The thirty Aethyrs, also written Aires, are the vertical dimension of the Parts of the Earth. Where the ninety-one Parts distribute the surface of the world, the thirty Aethyrs are described as surrounding the earth in layers, one within another, so that a Part carries a position in a hierarchy as well as a place on a map.
Their names were given at the very end of the 1584 work, on 13 July, together with the last portion of the Call of the Aethyrs. They run LIL, ARN, ZOM, PAZ, LIT, MAZ, DEO, ZID, ZIP, ZAX, ICH, LOE, ZIM, UTA, OXO, LEA, TAN, ZEN, POP, KHR, ASP, LIN, TOR, NIA, UTI, DES, ZAA, BAG, RII, TEX. LIL is the first and outermost; TEX is the thirtieth and nearest to earth.
Each Aethyr holds three Parts, with a single exception: TEX holds four. That is the reason the total is ninety-one and not ninety. The received material gives no explanation for the anomaly, and no later account has produced one that rests on anything in the manuscripts.
A single Call serves all thirty. It is spoken with the name of the Aethyr inserted at the appropriate point, so that thirty invocations are produced from one text. This economy is characteristic of the system and is one of the features that has struck readers as either elegant design or efficient improvisation, depending on their view of its origin.
Two points about ordering are worth fixing. First, the Parts within an Aethyr are grouped, not ranked; nothing in the table makes one govern the others. Second, Dee's presentation runs from the first Aethyr inward. The now-standard practice of working from the thirtieth toward the first is Crowley's, and follows from a model of ascent that Dee's material does not propose.