(1) Read over what we have said in the "Advanced Course" regarding the principle known as Matter. Realize that all Matter is One at the last--that the real underlying substance of Matter is _Akasa_ or Ether, and that all the varying forms evident to our senses are but modifications and grosser forms of that underlying principle. Realize that by known chemical processes all forms of Matter known to us, or rather all combinations resulting in "forms," may be resolved into their original elements, and that these elements are merely _Akasa_ in different states of vibration. Let the idea of the Oneness of the visible Universe sink deeply into your mind, until it becomes fixed there. The erroneous conception of diversity in the material world must be replaced by the consciousness of Unity--Oneness, at the last, in spite of the appearance of variety and manifold forms. You must grow to see behind the world of forms of Matter, and see the great principle of Matter (_Akasa_ or Ether) back of, within, and under it all. You must grow to _feel_ this, as well as to intellectually see it. (2) Meditate over the last mentioned truths, and then follow the matter still further. Read what we have said in the "Advanced Course" (Lesson XI) about the last analysis of Matter showing it fading away into Force or Energy until the dividing line is lost, and Matter merges into Energy or Force, showing them both to be but the same thing, Matter being a grosser form of Energy or Force. This idea should be impressed upon the understanding, in order that the complete edifice of the Knowing of the Oneness may be complete in all of its parts.