Then, finally, the water authority must have a reasonable power of inspection, and of inflicting penalties for willful or careless waste. But, as I have said before, experience has not shown that this is, or need be, carried out in an oppressive or offensive way. munication open between A and B, which ter into an engagement to conform to the fills B. When the handle of the appara- regulations, and to do their work in a tus is pulled, after using the water- proper and creditable manner; and the closet, the water contained in B is let moral control thus given has been usually down into the pan, but at the same time found effective. the opening between A and B is closed, so that no more water can be used than B contains, and therefore no waste can be caused, either by accident or design. When the handle is let go, the communication between B and the pan is closed, and that between B and A opened, which charges B again for another use when required. When this is properly made it will keep in order a long time, and is very easily repaired, and it forms as efficient a flushing apparatus for the drains as can be devised. These measure have been found to suffice for checking the waste, so far as the house fittings are concerned. But there is another cause of waste more difficult to deal with, namely, from leakage in the mains and service pipes in the This, or something equivalent to it, is streets. The mains often get disarthe only apparatus that is allowable for ranged by the traffic, and leak at the a water-closet, under the constant-supply joints, or the small pipes leading into system. All simple cocks and valves are houses decay or get damaged; and leaks expressly forbidden, not only as allowing from these sources will often go on for a waste, but on sanitary grounds also. In long time undiscovered, the water findthe poorest class of houses, where the ing its way into the drains. This cause expense of the waste preventer would of waste is often most troublesome in preclude its use, it is better, on every changing from the intermittent to the ground, to allow the water-closet pan to constant supply. be flushed down by hand, than to "lay on the water," as it is termed, by an imperfect and wasteful cock or valve. There are other precautions in regard to baths, hot-water boilers, and so on; but I need not trouble you with further details. I have said enough to give you a general idea of the nature of the precautions used. The difficulty is to find such leaks, and their discovery has been much facilitated by an operation that was introduced in Liverpool some years ago, and which has been fully described to this Institution by Mr. Deacon. It consists in isolating a certain district, and in ascertaining what quantity of water is used therein, at any given time, by applying, temporarily, These precautions are always embod- a meter on its supply main. This will ied in a set of regulations, which are indicate whether more water is passing carefully prepared, and which the water than ought to be consumed there, and authority of any town must have power then, by a detailed examination, the loto enforce strictly and stringently; other- cality where the waste takes place can be wise the great boon of constant water-soon identified. One means of doing supply cannot be given. this is ingenious, namely, by placing a But they must be supplemented by "hydrophone," or sounding-bar, against another power-that is, a control over any suspected pipe, when, by applying the plumbers who do the fitting work; the ear to the other end of the bar, the for, in spite of all provisions as to the passage of water through the pipe can be construction of particular articles, if the distinctly heard. This will not only dework generally is badly done, it may give tect street leakages, but may also give an immense trouble. I am sorry to say that idea whether waste to any serious extent the character of the trade generally is is going on in the houses. The leak-denot such as could be wished, and great tecting operation here described has been trouble has been experience on this head, of great utility, and has done much to facilfrom the difficulty of obtaining any legal itate the introduction of constant supply. control. But the water authorities have generally adopted the plan of keeping lists of "authorized plumbers," who en The history of the London supply in regard to constant service, is curious and instructive. Until within the last ten years the sup-tail), the constant service might be sucply was entirely on the intermittent plan. cessfully brought into the metropolis. The usual sanitary question had often And I ventured to express the opinion been agitated; in many districts the sup- that the change would be attended, in ply was disgracefully bad; the propriety the end, rather with an economy than of introducing the constant service had with a waste of water. been often suggested, and in the Water Act of 1852 a provision had been made to that effect. But notwithstanding the well-known fact that this system was successfully at work in other towns, the measure was always opposed by the companies, on the ground that the waste would be so enormous as to render the system impracticable. And, in the face of this opposition, nothing was done. Still, however, the demand for the change was very urgent. It was strong ly recommended by a House of Commons committee in 1867, and again by the Duke of Richmond's Royal Commission in 1869; and immediately after this last date the Government, earnestly desirous to carry out the measure, determined to institute inquiries as to its practicability. They did me the honor to entrust me with the investigation, instructing me to visit several country towns where the system was said to be in effective operation, and to make myself thoroughly acquainted with the facts, and, in particular, with the modes of preventing the waste that was so much dreaded; and, having done this, I was to examine the state of things in London, and report if there were any real obstacles to the application of the system there. The reports which I made on this matter were published as Parliamentary papers, and are well known to all parties interested in the question. The general results were these: In the first place, I found that the system was in perfect and successful operation in many towns; that several towns had been and were being successfully changed from the intermittent to the constant system, and that, under this system, the consumption of water was much less than under the intermittent plan in London. I also described fully the causes of waste and the means adopted, with success, for checking it. In the second place, I described the result of my examination of the circumstances of the London supply, and I endeavored to show that, if proper means were used (which I described in some de It was a great satisfaction to me to know that this report not only satisfied the Government, but also to a large extent satisfied the water companies. For when, in the following year, a bill was brought in for the purpose of effecting the change, the companies accepted it in a conciliatory spirit, and it became law on the 21st of August, 1871. Under the provisions of this Act, a long inquiry was held in 1872, by Commissioners appointed by the Board of Trade, for the purpose of settling the regulations to be adopted for efficiently carrying out the constant-service system; and, having paid so much attention to the subject, I took an important part in the discussions before the Commissioners. The result was the establishment of the code of regulations now in force. oon after that time the change began. It was introduced very gradually, and required much caution; but at the present time nearly half the houses are so supplied. In some districts I believe the change has effected a reduction in the consumption, but in other places this has not been so, a complaint being made of an increase in the waste. I do not know enough of the facts to give any positive opinion as to the causes of this; but I strongly suspect it may arise from a want of proper control over the plumbers and the fittings used, for I was obliged to point out that the character of the plumbing trade in London was, in my opinion, the greatest obstacle to the introduction of the new system. But I am confident that the difficulty may be got over, and I should hope, for the credit of our London water engineers, that the time will not be far distant when the metropolis of England will be as well supplied as Nottingham and Norwich and Manchester have been supplied for the last quarter of a century. It cannot be denied that the provisions for constant service involve a little more outlay, both to the suppliers and the consumers; but this is largely outweighed by the advantages to parties. The suppliers have to go to minimum possible, while under the intersomewhat greater expense in their service mittent plan it is always extravagant reservoirs and in their mains, so as to and wasteful. provide efficiently for the fluctuations in the demand at different times in the day, as I have before explained. But they may reap an enormous advantage in the saving of waste, which will most unquestionably be effected, if the system is carried out vigorously and thoroughly. The experience of all towns where constant service has been effectually acted on is positive, that under this system the consumption may be reduced to the Then the consumer has to incur a little more cost for fittings of more perfect character and of better quality, but he gets amply repaid, not only in the greater purity and wholesomeness of his supply, but in the freedom from accident, and the less necessity for repair. For, the very essence of the improved fittings is their less liability to derangement and their greater durability. PERFORMANCE OF STEAM-ENGINES. BY JOHN W. HILL, M. E. MUCH has been written upon the subject of steam-engine economy, as affected by various degrees of expansion, in one and more cylinders, and hot disputes have been observed between exponents of high and low expansions, each having proved by experiment that the other was wrong. Similarly the benefits of steam-jacketing are disputed by many capable, experienced engineers, and compounding regarded as an unnecessary expedient for economy. spects the engines were in good condition. In these instances, where steam-jacketing failed to show an improvement in economy, it is likely that the steam was of poor quality, or the exterior of jackets poorly protected against loss of heat by conduction and radiation, or the grade of expansion too low to make the benefits of steam-jacketing available. In these instances where single-cylinder engines have given a higher economy than compound engines, it is probable that the grade of expansion. It is true that the data upon which for the compound engine has been too these contrary opinions are based, are low, that the effect of intermediate exnot from engines alike in all respects, pansion may have been overlooked in except in the expansions of steam em- proportioning the engine; that the relaployed, in the use or disuse of steam-jack- tive proportions of steam cylinders were ets, or in the arrangement of single not adapted to maximum economy, or cylinder or compound steam end, but are that the division of work between the from different engines of dissimilar two (or more) cylinders was not fairly powers, operating under different and made. sometimes widely varying steam pressures and piston speeds, some from steam ship performance, others from engines driving mills, and still others from engines pumping water for cities. It is probable in these cases, where low expansion has given better results than high expansion, that the steam pressures or piston speeds have not been favorable to high expansion, or that the condition of The writer, from many experiments the steam, by reason of considerable upon first-class engines for various purentrainment, forbid high expansion; or poses, ventures the opinion that high that the cylinders were not properly grades of expansion, steam-jacketing, and clothed, assuming that in all other re- compounding of steam end are desirab'e, It is, of course, assumed that in every instance where the performance of a steam-engine has been the basis of an opinion upon the conditions best calculated for maximum economy, that the engine per se and its connections have been in fit condition for test purposes, and that no losses existed which were unknown and unaccounted for. if the conditions under which engines are to work are properly considered in fixing proportions, with the following suggestions as to application. 1st. Expansions: The economy of steam-engines, other things equal, will vary as a function of the expansion, provided the terminal pressure be but slightly below the atmosphere. When, however, high expansion can be had only by producing a terminal pressure much below the atmosphere, then the economy will not be materially increased above that due a lower grade of expansion, while the effective work of the engine will be greatly diminished. In compounding, however, consideration must be had for the number of expansions of steam that will occur. No benefit will be found in compounding for an engine working at six or less expansions. Of the two steam-engines the performance of which forms the substance of this paper, one is a horizontal tandem compound Corliss engine, built from designs by Mr. Edwin Reynolds, of E. P. Allis & Co., Milwaukee, Wis., and the other, a horizontal single-cylinder Corliss engine, built by Wm. A. Harris, of Providence, R. I. The comparison between these enOf two cases of high speed engines gines is not made to show that either with similar initial pressures, say, 90 builder constructs a better engine than pounds by gauge, and otherwise, operating his competitor, but to exemplify a few under similar conditions, where the first of the previous suggestions upon comshows an operation of the engine with 20 pounding of steam ends, and ratios of expansions and 4.75 pounds terminal expansion. pressure (absolute), and the second, 8.5 expansions, with 12 pounds terminal pressure (absolute), the economy in the second case will be the highest. Assuming that steam pressures under existing practice be limited to 140 pounds by gauge, or 154.5 pounds absolute, then maximum economy will be had with 14 to 20 expansions of the steam. 2d. Steam-jacketing will not be found advantageous in single cylinder engines operating under less than eight expansions, nor in compound engines operating under less than ten (10) expansions. Moreover, the external wall of jacket space must be thoroughly protected by a non-conducting covering to prevent abstraction of heat from the jacket steam by the atmosphere. In regulating the consumption of steam by the jackets, care should be had that not more than 5 or 6 per cent. of the total steam to engine be so expended, otherwise the use of the jackets may show a loss rather than a gain. Under favorable conditions the consumption of steam in the jackets should not exceed 3 to 3.5 per cent. of the total steam to engine. 3d. Compounding: For engines operating at piston speeds of one hundred to four hundred feet per minute compounding will be found beneficial, but for high piston speeds of 600 or more feet, the single cylinder can be made to furnish the best economy. The tandem compound engine was constructed by Mr. Reynolds, as an experiment, and placed in the "Daisy Roller Mill," an establishment in Milwaukee, the property of Messrs. Allis & Co.; where the designer had unusual facilities for testing the engine, with a view of securing information which might be made beneficial to his customers in the construction of future cut-off engines. The writer was employed to test this engine and report its performance to Messrs. Allis & Co., with the results given in the following excerpt from his report at the time: "The engine is a Reynolds-Corliss of the compound condensing type, with cylinders set tandem-small cylinder nearest the crank. The small cylinder has a diameter of 14 inches and a stroke of 42 inches, and the large cylinder, a diameter of 26 inches and a stroke of 42 inches. Both cylinders are unjacketed; but were protected from loss of heat by a plastic covering encased in a lagging of walnut. "Two trials were made, one from 8.45 A. M., April 26th, to 4.45 A. M., April 27th, 1882, embracing a period of twenty (20) hours, and the other from 11.45 A. M., April 29th, to 12.00 midnight, same date, embracing a period of twelve (12) hours and fifteen (15) minutes. "During the first trial the engine was operated for the ordinary requirements of the mill, which load being evidently too light for maximum economy, an effort not sufficient to furnish the additional was made to increase it for the second load required. trial by means of a small friction brake "In the accompanying table are given on the line shaft, which, however, was the principal dimensions of the engine. second cylinder.. Volume of steam exhausted at terminal pressure, per revolution.. each trial. The weighing scale used for the first trial was not very sensitive, and the first set of calorimeter data is rejected as unreliable. "Steam was furnished by a Babcock & | ity of steam were frequently made during Wilcox boiler. The water supplied to the boiler was drawn from the overflow of the condenser and measured in two small tanks, the delivery of which was connected with the boiler feed pump. The tanks were filled to an overflow pipe and drawn down to the lower edge of the outlet pipe. "Observations were made regularly every fifteen (15) minutes of the boiler gauge, receiver gauge, vacuum gauge, temperature of feed-water; hourly obser"The capacity of the tanks was deter- vations were made of the counter, and mined by filling and weighing at an ob- bi-hourly observations were made of the served temperature; from which the temperature of injection. Indicator diaweights of water at temperatures of over-grams from both ends of both cylinders flow were estimated. All water delivered by the tanks was pumped into the boiler, except as otherwise noted. "Calorimeter observations of the qual were taken quarter-hourly. "In the following table are given all the material data from the trials. |