the costless average, divine, original concrete

What is SPECIMEN DAYS but a life as told by blogging? Here's Whitman's last entry:

Democracy most of all affiliates with the open air, is sunny and hardy and sane only with Nature--just as much as Art is. Something is required to temper both--to check them, restrain them from excess, morbidity. I have wanted, before departure [that's "death," in case you missed it], to bear special testimony to a very old lesson and requisite. American democracy, in its myriad personalities, in factories, work-shops, stores, offices--through the dense streets and houses of cities, and all their manifold sophicticated life--must either be fibred, vitalized, by regular contact with out-door light and air and growths, farm-scenes, animals, fields, trees, birds, sun-warmth and free skies, or it will certainly dwindle and pale. We cannot have grand races of mechanics, work people, and commonalty, (the only specific purpose of America,) on any less terms. [Does anyone even understand such an utterance any more, much less believe in it?] I conceive of no flourishing and heroic elements of Democracy maintaining itself at all, without the Nature-element and beauty-element--to really underlie the whole politics, sanity, religion and art of the New World.

Finally, the morality: "Virtue," said Marcus Aurelius, "what is it, only a living and enthusiastic sympathy with Nature?" Perhaps indeed the efforts of the true poets, founders, religions, literatures, all ages, have been, and ever will be, our time and times to come, essentially the same--to bring people back from their persistent strayings and sickly abstractions, to the costless average, divine, original concrete.

[I'm not sure what "free skies" are, but I'm pretty sure we ought to go find out.]