526 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



MAGNESIUM. [Plate 2, Fig. 8.] 



Spark. Magnesium terminals. 

 Arc. Metallic magnesium on carbon electrodes. 

 Flame. Liveing and Dewar's measurements. 

 Wehnelt. Magnesium wire in hydrochloric acid. 



mann and Eberhard * have shown that in the spectrum of the arc be- 

 tween magnesium terminals under water, spark lines become strong, 

 X 4481 showing clearly. Ilartmann f has also shown that there is rea- 

 son to doubt that X 4481 corresponds to a higher temperature than 



* Astrophys. J., 17, 229 (1903). 



t Ibid., 17, 270 (1903). 



