Revelation 16:8

ἐπὶ τὸν ἥλιον. The three first vials are poured out εἰς, the last four ἐπί. The change may be intentional to mark the distinction between the two groups of plagues (in the Vision of the Trumpets the second group of the three Woes was the smallest as well as the severest): there is no other obvious reason for writing εἰς τὴν θάλασσαν … ἐπὶ τὸν�, though in 8, 10, and even 12, ἐπὶ may seem more appropriate as marking the stricken object, while εἰς marks the receptive medium.

ἐδόθη αὐτῷ καυματίσαι. Cf. Revelation 8:12 (the fourth trumpet); but there the light of the sun is diminished, here his heat is increased. It is barely possible with Bengel to explain αὐτῷ of the Angel.