Borges' essay The Analytical Language of John Wilkins is the source of that mythical animal categorisation from an unknown (or fictional) Chinese encyclopaedia, the one that includes a division of those animals
(n) that from a long way off look like flies.
But the essay is primarily about John Wilkins' invented language (Wilkins is an interesting character himself--in the 1600s he wrote a book about visiting the Moon, and proposed trade with any lunar beings that lived there). As Borges describes it:
He divided the universe in forty categories or classes, these being further subdivided into differences, which was then subdivided into species. He assigned to each class a monosyllable of two letters; to each difference, a consonant; to each species, a vowel. For example: de, which means an element; deb, the first of the elements, fire; deba, a part of the element fire, a flame.
To my mind, this is the best bit of the essay. What are the other 39 classes? How did Wilkins decide? Unfortunately the Chinese encyclopaedia acts as an attention swerve and so the analytical language doesn't appear to have been written up online. As Tom S and I were discussing, this is much like those streets in cities that people never notice because there's something shiny just to the right. They're in plain sight but hidden by the psychogeography, and you need constrained walks and algorithms to discover them.
I went to the library and got a facsimile copy of the original 1668 edition of "Notes from An Essay Towards a Real Character and a Philosophical Language" by John Wilkins. The list of 40 classes is first given on page 23, as an outline, and each is written in uppercase:
All kinds of things and notions, to which names are to be assigned, may be distributed into such as are either more
So there you go. The complete table of contents, as well as the mapping of these 40 genuses to syllables, can be found in my notes.
I'm making another trip to the library in a couple of days, as there's more I have on order. But I should be able to read one or two short sections from Wilkins' book, if anybody would like me to. Have a look at the Contents, drop me a mail if anything particularly catches your eye, and I'll make notes if time allows.