His scientific bile was beginning to rise.

He disapproved very strongly of the tone which his rival had begun.

Its quiet confidence was somewhat ominous.

The lecturer continued without this time noticing the interruption, and proceeded to give a lengthy and learned but singularly lucid _resume_ of the more recent progress in the higher mathematics and the deeply interesting speculations to which it had given rise.

This, with certain demonstrations which he made on the great black-board beside him, occupied nearly an hour.