§ 5. _d._) One of the most reliable, but at the same time most hazardous, sources of Hebrew, as of Aryan, mythological investigation is the _language_ itself, and above all, the appellations to which the myth is attached. These appellations, which in the process of transformation of the original meaning of the myth became personal names, are in their proper original sense appellatives; and we have to find the appellative signification in order to establish the mythological character. In this investigation it is best to follow the method, the use of which in Aryan mythology has brought such brilliant results to light. In many appellations the appellative sense can be found without much difficulty, being explicable from the language itself, in our case from the known treasures of the Hebrew tongue. In others the known material of the Hebrew language refuses its aid, and we must then take refuge in a cautious employment of the group of allied languages, i.e. the Semitic stock. In this connexion we must never leave out of sight the fact that the treasury of Hebrew words which is contained in the books of the Old Testament does not even approximately embrace the wealth of the ancient Hebrew vocabulary which we are enabled to infer from this fraction. In the proper names much ancient linguistic property is preserved which occurs nowhere else. The discovery of the appellative signification of mythological proper names consequently does an important service to mythological investigation, by finding a tangible starting-point for the determination of the mythical sense of the root-word in question. But it does more: it also fills up gaps in the Hebrew lexicon, and rescues many an old component part of that important language, which otherwise would remain utterly unknown. An example will make this clear, and show that linguistic investigation and mythology have an equal share in the instruction to be derived from such inquiries.