What happened here

What happened here Professor Pikestaffe has no clear Impression, but the little row Of stars above will serve to show What madly reeled before his eyes, As he went whirling to the skies. Below he heard a mocking laugh, That seemed to come from the Giraffe: “Go up! go up! You’ve proved enough; You’ve proved geometry is stuff! You’ve proved, till I am well nigh dead, And feel a thumping in my head, That I must spread my feet apart To take a drink—why, bless your heart! I knew that long ere you were born. I laugh geometry to scorn.”