194 G. F. BECKER ISOSTASY AND RADIOACTIVITY 



stances, it would be possible to manufacture synthetic radioactive sub- 

 stances. This. has not been accomplished, but I venture to say that it is 

 an achievement which would cause little surprise, though much admira- 

 tion. Suppose that ammonium had recently been discovered and proved 

 to consist of hydrogen and nitrogen; would any one doubt that the 

 synthesis of ammonium would eventually be effected? 



Mr. Barrel prior to 1906 suggested to Sir Ernest Eutherford that the 

 gradual building up of the heavy and more complex atoms of matter may 

 be slowly taking place in the interior of the earth.*"^ In 1908 I pointed 

 out that the bounds of legitimate hypothesis are not transgressed by sup- 

 posing that at the consistentior status the surplus energy of aqueo-igneous 

 fusion was potentialized by the formation of uranium. In 1909 Mr. 

 Arrhenius expressed his opinion''^ that at higher temperatures the process 

 uf the evolution of heat by radium must take place in the inverse direc- 

 tion under consumption of this inconceivable amount of energy. Mr. 

 Joly regards the mode of origin of uranium and thorium as question- 

 able.*^" Mr. F. C. S. Schiller,''^ Mr. Leigh Fermor,^« and Mr. Arthur 

 Holmes'^ all consider it doubtful whether radioactive transformations 

 can take place at very high temperatures and pressures. 



Thus the constancy of A or the uniformity of the disintegration of 

 radioactive substances is contrary to analogy and by no means generally 

 conceded. These substances are more endothermic than any others 

 known, and if their synthesis is possible it must be under extreme condi- 

 tions of temperature and pressure, such as have not yet been realized in 

 laboratories.'^^ 



"8 Radioactive transformations, 1906, p. 194. 



8' Tlie life of the universe, vol. 2, 1909, p. 236. This is a translation. I do not know 

 the date of the original. 



•^ Science Progress, July, 1914, p. 51. 



«» Nature, vol. 91, 1913, p. 424. 



71 Ibid., p. 476. 



''^ Science Progress, July, 1914. 



'2 The sun is not known to contain uranium. Rowland found none. In 1908 Mr. P. G. 

 Nutting was good enough to compare for me Exner and Haschek's table of the spectrum 

 of uranium with a 30-foot reproduction of the solar spectrum, but found no evidence of 

 its existence. In 1911 Mr. B. Hasselberg made a very elaborate investigation of the 

 spectrum of uranium and failed to identify any of its lines in the solar spectrum. Kgl. 

 Soc. Vetensk. Akad. Handl., vol. 45, 1911, No. 45. Mr. F. VV. Dyson has discussed sis 

 lines in the chromosphere which might be due to radium but coincide with lines of 

 other elements. The identitlcation seems to me unsatisfactory. Astr. Nachr., vol. 192, 

 1912, No. 4589. Mr. H. Gieljeler has apparently identified radium, uranium, and radium 

 emanation in Nova Gemiuorum 2. His conclusion is indorsed by Mr. F. Kiistner. .\str. 

 Nachr., vol. 191, 1912, No. 4582. Like the earth, the nun can not owe all of the heat it 

 radiates to radioactivity, and Sir B. Rutherford states that "if the sun consisted entirely 

 of uranium in equilibrium with its products, the generation of heat due to active matter 

 would only be about one-fourth of the total heat lost by radiation."' He suggests that 

 some of it may be due to the atomic disintegration of ordinary elements at the high 

 solar temperature. Op. clt„ p. 656. 



