Whatever may be thought of speculations of this kind, however, with respect to the relative distance of the atoms of bodies, it is not the less certain, that these atoms are separate substances, independent of the other similar or different substances that apparently adhere to them in continuity,--that they are, in truth, the only material substances which really exist, since the bodies which we term masses are only those very atoms under another name,--that they remain, and cannot but remain, identical, amid all the changes of chemical composition or decomposition,--and that the change which they suffer, therefore, however strikingly their physical character may be altered for the time, is a change not of _substance_ but of _state_ only. In the case of the formation of _ice_, for example, the elementary atoms themselves, which are all that truly exist in nature, are not, and cannot be, changed; but particles, which were formerly easily separable from adjacent particles, now resist this separation by a considerable force. There is a change in their _state_, therefore, since they now exist with a different degree of tendency toward each other,--a change, to which the separation of a quantity of caloric may, indeed, have given occasion, but which is to be distinguished from that momentary separation itself, since the solidity, which is only another name for the corpuscular resistance, continues after the separation is complete, and would continue forever, unless a change of temperature were again to restore that former state or tendency of the particles, in which they were easily separable. To him who has learned to consider bodies as, what they truly are, a multitude of separate and independent corpuscles, there is no change of identity, and cannot be any change of identity, in all the phenomena or changes of the universe. The atoms, which alone existed, continue as before; and all which constitutes the phenomenon, or varieties of successive phenomena, is a change of their place or tendency.