September 24, 1903] 



NATURE 



51S 



have been situate on the inlet instead of on the outlet side 

 of the reservoir. 



Having now followed the water in the case of a gravita- 

 tion supply from its source to the service reservoir from 

 which it is to be distributed to the consumers, it will be 

 convenient to follow in a similar manner water obtained by 

 means of pumping, leaving until later the consideration of 

 its distribution, which, after it leaves the service reservoir, 

 is common to both gravitation and pumped water. 



Pumping supplies may be divided into two sections — first, 

 those where the water is drawn from a source only slightly 

 below the level of the pumping engines, such as where the 

 water is taken from a stream or lake, or from culverts 

 formed in gravel beds, or is discharged from impounding 

 reservoirs situate at too low a level to enable the water to 

 gravitate to the point of distribution ; and secondly, where 

 the water is raised from deep wells sunk in the sandstone, 

 chalk, or other water-bearing strata. 



In the first-mentioned cases the water has usually to be 

 filtered, when it is generally found convenient to place the 

 filter-beds at the pumping station, the water being firstly 

 lifted (unless it will gravitate) on to the filter-beds, and 

 secondly, after filtration, and by means of a separate pump, 

 forced through pipes up to the service reservoir whence it 

 is to be distributed. 



In the case of deep wells, the water seldom, if ever, re- 

 quires filtration, and is usually raised either directly or 

 through pipes into the service reservoir, the total lift being 

 frequently divided between lift pumps and force pumps with 

 th° object of balancing the work to be done by the engine. 



Sometimes the well alone will yield a sufficient supply 

 water, but often it has to be aided by boreholes or by 

 Irifts or headings driven horizontally in the water-bearing 

 strata near the level of the bottom of the well, and occasion- 

 ally continued for a considerable distance, even as much 

 as a mile or more from the well, the length of the head- 

 ings depending on the quantity of water which can be 

 profitably obtained from them, and also on other consider- 

 ations too various to be mentioned here. There are cases 

 in which it is possible to obtain sufficient water by boring 

 fiom the surface of the ground and lowering a pump down 

 the bore hole. The e.xpense of a large well is thus saved, 

 but it is, of course, impossible to augment the supply by 

 drifting. 



The time at my disposal will not admit of any observ- 

 ations on the merits of the various kinds of engines and 

 pumps employed in raising water ; they are not only very 

 numerous, but each has to be considered in relation to its 

 suitability for the particular circumstances of the case in 

 question. Suffice it to say that, although most of the water 

 pumped in the United Kingdom is raised by means of steam 

 engines, water turbines, gas engines, oil engines, and (to 

 some slight extent) electric motors are also employed. It 

 may be mentioned that one of the largest oil engines in this 

 country is engaged in pumping water from a deep well, and 

 it is not improbable that gas and oil engines will in the 

 future become more largely employed for waterworks 

 jrposes. 



It should here be mentioned that there are a few in- 



ances in this country, and many in the United States of 

 \inerica, in which a service reservoir is dispensed with, 



id water is pumped directly into the main and distributing 

 pipes of the district to be served, a method which, although 

 employed with success, should not, in my opinion, be 

 adopted where the circumstances admit of the use of a 

 service reservoir. Where direct pumping is used, provision 

 must be made to ensure continuous pumping day and night 

 without intermission, so as to avoid interruption to the 

 supoly of the district, and the speed of the engines must 

 be constantly varied to meet the demands of the consumers 

 for the moment. The maintenance of uniformity of pressure 

 in the main pipes may be assisted by the employment of 

 large air vessels, or by accumulators such as are used for 

 the supply of hydraulic pressure, or preferably by a com- 

 bination of air vessels and accumulators. 



We will now return to the service reservoir. When this 

 reservoir is situate between the source of supply and the 

 i strict to be supplied, it receives the whole of the water 

 Mid delivers it into the district as needed for use; but when 

 iie district lies between the source and the service reservoir, 

 it receives the excess of supply over consumption, and on 



NO. 1769, VOL. 68] 



the other hand makes good any deficiency during those 

 hours when the consumption exceeds the supply. In either 

 case this reservoir has the effect of equalising the flow 

 from the source to the reservoir throughout the twenty-four 

 hours of the day. 



From the service reservoir the water is conveyed by one 

 or more main pipes into the district of supply. These pipes 

 are gradually reduced in diameter as they pass through the 

 district, the water which they convey is taken off by other 

 main pipes branching from them, and finally enters the 

 service pipes, which are usually from five inches to three 

 inches diameter, and are those from which the consumers' 

 communication pipes are taken. The service pipes should 

 in all cases be controlled by valves, so that the water can 

 be shut off from them without interfering with the flow 

 through the main pipes. Consumers' communication pipes 

 are not generally allowed to be attached to pipes of greater 

 diameter than five inches, and where a pipe of six inches 

 diameter and upwards is carried along a street, another 

 pipe of three or four inches diameter (preferably the latter 

 size), and called a ryder pipe, is laid alongside to receive 

 the attachments of the communication pipes. The ryder 

 pipe is divided into lengths of from 350 to 400 yards, each 

 of which is controlled by a valve at its junction with the 

 main pipe. Hydrants for use in case of fire are attached 

 to the ryder a^d other service pipes throughout the district 

 at a distance apart not exceeding 100 yards. Except in 

 streets where the houses are small and not high, it is 

 desirable to lay the service pipes of not less than four inches 

 diameter, not because a smaller pipe would not suffice to 

 meet the requirements of the domestic consumers, but in 

 order to ensure an ample supply of water in case of fire. 

 When determining the sizes of the main pipes to be laid 

 throughout a town, the engineer commences with the pipes 

 most remote from the service reservoir, and gradually in- 

 creases the diameter according to the probable number and 

 magnitude of the supplies to be taken from them. 



Pipes of cast iron having sockets run with lead and set 

 up with a hammer are mostly used for waterworks purposes, 

 but in some instances turned and bored joints put together 

 without lead have been used with success, but these are 

 only suitable where there is an unyielding foundation. I 

 remember a case in Yorkshire, where turned and bored 

 pipes were, much against the advice of the engineer, used 

 for the distribution of gas in a colliery district, with the 

 result that in a few years nearly every joint was leaking ; 

 fortunately the engineer had anticipated that result, and 

 had laid the pipes with sockets in addition to the turned 

 and bored joints ; consequently, by opening the ground at 

 each joint and running the joint with lead, the leakage was 

 stopped without necessitating the relaying of the system of 

 pipes. The main pipe of forty-four inches diameter, con- 

 veying water from Rivington to Liverpool, passes for several 

 miles over a coalfield, and the ground has in places sub- 

 sided over the coal workings as much as four feet without 

 interfering with the supply of water ; the ground having 

 been opened at the pipe joints, the lead, which had been 

 partially drawn from the joints, was forced back by hammer- 

 ing, and the joint was again made sound. 



In soms countries, where the cold is intense, water pipes 

 have to be laid at a depth of from 10 feet to 12 feet below* 

 the surface of the ground to protect the water from frost, 

 but in the United Kingdom a depth of from 2 feet 6 inches 

 to 3 feet has been found to be sufficient even in very severe 

 frosts. • 



Water, especially when soft, causes the interior of cast- 

 iron pipes to become incrusted with nodules of iron, which 

 reduce the effective diameter of the pipe and so diminish 

 its capacity. This action is greatly retarded and in some 

 instances entirely prevented by the application to the pipes, 

 soon after they have been cast, of the coating introduced 

 many years ago by the late Dr. Angus Smith, a process 

 now nearly always employed. 



It was at Southport that I witnessed the bursting of a 

 main pipe, the only occurrence of the kind that I have seen 

 during a period of forty years, of which a considerable 

 portion has been spent amongst waterworks. Owing to the 

 introduction of a new supply of water, the original main 

 pipe was charged with water at a higher pressure than it 

 had been intended to bear, with the result that several 

 fractures occurred. I happened to be standing on one of 



