BORON AND FLUORINE. 41 



the present case. A second fusion, under similar conditions, 

 produced practically no change in weight. 



The carbon dioxide used in this experiment, generated from 

 pure dilute hydrochloric acid and white marble, was passed 

 through a large tower containing beads, coated with moist sodium 

 bicarbonate; through a second tower charged with moist silver 

 carbonate; through a wash-bottle containing a solution of sodium 

 bicarbonate and four similar bottles charged with glass beads 

 and concentrated sulphuric acid, after which, before reaching the 

 platinum combustion tube, it passed through a column of freshly 

 fused granulated potassium carbonate. 



TABULATION. 



The results obtained in the experiments outlined in the pre- 

 ceding pages may now be presented in table 1 . The constants used 

 in the calculations have been given (p. 24). If it is remembered 

 that the results are based on a variety of methods and are referred 

 to five different antecedent atomic weights (of Na, Cl, S, C, N) the 

 agreement between the individual determinations is satisfactory. 



The objection may be raised, not entirely without justifica- 

 tion, that each type of analysis should be represented by a larger 

 number of individual determinations. That this would have 

 been highly desirable is not to be denied. While it is true that 

 any single determination in table 1 leading to B = 10.900 might 

 be of small value, it will be admitted that, in the aggregate, these 

 eight results, by virtue of their agreement, can not be without 

 significance. Furthermore, it may not be irrelevant to add that 

 each analysis, although the solitary representative of its type, 

 was carried out with considerable care and involved no small 

 expenditure of tune and labor. These eight results, therefore, 

 obtained by a number of different methods involving a great 

 variety of conditions are of greater value than an equal number 

 of determinations based on a single reaction and involving only 

 one set of conditions. The latter plan is less likely to lay bare 

 any constant error in the method than is the former. 



In brief, the borax (there is reason to believe) was of the 

 utmost purity and the general plan of analysis reduced the prob- 

 ability of introducing constant errors to a minimum; hence the 

 final value derived for boron is probably quite near the truth. 



