Baskerville and Lockhavt — Radium Emanations. 95 



Art. XII. — The Action of Radium Emanations on Min- 

 erals and Gems;* by Charles Baskerville and L. B. 

 Lockhart. 



Kuxz and Baskervillef have made some interesting observa- 

 tions concerning the action on minerals and gems of radium 

 compounds of the highest activity enclosed within glass, as 

 well as of mixtures of weaker preparations with a limited num- 

 ber of minerals, especially diamonds, willemite and kunzite.J 

 Rutherford used willemite most satisfactorily§ for demonstra- 

 ting to a large audience the condensation of the emanations by 

 means of liquid air. It was thought advisable to subject other 

 minerals, found by Kunz and Baskerville to be fluorescent or 

 phosphorescent, or both fluorescent and phosphorescent under 

 the influence of ultra-violet light, to similar treatment. We 

 wish to express our obligations to Dr. Geo. F. Kunz, who gen- 

 erously provided us with most of the minerals, all of which 

 were authenticated. 



The method of testing was as follows: About - 25 gram of 

 radium chloride, 7000 uranies] strong, was placed in a hard 

 glass tube 2 mm in diameter, sealed at one end. This was bound 

 to a glass tube, provided with a stop-cock, which was bent so 

 as to reach through one of the two holes in a rubber stopper to 

 the bottom of a test-tube 2 cm wide and 15 cm deep. Through 

 the other hole was passed a bent tube so that it just projected 

 below the rubber. This tube was provided with a glass stop- 

 cock and connected with an ordinary vacuum pump. The 

 material upon which the action of the emanation was to be 

 determined was placed in the wide test-tube. The tube was 

 then dipped into liquid air contained in a suitable unsilvered 

 Dewar bulb. 



On opening the cock next to the pump while it was in 

 operation a good vacuum was produced in the container tube. 

 When this cock was closed, the radium chloride was heated to 

 low redness. The cock between this and the test-tube was 

 opened. The emanations were swept in and condensed. In 

 every case the tube and contents were allowed to remain in the 

 liquid air until they were assumed to have obtained an uniform 

 temperature. All experiments were carried out in the dark 

 and observations were made only after the eyes had become 

 accustomed to the conditions. 



* Bead before the Washington Section of the American Chemical Society, 

 April 6th, 1904. f Science. \ Patent applied for. 



| Address before the American Association for the Advancement of Sci- 

 ence, St. Louis, Mo., Meeting. Dec, 1903. 



|| By an '-uranie" is meant the radio-activity of metallic uranium, which 

 is taken as the standard. 



