ATOMIC WEIGHT OF SILICON. 



253 



with hydrogen peroxide to contain titanium. The quantity of ti- 

 tanium contained in fraction j was very small, however, and none 

 could be found in fraction k. Furthermore the amount found in 

 fractions d and e seemed far too small to account for the quantity of 

 less volatile residue, so that we are inclined to believe that a con- 

 siderable portion of the residue consisted of higher chlorides of silicon. 

 Sample IV. Still a fourth sample of tetrachloride was purified as 



SiCI 4 III 



21 20 19 



Figure 3. 



3 2 I 



described under the preparation of Sample II. Owing to the discovery 

 of the less volatile residue in Sample II, the fractions originally ob- 

 tained in this way were not analyzed. After the preparation of 

 Sample III, however, Mr. A. F. Scott, who was engaged in the Coolidge 

 Memorial Laboratory in the purification of boron trichloride by 

 fractional distillation, found that a Hempel column could be con- 

 veniently employed in a distillation at low temperatures, provided the 



