; at the same time, he was free to confess that we had all to learn upon this subject, and he trusted that an inspection of the Devonshire meadows would lead to further inquiries on the important questions connected with this subject. III. Water for Cattle.-The Professor commenced this third head of his lecture by remarking that he believed it was a generally observed fact, that cattle liked the water of ponds, while they disliked that of limestone springs; that they preferred to quench their thirst in a green offensive collection of stagnant water, rather than in a running spring. In Bedfordshire he had seen cattle much relish a bad water filled with confervæ and animalculæ ; which, however, was the only water to which they happened to have access. Farmers generally supposed that the cattle were fond of such water, on account of the green vegetable matter it contained; and a distinguished professor had explained the fact by supposing such water to be "meat and drink" for the cattle. It was certain they did not like hard water; and it gave a staring coat to horses when they were obliged to drink it; and when it was considered that water in chalk districts contained from 60 to 70 grains of carbonate of lime in the gallon, while London water (which was hard compared with others) contained only from 15 to 16 grains, it would be obvious how much difference would be found to exist in different waters. He regarded a good supply of water essential to health, and thought it a point of great importance to ascertain the kinds of water most suitable to the animal economy under different local circumstances. Professor Way concluded his lecture by expressing a hope that the members present would communicate to the meeting such cases of the practical effects of hard water on the health of cattle, as it had been his object, in the remarks he had then made, to elicit from them. Filter for Sea Water.-M. Cardan lately described at the Academy of Sciences a new system of filtering intended to make sea water drinkable. The apparatus consists of a syphon, the long tube of which is filled with powdered charcoal. The author states that the sea-water after having traversed this syphon has lost its nauseous savour, and that the saline taste which remains is scarcely to be detected after it is mixed with wine. MM. Becquerel and Pouillet are named commissioners to examine into this communication, and we hope it will be tried at sea. DOVER MARKET AND MUSEUM. EDMUND WOODTHORPE, Architect. THE building here represented has been lately erected for the purpose of affording to the inhabitants of Dover the twofold advantage of a market and museum. The expense of erecting that portion of the building forming the museum has been defrayed by means of a halfpenny rate-an act having been recently passed for the purpose of favouring such eligible undertakings; the expenses of the market being defrayed from a separate fund dependent upon a toll. The different parties interested in this laudable scheme have united their resources upon the principle of utilitarian economy: hence the very agreeable and profitable result of adding a most valuable and effective feature to the town of Dover. The market, which serves as a basement to the museum, is surrounded by arcades, and is subdivided in the interior by castiron columns, which act as the main supports to the floor above. The staircase leading to the museum springs from a recess within the centre arch of the main front of the building, and is so planned as to completely separate the museum from the market below; The piers of the arches in the principal front are of stone; the remainder of the building is of brick, stuccoed. The building is 63 feet wide by 100 feet in depth; its cost in erecting was 4,000l. It has been built from the designs and under the superintendence of Mr. Edmund Woodthorpe, of London. We congratulate the projectors of this scheme upon having selected so appropriate a style of architecture for their building; the pure Italian style of which this building presents a graceful specimen-being so completely identified with the growth of intellect and the march of modern civilisation, is in the highest degree applicable to an edifice the chief purpose of which is so illustrative of the progress of learning and the development of taste which mark the present era. It will be remarked that in the composition of this design, much playfulness of effect is produced by a judicious treatment of very simple materials; the coupling of the pilasters at the angles of the building is an expedient much to be commended in this instance: for this feature not only completes the design which otherwise would appear as a mere portion of a façade, but it produces great variety with apparently but little effort; and is moreover agreeable to reason on the score of giving an appearance of strength to those parts of the building where additional strength is required. In compositions of this kind the coupling of the columns or pilasters at the extremities of the façade should ever be considered as a stringent law. Considering the two very different objects for which this building was erected, the composition as a whole possesses the very great merit of displaying a fit and appropriate character. The establishing museums in our provincial towns is an interesting subject; and one which as regards our own country presents the charm of novelty. We therefore feel much pleasure in selecting it as a theme for further consideration. WATER SUPPLY FOR LIVERPOOL. REPORT OF ROBERT STEPHENSON, C.E., on the Supply of Water to the Town of Liverpool. (Continued from page 235.) In the outset of this investigation, I certainly was not prepared to find that the multitude of fissures would not enable a greater quantity of water than has been proved by observation and experiment to flow to any given spot, as I was aware of the great facility with which water passes through some of the highly fissured primary rocks, as well as the mountain limestone and some portions of the chalk formation, which sometimes give birth at one point to considerable rivers. The difference is doubtless owing to the fissures being less in the new red sandstone at Liverpool than in those formations, and with such a variety of results, it is evident that experiment in each locality becomes the only true guide to the determination of the actual resistance offered by any The trials now particular formation to the free passage of water. brought together, which have been made in and near Liverpool, would appear to show distinctly that a larger supply, from one point, than about 1,000,000 gallons a day cannot be safely calculated on; and several distinguished scientific men and engineers concur in this opinion. It also appears that the wells, to yield large quantities of water, must be at considerable distances apart. With the conviction thus impressed on me that none of the plans hitherto suggested is adequate to the supply of the present and prospective wants of Liverpool, and, as no efficient scheme has, to my thinking, been brought forward for rendering fully available the supply of water in the sandstone, I venture to devise a system of independent wells, placed throughout the district, and lying generally to the east of Liverpool; and the stations at Green Lane and Windsor, so often already referred to, afford again materials for estimating the cost of such a plan, without liability to material error. The cost of the Green Lane pumping establishment, exclusive of that of mains, is already stated to have been about 19,000l. and the Windsor station nearly 30,000l. The former is scarcely complete, having no cottages for the engine-men and firemen; and the latter has a valuable parcel of disposable land attached to it. But judging from these instances, I think the cost of each of the new stations at a greater distance from the town may be fairly taken at 20,000. The price of the land might, from the localities, be somewhat less than at the existing stations, while engines of together equal to the supply of 2,000,000 gallons a-day; so that, greater power would be required. Green Lane and Windsor are assuming that they will continue this supply permanently, and that the total quantity required is 8,000,000, six new stations must be constructed, which, at a cost of 20,000. each, will amount to 120,000l.; and as the mains connecting them and the storage reservoirs at Kensington will cost about 48,000l., there will be (with 10 per cent. for contingencies) a total cost of 185,000/. requisite for the present supply; and for 11,000,000 of gallons, which will be required at the end of about 10 years, the cost will amount to 277,0007.,—an amount apparently in excess of the calculations already given, but in fact quite consistent, as the relation between the cost and supply cannot remain the same for quantities from different distances. The first objection which will perhaps be made to this plan is, the want of concentration, upon which so much stress has been laid, and which in some manufactures is doubtless the very essence of cheap production; but it is not so applicable in a case of the present kind. The chief argument that has been adduced in its support rests upon the opportunity it is supposed to afford of dispensing with duplicate engines; whereas, with so many constantly at work, the failure of one will produce slight inconvenience, and the objection may be entirely obviated, by having an additional station, to be worked in case of need. Besides which, in supplying a town varying in level from a number of detached pumping stations, the water need not all be pumped to the highest reservoir, and the saving of power would fully compensate for any advantages derivable from the concentration of the establishment, while economy would result from the substitution of mains for tunnels. The following estimate of the annual cost of working this system of wells is based upon the actual cost of Green Lane and Windsor, where the expense of obtaining 1,000,000 gallons a-day from each is: For current expenses including superintendence £1100 224 projects; and, in concluding my remarks upon this proposal, I am not insensible to one or two grave objections which may be made to it; but after much deliberation I am persuaded that distributing the establishment over a wide area of country is the only sure method of obtaining the requisite supply of water. The length of connecting mains is the first obvious objection, but they would be less costly than the amount of tunnelling necessary for connecting works even much less widely spread. Another objection is the payment of a royalty to landowners for the abstraction of water, of which I am unable to form any very accurate estimate, but do not think that the amount now paid to the Earl of Derby at Bootle ought to be taken as a basis for calculation. The remaining objection which is urged against a divided establishment consists in the necessity for some additional superintendence, but this is too trivial to operate while the present necessity for a supply of water exists, which I am convinced can only be adequately derived from the sandstone by such means. Mr. Hawksley's Proposed Supply from Rivington. The third question submitted is— "Whether such supply can be obtained by means of the Rivington Works, and the cost of obtaining and distributing the same as recommended by Mr. Hawksley? In order to become thoroughly familiar with all the details of this undertaking, I first visited the locality, accompanied by its projector, for the purpose of receiving his explanations personally on the spot, and to satisfy myself by actual inspection of the reasonableness or otherwise of his anticipations, both as regards its cost and capability of supplying the very large quantity of water calculated upon by him; and at the same time to examine several other extensive reservoirs in the adjoining districts. Shortly after this I went again to Rivington with Mr. Simpson, Mr. Newlands, Mr. Rowlandson, and Mr. Binny, in order to receive from them in like manner a detail of their objections, and, in addition to this, make myself master of the whole of the views and calculations developed in the printed report of the two first-named of these gentlemen; and having done this, I carefully reviewed every difficulty that had been raised. The first was, that the reservoirs were incapable of storing such an amount of flood-water as would maintain the uniform supply of 13,660,000 gallons a day to Liverpool, and 8,000,000 gallons a day to millowners and others throughout the usual as well as unusual droughts which sometimes occur, and that the fluctuations in the quantity of water were so extensive that at some periods of the year the reservoirs would be absolutely empty. If even a near approach to such a state of things were probable, this objection would at once be fatal. I therefore made myself acquainted with the mode of calculation by which this is said to be proved, and which may be succinctly described as follows. A series of rain-gauges had been carefully registered in the Belmont District, from the year 1843 to 1848 inclusive; and during the years 1847 and 1848 a similar series was also registered simultaneously by the projector of the Rivington Works in that district, with the view of establishing a relation between the amount of rain-fall in both; and the proportion found to exist was applied to the four preceding years, thus arriving at the probable rain-fall in the Rivington district during the whole six years. This mode appears quite unobjectionable, provided the levels occupied by the rain-gauges in the respective districts are identical, which is an essential condition in consequence of the total amount of rain varying very materially at different elevations. During the years 1847 and 1848, the actual quantity of rain which flowed down the brooks of the Rivington district having been accurately measured, the proportion of available water was ascertained to be within 18 or 19 per cent. of the whole rain-fall. The quantity during the four preceding years was then modified according to the amount of fall and evaporation, and the annual yield largely reduced by the assumption that the latter was considerably greater in the drier years. These total amounts were next apportioned to each month in the four years in accordance with the registration of the Belmont rain-gauge, and thus what was supposed to be the monthly supply to the reservoirs was arrived at. The draught upon the reservoirs was then taken at a mean of 21,660,000 gallons a-day, and this quantity altered to the extent of 19 per cent. less than the mean quantity to be appropriated to Liverpool for the winter months, and a like per centage more for the summer months. It then became easy to institute a debtor and creditor account between the demand and the supply upon the reservoirs, which account exhibited the reservoirs occasionally in a state of bankruptcy. Several objections have been urged to this mode of arriving at the result. In the first place, the total rain-fall at Rivington during the years 1847 and 1848 was obtained by averaging that represented by a series of rain-gauges, the average of which is stated by Mr. Hawksley to have occupied a position below the mean level of the area of the water-shed, and in the next place the assumption of the available quantity being in dry years less than four-fifths of the total rain-fall on the water-shed, from a supposition that the proportion wasted by evaporation was much increased; and again, that the allowance of 19 per cent. above and below the mean quantity of 13,660,000 gallons is too great; and objection is also taken to the supposition that the monthly supplies to the reservoirs are proportionate to the monthly falls of rain. This was established by reference to the tables contained in Messrs. Simpson and Newland's Report; as it appeared that in December, 1847, 8 inches of rain fell at Belmont, and 1,604,000,000 of gallons were discharged by the brooks at Rivington; whereas in December, 1845, a like quantity of rain fell, and the flow from it is calculated to yield only 1,080,000,000; and many other instances might be referred to where the same inconsistency was shown, by which the calculated quantity was sometimes more and as often less than that which was measured in 1847 and 1848. In the objections to this project, great importance is attached to the circumstance of the mains passing over an extensive coalfield, it being said that they will consequently be liable to fracture by subsidence when the coal is worked away, and that injury may be anticipated to mines from inundations. This, at the first glance, certainly appears formidable; it was deemed so in reference to railways some years ago, and was used with success in preventing the Grand Junction passing through the densely populated mining district at South Staffordshire. The demand for accommodation, and a more dispassionate consideration of the difficulties to be expected from this source have led to its being discarded; and indeed the conclusion might have been arrived at without diverting a great line of railway out of its proper course, by the experience of the canals which intersect extensively every part of the same coal-field where the beds are very thick, and give rise sometimes to extensive subsidences. In spite of these, however, no serious impediments have arisen. Attention, of course, is essential to those parts of the canal or railway under which it is known that the operation of mining is going on; and for the purpose of protecting the public against inconvenienae as far as possible, by the extraction of coals or other minerals without the knowledge of the companies, it is made imperative on the mining proprietors to give due notice of the advance of their operation before they work under any canal or railway; and similar provisions, I believe, are applicable in the case of waterworks. This objection, therefore, I regard as of little moment in the Rivington scheme, provided in other respects it may prove the most eligible source of the supply of water to Liverpool. Without entering here into further discussion of points which are rather of detail, and could not be made intelligible within any reasonable compass, I will state the manner in which I have proceeded to investigate this part of the subject. There is some discrepancy in the statement of the rain-fall at Rivington in 1847 and 1848, Mr. Hawksley averaging it at 55.5 inches and Mr. Newlands at 51.7 inches; but the difference (however occurring) is of little importance in this inquiry, as the quantity of water flowing down the brooks in these years has been actually measured, and amounts to 25,718,194 gallons a day. The years 1847 and 1848 having been wetter than the average of years, it is necessary to arrive by estimate at a fair average yield from such data as exist. The Belmont rain-gauge supplies the means of doing so, and I find, by its register, that while the years 1847 and 1848 show an average of 63.6 inches, the average of the six years (1843 to 1848) gives only 57-57 inches. These figures furnish a proximate ratio by which the yield of the brooks in 1847 and 1848 ought to be corrected; and, following them, the Measured quantity of 25,718,194 gallons is reduced to Chorley and outlying population, say 7,500,000 500,000 800,000 422,109 And for waste by additional evaporation from the reservoirs Gallons a day. 23,279,818 |