But it is evident that this is but one of many passages where Indra by implication is compared to the sun; and comparisons do not indicate allotropy.

So, in ii.II.

20, which Bergaigne gives as a parallel, the words say expressly "Indra [did so and so] _like a sun_."[4] To rest a building so important on a basis so frail is fortunately rare with Bergaigne.

It happens here because he is arguing from the assumption that Indra primitively was a general luminary.

Hence, instead of building up Indra from early texts, he claims a few late phrases as precious confirmation of his theory.[5] What was Indra may be seen by comparing a few citations such as might easily be amplified from every book in the Rig Veda.
According to the varying fancies of the poets, Indra is armed with stones, clubs, arrows, or the thunderbolt (made for him by the artificer, Tvashtar), of brass or of gold, with many edges and points.
Upon a golden chariot he rides to battle, driving two or many red or yellow steeds; he is like the sun in brilliancy, and like the dawn in beauty; he is multiform, and cannot really be described; his divine name is secret; in appearance he is vigorous, huge; he is wise and true and kind; all treasures are his, and he is a wealth-holder, vast as four seas; neither his greatness nor his generosity can be comprehended; mightiest of gods is he, filling the universe; the heavens rest upon his head; earth cannot hold him; earth and heaven tremble at his breath; he is king of all; the mountains are to him as valleys; he goes forth a bull, raging, and rushes through the air, whirling up the dust; he breaks open the rain-containing clouds, and lets the rain pour down; as the Acvins restore the light, so he restores the rain; he is (like) fire born in three places; as the giver of rain which feeds, he creates the plants; he restores or begets Sun and Dawn (after the storm has passed);[6] he creates (in the same way) all things, even heaven and earth; he is associated with Vishnu and P[=u]shan (the sun-gods), with the Acvins, with the Maruts (storm-gods) as his especial followers, and with the artisan Ribhus.
With Varuna he is an Aditya, but he is also associated with another group of gods, the Vasus (x.66.