These three vessels were made of squared slabs of best slate, 
varying in thickness from lin. (base) to lin. (sides), which were bolted 
together with iron rods, tightened by screws and nuts at the ends. All 
the internal angles were filled with Portland cement. The Tank had 
that side which faced the interior of the room, made of din. plate-glass. 
J) A MARINE AQUARIUM. 
The dimensions and capacities of these vessels were as follows :— 
Tank 42in. long, 18in. wide, 18in. deep, in the clear; each inch of depth 
equal to 2°73 gallons; 49 gallons in total. Reservoir 623in. long, 35}in. 
wide, 26}in. deep, each inch equal to 8 gallons; 210 gallons in total. 
Cistern 34in. long, 34in. wide, 27in. deep, holding 112 gallons. 
The Reservoir in the cellar was first put together, sunk in place, 
proved water tight, and the earth rammed around it, in May. Harly in 
June a water cart, viz., a hogshead on wheels, was filled thrice with the 
crystal water of Oddicombe shingle-beach, and emptied by a hose into it, 
giving me 210 gallons of pure sea-water in my Reservoir, which was 
protected from dust by a strong and tight cover of wood, divided and 
hinged in the middle for convenience of examination. 
Early in September the whole apparatus of pump, pipes, valves, 
&c., arrived from the engineers, to be described in detail ; and immediately 
the masonry of the house was opened to receive the Cistern and the 
Tank. A large opening having been made in the gable above the window, 
two cross-joists of 4in. square deal were inserted in the ceiling from the 
gable-wall to the centre beam. The base of the Cistern was got up, and 
laid in situ, square and level, save a din. inclination to §.W., that 
it might be emptyable to the last drop. A hole was now drilled in this 
S.W. part of the base, for insertion of the jet pipe, over the Tank; and 
another on the N.E. side, for insertion of the warning pipe. The sides of 
the Cistern were then set-up in Portland cement, bolted together, and 
smoothed within and without. 
The base and sides of the Tank were put into place, first tentatively, 
until the Cistern, and the pump with its pipes, were adjusted ; and then 
finally, cemented and bolted ; and the plate-glass front was bedded in lead 
putty in its grooves, well worked in, and smoothed off. Before this last, 
however, the siphonal apparatus was prepared and affixed, which will 
presently be described. 
Thus, then, the three continent vessels were in place, and appeared 
perfect. But these alone were of little avail. A large volume of sea- 
water, indeed, had been lying for more than three months quiescent in 
the lowest, dark and cool below the earth-level, and still brilliantly 
pure, as a tumblerful dipped out proved. But we wanted to lift this 
water out of the Reservoir into the Cistern in the roof, to transmit it 
thence into the Tank, and thence again into the Reservoir; and to do 
this perpetually, without an instant’s intermission, day and night, by a 
constant circular current. 
The apparatus by which this was effected I must now proceed to 
describe. 
1.—The Pump. This was an ordinary lift-pump, of great strength, 
and great accuracy of workmanship, the materials of which were steel, 
