Bhrigu said, It is true that after the consumption of fuel fire is no longer visible. It mixes with space because there is no longer any visible object wherein it can abide, and hence it cannot be perceived by us.
भृगुरुवाच समिधामुपयोगान्ते यथाग्निर्नोपलभ्यते। आकाशानुगतत्वाद्धि दुर्ग्राह्यो हि निराश्रयः॥