“Under the Persian rule Cappadocia became, and long continued to be, a great seat of the Zoroastrian fire-worship. In the time of Strabo, about the beginning of our era, the votaries of that faith and their temples were still numerous in the country. The perpetual fire burned on an altar, surrounded by a heap of ashes, in the middle of the temple; and the priests daily chanted their liturgy before it, holding in their hands a bundle of myrtle rods and wearing on their heads tall felt caps with cheek-pieces which covered their lips, lest they should defile the sacred flame with their breath. It is reasonable to suppose that the natural fires which burned perpetually on the outskirts of Mount Argaeus attracted the devotion of the disciples of Zoroaster, for elsewhere similar fires have been the object of religious reverence down to modern times. Thus at Jualamukhi [Jwalamukhi], on the lower slopes of the Himalayas, jets of combustible gas issue from the earth; and a great Hindoo temple, the resort of many pilgrims, is built over them. The perpetual flame, which is of a reddish hue and emits an aromatic perfume, rises from a pit in the fore-court of the sanctuary. The worshippers deliver their gifts, consisting usually of flowers, to the attendant fakirs, who first hold them over the flame and then cast them into the body of the temple. Again, Hindoo pilgrims make their way with great difficulty to Baku on the Caspian, in order to worship the everlasting fires which there issue from the beds of petroleum. The sacred spot is about ten miles to the north-east of the city. An English traveller,** who visited Baku in the middle of the eighteenth century, has thus described the place and the worship. ‘There are several ancient temples built with stone, supposed to have been all dedicated to fire; most of them are arched vaults, not above ten to fifteen feet high. Amongst others there is a little temple, in which the Indians now worship; near the altar, about three feet high, is a large hollow cane, from the end of which issues a blue flame, in colour and gentleness not unlike a lamp that burns with spirits, but seemingly more pure. These Indians affirm that this flame has continued ever since the flood, and they believe it will last to the end of the world; that if it was resisted or suppressed in that place, it would rise in some other. Here are generally forty or fifty of these poor devotees, who come on a pilgrimage from their own country, and subsist upon wild sallary [i.e., celery], and a kind of Jerusalem artichokes, which are very good food, with other herbs and roots, found a little to the northward. Their business is to make expiation, not for their own sins only, but for those of others; and they continue the longer time, in proportion to the number of persons for whom they have engaged to pray. They mark their foreheads with saffron, and have a great veneration for a red cow.’ Thus it would seem that a purifying virtue is attributed to the sacred flame, since pilgrims come to it from far to expiate sin.”
—J. G. Frazer, Adonis, Attis, Osiris, part 1 (The Golden Bough, vol. V, 1914, pp. 191-193)
**Jonas Hanway, An Historical Account of the British Trade over the Caspian Sea: with the Author’s Journal of Travels, Second Edition (London, 1762 [miscited as 1754, the pub. date of an earlier edition]), i. 263.