Vishnupurana 4.6.48

4.6.48

tatpramāṇaṃ cāṅgulaiḥ kurvan gāyatrīm apaṭhat |
paṭhataś cākṣarasaṃkhyāny evāṅgulāny araṇy abhavat |
tatrāgniṃ nirmathyāgnitrayam āmnāyānusārī bhūtvā juhāva urvaśīsālokyaṃ ca phalam abhisaṃhitavān ||

Having thus made up his mind he took the plants to his city and made their wood for attrition with pieces of as many inches as there are syllables in the Gayatri. He recited that verse and rubbed together sticks of as many inches as he recited syllables in the Gayatri, Having created fire there-from he divided it into three portions according to the precepts of the Vedas and offered oblations to it with the view of obtaining re-union with Urvasi. Having performed many sacrifices with this fire he attained to the region of the Gandharvas and suffered no more separation from his beloved Urvasi. Thus fire, that was at first one, was made three-fold in the present Manwantara by the son of Ilā.