BOKON. 



173 



The second method adopted by Ramsay and Aston was to distill anhy- 

 drous borax with hydrochloric acid and methyl alcohol, both scrupu- 

 lously pure, thereby converting it into sodium chloride. The operation 

 was conducted in a glass flask, and in the first series of determinations 

 ordinary soft glass was used. This, however, was somewhat attacked, 

 so that the sodium chloride contained silica; hence oxygen in the ma- 

 terial of the flask had been replaced by chlorine, thereby increasing its 

 weight, and lowering the apparent atomic weight of boron. In a second 

 series flasks of hard combustion tubing were taken, and the error, though 

 not absolutely avoided, was reduced to a very small amount. Both series 

 are subjoined, together with the percentage of chloride formed ; but the 

 weights, given by the authors to seven decimal places, are only quoted 

 to the nearest tenth milligramme. They are reduced to vacuum stand- 

 ards. 



General mean of both, 57.933, zh .0074 



As a check upon the last series of results, the sodium chloride was 

 dissolved in water, and precipitated with silver nitrate. The silver 

 chloride was collected and weighed in a Gooch crucible, and its weight 

 gives a new ratio with anhydrous borax. The cross ratio between the 

 two chlorides, silver and sodium, has already been used in the discussion 

 upon sodium. The new ratio I give in terms of Na^B^O^ equivalent to 

 100 parts of AgCl. 



