242 
Rustic Adornments . 
slope-back tank the back and ends are of an opaque material, and light 
is admitted from above only, so that the tank is in itself the closest possible 
imitation of a rock-pool, with the advantage of affording an uninterrupted 
view of the contents. The form in which these tanks were originally made 
has been improved upon, as shown in the annexed cut. After the shallow 
square tanks and the glass pans, these are certainly the next best in 
efficiency ; and, so far from being inelegant, nothing can surpass or even 
equal the beauty of the scene they present when well stocked, the subdued 
light being in favour of the view rather than against it. Were it 
otherwise, the health of the inmates would be a sufficient compensation, 
for in a matter of this sort it would be absurd to advocate any form 
of vessel, however elegant, which did not fulfil the conditions essential 
to the preservation of the 
creatures. 
Let us consider for a moment 
what are the advantages of this 
form. Owing to the slope of the 
back it can be fitted and unfitted 
more quickly than any other 
kind of vessel, except the little 
shallow ones already described. 
In fitting rockwork, not a par¬ 
ticle of cement is needed; 
hence, instead of losing the 
whole stock two or three times 
cement has been used, and has 
been supposed to be properly seasoned, the risk from that danger is 
reduced to nil. Any rough non-metallic mineral may be piled upon 
the slope in a few minutes, tufts of Alga inserted if desirable, and 
removed again when they decay, without the smallest disturbance of the 
general furniture. Better still, the most beautiful and appropriate background 
may be made up of old serpula, oyster, and other shells; blocks of coral, and 
such light rough debris as will be sure to accumulate in the hands of an 
aquarian. Oyster shells, incrusted with serpulae, balanae, and other small 
marine masons, add nothing to the weight of the vessel, yet serve all the 
purpose of heavy rockwork; and if the spontaneous vegetation so necessary 
to the success of the tank does not appear on them with sufficient profusion, 
WATER CHAMBER TANK. 
over, as is the case sometimes when 
