An X-ray generating machine is exhibited for the first time by H. L. Smith.

An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ranging from 10 nanometers to 10 picometers, corresponding to frequencies in the range of 30 petahertz to 30 exahertz (3×10¹⁶ Hz to 3×10¹⁹ Hz) and photon energies in the range of 100 eV to 100 keV, respectively.

An X-ray machine is a device that uses X-rays for a variety of applications including medicine, X-ray fluorescence, electronic assembly inspection, and measurement of material thickness in manufacturing operations. In medical applications, X-ray machines are used by radiographers to acquire x-ray images of the internal structures of living organisms, and also in sterilization.