Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
[Report of the Medical Officer of Health for London, City of ]
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APPENDIX. 123
The water from this well is perfectly bright, clear, and even
brilliant; it has an agreeable soft taste, and is much esteemed by
the inhabitants of the parish, although, as will be seen by the
subjoined analysis, it is an exceedingly hard water, and the
large quantity of earthy salts it contains renders it unfit for all
culinary and for most domestic purposes.
When heated to the boiling point, this water becomes turbid,
and by continued boiling of an imperial gallon of the water for
two hours, 23.03 grs. of solid matter were deposited, consisting
of 22.15 grs. carbonate of lime, and 0.88 carbonate of magnesia,
with a trace of phosphate of lime.
An imperial gallon of this water, when evaporated to dryness
and the residue dried at a temperature of about 300° Fahr. left a
residue which amounted to 88.07 grs. From another sample of
the same water taken a month afterwards, 84.53 grs. of solid residue
were obtained.
The residue left by evaporation was of a light brown colour;
when calcined at a low red heat it became slightly charred; but I
could not, with any degree of certainty, determine the precise quantity
of organic matter it contained : it was certainly very small.
The excess of solid matter, as shown by the analysis, over the
quantity obtained by evaporating the water to dryness, is owing
to the decomposition of the nitrate of ammonia.
The quantity of alkaline and earthy nitrates in this water is very
remarkable. These salts are doubtless derived from the decomposition
of animal matter in the adjacent churchyard. Their presence,
conjoined with the inconsiderable quantity of organic matter which
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