ON THE POLARITY OF THE DIAMAGNETIC FORCE. 
249 
while they corroborate the former ones, show that the instrument retained its power 
and delicacy unimpaired : — 
X. 
Bismuth cylinders. 
Current direct. 
Position 1. 612 
Position 2. 572 
Position 3. 526 
Current reversed. 
264 
230 
200 
The deflections, it will be observed, are the same in kind as before ; but by improved 
manipulation the effect is augmented. In passing from position 1 to 3 we have here 
a deflection amounting in one case to 64, and in the other to 86 divisions of the 
scale. 
To Mr. Noble I am indebted for two cylinders of pure statuary marble ; the 
examination of these gave the following results : — 
XI. 
Cylinders of Statuary Marble. 
length 4 inches, 
diameter 0*7. 
Current direct. 
Current reversed. 
Position 1. 
601 
215 
Position 2. 
598 
218 
Position 3. 
596 
220 
Here, in passing from position 1 to 3, we have a permanent deflection corresponding 
to five divisions of the scale. As in all other cases, the impulsion of the magnet 
might be augmented by changing the position of the cylinders at the limit of each 
swing. The deflections are the same in kind as those produced by bismuth, which 
ought to be the case, as marble is diamagnetic. 
An upright iron stove influenced by the earth’s magnetism becomes a magnet with 
its bottom a north and its top a south pole. Doubtless, though in an immensely 
feebler degree, every erect marble statue is a true diamagnet, with its head a north 
pole and its feet a south pole. The same is certainly true of man as he stands upon 
the earth’s surface, for all the tissues of the human body are diamagnetic. 
A pair of cylinders of phosphorus enclosed in thin glass tubes were next exa- 
mined. 
XII. 
Cylinders of Phosphorus. 
length 3‘5 inches, 
diameter 0*63. 
