It is remarkable how common the belief appears to have been that the remains of the Yule-log, if kept throughout the year, had power to protect the house against fire and especially against lightning.[676] As the Yule log was frequently of oak,[677] it seems possible that this belief may be a relic of the old Aryan creed which associated the oak-tree with the god of thunder.[678] Whether the curative and fertilizing virtues ascribed to the ashes of the Yule log, which are supposed to heal cattle as well as men, to enable cows to calve, and to promote the fruitfulness of the earth,[679] may not be derived from the same ancient source, is a question which deserves to be considered. [Public celebrations of the fire-festival at Midwinter; the bonfire on Christmas Eve at Schweina in Thuringia.] Thus far we have regarded only the private or domestic celebration of the fire-festival at midwinter. The public celebration of such rites at that season of the year appears to have been rare and exceptional in Central and Northern Europe. However, some instances are on record. Thus at Schweina, in Thuringia, down to the second half of the nineteenth century, the young people used to kindle a great bonfire on the Antonius Mountain every year on Christmas Eve. Neither the civil nor the ecclesiastical authorities were able to suppress the celebration; nor could the cold, rain, and snow of the season damp or chill the enthusiasm of the celebrants. For some time before Christmas the young men and boys were busy building a foundation for the bonfire on the top of the mountain, where the oldest church of the village used to stand. The foundation consisted of a pyramidal structure composed of stones, turf, and moss. When Christmas Eve came round, a strong pole, with bundles of brushwood tied to it, was erected on the pyramid. The young folk also provided themselves with poles to which old brooms or faggots of shavings were attached. These were to serve as torches. When the evening grew dark and the church bells rang to service, the troop of lads ascended the mountain; and soon from the top the glare of the bonfire lit up the darkness, and the sound of a hymn broke the stillness of night. In a circle round the great fire lesser fires were kindled; and last of all the lads ran about swinging their lighted torches, till these twinkling points of fire, moving down the mountain-side, went out one by one in the darkness. At midnight the bells rang out from the church tower, mingled with the blast of horns and the sound of singing. Feasting and revelry were kept up throughout the night, and in the morning young and old went to early mass to be edified by hearing of the light eternal.[680] [Bonfires on Christmas Eve in Normandy.]