light which is within man,' in which the highest light is identified with the gastric fire (the fire within man). Now such identifications can be made only where there is a certain similarity of nature; as is seen, for instance, in the passage, 'Of that person Bhu/h/ is the head, for the head is one and that syllable is one' (B/ri/. Up. V, 5, 3). But that the fire within the human body is not Brahman clearly appears from the passage, 'Of this we have visible and audible proof' (Ch. Up. III, 13, 7; 8), which declares that the fire is characterised by the noise it makes, and by heat; and likewise from the following passage, 'Let a man meditate on this as that which is seen and heard.' The same conclusion may be drawn from the passage, 'He who knows this becomes conspicuous and celebrated,' which proclaims an inconsiderable reward only, while to the devout meditation on Brahman a high reward would have to be allotted. Nor is there mentioned in the entire passage about the light any other characteristic mark of Brahman, while such marks are set forth in the passages (discussed above) which refer to pra/n/a and the ether. Nor, again, is Brahman indicated in the preceding section, 'the Gayatri is everything whatsoever exists,' &c. (III, 12); for that passage makes a statement about the Gayatri metre only. And even if that section did refer to Brahman, still Brahman would not be recognised in the passage at present under discussion; for there (in the section referred to) it is declared in the clause, 'Three feet of it are the Immortal in heaven'--that heaven constitutes the abode; while in our passage the words 'the light above heaven' declare heaven to be a boundary. For all these reasons the word jyotis is here to be taken in its ordinary meaning, viz. light.