It only remains to conjecture what the ‘silex’ or ‘lapis’ was which the Fetials took from the temple together with the sceptrum. Helbig has attempted to prove that it was not a survival of the stone age, e. g. an axe of stone. Had that been so, he argues, the Roman antiquaries, who were acquainted with such implements[1002], would have noticed it: and those who describe the rites of the Fetials would have stated that the stone was artificially sharpened. But this negative argument is not a strong one; and I am rather inclined to agree with the suggestion of Dr. Tylor[1003], that it was a stone celt believed to have been a thunder-bolt. There may indeed have been more than one of these kept in the temple, for in B.C. 201 the Fetials who went to Africa took with them _each a stone_[1004] (privos lapides silices) along with their ‘sagmina,’ &c. This fact seems to me to prove that the silices, like the sagmina and sceptrum, were only part of the ritualistic apparatus of the Fetials[1005], and not objects in which the god was supposed to be manifested. The idea that he was originally worshipped in the form of a stone may well have arisen from this use of stones in the ritual, especially if those stones were believed to be in some way his handiwork[1006]. We may think then of the cult of Jupiter Feretrius as an example of primitive tree-worship, but we are not justified in going further and finding him also in the form of a stone. There is yet another stone that may have belonged to the earliest Roman cult of Jupiter, but the connexion is not very certain. ‘The (rite of) Aquaelicium,’ says Festus[1007], ‘is when rain is procured (elicitur) by certain methods, as for example when the lapis manalis is carried into the city.’ This stone lay by the temple of Mars, outside the Porta Capena; we learn from other passages that it was carried by the pontifices[1008], but we are not told what they did with it within the walls. It has been ingeniously suggested that this rain-spell, as we may call it, was a part of the cult of Jupiter Elicius, to whom there was an altar close by under the Aventine[1009], the cult-title being identical with the latter part of the word ‘aquaelicium[1010].’ We may agree that the stone had nothing to do with the temple of Mars, which happened to be near it, and also that any such rain-spell as this would be more likely to belong to the cult of Jupiter than of any other deity. The heaven-god, who launches the thunder-bolt, is naturally and almost everywhere also the rain-giver[1011]: and that this was one of the functions of Jupiter is fully attested, for later times at least[1012].