The Moonspeaker:
Where Some Ideas Are Stranger Than Others...

Annotations

1. Neither the snark nor the bandersnatch are ever clearly described, though the creature in the Jabberwocky illustration seems more likely to be a bandersnatch than not. In that poem the bandersnatch is described as "frumious" which Carroll's introduction to this poem tells us means a balanced combination of fuming and furious. So the creature is apparently inclined to violent anger and emitting strong smelling vapours.
2. Remarkably, english originally had an adverb ná with a comparative neah, meaning near and nearer respectively. Their pronunciation shifted until they became nigh and near, with nigh falling into obsolescence not long after its appearance in this poem. Like many fossilized english words, it rarely appears outside of formulae like the cliché declarations that "the x is nigh!" insert whichever apocalyptic scenario you like for x.
3. It is clear enough that the verb "to fly" is used here for the sake of the rhyme, yet there are other circumstances where it may be used instead of the form we might expect, "flee." "Fly" and "flee" are separate though related verbs, the one meaning what we would expect, to move swiftly through the air. The connection between them connotation-wise is metaphorical: a person may flee so fast their feet hardly seem to touch the ground, and so they seem to fly. Since people can't literally fly, a not uncommon way of saying "it's hopeless to run but go ahead and try" was to shout "take to your heels, fly!" It's evidently pretty archaic though, something rather shakespeare-tinted.
4. "7 pounds 10" being 7 pounds and 10 shillings in pre-decimal english currency. For Carroll's time, this was a non-trivial amount of money, and times coming to approximately a third or more of a lower middle class annual salary.
5. Here alas, we have what turns out to be a lapse into a patch of inexcusable racism. Looking closely at the Banker's face in the picture, his mouth is noticeably assymmetrical, suggestive of a stroke or in the victorian era term "apoplexy." A person was considered to have suffered apoplexy when, in a state of great rage or other extreme excitement which would deeply flush the face, they suffered a cerebral haemorrhage. A common symptom of the acute phase of a stroke is slurred or garbled speech. At one time being called black in the face meant little more than being so dangerously flushed, and it referred obliquely to the deep purple-black of congealed blood. We can't take the depiction of the Banker to be purely about that meaning of the phrase though, because we have only to glance between the pigmentation of his hands and face, then between those and the skin tone indicated for the Bellman and the Butcher. At this point, Lewis Carroll has definitely lost the thread of his better quality and better considered surrealism, and the poem never really recovers.
6. Victorian men's evening dress was, as faithful watcher's of David Suchet's outings as Hercule Poirot will know, the tuxedo, characterized by white shirt and vest with black jacket, pants, and shoes.
7. Courtesy of Humpty Dumpty, we know that mimsy means "flimsy and miserable." A bit of an odd adjective to apply to a sound as opposed to a substance expected to support something like paper or wood, though this juxtaposition points back to the taste of the snark, which is "meagre and hollow, but crisp."
8. Part two of how and why the Banker's fate and how he is illustrated is racist and deeply unfortunate. The bones the Banker is rattling are a type of simple percussion instrument, played similarly to a pair of spoons. According to Goetz Kluge at flickr, the bone playing aspect and the way it is illustrated derives from The Bone Player, an 1856 painting by William Sidney Mount. The painting seems to have some problematic context in its own right, but to be fair my information on it is minimal.

   A great irony of the bone rattling in any case is there is a potential mathematical reference that may have been even better here. The Banker would likely have had to work with large numbers and calculations of interest and exchange rates. So he would have had many reasons to use Napier's bones, a calculating device available from 1617 when John Napier published his conceptualization of them. The rods used on the device could be literally carved from bone, or wood, or pasted up out of cardboard. (Wolfram MathWorld provides an excellent short article on how Napier's bones are used.)

   Picking out one last detail from the illustration, the sheet of paper at the Banker's feet says "con imbecillita." As John Tufail points out in his paper The Illuminated Snark: An enquiry into the relationship between text and illustration in 'The Hunting of the Snark' and I almost missed is that the paper is a sheet of music, with the direction "play like an imbecile." (The paper is well worth reading – Tufail works much harder than me when it comes to discussing the relationship between picture and text. There is more interesting material where Tufail's paper came from, at Contrariwise, website of the "Association for New Lewis Carroll Studies." That said, Martin Gardner emphatically did not care for this site, so your mileage may vary.)