Swithin, in the room overhead, had suspended his calculations, for the duologue interested him.

在头顶的房间里，斯维辛暂停了他的计算，因为二重奏引起了他的兴趣。

The hollow spiral, as he knew from old experience, would bring down to his ears the slightest sound from above; and it now revealed to him the words of a duologue in progress at the summit of the tower.

他从过去的经验中知道，空心的螺旋线会把上面最轻微的声音传到他的耳朵里；现在，它向他揭示了塔顶正在进行的对白话。