CHLORINE. TURNER. 97 



The individual deviations of the analytical ratios from 

 the atomic ratio are, in the order of the record, 8 high, i low, 

 zero, 1 6 high. 



The middle two determinations are exactly coincident 

 with the calculated value. The first deviates to about one 

 tenth and the last to about two tenths of unit on the atomic 

 weight of mercury, raising the same. 



But the range or uncertainty of 17 (corresponding to 2^3 

 tenths) is greater than these deviations 



Accordingly, we are compelled to admit that the experi- 

 mental determinations fix the true atomic weight of mercury 

 at the value of its standard atomic weight, within the limit 

 of precision of the determinations made. 



But the work on the oxide fully establishes the atomic 

 weight of mercury as 200. We can, therefore, use these 

 distillations of the sulphide for the determination of the 

 atomic weight of sulphur, precisely as originally intended 

 by these eminent chemists. 



To do so, we need only calculate the change in the atomic 

 ratio corresponding to a rise of o.i in the standard atomic 

 weight of sulphur, namely 32. 



We find this change (for S) 37 low. Now, the mean 

 analytical excess was found above to be 6 high. This is a 

 trifle less than of the change; hence corresponds to a 

 departure of of one tenth or 0.017, direction low. 



Hence 8 = 31.983. 



We understand, of course, the true signification of this 

 expression. It means that the determinations of Erdmann 

 and Marchand give a possible departure of 0.02 low of the 

 true atomic weight of sulphur 32, but that this departure is 

 not established, rather simply marks the limit of precision. 



VI. THE ATOMIC WEIGHT OF CHLORINE. TURNER. 



The atomic weight of mercury having been established, 

 we can next use other mercury compounds for the determi- 

 nation of other metalloids. 



Since mercuric chloride can be produced in purest crystal 

 form, its distillation will furnish the atomic weight of 

 chlorine. 



