same name.’  There you have the Iliad in a nutshell as regards the authenticity of great works.  All we know about the supposed Homer (if anything) is that he was the reputed author of the two unapproachable Greek epics; and all we know directly about my old master, viewed personally, is that he once carved with a rude flint flake on a fragment of reindeer horn these two clumsy prehistoric horses.  Yet by putting two and two together we can make, not four, as might be naturally expected, but a fairly connected history of the old master himself and what Mr. Herbert Spencer would no doubt playfully term ‘his environment.’

The work of art was dug up from under the firm concreted floor of a cave in the Dordogne.  That cave was once inhabited by the nameless artist himself, his wife, and family.  It had been previously tenanted by various other early families, as well as by bears, who seem to have lived there in the intervals between the different human occupiers.  Probably the bears ejected the men, and the men in turn ejected the bears, by the summary process of eating one another up.  In any case the freehold of the cave was at last settled upon our early French artist.  But the date of his occupancy is by no means recent; for since he lived there the long cold spell known as the Great Ice Age, or Glacial Epoch, has swept over the whole of Northern Europe, and swept before it the shivering descendants of my poor prehistoric old master.  Now, how long ago was the Great Ice Age?  As a rule, if you ask a geologist for a definite date, you will find him very chary of giving you a distinct answer.  He knows that the chalk is older than the London clay, and the oolite than the chalk, and the red marl than the oolite; and he knows also that each of them took a very long time indeed to lay down, but exactly how long he has no notion.  If you say to him, ’Is it a million years since the chalk was deposited?’ he will answer, like the old lady of Prague, whose ideas were excessively vague, ‘Perhaps.’  If you suggest five millions, he will answer oracularly once more, ‘Perhaps’; and if you go on to twenty millions, ‘Perhaps,’ with a broad smile, is still the only confession of faith that torture will wring out of him.  But in the matter of the Glacial Epoch, a comparatively late and almost historical event, geologists have broken through their usual reserve on this chronological question and condescended to give us a numerical determination.  And here is how Dr. Croll gets at it.

Every now and again, geological evidence goes to show us, a long cold spell occurs in the northern or southern hemisphere.  During these long cold spells the ice cap at the poles increases largely, till it spreads over a great part of what are now the temperate regions of the globe, and makes ice a mere drug in the market as far south as Covent Garden or the Halles at Paris.  During the greatest extension of this ice sheet in the last glacial epoch, in fact, all England except