1:>J THK AMKKI(^\N MONTHLY (May, 



of the ti)tal M)liils aiui the total ortjaiiic matter, this hitter tleter- 

 inination heinjj ahsohitely without reference to tlie question of 

 ijuality. The recent examination of a hi r<;e number of published 

 analyses has forcibly impresseil upon the writei' the almost entire 

 lack of appreciation of a necessity for information as to what may 

 be termeil the iletail of the or^janic constitutents wliich pre\aileil 

 as recently as thirty to forty years ajjo. 



A few tar-seeiuij stuilents had, indeed. percei\ed clearK lliat the 

 current analyses ot the day were consiilerabiy short of reyealinj; 

 the thinj; necessary to be known, namely, what may be termed 

 the natural history of potable water. Chief amonj; such must be 

 mentioned Dr. Ilassall, whose illustrateil memoir on the water 

 supply of London was publisheil in iS;;o. I'his. however, was 

 too far in adyance of the day of its publication, and stood alone 

 for twenty years as the first jjuidc-post on a new road to a more 

 exact knowlecjtje of the detail of the natinal iiistorv of potable 

 water. 



Li the meantime a number of eminent chemists had clearly 

 perceivetl the necessity foi' additional information in rej;;ard to the 

 condition of the contaminatinjj^ organic material more or less 

 present in all waters, and yarious refinements in chemical meth- 

 ods of study were accordinj^ly made : for instance, the distinction 

 between the free and the albuminoid ammonia of the W'anklyn, 

 Chapman and Smitli process ; the distincti<»n l)etween the or<i;anic 

 carlion anil the organic nitrogen of Frankland's combustion pro- 

 cess, etc. Without going too much into the detail, let us consider 

 some peculiarities of the combustion process which are of his- 

 torical value in the present connection and at the present time. 



Probably, among the working water analysts of two decades 

 ago, Dr. Frankland perceive<l, more clearly than any other, the 

 necessity for distinguishing between the contamination resulting 

 from the waste products of animals, etc., and that produced either 

 by purely vegetable growth in water itself, or by surface water 

 coming in contact with vegetable matter in its ordinary course or 

 flow ; hence we find as distinctive features of the comliustion 

 process the determination of the organic carbon, the organic nitro- 

 gen, and the estimation of the previous sewage or animal con- 

 tamination, a knowledge of these three together with that of the 

 free ammonia, nitrites, nitrates, and chlorine constituting in Dr. 

 Frankland's view a nearly complete natural history of water. 



With regard to the organic carbon and the organic nitrogen. 

 Dr. Frankland remarks in the Sixth Report of the Rivers Pollu- 

 tion Commission (1S74) that the animal or vegetable origin of 

 the organic matter contained in potable water may, in most 

 cases, be judged by the relative proportions in which the two 

 elements, carbon and nitrogen, f)ccur in the organic matter, and 

 that in waters contaminated by organic matter •• the smaller the 

 absolute quantity of organic nitrogen, and the less the proportion- 

 ate amount as compared with organic carbon, the better is the 



