AV 



194 RADIUM. 



the volume of gas evolved. This experiment may he performed with 

 methyl chloride (at —21° C). Professor Dewar and M. Curie have 

 conducted such experiments with liquid oxygen (at —ISO C.) and li<|uid 

 hydrogen (at —292 -' C). This last licpiid serves the purpose pj) rticularl}^ 

 well. A tuhe A (tig. 7) (closed at the lower end and inclosed by a 

 vacuum heat insulator of Dewar) contains a little li([uid hydrogen H. 

 A tube tt' serves to conve}'^ the gas to be collected o\'er water in the 

 inverted graduate E. The tube A and its insulator arc plunged into 

 a bath of liquid hydrogen H'. In these conditions no evolution of gas 

 is produced in A. But when a tube a containing 0.7 gram of radium 

 bromide is placed in the hydrogen in the tube A, the gas is continually 

 evolved at the rate of 78 cubic centimeters pei' minute. 



VT. 



The radiations of radium provoke many chemical reactions. Ihey 

 ^ act upon the substances employed in photography in the 



"I same manner as light. Glass is tinged violet or brown, 



j l i . ; J and salts of the alkalies are cohered yellow, violet, blue, 



'\ n '^^'^^^ or green. Under the action of the rays paratKn, paper, 

 and celluloid turn yellow, paper becoiucs brittle, and 

 ordinary phosphorus is transformed into the red va- 

 riety. In general, bodies phosphorescent under the 

 ^X^yj action of radium rays undergo a transfoi'mation, and at 



„ „ ... ,. the same time their phosphorescence tends to disappear. 



Fti;. 7. — Boiling Ikj- ^ ^ ^ ^ _ 



nid hydrogen by Finally it has been shown that the presence of radium 

 '''^'^'"™" salts promotes the formation of ozone in the air. 



VII. 



The radiations of radium produce A.irious ])hysiological eti'ects. 



A salt of radium contained in an opaijue tube of metal or pasteboard 

 produces a sensation of light upon the eye. This may be shown by 

 placing the tube of radium before the closed eye or against the temple. 

 The eye then becomes phosphorescently luminous under the influence 

 of the rays and light is perceived within the eye itself." 



Radium acts upon the skin so that if one holds a tube of radium in 

 the hand for some minutes, though no particular sensation is felt at 

 the time, after fifteen or twenty days an inflammation is produced 

 and then the skin sloughs off at the place where the radium was 

 applied. If the action of radium is continued long enough a sore is 

 formed which may take months to heal. The action of radium rays 

 on the skin is analogous to that of the Rontgen rays. It has been 

 attempted to utilize it in the treatment of lupus and cancer.^ 



«Giesel, NaUirforscherversammlnnir, Miinclien, 1899. Himsteilt and Nau;e], Ann. 

 der Physik, Vol. IV, 1901. 



f'Walkoff, Phot. Rundschau, Oct. 1900. (lici^cl, Berichte d. Deutsche Chein. 

 GeselL, Vol. XXIII. Becquerel and Curie, C:. R., Vol. CXXXII, p. 1289. 



