For example , Hertz was able to focus the waves using a lens made of tree resin .
Hertz also demonstrated that the new radiation could be both reflected and refracted by various dielectric media , in the same manner as light .
Hertz was able to focus the waves using a lens made of tree resin .
Hertz also demonstrated that the new radiation could be both reflected and refracted by various dielectric media , in the same manner as light .