  Elastic scattering of relativistic electrons from the nucleon yields Lorentz
invariant form factors that describe the fundamental distribution of charge and
magnetism. The spatial dependence of the nucleon's charge and magnetism is
typically interpreted in the Breit reference frame which is related by a
Lorentz boost from the laboratory frame, where the nucleon is at rest. We
construct a toy model to estimate how the charge and magnetic radii of the
nucleon are modified between the Breit and lab. frames. This has implications
for the ratio of the proton electric to magnetic elastic form factors as a
function of momentum transfer as well as for determinations of the proton
charge radius. Predicted corrections based on the model are provided for the
rms charge radii of the deuteron, the triton, and the helium isotopes.
