The evidence for bodies much smaller than atoms primarily came from experiments involving cathode rays in the late 19th century. J.J. Thomson's work in 1897 was crucial: he showed that cathode rays could be deflected by electric and magnetic fields, which indicated that these rays were composed of negatively charged particles, not light. He measured these particles to be about 1,700 times lighter than hydrogen, the lightest atom known, and called them "corpuscles," later renamed electrons

. Thomson's experiments demonstrated that these particles were universal constituents of atoms, as they were emitted from different materials and had consistent charge and mass. This showed atoms were divisible and contained smaller charged bodies. Thomson also used Faraday's laws of electrolysis to deduce that the electric current was carried by these small charged particles, further confirming their existence

. Later, Ernest Rutherford's alpha particle scattering experiments provided evidence for a small, dense atomic nucleus, showing that atoms were not indivisible but had internal structure with even smaller components like protons and neutrons

. In summary, the key evidence for bodies smaller than atoms was:

• Deflection of cathode rays by electric and magnetic fields proving the existence of charged particles (electrons) much smaller than atoms

• Consistent charge-to-mass ratio of these particles regardless of the source material

• Electrolysis experiments showing charge is carried by small particles within atoms

• Alpha particle scattering experiments revealing a dense nucleus inside atoms, composed of protons and neutrons, smaller than the atom itself

These findings overturned the idea of atoms as indivisible and established the existence of subatomic particles.