The best of these is where he illustrates the restless desire of a poet for the renewal of energy, for finding new worlds to sing.  The poet often seems to stop his work, to be satisfied.  “Here I will rest,” he says, “and do no more.”  But he only waits for a fresh impulse.

    ’Tis but a sailor’s promise, weather-bound: 
    “Strike sail, slip cable, here the bark be moored
    For once, the awning stretched, the poles assured! 
    Noontide above; except the wave’s crisp dash,
    Or buzz of colibri, or tortoise’ splash,
    The margin’s silent:  out with every spoil
    Made in our tracking, coil by mighty coil,
    This serpent of a river to his head
    I’ the midst!  Admire each treasure, as we spread
    The bank, to help us tell our history
    Aright; give ear, endeavour to descry
    The groves of giant rushes, how they grew
    Like demons’ endlong tresses we sailed through,
    What mountains yawned, forests to give us vent
    Opened, each doleful side, yet on we went
    Till ... may that beetle (shake your cap) attest
    The springing of a land-wind from the West!”
    —­Wherefore?  Ah yes, you frolic it to-day! 
    To-morrow, and the pageant moved away
    Down to the poorest tent-pole, we and you
    Part company:  no other may pursue
    Eastward your voyage, be informed what fate
    Intends, if triumph or decline await
    The tempter of the everlasting steppe!

This, from Book iii., is the best because it is closer than the rest to the matter in hand; but how much better it might have been!  How curiously overloaded it is, how difficult what is easy has been made!

The fault of these illustrations is the fault of the whole poem. Sordello is obscure, Browning’s idolaters say, by concentration of thought.  It is rather obscure by want of that wise rejection of unnecessary thoughts which is the true concentration.  It is obscure by a reckless misuse of the ordinary rules of language.  It is obscure by a host of parentheses introduced to express thoughts which are only suggested, half-shaped, and which are frequently interwoven with parentheses introduced into the original parentheses.  It is obscure by the worst punctuation I ever came across, but this was improved in the later editions.  It is obscure by multitudinous fancies put in whether they have to do with the subject or not, and by multitudinous deviations within those fancies.  It is obscure by Browning’s effort to make words express more than they are capable of expressing.