A sanitary enquiry into the probable causes of yearly epidemics in England, as observed at Leicester / Richard Weaver.

  • Weaver, Richard
Date:
1871
Catalogue details

Licence: Public Domain Mark

Credit: A sanitary enquiry into the probable causes of yearly epidemics in England, as observed at Leicester / Richard Weaver. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    age system considered as a whole, and not ventilation of particular places, fixed upon indescriniinately, simply because certain factory cliimuies or other convenient modes of ventilation are at hand. A dozen such ventila- tors in any one district will he of no inateriarbenefit to an adjacent dis- trict or system j in a word, each single sewer or drain must have its own perfect ventilation. And unless this is actually the case no town sewerage can be considered satisfactory. Proceeding a little further, in periods of heavy rains and floods, unusual quantities of gas are produced; in the first instance each given volume of water entering the sewers displaces an equal volume of gas, and, secondly, as the waters rush through the sewers with accelerated velocity, the accumulated foul deposits on the sides and inverts are agitated, which operation sets free a great volume of gas previously con- tained in the deposits. Hence, efficient ventilation during floods is of the first consequence; in reality, proper ventilation of sewers is of quite as much sanitary importance to a town as the sewers. High winds, and winds blowing from certain quarters, such as the noith and east, are dis- turbing elements to the sewers in the absence of proper ventilation ; indeed we have noted greater pressure within the sewers during these winds, and in dry weather, than in periods of floods. The reasons of this are not quite obvious, but it is just possible that the change in barometric pres- sure in the case of a high wind may be the cause; and in the example of an east or northerly wind it may be due to the aqueous saturated and warm air of the sewers rushing to meet the dry cold air blowing from the direction just indicated. We have noted the pressure to be greatest when the wind is a high one, and blows from the east or north; this would be accounted for by such air being both rarified, dry, and cold. It will be observed that when the sewers are imperfectly ventilated internal pressure is created, and the gas being very subtle and penetrating will pass through the merest crevice conceivable when the sinks and grate traps are perfect; and when these are, as usually happens, imperfect, or the drain pipes are broken, improperly laid, possibly disjointed, brickwork decayed, joints without mortar, mortar rotten, and the thousand and one mishaps that are found in house drains, there the gas often issues with as- tonishing velocity, frequently a small hole in a pipe or brick emits gas enough to extinguish a lighted match or candle in a moment. Therefore, ventilation in sewers is essential, because the gas will otherwise enter houses, notwithstanding the usual precautions taken to keep it out; and it is somewhat remarkable that these escapes happen in many houses-
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