“The similes by which he illustrates the steepness of that ascent are all taken from the Riviera of Genoa, now traversed by a good carriage road under the name of the Cornice; but as this road did not exist in Dante’s time, and the steep precipices and promontories were then probably traversed by footpaths, which, as they necessarily passed in many places over crumbling and slippery limestone, were doubtless not a little dangerous, and as in the manner they commanded the bays of sea below, and lay exposed to the full blaze of the southeastern sun, they corresponded precisely to the situation of the path by which he ascends above the purgatorial sea, the image could not possibly have been taken from a better source for the fully conveying his idea to the reader: nor, by the way, is there reason to discredit, in this place, his powers of climbing; for, with his usual accuracy, he has taken the angle of the path for us, saying it was considerable more than forty-five. Now a continuous mountain slope of forty-five degrees is already quite unsafe either for ascent or descent, except by zigzag paths; and a greater slope than this could not be climbed, straightforward, but by help of crevices or jags in the rock, and great physical exertion besides.”