Even the simpler and purely astral operation is a difficult one to describe, though quite an easy one to perform. It may be said to partake somewhat of the nature of the magnetization of a bar of steel; for it consists in what we might call the polarization, by an effort of the human will, of a number of parallel lines of astral atoms reaching from the operator to the scene which he wishes to observe. All the atoms thus affected are held for the time with their axes rigidly parallel to one another, so that they form a kind of temporary tube along which the clairvoyant may look. This method has the disadvantage that the telegraph line is liable to disarrangement or even destruction by any sufficiently strong astral current which happens to cross its path; but if the original effort of will were fairly definite, this would be a contingency of only infrequent occurrence. The view of a distant scene obtained by means of this "astral current" is in many ways not unlike that seen through a telescope. Human figures usually appear very small, like those on a distant stage, but in spite of their diminutive size they are as clear as though they were close by. Sometimes it is possible by this means to hear what is said as well as to see what is done; but as in the majority of cases this does not happen, we must consider it rather as the manifestation of an additional power than as a necessary corollary of the faculty of sight. It will be observed that in this case the seer does not usually leave his physical body at all; there is no sort of projection of his astral vehicle or of any part of himself towards that at which he is looking, but he simply manufactures for himself a temporary astral telescope. Consequently he has, to a certain extent, the use of his physical powers even while he is examining the distant scene; for example, his voice would usually still be under his control, so that he could describe what he saw even while he was in the act of making his observations. The consciousness of the man is, in fact, distinctly still at this end of the line. This fact, however, has its limitations as well as its advantages, and these again largely resemble the limitations of the man using a telescope on the physical plane. The experimenter, for example, has no power to shift this point of view; his telescope, so to speak, has a particular field of view which cannot be enlarged or altered; he is looking at his scene from a certain direction, and he cannot suddenly turn it all round and see how it looks from the other side. If he has sufficient psychic energy to spare, he may drop altogether the telescope that he is using and manufacture an entirely new one for himself which will approach his objective somewhat differently; but this is not a course at all likely to be adopted in practice.