IT is not (as some are of opinion) that heat is a quality, and cold only a privation of that quality, and so that an entity is even less a cause than a non-entity. But we do it because Nature has attributed admiration to what is rare, and she puts men upon enquiry how any thing comes to pass that seldom happens. As Euripides saith, Behold the boundless Heaven on high, Bearing the earth in his moist arms,— what wonders he brings out by night, and what beauty he shows forth by day!... The rainbow and the varied beauty of the clouds by day, and the lights which burst forth by night...