Radio-Activity

by Ernest Rutherford

CAMBRIDGE PHYSICAL SERIES.

CONTENTS OF Mr Whetham’s ‘Solution and Electrolysis.’

I. Thermodynamics.

II. The Phase Rule.

III. The Phase Rule. Two Components. Solutions.

IV. Solubility.

V. Osmotic Pressure.

VI. Vapour Pressures and Freezing Points.

VII. Theories of Solution.

VIII. Electrolysis.

IX. Conductivity of Electrolytes.

X. Galvanic Cells.

XI. Contact Electricity and Polarization.

XII. The Theory of Electrolytic Dissociation.

XIII. Diffusion in Solutions.

XIV. Solutions of Colloids.

Additions.

Table of Electro-chemical Properties of Aqueous Solutions.

Electricity and Magnetism: an Elementary Text-book, Theoretical and Practical. By R. T. Glazebrook, M.A., F.R.S., Director of the National Physical Laboratory and Fellow of Trinity College, Cambridge. Crown 8vo. Cloth. 1–440 pp. 7s. 6d.

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PREFACE. Some words are perhaps necessary to explain the publication of another book dealing with Elementary Electricity. A considerable portion of the present work has been in type for a long time; it was used originally as a part of the practical work in Physics for Medical Students at the Cavendish Laboratory in connexion with my lectures, and was expanded by Mr Wilberforce and Mr Fitzpatrick in one of their Laboratory Note-books of Practical Physics.

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Footnotes

[1]. Niewenglowski, C. R. 122, p. 385, 1896.

[2]. Becquerel, C. R. 122, p. 559, 1896.

[3]. Troost, C. R. 122, p. 564, 1896.

[4]. Arnold, Annal. d. Phys. 61, p. 316, 1897.

[5]. Le Bon, C. R. 122, pp. 188, 233, 386, 462, 1896.

[6]. Becquerel, C. R. 122, pp. 420, 501, 559, 689, 762, 1086, 1896.

[7]. Mme Curie, Thèse présentée à la Faculté des Sciences de Paris, 1903.

[8]. Nature, 56, 1897; Phil. Mag. 43, p. 418, 1897; 45, p. 277, 1898.

[9]. Rutherford, Phil. Mag. Jan. 1899.

[10]. Ibid.

[11]. Le Bon, C. R. 130, p. 891, 1900.

[12]. Lenard, Annal. d. Phys. 1, p. 498; 3, p. 298, 1900.

[13]. Schmidt, Annal. d. Phys. 65, p. 141, 1898.

[14]. Mme Curie, C. R. 126, p. 1101, 1898.

[15]. Owens, Phil. Mag. Oct. 1899.

[16]. Rutherford, Phil. Mag. Jan. 1900.

[17]. M. and Mme Curie and G. Bemont, C. R. 127, p. 1215, 1898.

[18]. Giesel, Phys. Zeit. 3, No. 24, p. 578, 1902.

[19]. Giesel, Annal. d. Phys. 69, p. 91, 1890. Ber. d. D. Chem. Ges. p. 3608, 1902.

[20]. Demarçay, C. R. 127, p. 1218, 1898; 129, p. 716, 1899; 131, p. 258, 1900.

[21]. Runge, Astrophys. Journal, p. 1, 1900. Annal. d. Phys. No. 10, p. 407, 1903.

[22]. Exner and Haschek, Wien. Ber. July 4, 1901.

[23]. Crookes, Proc. Roy. Soc. 72, p. 295, 1904.

[24]. Runge and Precht, Annal. d. Phys. XIV. 2, p. 418, 1904.

[25]. Runge and Precht, Phil. Mag. April, 1903.

[26]. Watts, Phil. Mag. July, 1903; August, 1904.

[27]. Runge, Phil. Mag. December, 1903.

[28]. Debierne, C. R. 129, p. 593, 1899; 130, p. 206, 1900.

[29]. Giesel, Ber. d. D. Chem. Ges. p. 3608, 1902; p. 342, 1903.

[30]. Debierne, C. R. 139, p. 538, 1904. Miss Brooks, Phil. Mag. Sept. 1904. Giesel, Phys. Zeit. 5, p. 822, 1904. Jahrbuch. d. Radioaktivität, no. 4, p. 345, 1904.

[31]. Giesel, Ber. d. D. Chem. Ges. 37, p. 1696, 1904; Hartmann, Phys. Zeit. 5, No. 18, p. 570, 1904.

[32]. Mme Curie, C. R. 127, p. 175, 1898.

[33]. Mme Curie, Thèse, Paris, 1903.

[34]. Crookes, Proc. Roy. Soc. May, 1900.

[35]. Berndt, Phys. Zeit. 2, p. 180, 1900.

[36]. Marckwald, Phys. Zeit. 4, No. 1 b, p. 51.

[37]. Marckwald, Ber. d. D. Chem. Ges. p. 2662, No. 12, 1903.

[38]. Elster and Geitel, Annal. d. Phys. 69, p. 83, 1899.

[39]. Giesel, Ber. d. D. Chem. Ges. p. 3775, 1901.

[40]. Hofmann and Strauss, Ber. d. D. Chem. Ges. p. 3035, 1901.

[41]. Hofmann, Gonder and Wölfl, Annal. d. Phys. No. 13, p. 615, 1904.

[42]. Hofmann and Zerban, Ber. d. D. Chem. Ges. No. 12, p. 3093, 1903.

[43]. Baskerville and Zerban, Amer. Chem. Soc. 26, p. 1642, 1904.

[44]. J. J. Thomson and Rutherford, Phil. Mag. Nov. 1896.

[45]. The word ion has now been generally adopted in the literature of the subject. In using this word, it is not assumed that the ions in gases are the same as the corresponding ions in the electrolysis of solutions.

[46]. A minute current is observed between the plates even if no radio-active matter be present. This has been found to be due mainly to a slight natural radio-activity of the matter composing them. (See [chapter XIV.])

[47]. This nomenclature has arisen from the similarity of the shape of the current-voltage curves to the magnetization curves for iron. Since, on the ionization theory, the maximum current is a result of the removal of all the ions from the gas, before recombination occurs, the terms are not very suitable. They have however now come into general use and will be retained throughout this work.

[48]. J. J. Thomson, Phil. Mag. 47, p. 253, 1899; Conduction of Electricity through Gases, p. 73, 1903.

[49]. Rutherford, Phil. Mag. Jan. 1899.

[50]. Townsend, Phil. Mag. Feb. 1901.

[51]. Rutherford, Phil. Mag. Nov. 1897, p. 144, Jan. 1899.

[52]. Townsend, Phil. Trans. A, p. 157, 1899.

[53]. McClung, Phil. Mag. March, 1902.

[54]. Langevin, Thèse présentée à la Faculté des Sciences, p. 151, Paris, 1902.

[55]. Owens, Phil. Mag. Oct. 1899.

[56]. Rutherford, Phil. Mag. p. 429, Nov. 1897.

[57]. Zeleny, Phil. Trans. A, p. 193, 1901.

[58]. Langevin, C. R. 134, p. 646, 1902.

[59]. Zeleny, Phil. Mag. July, 1898.

[60]. Rutherford, Phil. Mag. Feb. 1899.

[61]. Zeleny, Phil. Trans. 195, p. 193, 1900.

[62]. Langevin, C. R. 134, p. 646, 1902, and Thesis, p. 191, 1902.

[63]. Rutherford, Proc. Camb. Phil. Soc. 9, p. 410, 1898.

[64]. Langevin, Thesis, p. 190, 1902.

[65]. Helmholtz and Richarz, Annal. d. Phys. 40, p. 161, 1890.

[66]. Wilson, Phil. Trans. p. 265, 1897; p. 403, 1899; p. 289, 1900.

[67]. Thomson, Phil. Mag. p. 528, Dec. 1898.

[68]. Wilson, Phil. Trans. A, 193, p. 289, 1899.

[69]. Thomson, Phil. Mag. p. 528, Dec. 1898, and March, 1903. Conduction of Electricity through Gases, Camb. Univ. Press, 1903, p. 121.

[70]. Wilson, Phil. Mag. April, 1903.

[71]. Townsend, Phil. Trans. A, p. 129, 1899.

[72]. Townsend, loc. cit. p. 139.

[73]. Some difference of opinion has been expressed as to the value of V required to produce ions at each collision. Townsend considers it to be about 20 volts; Langevin 60 volts and Stark about 50 volts.

[74]. Rutherford, Phil. Mag. Jan. 1899.

[75]. Rutherford, Phil. Mag. Jan. 1899.

[76]. Strutt, Phil. Trans. A, p. 507, 1901 and Proc. Roy. Soc. p. 208, 1903.

[77]. McClung, Phil. Mag. Sept. 1904.

[78]. Eve, Phil. Mag. Dec. 1904.

[79]. Rutherford, Phil. Mag. p. 137, Jan. 1899.

[80]. Child, Phys. Rev. Vol. 12, 1901.

[81]. Rutherford, Phil. Mag. p. 210, August, 1901; Phys. Rev. Vol. 13, 1901.

[82]. Rutherford, Phil. Mag. Aug. 1901.

[83]. A simple and excellent account of the effects produced by the motion of a charged ion and also of the electronic theory of matter was given by Sir Oliver Lodge in 1903 in a paper entitled “Electrons” (Proceedings of the Institution of Electrical Engineers, Part 159, Vol. 32, 1903). See also J. J. Thomson’s Electricity and Matter (Scribner, New York, 1904).

[84]. J. J. Thomson, Phil. Mag. April, 1887.

[85]. Heaviside, Collected Papers, Vol. II. p. 514.

[86]. Searle, Phil. Mag. Oct. 1897.

[87]. Abraham, Phys. Zeit. 4, No. 1 b, p. 57, 1902.

[88]. A full account of the path described by a moving ion under various conditions is given by J. J. Thomson, Conduction of Electricity in Gases (Camb. Univ. Press, 1903), pp. 79–90.

[89]. J. J. Thomson, Phil. Mag. p. 293, 1897.

[90]. Lenard, Annal. d. Phys. 64, p. 279, 1898.

[91]. Kaufmann, Annal. d. Phys. 61, p. 544; 62, p. 596, 1897; 65, p. 431, 1898.

[92]. Simon, Annal. d. Phys. 69, p. 589, 1899.

[93]. A complete discussion of the various methods employed to measure the velocity and mass of electrons and also of the theory on which they are based will be found in J. J. Thomson’s Conduction of Electricity through Gases.

[94]. Goldstein, Berlin Sitzber. 39, p. 691, 1896; Annal. d. Phys. 64, p. 45, 1898.

[95]. Wien, Annal. d. Phys. 65, p. 440, 1898.

[96]. Larmor, Phil. Mag. 44, p. 593, 1897.

[97]. J. J. Thomson, Phil. Mag. Feb. 1897.

[98]. Barkla, Phil. Mag. June, 1903.

[99]. Soddy, Trans. Chem. Soc. Vol. 81, p. 860, 1902.

[100]. Wilson, Proc. Roy. Soc. Vol. 68, p. 152, 1901.

[101]. If the apparatus is required to be air-tight, the gold-leaf system can be charged by means of a piece of magnetized steel wire, which is made to touch the rod R by the approach of a magnet.

[102]. It is sometimes observed that the motion of the gold-leaf, immediately after charging, is irregular. In many cases, this can be traced to air currents set up in the electroscope in consequence of unsymmetrical heating by the source of light used for illumination.

[103]. Wilson, Proc. Camb. Phil. Soc. Vol. 12, Part II. 1903.

[104]. Walker, Phil. Mag. Aug. 1903.

[105]. Strutt, Phil. Trans. A, p. 507, 1901.

[106]. Dolezalek, Instrumentenkunde, p. 345, Dec. 1901.

[107]. It is very desirable that care should be taken not to release large quantities of the radium emanation inside a laboratory. This emanation has a slow rate of decay and is carried by currents of air throughout the whole building and finally leaves behind an active deposit of very slow rate of change (see [chapter XI.]). Eve (Nature, March 16, 1905) has drawn attention to the difficulty of making refined radio-active measurements under such conditions.

[108]. J. J. Thomson, Phil. Mag. 46, p. 537, 1898.

[109]. Bronson, Amer. Journ. Science, Feb. 1905.

[110]. J. and P. Curie, C. R. 91, pp. 38 and 294, 1880. See also Friedel and J. Curie, C. R. 96, pp. 1262 and 1389, 1883, and Lord Kelvin, Phil. Mag. 36, pp. 331, 342, 384, 414, 453, 1893.

[111]. In an examination of uranium the writer (Phil. Mag. p. 116, Jan. 1899) found that the rays from uranium consist of two kinds, differing greatly in penetrating power, which were called the α and β rays. Later, it was found that similar types of rays were emitted by thorium and radium. On the discovery that very penetrating rays were given out by uranium and thorium as well as by radium, the term γ was applied to them by the writer. The word “ray” has been retained in this work, although it is now settled that the α and β rays consist of particles projected with great velocity. The term is thus used in the same sense as by Newton, who applied it in the Principia to the stream of corpuscles which he believed to be responsible for the phenomenon of light. In some recent papers, the α and β rays have been called the α and β “emanations.” This nomenclature cannot fail to lead to confusion, since the term “radio-active emanation” has already been generally adopted in radio-activity as applying to the material substance which gradually diffuses from thorium and radium compounds, and itself emits rays.

[112]. This method of illustration is due to Mme Curie, Thèse présentée à la Faculté des Sciences de Paris, 1903.

[113]. Giesel, Annal. d. Phys. 69, p. 834, 1899.

[114]. Meyer and Schweidler, Phys. Zeit. 1, pp. 90, 113, 1899.

[115]. Becquerel, C. R. 129, pp. 997, 1205, 1899.

[116]. Curie, C. R. 130, p. 73, 1900.

[117]. Rutherford, Phil. Mag. January, 1899.

[118]. Rutherford and Grier, Phil. Mag. September, 1902.

[119]. Becquerel, C. R. 130, pp. 206, 372, 810, 979. 1900.

[120]. M. and Mme Curie, C. R. 130, p. 647, 1900.

[121]. The activity of the radium preparation was not stated in the paper.

[122]. Dorn, Phys. Zeit. 4, No. 18, p. 507, 1903.

[123]. Strutt, Phil. Mag. Nov. 1903.

[124]. Wien, Phys. Zeit. 4, No. 23, p. 624, 1903.

[125]. Dorn, C. R. 130, p. 1129, 1900.

[126]. Becquerel, C. R. 130, p. 809, 1900.

[127]. Kaufmann, Phys. Zeit. 4, No. 1 b, p. 54, 1902.

[128]. Abraham, Phys. Zeit. 4, No. 1 b, p. 57, 1902.

[129]. Kaufmann, Nachrichten d. Ges. d. Wiss. zu Gött., Nov. 8, 1901.

[130]. Simon, Annal. d. Phys. p. 589, 1899.

[131]. Kaufmann, Phys. Zeit. 4, No. 1 b, p. 54, 1902.

[132]. Paschen, Annal. d. Phys. 14, p. 389, 1904.

[133]. Meyer and Schweidler, Phys. Zeit. pp. 90, 113, 209, 1900.

[134]. Lenard, Annal. d. Phys. 56, p. 275, 1895.

[135]. Strutt, Nature, p. 539, 1900.

[136]. Seitz, Phys. Zeit. 5, No. 14, p. 395, 1904.

[137]. It is presumed that the results were corrected, if necessary, for the discharging action due to the ionized gas, although no direct mention of this is made in the paper by Seitz.

[138]. Strutt, Phil. Trans. A, p. 507, 1901.

[139]. Crookes, Proc. Roy. Soc. 1902. Chem. News, 85, p. 109, 1902.

[140]. Mme Curie, C. R. 130, p. 76, 1900.

[141]. Rutherford, Phil. Mag. Feb. 1903. Phys. Zeit. 4, p. 235, 1902.

[142]. Becquerel, C. R. 136, p. 199, 1903.

[143]. Becquerel, C. R. 136, p. 431, 1903.

[144]. Des Coudres, Phys. Zeit. 4, No. 17, p. 483, 1903.

[145]. Becquerel, C. R. 136, p. 1517, 1903.

[146]. Bragg, Phil. Mag. Dec. 1904; Bragg and Kleeman, Phil. Mag. Dec. 1904.

[147]. Further experimental results bearing on this important question are given in an Appendix to this book.

[148]. Bakerian Lecture, Phil. Trans. A, p. 169, 1904.

[149]. Strutt, Phil. Mag. Aug. 1904.

[150]. J. J. Thomson, Proc. Camb. Phil. Soc. 13, Pt. I. p. 39, 1905. Nature, Dec. 15, 1904.

[151]. Rutherford, Nature, March 2, 1905. J. J. Thomson, Nature, March 9, 1905.

[152]. Crookes, Proc. Roy. Soc. 81, p. 405, 1903.

[153]. Elster and Geitel, Phys. Zeit. No. 15, p. 437, 1903.

[154]. Glew, Arch. Röntgen Ray, June 1904.

[155]. Becquerel, C. R. 137, Oct. 27, 1903.

[156]. Tommasina, C. R. 137, Nov. 9, 1903.

[157]. An interesting side-light is thrown on this question by the experiments described in [Appendix A] of this book.

[158]. Rutherford and Miss Brooks, Phil. Mag. July 1902.

[159]. In order to obtain a thin layer, the compound to be tested is ground to a fine powder and then sifted through a fine gauge uniformly over the area, so that the plate is only partially covered.

[160]. Rutherford, Phil. Mag. Jan. 1899.

[161]. Owens, Phil. Mag. Oct. 1899.

[162]. Rutherford and Miss Brooks, Phil. Mag. July, 1900.

[163]. Since the ionization at any point above the plate is the resultant effect of the α particles coming from all points of the large radio-active layer, λ is not the same as the coefficient of absorption of the rays from a point source. It will however be proportional to it. For this reason λ is called the “absorption constant.”

[164]. Townsend, Phil. Mag. Feb. 1901.

[165]. Durack, Phil. Mag. July 1902, May 1903.

[166]. Bragg and Bragg and Kleeman, Phil. Mag. Dec. 1904.

[167]. Villard, C. R. 130, pp. 1010, 1178, 1900.

[168]. Becquerel, C. R. 130, p. 1154, 1900.

[169]. Rutherford, Phys. Zeit. 3, p. 517, 1902.

[170]. McClelland, Phil. Mag. July 1904.

[171]. Paschen, Phys. Zeit. 5, No. 18, p. 563, 1904.

[172]. A. S. Eve, Phil. Mag. Nov. 1904.

[173]. Paschen, Annal. d. Physik, 14, p. 114, 1904; 14, 2, p. 389, 1904. Phys. Zeit. 5, No. 18, p. 563, 1904.

[174]. Paschen, Phys. Zeit. 5, No. 18, p. 563, 1904.

[175]. Rutherford and Barnes, Phil. Mag. May 1905. Nature, p. 151, Dec. 15, 1904.

[176]. Barkla, Nature, March 17, 1904.

[177]. Becquerel, C.R. 132, pp. 371, 734, 1286. 1901.

[178]. Mme Curie, Thèse présentée à la Faculté des Sciences, Paris 1903, p. 85.

[179]. A. S. Eve, Phil. Mag. Dec. 1904.

[180]. In a recent paper (Phil. Mag. Feb. 1905), McClelland has, in the main, confirmed the experimental results obtained by Eve. An electrometer was used instead of an electroscope. He finds, in addition, that the amount of secondary radiation depends on the angle of incidence of the primary rays, and is greatest for an angle of 45°. In a letter to Nature (Feb. 23, p. 390, 1905), he states that more recent experiments have shown that the amount of secondary radiation from different substances is a function of their atomic weights rather than of their densities. In every case examined, the amount of secondary radiation increases with the atomic weight, but is not proportional to it.

[181]. Rutherford and McClung, Phil. Trans. A. p. 25, 1901.

[182]. Meyer and Schweidler, Wien Ber. 113, July, 1904.

[183]. Rutherford and Grier, Phil. Mag. Sept. 1902.

[184]. Becquerel, C. R. 129, p. 912, 1899.

[185]. Bary, C. R. 130, p. 776, 1900.

[186]. Kunz and Baskerville, Amer. Journ. Science XVI. p. 335, 1903.

[187]. See Nature, p. 523, March 31, 1904.

[188]. Crookes, Proc. Roy. Soc. 74, p. 47, 1904.

[189]. Kunz and Baskerville, Science XVIII, p. 769, Dec. 18, 1903.

[190]. Beilby in a recent communication to the Royal Society (Feb. 9 and 23, 1905) has examined in some detail the production of phosphorescence by the β and γ rays of radium and has put forward a theory to account for the different actions observed.

[191]. Huggins, Proc. Roy. Soc. 72, pp. 196 and 409, 1903.

[192]. The spark spectrum of the radium bromide showed the H and K lines of calcium and also faintly some of the strong lines of barium. The characteristic lines of radium of wave-lengths 3814·59, 3649·7, 4340·6 and 2708·6, as shown by Demarçay and others are clearly shown in the figure. The strong line of wave-length about 2814 is due to radium.

[193]. Giesel, Ber. d. D. Chem. Ges. 37, p. 1696, 1904.

[194]. Hartmann, Phys. Zeit. 5, No. 18, p. 570, 1904.

[195]. In a recent paper, Giesel (Ber. d. D. Chem. Ges. No. 3, p. 775, 1905) has shown that the bright lines are due to didymium, which is present as an impurity. Exposure of didymium to the radium rays also causes the appearance of the lines.

[196]. Wiedemann and Schmidt, Wied. Annal. 59, p. 604, 1895.

[197]. Wiedemann, Phys. Zeit. 2, p. 269, 1901.

[198]. Elster and Geitel, Annal. d. Phys. 69, p. 673, 1899.

[199]. Willons and Peck (Phil. Mag. March, 1905) found that under some conditions, especially for long sparks, the rays of radium hindered the passage of the spark.

[200]. Hemptinne, C. R. 133, p. 934, 1901.

[201]. Himstedt, Phys. Zeit. p. 476, 1900.

[202]. Henning, Annal. d. Phys. p. 562, 1902.

[203]. Kohlrausch and Henning, Verh. Deutsch. Phys. Ges. 6, p. 144, 1904.

[204]. Kohlrausch, Verh. Deutsch. Phys. Ges. 5, p. 261, 1904.

[205]. P. Curie, C. R. 134, p. 420, 1902.

[206]. Becquerel, C. R. 136, p. 1173, 1903.

[207]. Becquerel, C. R. 133, p. 199, 1901.

[208]. P. Curie, Société de Physique, March 2, 1900.

[209]. Joly, Phil. Mag. March, 1904.

[210]. S. and P. Curie, C. R. 129, p. 823, 1899.

[211]. Giesel, Verhandlg. d. D. Phys. Ges. Jan. 5, 1900.

[212]. Salomonsen and Dreyer, C. R. 139, p. 533, 1904.

[213]. Elster and Geitel, Phys. Zeit. p. 113, No. 3, 1902.

[214]. Becquerel, C. R. 133, p. 709, 1901.

[215]. Hardy and Miss Wilcock, Proc. Roy. Soc. 72, p. 200, 1903.

[216]. Hardy, Proc. Physiolog. Soc. May 16, 1903.

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• Transcriber’s Notes:
  • Inconsistent spelling and hyphenation were made consistent only when a predominant form was found in this book.
  • Footnotes have been collected at the end of the text, and are linked for ease of reference.