ON RECORDING THE RESULTS OF WATER ANALYSIS. 57 



litre) would too frequently give rise to fractional results. The special 

 advantages attaching t« ' parts per 100,000 ' are that the figures for 

 mineral waters are not inconveniently large, nor those for potable waters 

 inconveniently small, whilst their conversion into grains per gallon is a 

 very simple operation. 



We cannot agree with the American Committee that different scales 

 should be adopted for mineral and potable waters respectively, for such 

 a dual system must, in our opinion, inevitably lead to confusion. 



(2) We attribute the greatest importance above all to the clear 

 statement, in every case, of the actual determinations made, and that all 

 results derived by calculation should be sharply distinguished from those 

 obtained by direct determination. 



Thus we view with particular disapprobation the statement of the 

 mineral ingredients combined as salts, unless accompanied by a clear 

 account of the analytical data upon which this statement is founded. 



(3) As regards the statement of the mineral ingredients, we have 

 considered the method suggested by the American Committee, and which 

 consists in recording the proportion of each metallic element (K, Na, Li, 

 Ca, Mg, Fe", Fej, &c.), as well as that of each electronegative element (P, 

 CI, Br, I, S, &c.) contained in binary compounds, whilst in the case of 

 oxy-componnds the electronegative element is given as combined with 

 the whole of the oxygen (SOj, PO^, ^03,00,), Ac), and we are of opinion 

 that this arrangement is decidedly the most convenient for all purposes 

 of calculation, although the absence of any recognised names for these 

 acid-groups, as well as the prevailing custom of estimating the metallic 

 elements in the condition of bases (KoO, NaoO, CaO, &c.) are undoubted 

 objections to this system. 



(4) That the amount of dissolved gases (0, N, CO.,, SHj, &c.) may 

 be most conveniently expressed either in cubic centimetres per litre or in 

 volumes of gas per 100 volumes of watei-, the latter being the more 

 general practice in this counti-y. 



The system of statement which we wish to recommend will be most 

 readily understood from the following form for a complete analysis : — 



RESULTS OF ANALYSIS EXPRESSED IN P.\RTS 



PER 100,000. 



Potable M'atcr ;— 



l'(ff) In suspension. . 



Total solid matters . 



t(&) In solution.. 



Organic carbon. 

 Organic nitrogen. 



Oxj-gen consumed, as indicated by decolouration of permanganate.. 

 Ammonia expelled on boiling with sodium carbonate. 



Ammonia expelled on boiling with alkaline permanganate. 



Nitrogen as nitrates and nitrites. . 



Chlorine. 



