DRINKING-WATER FROM AGRICULTURAL LANDS. 45 



in this country and in Europe, to economically furnish water in ample 

 quantity, a corresponding degree of skill and enterprise has not always 

 been directed to the determination of its quality. 



It is not impossible to point out authorities on sanitary matters so 

 wedded to pet theories that they unhesitatingly deny that the conver- 

 sion of a pure running stream, or even a large river, into a conduit for 

 the sewag€-filth of a great city, will have any deleterious effect on the 

 potable quality of the water taken a few milesbelow the filth-entering 

 point. It has been demonstrated that this is not only false in theory 

 but also in fact. It was Dr. Letheby, of the English « Royal Commis- 

 sion on the Water-Supply of London," it is believed, who was the first 

 to announce what has since been proved a fallacy, viz., that " if sewage 

 be mixed Avith twenty times its volume of river-water, the organic mat- 

 ter which it contains will be oxidized and completely disappear while 

 the river is flowing a dozen miles or so;" and further, that "it is safe 

 to drink sewage-contaminated water after filtration." The " Royal 

 Rivers Pollution Commission" of 1868, unwilling that this expression 

 of opinion should remain untested, submitted it to careful and ingen- 

 ious experimental investigation. The result is thus announced : . . . 

 " It is thus evident that so far from sewage mixed with twenty times 

 its volume of water being oxidized during a flow of ten or twelve miles, 

 scarcely two-thirds of it would be so destroyed in a flow of one hundred 

 and sixty-eight miles, at the rate of one mile per hour, or after the lapse 

 of a week." And, after mentioning certain details in support of this, 

 the commissioners conclude with the remark that " it will be safe to 

 infer, however, from the above results, that there is no river in the 

 United Kingdom long enough to effect the destruction of sewage by 

 oxidation." Dr. Frankland, an eminent English authority, before the 

 Royal Commission on Water-Supply, gives some strong testimony in 

 support of the statement that it is impossible to remove the sewage- 

 contamination from water by any known process, natural or artificial, 

 so as to render it harmless, except by boiling for a long time, or by 

 distillation ; and, as these two processes are impracticable on a large 

 scale, then, he says, in his opinion, " water that has once been contami- 

 nated by sewage ought not afterward to be used for domestic pur- 

 poses ; and, inasmuch as it is generally believed that the noxious matter 

 of sewage exists there in the form of minute germs, which are proba- 

 bly smaller than blood-globules, I do not believe that even filtration 

 through a stratum of chalk could be relied upon to free the water per- 

 fectly from such germs." iVccording to the same authority, "the 

 noxious part in sewage is that which is held in mechanical suspension, 

 not held in solution;" and yet, he says, and truly, "no system of filtra- 

 tion will secure its removal." Colonel J. W. Adams, C. E., in a valu- 

 able paper on river-pollution,* follows up this subject to its logical con- 



1 " Report on Water-Supply for the City of Philadelphia," made by a commission of 

 cn2;itieers in 1875. 



