240 The Future Waier-supphj nf London. [April, 



experimented upon, oxalic acid was the only one which was per- 

 fectly oxidized even in six hours. All the others escaped oxidation 

 to a greater or less extent ; and such important compounds as urea, 

 creatiu, and cane sugar, were scarcely oxidized at all. Moreover, 

 although one part of oxygen will oxidize eight parts of oxalic 

 acid, it could only oxidize perfectly 0*47 part of urea, 0*45 of 

 creatin, or 0*89 of sugar; so that even if the oxidation effected 

 by the permanganate were perfect, the calculation would be wrong. 

 The consideration of the irregularity in the action of the perman- 

 ganate test has induced Dr. Frankland and some other eminent 

 chemists to abandon its use altogether ; and in the present state of 

 om' knowledge this is perhaps the safest com'se to pursue ; but I am 

 by no means convinced that it may not, even yet, be made a most 

 valuable auxiliary test in water analysis when properly used. In an 

 interesting and suggestive pamphlet ' On the Examination of Water 

 for Organic Matter,' by Dr. Angus Smith,* to whom we owe the 

 earhest and some of the most successful attempts to discriminate 

 between difierent kinds of organic matter in water, will be found 

 many important details on the mode of using the test, and inter- 

 preting its results. I regret that space precludes me from quoting 

 some of his results. I have derived much instruction from the 

 perusal of the paper, and can only hope that the author will follow 

 up his experiments, which aj)pear to have been unavoidably post- 

 poned. 



A new and very ingenious method of water analysis was pre- 

 sented to the Chemical Society of London on June 20, 1867, by 

 Messrs. Wanklyn, Chapman, and Smith, and is more fully described 

 in a little work pubhshed by the two first-named chemLsts in 1868.t 

 The chief process is conducted in the following manner: — The 

 quantity of ammonia in the water to be examined is first determined 

 in the usual way by means of the Nessler test. Another portion is 

 then mixed with carbonate of soda, and a fraction of it, usually 

 about one-third, is distilled off, measured, and the ammonia it 

 contains estimated as before. To the residue in the retort is now 

 added an alkaline solution of permanganate of potash, and the 

 liquid again distilled until a very small l)ulk remains. A third 

 determination of ammonia is made in this distillate, and from these 

 results three different portions of nitrogen are determined in the 

 original water. The first portion exists in the water, as ammonia ; 

 the second is believed by the authors to exist as urea ; and the third 

 as albuminoid substances. If those distinctions were exact ; if the 

 whole of the nitrogen of urea could be recovered as ammonia in 

 the first distillation, and the whole of the nitrogen of the albumi- 

 noid compounds in the second, this method would be, as far as it 



* Londrm : Taylor and Francis, 1868. 



+ ' Water Analy.«is : A Practicnl Trcalisc on tlie Exuniinatiun of PuUilile 

 "Water.' Lumlon : TriibMer and Cu. 



