She coloured under Odo’s wondering gaze, and at his random rejoinder that it was a risk any man would gladly take without considering, she turned from him with a gesture in which he fancied a shade of disappointment.

By this they had reached the cabinet of fossils, about which the interest of the other guests still seemed to centre.  Alfieri, indeed, paced the farther end of the room with the air of awaiting the despatch of some tedious business; but the others were engaged in an animated discussion necessitating frequent reference to the folios Vivaldi had brought from his study.

The latter turned to Odo as though to include him in the group.  “I do not know, sir,” said he, “whether you have found leisure to study these enigmas of that mysterious Sphinx, the earth; for though Count Alfieri has spoken to me of your unusual acquirements, I understand your tastes have hitherto lain rather in the direction of philosophy and letters;” and on Odo’s prompt admission of ignorance, he courteously continued:  “The physical sciences seem, indeed, less likely to appeal to the imaginative and poetical faculty in man, and, on the other hand, religion has appeared to prohibit their too close investigation; yet I question if any thoughtful mind can enter on the study of these curious phenomena without feeling, as it were, an affinity between such investigations and the most abstract forms of thought.  For whether we regard these figured stones as of terriginous origin, either mere lusus naturae, or mineral formations produced by a plastic virtue latent in the earth, or whether as in fact organic substances lapidified by the action of water; in either case, what speculations must their origin excite, leading us back into that dark and unexplored period of time when the breath of Creation was yet moving on the face of the waters!”

Odo had listened but confusedly to the first words of this discourse; but his intellectual curiosity was too great not to respond to such an appeal, and all his perplexities slipped from him in the pursuit of the Professor’s thought.

One of the other guests seemed struck by his look of attention.  “My dear Vivaldi,” said this gentleman, laying down a fossil, and fixing his gaze on Odo while he addressed the Professor, “why use such superannuated formulas in introducing a neophyte to a study designed to subvert the very foundations of the Mosaic cosmogony?  I take it the Cavaliere is one of us, since he is here this evening:  why, then, permit him to stray even for a moment in the labyrinth of theological error?”

The Professor’s deprecating murmur was cut short by an outburst from another of the learned group, a red-faced spectacled personage in a doctor’s gown.

“Pardon me for suggesting,” he exclaimed, “that the conditional terms in which our host was careful to present his hypotheses are better suited to the instruction of the neophyte than our learned friend’s positive assertions.  But if the Vulcanists are to claim the Cavaliere Valsecca, may not the Diluvials also have a hearing?  How often must it be repeated that theology as well as physical science is satisfied by the Diluvial explanation of the origin of petrified organisms, whereas inexorable logic compels the Vulcanists to own that their thesis is subversive of all dogmatic belief?”