WATER AND WATERING. 
15 
hand in a fit state for immediate use ; and in every case the tank 
should be so constructed, that the rain-water falling on the roof 
of the house may flow into it, for, as was before remarked, this 
kind of water being comparatively free of impurities is greatly to 
be preferred for the more delicate objects of the cultivator’s care. 
In our application of water, we undertake a very important 
office, requiring constant watchfulnesss, great care, and a rather 
extended knowledge of the physiology of plants ; a thorough know¬ 
ledge of the subject also embracing an acquaintance with the 
physical character of the country from whence each plant is 
derived ; it may be that some will exclaim :—Surely it cannot be 
necessary to possess all this information in order to determine 
when a plant is dry, and therefore wants water; but however 
ordinary the occurrence, there can be no question that on it 
hinges the entire art of cultivation For a basis to these observa¬ 
tions, let us again look to the functions of water in the growth of 
plants when in a state of nature ; it enters into their systems more 
abundantly than any other substance, both at the roots and 
through the pores of the foliated parts, it gives elasticity to every 
portion, it prepares and assists in the assimilation of the more 
solid food, performing, in the last respect, functions the most 
important of all; some notion of the quantity which enters into 
the composition of ordinary plants, may be ascertained by weigh¬ 
ing a healthy branch with its leaves, of such a subject as the 
Pelargonium, and after reducing it to ashes by means of fire, 
again weigh the residuum ; by carefully conducting the opera¬ 
tion, all the solid parts may be retained, and nothing will escape 
save in the form of vapour ; the water taken into the frame of a 
plant does not, however, remain there, but is continually being 
imbibed and respired, a sprig of spearmint weighing twenty- 
seven grains, having been found to exhale, on an average, not 
less than ninety grains of water daily for a long period, and a 
sun-flower of three feet in height, has been ascertained to evolve 
nearly two pounds of water in a day; such a quantity being 
transmitted from the frame of any plant, it follows an equally 
great supply must be presented in order to meet the waste and 
keep the plant in vigour. This action of inspiration and respira¬ 
tion, varies considerably in different families, for there are certain 
vegetable forms which may be preserved in all their vigour for a 
