The Meaning of "Third Part" in Revelation 7

My impression is, for I do not dogmatize on such points, that "the third part" (Rev. 8:7) is the Roman earth considered in its body in the West. In chapter 9. I apprehend there is the action of the Euphratean horsemen, so-called, against the powers of the Roman earth. In chapter 8. the judgments fall on the Roman earth. Chapter 12:4 confirms the idea of this use of "third," because this is clearly, I suppose, the power of Satan in the Roman empire, and his tail draws down the third part of the stars and casts them to the earth; that is, a third part of the independent but smaller powers were reduced into subjection to Satan's power displayed in this form.
Dublin,
June, 1871.