But, besides these, there is a large section of his works, the aim of which is purely intellectual, where feeling is not at all involved; and surely there is not, in either ancient or modern literature, a section which, in the same amount of space, exhibits the same degree of intense activity on the part of the analytic understanding, applied to the illustration of truth or to the solution of vexed problems.  This latter class is the more remarkable from its polar antithesis to the former; just as, in his life, it is a most remarkable characteristic of the man, that, rising above all other men through the rhapsodies of dreams, he should yet be able truly to say of himself that he had devoted a greater number of hours to intellectual pursuits than any other man whom he had seen, heard of, or read of.  A wider range is thus exhibited, not of thought merely, but also of the possible modes of expressing thought, than is elsewhere to be found, even in writers the most skilled in rhetorical subtilty.  The distance between these two opposites De Quincey does not traverse by violent leaps; he does not by some feat of legerdemain evanish from the fields of impassioned eloquence, where he is an unrivalled master, to appear forthwith in those of intellectual gymnastics, where, at least, he is not surpassed.  He is familiar with every one of the intervening stages between the rhapsody and the demonstration,—­between the loftiest reach of aspirant passion, from which, with reptile instinct, the understanding slinks downwards to the earth, and that fierce antagonism of naked thoughts, where the crested serpent “mounts and burns.”  His alchemy is infinite, combining light with warmth in all degrees,—­in pathos, in humor,[A] in genial illumination.  Let the reader, if he can, imagine Rousseau to have written “Dinner, Real and Reputed,” or the paper on “The Essenes,” in both of which great erudition is necessary, but in which erudition is as nothing when compared to the faculty of recombining into novel forms what previously had been so grouped as to be misunderstood, or had lacked just the one element necessary for introducing order.  To have written these would have entitled Rousseau to a separate sceptre.  Or, moving into a realm of art totally distinct from this, suppose him to have been the author of “Murder considered as one of the Fine Arts”:  that would mount a new plume in Rousseau’s hat.  But I happen just now to be reminded of another little paper, numbering about six pages, entitled, “On the Knocking at the Gate, in Macbeth”:  give him that, too.  Why, the little French king is beginning to assume an imperial consequence!  We beg the reader’s pardon for indulging in comparisons of this nature, which are always disagreeable; but we have this excuse, that the two writers are often mentioned as on the same level, and with no appreciation of that unlimited range of power which belongs to De Quincey, but not at all to Rousseau.  All but one of the trophies which we have hypothetically transferred