Public health laboratory work / by Henry R. Kenwood.

Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: Public health laboratory work / by Henry R. Kenwood. 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.

    47/542 (page 17)
    1/ CHAPTER II. A Water Report. For hygienic purposes such a report must include all the information which can be obtained regarding the extent to which organic matter at present exists; the evidence of former pollution by this material in the oxidised, &c., products of its decomposition ; and the amount to which poisonous metals—if any—are present. Much unnecessary confusion is created by the fact that no fixed terms are recognised and adopted by which results may be universally expressed. The results in the several steps of the analysis are, in conse- quence, variously returned by different analysts in terms of: — Parts per loo. Grains per gallon. Parts per 100,000 Parts per 1,000,000. Parts per 100,000,000. It seems most desirable, therefore, that some decision should be come to upon this point. Undoubtedly the best amount for working purposes in many of the stages of the analysis is 100 c.c. of the water, and the result, if this quantity be taken, can generally be at once expressed in parts per 100,000 (since 100 c.c = 100,000 milligrammes) ; this is by far the most com- mon term employed in this country, and it is moreover c