204 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[JXTNE, 



iemerilt/ to tell the Companies that the present mode of filtering as 

 practised by them is insufficient effectually to cleanse Thames water 

 of all the impurities which are suspended in it after heavy rains (vide 

 page 9j, and he recommends as the most effectual method, the |)lan of 

 nlteriiig through charcoal, which we shall hereafter notice. We be- 

 lieve that most of the ( 'omijanies have done their best in endeavouring 

 to improve their supply from the Thnmtst, but whether that resort he 

 the best for obtaining water is a subject well worthy of inquiry. We 

 believe it is not dis|mted, by any party, that water obtained by the aid 

 of deep wells and Artesian boring is far better than obtaining the sup- 

 ply from the Thames, as by the latter, enormous expences are annually 

 incurred in filtering the water, besides the expense of pumping first 

 the supply into a reservoir and thence to the mains, whereas by the 

 former process the water might at once be pumped into the pipes, 

 and forced up to the elevated situation, without the expense, trouble, 

 or delay of filtering, or pumping a second time, but the objections 

 to the former plan have been that a sufficient quantity of water 

 cannot be obtained for this great metropolis, and also that any at- 

 tempt to obtain a supply by such means would materially affect 

 the numerous wells about the metropolis, particularly those which 

 belong to the manufactories and the large breweries, the latter, until 

 ■within the last "20 years, were supplied by the various companies, but 

 in consequence of the heavy rental the brewers and manufacturers 

 were compelled to pay, they had recourse to the sinking of wells of 

 great extent, and, we believe, we may say safely, not one of them ever 

 failed affording an ample supply, and if the companies do not take 

 care, their other customers will be obliged to resort to the same means, 

 as very little consideration of the geology of London would be suf- 

 ficient to convince any one that an abundant supply of water for all, 

 exists in the lower strata, in the same manner as at Paris, a descrip- 

 tion of wdiich, in one of our recent numbers, will serve to illustrate 

 the present subject. 



Before we |)roceed further with our remarks, however, we must 

 refer to the contents of the pamphlet which has given rise to this 

 notice. The work is published anonymously, but we understand that 

 it is by Mr. Peppercorns, a highly respectable member of the profession, 

 and in no way connected Vfith a gentleman of the same name acting as 

 secretary to one of the metropolitan water companies. 



The pamphlet first proceeds to describe the several metropolitan 

 companies, how they obtain their supplies of water and the quality of 

 it. it then details the various plans devised by the water companies, 

 or by private individuals, wdiich are divided into three classes: 



1st. Those which propose the purificatiou of the Thames water either by 

 filtration or by sulisidence, or by both combined, aud which method has been 

 put in practice on an extensive scale by some of the water companies. 



2ncl. Those which suggest the taking of the water supply fi'om a higher 

 part of the river than where it is now obtained. 



3rd. Those which recommend to draw the supply from other sources than 

 the Thames, and to convey it by means of extensive aqueducts to London. 



Respecting the first class, it is a well known fact that although filtration 

 througli sand, or through sand and gravel, (as, in the case of the Chelsea 

 water-works,) produces a perfectly clear and transparent fluid, free from seih- 

 mcnt and colour, yet that it is insufficient to free the water from animal or 

 vegetable im])uritics held in solution, or from any taint which the water may 

 have thereby ac(|uire<l ; hut that filtration through charcoal, or through sand 

 and charcoal, as jjractised to some extent with the water of the Seine at 

 Paris, is cni)able of removing the whole ot the sediment, and also, by a pro- 

 perly regulated system, the entire of the animal and vegetable impurities con- 

 tained in Thiimes water taken from the London district. 



With respect to the method of subsidence alone in reservoirs, as practised 

 now by almost all the water companies, although a large portion of the 

 muddy sediment contained in Thames water is thereby deposited, yet it is 

 clear that it cannot free the water from all the impurities dissolved in it. 

 The process of subsidence might, it is true, he made to free the water from 

 nearly the whole of theanim.al impurities contained in it, but in tliat case the 

 state of rest of the water, to he so purified, ought to contimie for a nmch 

 longer period of time than the companies usually allow, or can art'ord to 

 allow. It has been ascertained that if Thames water ho snfi'cred to remain 

 at rest, completly undisturbed, for a period of several weeks, fermentation 

 will take place in consequence of the presence of animal and vegetable matter, 

 and the liquid will become clear and transparent, with the exception of a 

 small proportion of insoluble sediment, and will lose all unpleasant smell, 

 taste, or colour. This curious fact was ascertained by Dr. liostock, who 

 commmiicated the result of his interesting enquurv to the Royal Society in 

 1829. 



Of the second class, it is only necessary to observe, that mdess all the water 

 companies, north and south of the Thames, were simultaneously to esfaldish 

 their works as far to the west as at Teddington, no renmval to auv part within 

 the influence of the tide, conhl accomplish their intention of supplying a 

 purer water than they now do to the metropolis. * * 



In regard to the third and last class of projects tliat have been suhuiitted 

 to parliament, it is only necessary to state in passing, that the one wliich 



seems to have been d\dy considered by a select committee of the House of 

 Connnons so late as 18.'54, and which was presented by the late .Mr. Telford, 

 involves so much ditficidty, anil the outlay of so exorbitant a capital for the 

 supply of six only out of the eight w.itcr companies, that there ajipears to be no 

 likelihood of its ever being carried into cfli'ect. It is not ]>robal)lc, indc<'d, 

 that any government will authorize the expenditure of .€1,200,000 for the 

 construction of two aqueducts, the one sixteen, the other six mUes in length, 

 according to Mr. Telford's estimate, in order to bring water of very t/uestiun- 

 ahlc purity from the Yerulam aud the AVandle to assist «.r only of the water 

 companies of the metropolis. 



We shall not stop now to make any inquiry as to the a\ithority, 

 which the author has for stating that the water from the Verulam and 

 Wandle is " of very questionable purity " but shall reserve it until we 

 notice another ])art of the pamphlet relating to Mr. Telford's evidence. 



The author jiroceeds to give an interesting account of the numerous 

 plans which have been devised since the year 1821, for supplying the 

 metropolis, but as it is not our intention to notice all these schemes, 

 we must confine ourselves to that part wdiich relates to the supply 

 from the Colne near Watford, the locality of the pro))osed London and 

 Westminster Water (Company, now occupying the public attention and 

 a Committee of the House of Lords, and to wdiich the following ex- 

 tracts from the pamphlet alludes. 



.\mong the numerous schemes for the so-called better supply of the me- 

 tropolis -wMi pure water, from other sources than the Thames, there are two 

 which at the present time claim particular attention, from an abortive attempt 

 that has been lately made to revive one at least of them. The one of these 

 relates to the supply of the south side of the metropolis from the river Wan- 

 dle, as proposed in 1834 by Mr. Telford, and the other of the north side from 

 the Colne, also originally suggested by Mr. Telford, hut the idea of which 

 was abandoned by him owing to the insignificancy of its stream imless after 

 hea\-y rains, when its waters were in a very tiuhid state. (See Mr. Telford's 

 report March 1834, page 3.) 



A\f th respect to the water of the Colne, Mr. Telford's experiments clearly 

 jiroved that this river was totally inade(|uate in quantity for the supi)ly of 

 even tliree out of the five Water Companies on the north of the Thames, and 

 that with regard to ijuality, it is frequently in so tiu'bid and muddy a state, 

 caused by its flowing over a red soil, as to be totally unfit for use. 



Mr. Telford indeed gauged t/ie river Coluc, and the result of his experi- 

 ments showed that that river was totally inader/iiate for the supply of even 

 ttiree out of the five Water Companies on the north of the Thames. 



These quotations, unsupported by other parts of Mr. Telford's re- 

 port and evidence, would naturally, with a stranger to the subject, lead 

 to the belief that the efforts now being made for establishing the pro- 

 posed company are entirely delusive, and that all their statements are 

 only intended to dupe the respectable individuals who are disposed to 

 lend it their patronage. We have, therefore, thought it necessary to 

 reperuse the reports and evidence, and also at the beginning of last 

 month to visit the spot where the experiments are now being made. 



Let us first explain the situation and course of the river Colne. It 

 unites with the Thames near Isleworth, in its course to Watford, it 

 receives several tributary streams; from Watford it proceeds (still 

 under the name of the Colne) for a distance of about four miles, through 

 O Iters Pool, the scene of the company's experiments, aud Bushey Mills, 

 the place from which Mr. Telford proposed to take his supply, it 

 then goes on to the place at which the river Verulam falls in ; the 

 Colne continuing on as a very small stream beyond this spot, to the 

 north-east, towards Colney and .South Mims, and the larger stream, the 

 Verulam, proceeding to the north by St. Alban's, for some distance up 

 the country — therefore it will be observed that the river is called the 

 Colne from its junction with the Verulam to the river Thames. When 

 Mr. Telford stated that the Colne is an insignificant stream, i&c, it 

 may be clearly seen by his evidence, that he alluded to that part of 

 the stream above its junction with the Verulam, and he proposed to 

 divert that part of the Colne, so as to prevent it from affording any 

 supply to the intended water-works at Bushey Mills, on the banks of 

 the Colne, but lower down the river, and that in his report he called 

 that part of the river Colne from the junction of the two rivers to 

 Watford " the Verulam," wdiereas as we have already shewn, it is 

 called "the Colne." Wc will now give a few extracts from the 

 evidence of Mr. Telford to show that at that part of the Colne " Bushey 

 Mills," there was an ample supjjly of pure water to be obtained in the 

 driest season without filtration, or pumping, sufficient to supply the 

 principal part of the metropolis. All this evidence the author has 

 carelullv kept out of view, for what purpose we will not pretend to 

 say, unless from a misunderstanding of Mr. Telford's evidence. 



Mr. Telford in his report to the Lords of the Treasury, February 

 1834, states, that after having exannned the streams which fall into 

 the river Thames in the vicinity of London, he found an abundance of 

 pure, transparent water, within "the distance of IB miles on the north 

 (of London}, amply sufficient for the supply of three of the present 



