24 RADIOACTIVITY A FACTOR OF PLANT ENVIRONMENT 



tained both radium and thorium. Schmidt and Kurz conclude that 

 all spring waters contain an emanation, usually that of radium, but 

 in some cases that of thorium. Skinner"*' states that Mr. H. Cottam 

 did not succeed in finding *' any marked quantity of active gas " 

 from samples of clays from various districts near London (Eng.), 

 but found a radioactive gas in water of a deep well which goes be- 

 low the clay to the green sand. 



The radioactivity of deep well waters, mineral water, and water 

 from a cistern in Columbia, Missouri, is attributed by Schlundt and 

 Moore ^"'^ to the presence of radium emanation in the water. Waters 

 from 123 springs in southwest German}^, Austria, and Italy, and 

 from an old Roman spring, the " Queen Isabella," in the island of 

 Ischia, bay of Naples, were, in nearly every instance, found to be 

 decidedly radioactive by Engler and Sieveking.^^ The sediment 

 deposited by the water of the springs was often active, and self- 

 luminous radium preparations were prepared from one of the sedi- 

 ments. The radium emanation was detected by Sury^^^ in spring 

 water of Baden, Switzerland, Leuker Bad, Garasp, and Disentis. 

 The water from St. Placidus spring contains a radioactive salt which 

 produces the emanation. In 1908 Joly'" measured the activity of a 

 sample of ocean water from Valencia, County Kerry, and suggested 

 that oceanic radioactivity is due to radioactive materials brought to 

 the ocean by streams. Much uranium, he says, is carried in solu- 

 tion or in fine suspension, and deposited in the ooze. 



Radioactivity in Mud and Rocks : The following investigators 

 have reported radioactivity in deposits from various springs, and in 

 mud from other sources: Elster and GeiteP^' ^^ in the " fango," or 

 mud from the hot springs of Battaglia, North Italy, and also'^^- ^* in de- 

 posits from Baden-Baden, Nauheim and Wiesen baths. The activity 

 of fango they attribute to the presence of radium, and state that 1,180 

 tons of this mud would yield i gr. of radium chloride. Borgmann^'' 

 in mud from Odessa, and from Arensburg, on the island of Oesel ; 

 Blanc ^^ in sediment from 9 springs in the region of the Alps; Cas- 

 torina^^ in lava from Mt. Aetna. Giesel''^ found radium and radioactive 

 rare earths in fango mud, and in earth from the fields of Capri ; Vin- 

 centini and Da Zara,^^^' ^^^ radium emanation in the water and sedi- 

 ments from a number of hot springs in northern Italy. Sediments 

 from 20 springs from different parts of Germany were found radio- 

 active by Schmidt and Kurz,^^* and in 1906 Mogri^^ detected the same 



