20 PAPERS, ETC. 
piece of oak plunged into the solution of flint. On a 
platina wire, immersed in the same solution, and connected 
with the positive pole, is forming a deposit of silici- 
ous matter larger than a crown-piece, and arranged in 
concentric layers of white and brown shades—closely 
resembling what is termed fortification agate. It was 
very soft and gelatinous at first, but has been gradually 
indurating, and is at present considerably more solid than it 
was, although it is entirely covered by the solution. The 
old saying, “ Ars longa, vita brevis,” is strikingly exem- 
plified here. Thus, time is required to bring these matters 
to perfection. The diamond is probably the electrical 
erystallization of ages. Now there are two reasons why 
heat and motion are greatly conducive to electrical erys- 
tallization. The first occasions a more rapid evaporation 
of the water holding the crystallizable matter in solution, 
and causes the fluid acted on to be a far better conductor 
of electricity. The second, or motion, so disposes the 
atoms that it agitates, that, being polarized by the electric 
action—that is, each atom having its opposite extremities 
rendered respectively positive and negative—they present 
themselves more readily to the opposite pole of the 
battery—the negative end of the atom to the positive 
pole having its outside still positive, or the positive end of 
the atom, as the case may be, being drawn to the negative 
pole, having its outside still negative ; so that there is no 
impediment to the even and quiet passage of the electric 
current, and the continual transfer of the atoms acted 
upon to their respective poles. 'This may be better un- 
derstood by placing a common magnet flat upon a table, 
with a sheet of paper lying upon it. If you let fall a mass 
of iron filings at once upon the paper, they will be 
attracted by the magnet below it into the form of a rude 
