The traces of this primitive belief the Aryan people carried with them on their wanderings. This sky-god was the Dyâus (the sky) of Indian mythology, the Zeus of the Greeks, the Jupiter of the Romans, and the Zio, Tew, or Tyr of the Germans and Norsemen. For all these names are etymologically allied. Zeus (gen. Dios) and Dyâus are from the same root; so are Jupiter (anciently Diupiter) and the compound form Dyâus-pitar (father Dyâus); and Zio and Tew also bear traces of the same origin. Indeed, it is by the reappearance of this name as the name of a god among so many different nations that we argue his having once been the god of all the Atyan people. The case is like that of our word _daughter_. As we find this reappearing in the Greek _thugatêr_, and the Sanskrit _duhitar_, we feel sure that the old Aryans had a name for daughter from which all these names are derived; and as we find the Sanskrit name alone has a secondary meaning, signifying ‘the milker,’ we conclude that this was the original meaning of the name for a daughter. Just so, Zeus and Jupiter and Zio and Dyâus show a common name for the chief Aryan god; but the last alone explains the meaning of that name, for Dyâus signifies the sky. This sky-god, then, stood to the old Aryans for the notion of a supreme and common divinity. Whatever may have been the divinities reigning over local streams and woods, they acknowledged the idea of one overruling Providence whom they could only image to their minds as the over-spreading sky. This, we may say, was the essential feature in their religion, its chief characteristic; whereas to the Semitic nations, the sun, the visible orb, was in every case the supreme god. The reason of this contrast does not, it seems to me, lie _only_ in the different parts which the sun played in the southern and more northern regions; or, if it arises in the difference of the climate, it not the less forms an important chapter in religious development. There are discernible in the human mind two diverse tendencies in dealing with religious ideas. Both are to be found in every religion, among every people; one might almost say in every heart. The first tendency is an impulse upwards--a desire to press the mind continually forward in an effort to idealize the deity, but, by exalting or seeming to exalt Him into the highest regions of abstraction, it runs the risk of robbing Him of all fellowship with man, and man of all claims upon His sympathy and love. Then comes the other tendency, which oftentimes at one stroke brings down the deity as near as possible to the level of human beings, and leaves him at the end no more than a demi-god or exalted man. One may be called the metaphysical, the other the mythological tendency; and we shall never be able to understand the history of religions until we learn to see how these influences interpenetrate and work in every system. They show at once that a distinction must be drawn between mythology and religion.