The fire in whose honour oblations of Ghee are poured in the Darsha and Paurnamasya sacrifices is known as Vishnu in this world. He is called Dhritiman or Angira.
दर्श च पौर्णमासे च यस्येह हविरुच्यते। विष्णुर्नामेह योऽग्निस्तु धृतिमान्नाम सोऽङ्गिराः॥