On a cloudy night, when dews are not so much required, a great part of the heat thus radiated is sent back, being reflected by the clouds. Hence the dew falls less heavily at such a time than on a clear starlight night, when every blade of grass and every little flower sends out its ray of heat to an indefinite extent, and may possibly meet another ray from the Dog-stars or one of the Pleiades! This is very wonderful; but if you think, you will perceive that it is not more wonderful than that a ray of light should travel so far. Every particle of the surface of these stars does its part in emitting light, and by that the light of our nights is increased; and if Light is affected by such remote influences, why should not Climate be so affected? IX. As everything has a place to fill up amongst the creatures by which it becomes connected with the universal system, we find innumerable instances of things being most wonderfully provided with powers of retaining the position for which they were created, when circumstances may oppose it. The tendency which every animal has to preserve its own life, supplies abundant illustration. It is this which causes the Arctic animals to change their colour to white in winter, and the swallows to migrate to warmer regions. But there is something selfish in this, as the provision is merely to save the animal's own life. Much more beautiful is it to observe the operation of the affections of parent animals towards their offspring, by which the young, when they are incapable of taking care of themselves, are kept alive and preserved from injury often at the sacrifice of the enjoyment, and even of the life of their parent. You will remember what I told you respecting the love of the old whales towards the _suckers_. Nothing parts with its own life willingly, but in a great many animals it may be seen that there is a greater regard to the preservation of their race than of their own individual lives. [Illustration] X. These tendencies may be seen in vegetables as well as in animals. The young buds of various plants, of the common poppy for example, hang down their heads, so that the bottom of the _calyx_, as it is called by botanists, is placed upwards, and forms a sort of thatch or roof. When the flower spreads out its bright broad leaves, although its weight is increased, yet it then boldly lifts up its head to the sun, and the neck of the stalk which seemed unable to bear up the bud, is well able to sustain the full flower. Now if it were otherwise, and if the bud held the same position as the flower, the rain would run into the calyx and would lie there, so as to cause the _petals_ or leaves of the future flower to become rotten. In this Kingdom of Nature, the unwillingness to part with life is even more wonderfully exhibited than in animals.