Sources Of Light And Heat

Vault Of Ages, Chapter 2.

Ronwy, the Chief of the City dwellers lives on the first floor of an ancient tower where he:

"...lit candles, chasing the gloom back into corners..." (p. 30)

Again, darkness cannot be completely driven back, even indoors.

When one of his guests shivers in the evening chill, Ronwy stokes the fireplace which:

"...had been built in later days, with a chimney going up through the cracked ceiling." (p. 31)

Improvisation. Ronwy retains knowledge of ancient times:

"'In the ancient time,' said the Chief, 'there was always warmth in here, without fire; and if you wanted light, it game from little glass balls which only had to be touched.'" (ibid.)

Ronwy describes the achievements of the ancients as "'...magic...,'" (ibid.) which reminds us of Clarke's third law. The term, "magic," suffices for practical purposes, post-Doom.

We know about electricity but not about every other source of energy. It is to be hoped that we will survive long enough to learn more. Futuristic sf seems very relevant here and now.