MINIATURE EERN CAVERNS. 
209 
to form a cave closed on every side, save the one 
facing the room. At the top a small aperture 
must be left, in order to admit some light, and to 
give ventilation. The floor of the cavern may be 
cemented so as to retain the water which flows 
from the extemporized fountain—provision being 
made by means of a pipe some two or three 
inches long in the floor of the cavern communi¬ 
cating with the sink, to allow all water which 
rises beyond a certain fixed level to flow away. 
In the walls of such a cavern, in its interior, at 
its top, and at its entrance, as well as amongst 
the rockery at the base of the fountain, Ferns 
may be planted. We show no Ferns in our illus¬ 
tration (page 210), but they should be selected 
from the list given in our chapters on £ Ferns and 
Fern Culture, 5 according to the capabilities of 
each, as there described, for darker or lighter, 
dryer or moister situations. 
Such caverns as we have suggested may be 
made in many other parts of a house than its area 
£ well 5 or £ wells. 5 There is no reason, indeed, 
why they should not be constructed in dining or 
drawing-rooms, or indeed in any rooms of a 
