WATER AND WATERING. 
13 
as an application to plants. Holding, as it does, the sulphate or 
carbonate of iron, its corroding, poisonous effect on their roots 
maybe readily imagined; and as well might a dilution of vitriol 
be employed as the frequent use of such water. That taken from 
rivers or streams is most open to this objection; and if, in its 
course, it is observed to flow over frequently recurring beds of 
the kind, which may be easily detected by the rusty deposit, that 
water should be avoided. At the same time it must be remem¬ 
bered, we are not seeking for positively pure water, but only 
for such as shall be free from injurious properties; and hence, 
in the absence of qualities of the kind described, river water is 
likely to be more beneficial than any other, from its containing a 
larger proportion of disintegrated animal and vegetable matter, 
accumulated in its passage, the admitted character of which is 
that of a powerful manure. Well-water has none of this, and 
that taken from ponds but very little, while the latter is often so 
filled with the sporules of Marcliantia and other aquatic weeds, 
that its employment is certain to be followed by a coating over 
the whole surface of the soil, pots, &c., of green, slimy vegeta¬ 
tion, disgusting in appearance and injurious in tendency, by ex¬ 
cluding air to the soil, and, through it, to the roots. 
Besides the relation to its chemical properties, water has to be 
considered in a mechanical sense, and especially as regards its 
temperature when applied to the support of vegetation; its effects 
in this respect are always great, and the consequences of an 
extreme error become apparent in a very short time; as a rule, 
the temperature of water should be somewhat above that of the 
earth it is applied to, rather than below it, especially in the winter 
season, when the abstraction of heat associated with and con¬ 
sequent on the presence of an extra amount of fluid would be most 
severely felt; even in summer when the proper balance is more 
quickly restored, no greater error can be committed in relation 
to this subject, than to pour upon the roots of a parching sun¬ 
burnt plant water that is much colder than the earth in which 
they are located ; the consequences are nearly identical with what 
would take place in the animal system, and not unfrequently the 
result is death. 
The provision of tanks or other receptacles for water, required 
in the culture of plants, is then as essential as the most ordinary 
