eS Se a ie La ae Ss 
Dr. Faraday on Magnetic and Diamagnetic Action. 235 
class, a substance having any intermediate degree of the 
of either may be obtained. Protosulphate of iron belongs to the 
_ Magnetic, and water to the diamagnetic class; and using these 
substances, I found it easy to make asolution which was neither 
attracted nor repelled, nor pointed when in air. Such a solution 
pointed axially when surrounded by water. If made somewhat 
weaker in respect of the iron, it would point axially in water but 
equatorially in air; and it could be made to pass more and more 
into the magnetic or the. diamagnetic class by the addition of 
more sulphate of iron or more water. 
2423. Thus a fluid medium was obtained, which, practically, 
as far as I could perceive, had every magnetic chirakter and effect 
of a gas, and even of a vacuum; and as we possess both magnetic 
and diamagnetic glass, it is evidently possible to prepare’a solid 
Substance possessing the same neutral magnetic character. 
2424. The endeavor to form a general list of substances in the 
_ present imperfect state of our knowledge would be very prema- 
ture: the one below is given therefore only for the purpose of 
conveying an idea of the singular association under which bodies 
Come in relation to magnetic force, and for the purpose of general 
reference hereafter :—Jron, nickel, cobalt, manganese, palladium, 
frown-glass, platinum, osmium—0° air and vacuwm, arsenic, 
ether, alcohol, gold, water, mercury, flint-glass, tin, heavy-glass, 
antimony, phosphorus, bismuth. 
. It is very interesting to observe that metals are the sub- 
stances aahich stand at the extremities of the list, being of all 
those which are most powerfully opposed to each other in 
their magnetic condition. It is also a very remarkable circum- 
Stance that these differences and departures from the medium 
condition, are in the metals of the two extremes, iron and bis- 
muth, associated with a small conducting power for electricity. 
At the same time the contrast between these metals, as to their 
fibrous and granular state, their malleable and brittle character, 
will press upon the mind whilst contemplating the possible con- 
urea of their molecules when subjected to magnetic force. 
. In reference to the metals, as well as the diamagnetics 
‘hot of that class, it is satisfactory to have such an answer to the 
pinion that all bodies are magnetic as iron, as does not consist 
in a mere negation of that which is affirmed, but in proofs that 
they are in a different and opposed state, and are able to counter- 
act a very considerable degree of magnetic force (2448). 
