Now each thought we think is accompanied by certain molecular motions and displacements in the brain, and parts of these, let us allow, are in some way stored up in that organ, so as to produce what may be termed our material or physical memory. Other parts of these motions are, however, communicated to the invisible body, and are there stored up, forming a memory which may be made use of when that body is free to exercise its functions. 201. Again, one of the arguments (Art. 84) which proves the existence of the invisible universe, demands that it shall be full of energy when the present universe is defunct. We can therefore very well imagine that after death, when the soul is free to exercise its functions, it may be replete with energy, and have eminently the power of action in the present, retaining also, as we have shown above, a hold upon the past, inasmuch as the memory of past events has been stored up in it, and thus preserving the two essential requisites (Art. 61) of a continuous intelligent existence. 202. The conception of an unseen universe is not a new one, even among men of science. The deservedly famous Dr. Thomas Young has the following passage in his lectures on Natural Philosophy:—‘Besides this porosity, there is still room for the supposition, that even the ultimate particles of matter may be permeable to the causes of attractions of various kinds, especially if those causes are immaterial: nor is there anything in the unprejudiced study of physical philosophy that can induce us to doubt the existence of immaterial substances; on the contrary, we see analogies that lead us almost directly to such an opinion. The electrical fluid is supposed to be essentially different from common matter; the general medium of light and heat, according to some, or the principle of caloric, according to others, is equally distinct from it. We see forms of matter, differing in subtility and mobility, under the names of solids, liquids, and gases; above these are the semi-material existences, which produce the phenomena of electricity and magnetism, and either caloric or a universal ether. Higher still, perhaps, are the causes of gravitation, and the immediate agents in attractions of all kinds, which exhibit some phenomena apparently still more remote from all that is compatible with material bodies. And of these different orders of beings, the more refined and immaterial appear to pervade freely the grosser. It seems therefore natural to believe that the analogy may be continued still further, until it rises into existences absolutely immaterial and spiritual. We know not but that thousands of spiritual worlds may exist unseen for ever by human eyes; nor have we any reason to suppose that even the presence of matter, in a given spot, necessarily excludes these existences from it. Those who maintain that nature always teems with life, wherever living beings can be placed, may therefore speculate with freedom on