The Upanishads, Part 2 (SBE15), by Max Müller, , at sacred-texts.com
1. That (the invisible Brahman) is full, this (the visible Brahman) is full} 2. This full (visible Brahman) proceeds from that full (invisible Brahman). On grasping the fulness of this full (visible Brahman) there is left that full (invisible Brahman) 3.
Om (is) ether, (is) Brahman 4. 'There is the old ether (the invisible), and the (visible) ether of the atmosphere,' thus said Kauravyâyanîputra. This (the Om) is the Veda (the means of knowledge), thus the Brâhmanas know. One knows through it all that has to be known.
189:1 This is called a Khila, or supplementary chapter, treating of various auxiliary means of arriving at a knowledge of Brahman.
189:2 Full and filling, infinite.
189:3 On perceiving the true nature of the visible world., there remains, i.e. there is perceived at once, as underlying it, or as being it, the invisible world or Brahman. This and the following paragraph are called Mantras.
189:4 This is explained by Saṅkara as meaning, Brahman is Kha, the ether, and called Om, i.e. Om and Kha are predicates of Brahman.