Water-analysis : a practical treatise on the examination of potable water / by J. Alfred Wanklyn and Ernest Theophron Chapman.

  • Wanklyn, J. Alfred (James Alfred), 1834-1906.
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: Water-analysis : a practical treatise on the examination of potable water / by J. Alfred Wanklyn and Ernest Theophron Chapman. Source: Wellcome Collection.

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    generis, as an index to the nitrogenous organic matter at least as valuable in itself as a determination of the total nitro- gen •would be. Indeed, it is more valuable; inasmuch as the cases of nitro-compounds and of urea are by our process dis- tinguished from the cases where albumen and like substances are present. The fallacy which lurks in Dr. Frankland's commentary is, that the only quantitative operation to which organic com- pounds can be submitted is the process of elementary analysis into carbonic acid, water, and nitrogen. I will answer it by a parallel. Acetic ether may be made to yield acetic acid quite quantitatively ; and in whatever sense the carbon contained by acetic ether can be said to be a measure or index to the acetic ether, in that same sense the acetic acid is a measure or index to the acetic ether. An unknown mixture of acetates could not be absolutely measured by the carbon it contains, neither could the mixture be abso- lutely measured by the acetic acid which it gives. But in whatever sense the carbon can be said to be an approximate measure of the mixed acetates, in that same sense is the acetic acid a measure. For acetic acid read albuminoid ammonia, for acetic ether read albuminous substances, and for mixed acetates read the miscellaneous nitrogenous organic matters in drinking-water, and the parallel is complete. To the lecturer's objection that there are nitrogenous organic substances which yield no albuminoid ammonia, I answer that urea is the only one which is likely to occur in drinking-water, and urea is fully provided for by the ammonia-process. If, perchance, a trace of nitro-compound ever make its way into drinking-water, it would not be detected by the ammonia- process. But that is no objection to the ammonia-process, which is designed to measure the albuminoid substances and o