Blue lights, or blue fire, is a preparation in which zinc and sulphur, or sulphur alone, are used. The particular colour is communicated by the zinc and sulphur.

the bent of a bow

Yes, and we call it a waving forestroke. It sometimes waves upward, sometimes downward.

If we conceive God's sight or science, before the creation, to be extended to all and every part of the world, seeing everything as it is, […] his science or sight from all eternity lays no necessity on anything to come to pass.