Water Analysis : a practical treatise on the examination of potable water / by J. Alfred Wanklyn.

Date:
1874
Catalogue details

Licence: Public Domain Mark

Credit: Water Analysis : a practical treatise on the examination of potable water / by J. Alfred Wanklyn. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    attention directed to it. We have not met with any base except ammonia which gives the peculiar brownish coloration with the Nessler-reagenr. Amylamine, diamylamine, and liiperidine in very dilute solutions, give white opalescence or precipitate when treated with the Nessler-test ] naphthy- lamine, toluidine, and nicotine, under these circumstances, occasion no reaction of any kind. (Although, however, these volatile bases cause no coloration, yet their presence more or less affects the tint which ammonia gives with the Nessler- test, and they thus, to some extent, interfere with the sharp- ness of the estimation of ammonia.) There is, therefore, every reason for believing that the pro- duction of the brownish tint with the Nessler-test is quite characteristic of ammonia. The degree of precision attain- able in reading the indications of the Nessler-test is much greater than would be imagined at first sight. The of a milligrm. of NH3 in 100 c. c. of liquid is a quantity very easily seen. The difference between and — of a milligramme of NH^ will, we think, be visible to most people. With practice a higher degree of precision is attainable. When, instead of using 100 c. c. of water for the Nessler-test, a smaller bulk is taken, the indications become more delicate. So small a quantity as of a milligramme of ammonia may be seen in a small bulk of liquid. In short, the Nessler-determination of ammonia is suscep- tible of the most wonderful delicacy. On referring to the results given by different substances, as described in this paper, it will be seen that, putting nitro- compounds on one side, organic nitrogenous substances in general evolve ammonia on being heated ,to 100° C. with strongly alkaline solution of permanganates. This reaction