Translation:Shulchan Aruch/Orach Chaim/255
255ː Preparation of the Fire before the Onset of Shabbos. Contains 4 seifim.
1 A fire is not made from wood close to dark unless the fire catches hold to the extent that the flame burns on its own accord without the assistance of other wood. And if it's a single log, the fire must take hold of the majority of its width and of the majority of its circumference. And if it was not kindled as such, it is forbidden to derive benefit of it on Shabbat. This is a decree, lest one stir it and move the wood so that the flame should ascend. And if it was kindled to the extent described, one can warm himself by it on Shabbat and use its light, regardless of whether it's on the ground or on the menorah, and even if it's from substances from which wicks are not made for Shabbos.
2 There are those who say that regarding coals, even though the fire only took hold of them minimally, it is permitted, because they continue to burn.
3 A fire from tar and from sulfur and from straw and stubble – even though it only took hold of them minimally, it is permitted. And the same applies regarding a fire from reeds and from pits of dates when they are spread out. If, however, the reeds are bound and the pits are in a basket, it's needed that he should kindle the fire in them until the flame ascends on its own accord. And there are those who say the opposite.