54 Br. Edivard Franhland [Feb. 21, 



Institution, Mr. Telford, the celebrated engineer, and Dr. Eoget, 

 Secretary of the Eoyal Society, were appointed a Royal Commission 

 to inquire into the quality and salubrity of the water supplied to the 

 metropolis. 



The Commissioners made careful examinations and analyses, and 

 reported as follows : " We are of opinion that the present state of the 

 supply of water to the metropolis is susceptible of, and requires 

 improvement ; that many of the complaints respecting the quality of 

 the water are well founded ; and that it ought to be derived from other 

 sources than those now resorted to, and guarded by such restrictions 

 as shall at all times ensure its cleanliness and purity." (At this time 

 the water was pumped from the Thames between London Bridge and 

 Battersea). " To obtain an effective supply of clear water, free from 

 insects and all suspended matter, we have taken into consideration 

 various plans of filtering the river water through beds of sand and 

 other materials ; and considering this, on many accounts, as a very 

 important object, we are glad to find that it is perfectly possible to 

 filter the whole supply, and this within such limits, in point of 

 cxj^ense, as that no serious objection can be urged against tbo plan 

 on that score, and with such rapidity as not to interfere with the 

 regularity of service." 



Before the year 1829, therefore, the river water supplied to 

 London was not filtered at all ; but after the issue of this report, the 

 companies set themselves earnestly to work to improve the quality of 

 the water by filtration. 



The first filter on a working scale was constructed and brought 

 into use by the Chelsea Water Company in the year 1829. But even 

 as late as 1850, only three out of the seven principal companies filtered 

 the river water which they delivered in London ; and it was not until 

 1856 that filtration was made compulsory by Act of Parliament ; 

 whilst it can scarcely be doubted that between this date and the year 

 1868, when my observations on turbidity were first commenced, the 

 operation was very imperfectly performed. 



In the year 1832, and again in 1849, London was severely visited 

 by epidemic cholera, and the agency of drinking water in spreading 

 the disease forced itself upon the attention of the observant portion 

 of the medical profession. It was Dr. Snowe, however, who in 

 August 1849 first formally enunciated the doctrine that drinking 

 water, polluted by choleraic matters, is the chief agent by which 

 cholera is propagated. 



Keceived at first with incredulity, this doctrine was supported by 

 numerous facts, and it soon caused renewed attention to be directed 

 to the quality of the water then being supplied to the metropolis, 

 with the result that the intakes of the various companies drawing 

 from rivers were, one after another, removed to positions above the 

 reach of tidal influence, tlie Thames water being withdrawn from the 

 river above Teddington Lock, and the Lea water at Ponders End, 

 above the tidal reaches of that river. 



