Q34: FRAGMENTS OF SCIENCE. 
their disciples? Because they assumed, and were justified 
in assuming, that those whom they addressed had that 
within them which would respond to their appeal. If 
Germany should ever change for something less noble the 
simple earnestness and fidelity to duty, which in those days 
characterized her teachers, and through them her sons 
generally, it will not be because of rationalism. Such a 
decadent Germany might coexist with the most rampant 
rationalism without their standing to each other in the 
relation of cause and effect. 
My first really laborious investigation, conducted jointly 
with my friend Professor Knoblauch, landed me in a 
region which harmonized vvitli my speculative tastes. It 
was essentially an inquiry in molecular physics, having 
reference to the curious, and then perplexing, phenomena 
exhibited by crystals when freely suspended in the mag- 
netic field. I here lived amid the most complex operations 
of magnetism in its twofold aspect of an attractive and a 
repellent force. Iron was attracted by a magnet, bismuth 
was repelled, and the crystals operated on ranged them- 
selves under these two heads. Faraday and Pliicker had 
worked assiduously at the subject, and had invoked the 
aid of new forces to account for the phenomena. It was 
soon, however, found that the displacement in a crystal of 
an atom of the iron class by an atom of the bismuth class, 
involving no change of crystalline form, produced a com- 
plete reversal of the phenomena. The lines through the 
crystal which were in the one case drawn toward the poles 
of the magnet, were driven, in the other case, from these 
poles. By such instances and the reasoning which they 
suggested, magne-crystallic action was proved to be due, 
not to the operation of new forces, but to the modification 
of the old ones by molecular arrangement. Whether 
diamagnetism, like magnetism, was a polar force, was in 
those days a subject of the most lively contention. It was 
finally proved to be so; and the most complicated cases 
of mague-crystallic action were immediately shown to be 
simple mechanical consequences of the principle of 
diamagnetic polarity. These early researches, which 
occupied in all five years of my life, and throughout which 
the molecular architecture of crystals was an incessant 
subject of mental contemplation, gave a tinge and bias 
to my subsequent scientific thought, and their influence 
