14 
WATER AND WATERING. 
operation; these should be situated so that, either through the 
influence of the sun or other means, the water may be raised to 
the required temperature; for open-air culture when water 
is not often wanted except in summer, the heat imparted by the 
rays of the sun may be regarded as sufficient, and the supply 
being stationed for some hours where it may receive their influence 
will be fit for use when required, but for plants grown in glazed 
structures and subject to a constantly elevated temperature, some 
more certain means must be devised. A very general practice is, 
to keep the supply in tanks sunk beneath the floor of the house, 
and covered closely in ; now, unless this kind of receptacle can 
be stationed within the influence of the apparatus employed for 
heating the erection nothing more absurd can be imagined; to 
suppose that water so situated can equal in temperature the 
atmosphere of the house, or be anything better than that at the 
bottom of a well, is decidedly erroneous ; for any addition of heat 
it is intended to be indebted to the atmosphere of the house/and 
from that it is effectually excluded by the covering, usually a 
wooden flap, the absolute impossibility of water so placed becom¬ 
ing warmer must be apparent. 
The necessity of an equality of temperature between the soil 
and the water being granted, we must in reason place them both 
under the same influences, and from the circumstance of water 
being a bad conductor of heat, we should allow them to incline 
most favorably towards the latter ; to accomplish this, the water 
tank instead of being buried should be elevated if possible above 
the heating apparatus, or if the arrangement of the house will not 
permit of this, it should either stand on the floor so that the 
atmosphere of the erection may have an effect on all sides, or if 
the sinking it out of view is insisted on, it must positively stand 
so near to the fireplace as to become sufficiently warmed through 
its whole contents in a few hours after being filled; in no case, 
however, should it be covered, unless of a size to cause appre¬ 
hension of too much moisture in the atmosphere of the house, a 
circumstance by no means probable in any ordinary case. In 
forcing-houses where much moisture, both at the roots of the 
plants and in the form of vapour, is constantly required, the 
supply of water and its position in the house are important 
considerations, that the required abundance may always be at 
