J.R.R. Tolkein, The Shaping of Middle-Earth, Ballantine Books, NY. Chapter II, Section 1. This is about the earliest sketch of "Silmarillion".

After the despatch of the Nine Valar for the governance of the world Morgoth (Demon of Dark) rebels against the overlordship of Manwe, overthrows the lamps set up to illumine the world, and floods the isle where the Valar (or Gods) dwelt. He fortifies a palace of dungeons in the North. The Valar remove to the uttermost West, bordered by the Outer Seas and the final Wall, and eastward by the towering Mountains of Valinor which the Gods built. In Valinor they gather all light and beautiful things, and build their mansions, gardens, and city, but Manwe and his wife Bridhil have halls upon the highest mountain (Timbrenting or Tindbrenting in English, Tengwthil in Gnomish, Taniquetil in Elfin) whence they can see across the world to the dark East. Ifan Belaurin¹ plants the Two Trees in the middle of the plain of Valinor outside the gates of the city of Valmar. They grow under her songs, and one has dark green leaves with shining silver beneath, and white blossoms like the cherry from which a dew of silver light falls; the other has golden-edged leaves of young green like the beech and yellow blossom like the hanging blossoms of laburnum which gives out heat and blazing light. Each tree waxes for seven² hours to full glory and then wanes for seven; twice a day therefore comes a time of softer light when each tree is faint and their light is mingled.

1. Yavanna Palurien added in the margin.

2. At both occurrences of seven in this sentence, my father first wrote six, but changed it in the act of writing the manuscript.