FIG. 4. Expected behavior of a hypothetical "perfect conductor" in a magnetic field. (a)-(b) With no applied magnetic field, the sample is cooled to below its transition temperature T_{c}. The sample becomes resistanceless. (c) Because induced currents flow without resistance, the cooled sample is able to expel completely an applied magnetic field **B**_{a} that is less than H_{c}(T) in magnitude. (d) When the applied magnetic field **B**_{a} is removed, the sample has no residual magnetization. (e) With a magnetic field **B**_{a} applied, the sample is cooled below its transition temperature T_{c}. (f) The process of cooling does not induce currents in the "perfect conductor" so that the applied magnetic field **B**_{a} remains in the interior of the sample. (g) When the applied magnetic field **B**_{a} is removed, induced currents flow without resistance to maintain a magnetic field **B**_{a} throughout the interior of the sample. The sample is left with a net magnetization. The sample states depicted in (f) and (g) do *not* correspond to the observed behavior of a superconductor.^{5}

To Fig. 3
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