Note 166 — PARTICULAR CONSIDERATIONS RESPECTING THE ORIGIN OF THE ANIMATED TRIBES.

“A glass tube is to be bent into a syphon, and placed with the curve downwards, and in the bend is to be placed a small portion of mercury, not sufficient to close the connexion between the two legs; a solution of nitrate of silver is then to be introduced until it rises in both limbs of the tube. The precipitation of the mercury, in the form of an Arbor Dianæ, will then take place, slowly, only when the syphon is placed in a plane perpendicular to the magnetic meridian; but if it be placed in a plane coinciding with the magnetic meridian, the action is rapid, and the crystallization particularly beautiful, taking place principally in that branch of the syphon towards the north. If the syphon be placed in a plane perpendicular to the magnetic meridian, and a strong magnet brought near it, the precipitation will commence in a short time, and be most copious in the branch of the syphon nearest to the south pole of the magnet.”