Adam Clarke on Daniel 8:14

Unto two thousand and three hundred days - Though literally it be two thousand three hundred evenings and mornings. Yet I think the prophetic day should be understood here, as in other parts of this prophet, and must signify so many years. If we date these years from the vision of the he-goat, (Alexander's invading Asia), this was A.M. 3670, b.c. 334; and two thousand three hundred years from that time will reach to a.d. 1966, or one hundred and forty-one years from the present a.d. 1825. This will bring it near to the time mentioned Dan 7:25 (note), where see the note.