> as lemmas

1899 E. Rutherford in London, Edinb. & Dublin Philos. Mag. 5th Ser. 47 116 These experiments show that uranium radiation is complex, and that there are present at least two distinct types of radiation—one that is very readily absorbed, which will be termed for convenience the α radiation, and the other of a more penetrative character, which will be termed the β radiation.

1902 E. Rutherford & A. G. Grier in London, Edinb. & Dublin Philos. Mag. 6th Ser. 4 325 For brevity and convenience we will call the non-deviable rays of all radioactive substances α rays and the deviable rays β rays.

1904 Rutherford in Nature 10 Mar. 437/1 It is to be expected that Röntgen rays would be set up at the sudden starting as well as the sudden stopping of the electron or β particle.

1909 F. Soddy Interpr. Radium 55 In ordinary circumstances radium appears to be expelling both α- and β-particles together.

1922 A. S. Eddington Theory of Relativity 19 The β particles shot off from radioactive substances are negative electrons which sometimes attain speeds of 100,000 miles a second.

1933 Discovery Feb. 45/1 Beta radiations, which are streams of electrons.

1957 Technology Mar. 14/2 Both beta and gamma rays can also be used for gauging thickness or height in the examination, for instance, of red-hot sheets of steel.