The New Student's Reference Work/Becquerel Rays
1. They are propagated in straight lines, as is ordinary light.
2. They affect the photographic plate, as does ordinary light, though in a much less degree.
3. They traverse thin plates of opaque bodies, unlike ordinary light.
4. They are not reflected, refracted or polarized, as is ordinary light.
5. They render the air through which they pass a conductor of electricity, or, as the chemist says, they ionize air.
A full account of this discovery is to be found in Becquerel's papers, which are published in the Comptes Rendus for the first few months of 1896.