To trace their origins we must, as in the case of social institutions, look first at the ideas prevailing among those savage and barbarous races who are the best representatives of our early progenitors; and secondly at historical records. In the first case we find the earliest rudiments of religious ideas in the universal belief in ghosts and spirits. Every man is conceived of as being a double of himself, and as having a sort of shadowy self, which comes and goes in sleep or trance, and finally takes leave of the body, at death, to continue its existence as a ghost. The air is thus peopled with an immense number of ghosts who continue very much their ordinary existence, haunt their accustomed abodes, and retain their living powers and attributes, which are exerted generally with a malevolent desire to injure and annoy. Hence among savage races, and by survival even among primitive nations of the present day, we find the most curious devices to cheat or frighten away the ghost, so that he may not return to the house in which he died. Thus, the corpse is carried out, not by the door, but by a hole made for the purpose in the wall, which is afterwards built up, a custom which prevails with a number of widely separated races—Greenlanders, Hottentots, Algonquins, and Fijians; and the practice even survives among more civilised nations, such as the Chinese, Siamese, and Thibetans; nor is it wholly extinct in some of the primitive parts of Europe. This idea obviously led to the practice of constructing tents or houses for the ghosts to live in, and of depositing with them articles of food and weapons to be used in their ghostly existence. In the case of great chiefs, not only their arms and ornaments are deposited, but their horses, slaves, and wives were sacrificed and buried with them, so that they might enter spirit-land with an appropriate retinue. The early Egyptian tombs were as nearly as possible facsimiles of the house in which the deceased had lived, with pictures of his geese, oxen, and other possessions painted on the walls, evidently under the idea that the ghosts of these objects would minister to the wants and please the fancy of the human ghost whose eternal dwelling was in the tomb where his mummy was deposited.