One of the finest accounts ever given of the nature of thunderbolts is that mentioned by Adrianus Tollius in his edition of 'Boethius on Gems.' He gives illustrations of some neolithic axes and hammers, and then proceeds to state that in the opinion of philosophers they are generated in the sky by a fulgureous exhalation (whatever that may look like) conglobed in a cloud by a circumfixed humour, and baked hard, as it were, by intense heat. The weapon, it seems, then becomes pointed by the damp mixed with it flying from the dry part, and leaving the other end denser; while the exhalations press it so hard that it breaks out through the cloud, and makes thunder and lightning. A very lucid explanation certainly, but rendered a little difficult of apprehension by the effort necessary for realising in a mental picture the conglobation of a fulgureous exhalation by a circumfixed humour. One would like to see a drawing of the process, though the sketch would probably much resemble the picture of a muchness, so admirably described by the mock turtle. The excellent Tollius himself, however, while demurring on the whole to this hypothesis of the philosophers, bases his objection mainly on the ground that, if this were so, then it is odd the thunderbolts are not round, but wedge-shaped, and that they have holes in them, and those holes not equal throughout, but widest at the ends. As a matter of fact, Tollius has here hit the right nail on the head quite accidentally; for the holes are really there, of course, to receive the haft of the axe or hammer. But if they were truly thunderbolts, and if the bolts were shafted, then the holes would have been lengthwise, as in an arrowhead, not crosswise, as in an axe or hammer. Which is a complete _reductio ad absurdum_ of the philosophic opinion.