RADIOACTIVITY A FACTOR OF PLANT ENVIRONMENT 23 



vvas decidedly radioactive. Since then a large number of investi- 

 gations seem to establish the fact that various waters, widely dis- 

 tributed, are sources of radioactivity. This property was present in 

 15 out of 18 specimens of water examined later by Thomson,"" and 

 in water from Italian springs examined by Pocchettino and Sella. ''^ 

 The radioactivity is due to the presence in the water of some radio- 

 active substance, usually radium or its emanation. Allen and Blyths- 

 wood " obtained a radioactive emanation from the water of the hot 

 springs of Bath and Buxton, and, as might have been expected, 

 Dewar has found helium in the same waters. Himstedt "' demon- 

 strated the evolution of a radioactive emanation from water- and oil- 

 springs, and, later in the year, Adams ^ announced that a radioactive 

 gas is evolved from the water of deep wells. When the emanation 

 was removed by boiling, the water recovered the power of giving it 

 off. It is probable that there is a slight amount of radioactive ma- 

 terial dissolved in the water. The emanation was very similar to 

 that of radium, and probably identical with it. 



Artesian water from several wells, and the town water of Ely, Bir- 

 mingham, and Ipswich was found by Thomson ^^^ to give off a radioac- 

 tive gas when boiled. Bumstead and Wheeler^'' obtained a radioac- 

 tive gas from a well 1,500 feet deep near New Milford, Connecticut 

 (U. S. A.), and found that the city water of New Haven, Con- 

 necticut, was radioactive, whether taken directly from the reservoir 

 or from a faucet after passing through the city mains. The latter 

 writers ^^ established the identity of this emanation with that of radium. 



Vichy from Chomel was found to contain a radioactive emana- 

 tion,^^- ^^ as was also the water from the hot springs of Baden-Baden,^^ 

 from Aix-les-Bains,^^ and from Karlsbad.''" Radioactivity in the 

 water from many German springs was detected by Schenck,^"^ from 

 Buxton sprmgs by Blythswood and Allen,^* and Strutt."^ and from 

 Lavey-les-Bains by Sarazin, Guye, and Micheli.^"^ Strutt found 

 traces of the salts of radium in the mud deposited from the hot 

 springs of Bath and of Buxton, as well as radium emanation in 

 their waters, while Boltwood states that he found radium dissolved 

 in the waters of Bath and Baden-Baden under high pressure and 

 temperature. Mache^^ tested the water in 17 springs in different 

 parts of Germany, Schmidt and Kurz^''^ that of 117 springs, and 

 Dienert and Bouquet^* the waters of four springs in France. Radio- 

 activity was found associated with them all, and one hot spring con- 



