The organic analysis of potable waters / by J. A. Blair.

  • Blair, J. A. (James Andrew)
Date:
1891
Catalogue details

Licence: Public Domain Mark

Credit: The organic analysis of potable waters / by J. A. Blair. Source: Wellcome Collection.

    48/136 (page 36)
    is used, there is no advantage in using large quantities of sulphuric acid. The fourth question is answered by Table XII and the remarks made upon it. There is no reduction of permanganate during evaporation, if the concentra- tion be kept within certain limits. A quarter of a litre of permanganate solution may be boiled for one hour, and half a litre for two hours, without suffering any reduction of permanganate, if certain precautions be observed. (See working details of the oxygen process at 100° C.) Roughly speaking, an acid solution of permanganate can be reduced to half its original volume by evaporation, whilst boiling, without suffer- ing any reduction of permanganate. Table XY answers the fifth question by showing that oxidation of the organic matter in Edinburgh water is not hastened by allowing a J litre of the water to be boiled down to 60 c.c., if the loss of per- manganate due to concentration—the quantity due to this cause being experimentally found—be deducted from the total quantity reduced. The answers to these five questions are favourable to the use of a temperature of 100° C. for the oxygen process, if certain precautions be observed.