Examination of water (chemical and bacteriological) / by William P. Mason.

  • Mason, William Pitt, 1853-1937.
Date:
1899
Catalogue details

Licence: Public Domain Mark

Credit: Examination of water (chemical and bacteriological) / by William P. Mason. Source: Wellcome Collection.

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    ing so as to displace the air, and then completely empty it. If the water is to be taken from a tap, let enough run to waste to emp*fy the local lateral before sam- pling ; if from a pump, pump enough to empty all the pump connections; if from a stream or lake, take the sample well out from the shore, and sink, the stoppered sampling-vessel towards mid-depth before removing the stopper (or cork), so as to avoid both surface-scum and bottom mud. In every case fill the vessel nearly full, leaving but a small space to allow for possible expansion, and cork securely. Under no circumstances place sealing- wax upon the cork, but tie a piece of cloth firmly over the neck to hold the cork in place. The ends of the string may be afterwards sealed if necessary. Bear in mind, throughout, that water-analysis deals with material present in very minute quantity, and that the least carelessness in collecting the sample must vitiate the results. Give the date of taking the sample, as full a description as possible of the soil through which the water flows, together with the im- mediate sources of possible contamination. Having secured the sample, the analysis should be begun at once, for the reason that water is liable to rapid changes in character during laboratory storage. For instance, the following analyses are of the same sample of water from the laboratory tap, drawn