New Gem | No More Learning

For in his brain, as in a burning-glass
Wide glow of sun drawn to a pin of fire,
Are gathered into incredible fierceness all
The rays of the dark heat of heathen strength.

Word:

one

Question:

Why does the speaker compare the protagonist's brain to a burning-glass and what does it reveal about the protagonist's mental state?

Answer (optional):

The speaker compares the protagonist's brain to a burning-glass to illustrate how all the dark and intense emotions and power within him are concentrated in one place and magnified to a great degree. This suggests that the protagonist's mental state is intense and perhaps even dangerous, as his thoughts are compared to a burning-glass that can create a destructive fire.