
OOP eG = 


TRANSACTIONS OF THE SECTIONS. v4 
the small cavity in the bar of lime with a piece of paper besmeared with oxide of 
iron, one can easily arrange so that the bar is attracted; and when the quantity of 
oxide is sufficient, the bar continues to be attracted even when strongly heated, 
Fill the cavity with bismuth, 1 gramme, for instance, and the bar will be again 
repelled when the magnetism is developed. But if, before passing the current, the 
bismuth is fused, the bar will be attracted, and will attach itself to the extremity of 
the pole when the magnetism is produced. At the instant that the bismuth becomes 
solid, the bar detaches itself abruptly from the pole, and the diamagnetic repulsion 
of the bismuth prevails. 
It now remained for me to ascertain whether bismuth in a state of fusion was 
indifferent to magnetic action, or whether, on the contrary, it became magnetic, 
For this purpose, I measured by the number of oscillations the diamagnetic force of 
a cylinder of bismuth contained in a corresponding cavity formed in a bar of lime 
suspended by a glass hook to a cocoon silk. Operating with the necessary pre- 
cautions, which are too long to be described here, I have found that the bar of lime, 
with its cylinder of bismuth in a state of fusion, made the same number of oscilla- 
tions as when without bismuth. The lime being constantly diamagnetic, this might 
have masked the change of the bismuth transformed into a magnetic body by fusion. 
I therefore suspended between the poles of the electro-magnet a bar of lime, formed 
somewhat like a salt-spoon, in order to increase greatly the quantity of bismuth in 
fusion compared with that of the lime. In one experiment I employed as much as 57 
grammes of fused bismuth, and nevertheless the repulsion continued. Thus, then, the 
diamagnetic power of bismuth diminishes suddenly at the point of fusion, and during 
the state of fusion the bismuth remains indifferent, without being apparently changed 
into a magnetic body. 
I have studied the influence of mechanic action on diamagnetism. By means of 
a copper box provided with a screw, I was able to compress a pure bismuth cylinder, 
3 millims. in diameter and 34 millims. in length, so as to reduce it to 28 millims. 
I then made two cylinders of bismuth precisely of the same dimensions, the one 
compressed, the other in its natural state, and I found that the compressed cylinder 
had a diamagnetic power distinctly superior to that of natural bismuth. I think it 
advisable here to call your attention to the fact which Coulomb, and more recently; 
Pliicker, have discovered respecting feebly magnetic substances; namely, that all 
cylinders of bismuth have the same oscillation independently of their weight, or in 
other words, that the diamagnetic power is proportionate to the weight of the 
cylinders. Cylinders of bismuth, varying in weight from 0°576 gr, to 18°600 gr., 
give the same oscillation. I studied afterwards, at some length, the influence of a 
powerful electro-magnet upon chemical affinity and cohesion. You have proved 
that gases, and even the most magnetic of the gases, do not suffer any variation in 
density by magnetic action. I have repeated the same experiments on gases, em- 
ploying a glass tube closed or open, such as that of a spirit-level, filled with gas 
and different liquids. ‘The gaseous bubble placed between the two polar extremities 
suffers considerable contraction and elongation, according to the nature of the liquid 
and gas. I think I have proved that these appearances are owing to a simple. 
change of form in the bubble without variation of density produced by the differential 
action of the magnet on the gas and on the liquid. I made a great number of expe- 
riments in order to measure the electrolyzation of acidulated water in a very powerful 
magnetic field, or independently of this influence. Several precautions, not gene- 
Yally followed, are absolutely necessary to obtain a uniform result in the use of the 
voltameter. These experiments led me to conclude that the most powerful magnetic 
action has no influence whatever on the electrolyzation of water. There is however 
a phenomenon which I do not think has been observed hitherto, and on which I 
must say a word. In electrolyzing water in a powerful electro-magnetic field, and’ 
if the experiment is properly arranged, the streams of gas bubbles which rise from 
the two electrodes are violently carried away in certain directions when the magnetism 
is put in activity. I think this movement is communicated by the liquid currents 
discovered by Davy. By employing a saturated solution of sulphate of copper for 
electrolyte, and by blowing into that liquid through a glass capillary tube a stream_of 
atmospheric bubbles instead of those formed by electrolyzation in water, I could. 
easily convince myself that the phenomenon is independent of any peculiar state of 
