ATOMIC WEIGHT OF SILICON. 



249 



tions, and was purified and dried by passing through two towers filled 

 with beads wet with water, then three similar towers containing con- 

 centrated sulfuric acid, and finally through a tube containing resub- 

 limed phosphorus pentoxide. The silicon, in the form of a coarse 

 powder, was contained in a hard glass tube which could be electrically 

 heated and which was inclined toward the large glass bulb cooled with 

 ice which served as condenser. Connection with both the chlorine 

 purifier and the condenser was made with dry ground joints, and all 

 other connections in the apparatus were made with glass seals, except 



Figure 1. 



that between the chlorine tank and the purifying apparatus, which 

 consisted of a very short rubber connector. Since the reaction is 

 highly exothermic, comparatively little heat was required. 



The material obtained from the General Electric Company was a 

 clear colorless liquid. The initial product of our own process was a 

 dark colored liquid containing both dissolved and suspended ferric 

 chloride, titanium chloride, chlorine, hydrochloric acid and probably 

 some or all of the other impurities mentioned above. 



Sample I was a mixture of General Electric Company product with 

 some of our own. Sample II consisted entirely of General Electric 

 Company material. Samples III and IV were two separate prepa- 

 rations of our own. 



The fractional distillation of the first three samples was effected in 

 apparatus of the general type shown in Figure 1. This apparatus 



