answers: unknown type of radiation
context: "X-radiation" to signify an unknown type of radiation. Spelling of "X-ray(s)" in the English language includes the variants "x-ray(s)", "xray(s)", and "X ray(s)". Before their discovery in 1895 X-rays were just a type of unidentified radiation emanating from experimental discharge tubes. They were noticed by scientists investigating cathode rays produced by such tubes, which are energetic electron beams that were first observed in 1869. Many of the early Crookes tubes (invented around 1875) undoubtedly radiated X-rays, because early researchers noticed effects that were attributable to them, as detailed below. Crookes tubes created free electrons by ionization of the residual air </s> X X (named "ex" , plural "exes") is the 24th and antepenultimate letter in the modern English alphabet and the ISO basic Latin alphabet. In Ancient Greek, 'Χ' and 'Ψ' were among several variants of the same letter, used originally for and later, in western areas such as Arcadia, as a simplification of the digraph 'ΧΣ' for . In the end, more conservative eastern forms became the standard of Classical Greek, and thus 'Χ' "(Chi)" stood for (later ; palatalized to in Modern Greek before front vowels). However, the Etruscans had taken over 'Χ' from western Greek, and it therefore </s> of the singles therefrom. The image, which is visualized through a combination of colours and blocks, is a graphical representation of the Baudot code, an early form of telegraph communication using a series of ones and zeros to communicate. The code was developed by Frenchman Émile Baudot in the 1870s, and was a widely used method of terrestrial and telegraph communication. The alphabet of the code is presented in the liner notes of "X&Y". The track listing, included on the booklet, CD, and back of the album, uses "X#" on tracks 1 to 6 and "Y#" on tracks 7 to
question: what does the x mean in x ray