_Seventh._ Occasionally we were made conscious of the occurrence of a powerful shock, which produced a vibratory motion of the floor of the apartment. It seemed like the motion occasioned by distant thunder, or the firing of ordnance far away, causing the tables, chairs, and other inanimate objects, and all of us, to tremble in such a manner that the effect was both seen and felt. In conclusion, it was observed that D. D. Hume, the medium, frequently urged the company to hold his feet and hands. The room was well lighted, and a lamp was placed on and under the table, and every possible opportunity afforded for the closest inspection. They were therefore positive that there was no deception in the case. The conclusion was, _that it must be the work of spirits_--a singular conclusion, indeed, for men of such standing and acquirements. It might all have been accomplished, _biologically_; but admitting the whole to be literally and substantially true, they fall far short of well-attested phenomena, where it was not so much as _conjectured_ even to be _at all supernatural_." The fact is incontrovertibly evident, that physical agents, subtile and unseen, are every where at work. "Force shows itself," as the elegant Somerville remarks, in his Connection of the Physical Sciences, "in every thing that exists in the heavens or on the earth." There is a physical power which not only binds satellites to their planet, and planets with suns, and sun with sun throughout the wide extent of creation, which is the cause of the disturbances, as well as the order of nature, but it physically binds man to man, and man to nature. And as every tremor it excites in one planet is immediately transmitted to the farthest limits of the system, in oscillations, which correspond in their periods with the cause producing them, like sympathetic notes in music, or vibrations from the deep tones of an organ, so every vibration, thus excited, is transmissible to the delicate centres of every organic being, provided the repulsive agent of those beings is changed in its relative condition so as to admit its influx. (See Geometry and Faith, by Rev. T. Hill, of Waltham.) "It is well known to every chemist, that wherever there is chemical action going on, there is a constant evolution of some force. Now, that there is a constant chemical action taking place is certain, and the sources of this action are very numerous. Among others, we have that of water, (often holding in solution saline ingredients, thus increasing its action upon metallic substances,) which, percolating through the surface, acts upon all those surfaces whose materials have a strong chemical affinity for the oxygen or hydrogen of the water.