Can someone explain to me this text passage? What does it mean?
"One time as a child, in a power-failure, his mother had found and lit a last candles and there had been a brief hour of rediscovery of such illumination that space lost its vast dimension and drew comfortably around them, and they mother and son, alone, transformed, hoping that the power might not come on again soon"
Yes, this is the story of a boy and his mother, alone in a power outage, with only candles to offer light. It is an important passage in the novel because it shows us that all is not lost for Montag. He once had the power of imagination and could enjoy a sense of wonder. Years of being a firemen and years of not really thinking have robbed him of some of this. Of course, it is Clarisse that re-awakens this power of imagination and sense of wonder in Montag.
It is also serves to foreshadow the novel's ending. The city is destroyed while Montag and the other book men are sheltered in the woods. The 'power' both literally (electricity) and figuratively (the government and entertainment) will be shut off.
In this section, Montag relates a childhood memory. He has been torn because the people in his community don't connect on an emotional level. In this quote about his childhood, he is rembering a time when his mother and he were in a situation where all electricty and power were lacking. His mother lit some candles and they sat there in the glow of the candle light and connected on that very level that he misses so much. The moment was so special between he and his mother, that both hoped the power might not return. This is a powerful quotation from the novel and one in which Bradbury really touches the true internal conflict of Montag. No one listens anymore. I just want someone to hear me.
If the text is correct then mother and son are the candles. Dimesion is lost because they transformed as the wax meltted.