558 
Proceedings of the Royal Society 
in abundance, and in twenty-three days a plate an inch and a half 
square lost I'll grain in weight. 
The bottom water, taken where the depth was 594 feet, differed 
materially in these characters. The cistern brought up some finely 
comminuted peat-like matter, in which the microscope detected a 
profusion of various diatoms, and two species of active microcosmic 
animals. The colour of the water was deeper than that of the sur- 
face, and became the same not till the addition of half its volume of 
colourless distilled water. Nitrate of silver produced an immedi- 
ate scanty precipitate, oxalate of ammonia scarcely any effect. 
The soap-test indicated T015 of hardness, which is the equivalent 
of a 69,000th of carbonate of lime. The solids amounted to a 
16,000th of the water, and lost a third by incineration.* When the 
water was evaporated to a tenth of its volume, nitrate of silver 
indicated chlorides in abundance, nitrate of baryta sulphates feebly, 
oxalate of ammonia lime sparingly, and phosphate of ammonia 
magnesia faintly. The original water had no action at all on 
lead. The lead plate became dull in a few hours, but no other 
change ensued which the eye could discover; and in twenty- 
three days the plate, which originally weighed 405*73 grains, 
weighed 405*74 grains. 
These differences between the bottom and surface waters were so 
great, that it became desirable to repeat the examination, which I 
was able to do on the 6th of the present month. A good deal of 
easterly rain had fallen for some days until two days before this 
visit ; but the hill streams had already become low. The waters 
were collected near the same place as before, — the bottom water 
from a depth of 94 fathoms, or 564 feet. The cistern brought up, 
as formerly, some peaty-like matter, which speedily subsided, and 
was promptly removed by decantation. Both specimens of water 
were very pure. But the bottom water was more affected than the 
surface water both by nitrate of silver and by oxalate of ammonia, 
and its colour was decidedly deeper, so that fully more than half its 
volume of colourless distilled water required to be added, to produce 
the feeble tint of the water from the surface.f The peaty matter 
* 13,125 grains left 0*82 grains at 300, and 0-55 after incineration. 
t The cistern which brought up the water was new, made of copper, and 
urnished, for valves, with spherical copper balls resting on hemispherical beds, 
