Report on an examination of Schutzenberger's process for the estimation of dissolved oxygen in Thames water / by Henry E. Roscoe.

  • London County Council.
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: Report on an examination of Schutzenberger's process for the estimation of dissolved oxygen in Thames water / by Henry E. Roscoe. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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    APPENDIX. Apparatus for the Extraction and Analysis of the Gases dissolved in Water, and the method of using it. The apparatus in which the gases are extracted from the water under examination is shown in figure II. It is first completely exhausted of air by pumping about 200cb.c. of water into the largebolt-head A, of about three litres capacity, filling the side tube F with the water to be examined from the bottle S. The lamp beneath A is lit, and the apparatus ex- hausted of air by the air-pump shown in the figure. When the exhaustion has proceeded as far as possible by the air-pump, the three-way tap beneath B is turned to communicate with the mercury reservoir E, the mercury rises in the tube beneath B, and is allowed to flow, by a suitable turn of the tap, into the U tube, thus shutting off communication with the air. The three-way tap beneath B is kept closed during the rest of the operation, and the outlet is sealed by mercury. The boiling is continued, and the vapour drives all the gas before it into D and E. The tap beneath E, in the glass bowl full of water, is opened, and the mercury reservoir raised. Mercury rises in E, and all the air which has there collected is driven out through the capillary barometer tube, and the mercury trough T. On lowering the reservoir a vacuum is produced in E. The contents of D are trans- ferred to E and thence out by the trough. This is repeated three or four times until the contents of D and E, when condensed into the capillary barometer tube, show no gas. The apparatus is now ready for the introduction of the w^ater to be examined, the tap communicating with S is opened, and the water rushes into the vacuous space with an immediate escape of the greater part of the gases previously held in solution. When a sufficient quantity of water has been introduced, about 1500- 1700 cb. c. the tap is shut off, and the flame placed beneath the bolt-head A. The gases are given off with brisk effervescence, and make their way into E, free from w^ater, which has con- densed in its passage through B, C, and D. The dry gas is passed over into the gas tube G, full of mercury, b}^ raising K, and on lowering it more gas enters the