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122 APPENDIX.
It did not contain carbonic acid in a free state, for when mixed
with a solution of chloride of calcium and of ammonia, not the
slightest turbidity was produced. When boiled it did not lose
its transparency, nor produce any deposit, until concentrated to
about one sixth of its volume, when glittering scales of hydrated
silicic acid separated.
An imperial gallon, when evaporated to dryness, left a solid
residue, which weighed 5.24 grs.
This residue was perfectly white when dried at 300° Fahr.;
when heated to low redness, it charred slightly at the edges. The
quantity of organic matter was therefore exceedingly small.
Hardness in reference to distilled water as unitv = 2.4.

Traces of an alkaline nitrate were also detected.
During the short visit I made with you to Farnham, we examined
several other springs near to their sources. In their general
characters these waters closely resembled the preceding sample,
all of them being remarkably soft, clear, transparent, inodorous,
and free from any excess of organic matter, or of oxide of iron.
By your desire two samples were subsequently sent to me ;
one marked " Barford," the other " Boorley."
The water marked Barford contained 6.30 grs. of solid matter
in the imperial gallon; when evaporated, scales of silicic acid separated
from it in the same manner as from the water taken at
Haslemere. Neither of these waters contained any trace of carbonic
acid. Their relative hardness (distilled being unity) was—
Barford 2.4, Boorley 1.5.
D. The fourth sample of water was drawn from the pump near
the church in Bishopsgate street.
This water was selected as exemplifying the general composition
of the shallow well-water of the City of London, when the
well is situated near to a burial-ground, as is frequently the case
with the parochial wells.