The emanation particles gradually break up, each particle as it breaks up expelling a charged body. The emanation after it has radiated ceases to exist as such, but is transformed into a new kind of matter, which is deposited on the surface of bodies and gives rise to the phenomena of excited activity. This last property, and the connection of the emanation with it, are discussed in detail in the next chapter. Footnote 231: Owens, _Phil. Mag._ p. 360, Oct. 1899. Footnote 232: Rutherford, _Phil. Mag._ p. 1, Jan. 1900. Footnote 233: Rossignol and Gimingham, _Phil. Mag._ July, 1904. Footnote 234: Bronson, _Amer. Journ. Science_, Feb. 1905. Footnote 235: _Phil. Mag._ April, 1904. Footnote 236: Dorn, _Abh. der. Naturforsch. Ges. für Halle-a-S._, 1900. Footnote 237: P. Curie, _C. R._ 135, p. 857, 1902. Footnote 238: Rutherford and Soddy, _Phil. Mag._ April, 1903. Footnote 239: P. Curie, _C. R._ 136, p. 223, 1903. Footnote 240: Debierne, _C. R._ 136, p. 146, 1903. Footnote 241: Giesel, _Ber. D. deutsch. Chem. Ges._ p. 3608, 1902. Footnote 242: Curie and Debierne, _C. R._ 132, pp. 548 and 768, 1901. Footnote 243: Curie and Debierne, _C. R._ 133, p. 931, 1901. Footnote 244: Rutherford and Soddy, _Trans. Chem. Soc._ p. 321, 1902. _Phil. Mag._ Sept. 1902. Footnote 245: Rutherford, _Phys. Zeit._ 2, p. 429, 1901. Footnote 246: Rutherford and Soddy, _Phil. Mag._ Nov. 1902. Footnote 247: Rutherford and Soddy, _Phil. Mag._ April, 1903. Footnote 248: Rutherford and Soddy, _Phil. Mag._ Nov. 1902. Footnote 249: Rutherford and Soddy, _Phil. Mag._ April, 1903. Footnote 250: Curie and Debierne, _C. R._ 133, p. 931, 1901. Footnote 251: Rutherford and Soddy, _Phil. Mag._ Nov. 1902. Footnote 252: Ramsay and Soddy, _Proc. Roy. Soc._ 72, p. 204, 1903. Footnote 253: Rutherford and Miss Brooks, _Trans. Roy. Soc. Canada 1901_, _Chem. News 1902_. Footnote 254: Loschmidt, _Sitzungsber. d. Wien. Akad._ 61, II. p. 367, 1871. Footnote 255: See Stefan, _Sitzungsber. d. Wien. Akad._ 63, II. p. 82, 1871. Footnote 256: P. Curie and Danne, _C. R._ 136, p. 1314, 1903. Footnote 257: Bumstead and Wheeler, _Amer. Jour. Science_, Feb. 1904. Footnote 258: Makower, _Phil. Mag._ Jan. 1905. Footnote 259: Wallstabe, _Phys. Zeit._ 4, p. 721, 1903. Footnote 260: Stefan, _Wien. Ber._ 2, p. 371, 1878. Footnote 261: Rutherford and Soddy, _Phil. Mag._ Nov. 1902. Footnote 262: _Phil. Mag._ May, 1903. Footnote 263: P. Curie, Société de Physique, 1903. Footnote 264: Rutherford and Soddy, _Phil. Mag._ May, 1903. Footnote 265: _Nature_, Aug. 20, 1903. Footnote 266: _Proc. Roy. Soc._ 73, No. 494, p. 346, 1904. Footnote 267: _Proc. Roy. Soc._ 73, No. 495, p. 470, 1904. Footnote 268: Pickering, _Astrophys. Journ._ Vol. 14, p. 368, 1901. CHAPTER VIII. EXCITED RADIO-ACTIVITY.