A DROP OF WATER. IOI 
the earth is being washed away by the rivers and 
springs it is being built up again, out of the same 
materials, in the depths of the great ocean. 
And now we have reached the end of the travels of 
our drop of water. We have seen it drawn up by the 
fairy "heat," invisible into the sky; there fairy " co- 
hesion " seized it, and formed it into water-drops, and 
the giant, " gravitation," pulled it down again to the 
earth. Or, if it rose to freezing regions, the fairy of 
" crystallization " built it up into snow r -crystals, again 
to fall to the earth, and either to be melted back into 
water by heat, or to slide down the valleys by force 
of gravitation, till it became squeezed into ice. We 
have detected it, when invisible, forming a veil round 
our earth, and keeping off the intense heat of the sun's 
rays by day, or shutting it in by night. We have seen 
it chilled by the blades of grass, forming sparkling 
dew-drops or crystals of hoarfrost, glistening in the 
early morning sun; and we have seen it in the dark 
underground, being drunk up greedily by the roots 
of plants. We have started with it from the tropics, 
and travelled over land and sea, watching it forming 
rivers, or flowing underground in springs, or moving 
onward to the high mountains or the poles, and com- 
ing back again in glaciers and icebergs. Through all 
this, while it is being carried hither and thither by 
invisible power, we find no trace of its becoming worn 
out, or likely to rest from its labours. Ever onward it 
goes, up and down, and round and round the world, 
taking many forms, and performing many wonderful 
feats. We have seen some of the work that it does, 
in refreshing the air, feeding the plants, giving us 
