Probably all will agree that the simplest possible change is the accidental sort, that where only relations of space are altered. My watch, now lying in the middle of the desk, is shifted to the right side, is laid in its case, or is lost in the street. I call these changes accidental, because they in no way affect the nature of the watch. They are not really changes in it, but in its surroundings. The watch still remains what it was before. To the same group we might refer a large number of other changes where no inner alteration is wrought. The watch is now in a brilliant light; I lay my hand on it, and it is in darkness. Its place has not been changed, but that of the light has been. Many of the commonest changes in life are of this sort. They are accidental or extraneous changes. In them, through all its change, the thing abides. There is no necessary alteration of its nature. IV But unhappily this is not the only species of change. It is not that which has brought a wail from the ages, when men have seen what they prize slip away. The common root of sorrow has been destructive change. Holding the watch in my hand, I may drop it on the floor; and at once the crystal, which has been so transparently protective, is gone. If the floor is of stone, the back of the watch may be wrenched away, the wheels of its delicate machinery jarred asunder. Destruction has come upon it, and not merely an extraneous accident. In consequence of altered surroundings, dissolution is wrought within. Change of a lamentable sort has come. What before was a beautiful whole, organically constituted in the way described in my first two chapters, has been torn asunder. What we formerly beheld with delight has disappeared.