278 REDUCTION TO AIR. 



silver process, he reduces the range to one-tenth, but 

 increases the analytical excess threefold. In the silver bro- 

 mide process, he reduces the range from 23 to i, while the 

 analytical excess is lowered from 2 high to 12 low! 



I must confess that I have, for some time, thought this 

 work reasonably reliable, on account of its being done with 

 bromine, and not with chlorine. 



But upon carefully looking over the entire field, and 

 remembering the ordinary deviation of this wet way work 

 (which for the most concordant brings it 0.05 below) I am 

 compelled to drop this as fictitious, and to adopt the dry 

 way work of Axel Erdmann done under the old master's 

 eye, before modern fancy methods got a start. 



Indeed, the record of the determination of the atomic 

 weight of zinc, since 1850, is a disgraceful one; even Mar- 

 ignac, in 1883, went astray. 



It is to be hoped, that strictly rational, common sense 

 work of revision will be done for this metal at an early day. 



Zr = 90. ZIRCONIUM. 



ZrOz : Zr (Ch 8)2 122 : 2820.43 262. Chg. 21 high. 

 Berzelius, 1825, 6 Det., Mean 128 low. 



Weibull, 1881, 7 Det., 321 081 ; 241. " 112 low. 

 Bailey, 1889, 8 Det., 402 337; 65. " no low. 



ZrO2 : Zr (O4 Se)2 122 1376 = 0.32 447. Chg. 18 high. 

 Bailey, 1889, 5 Det., 640 470; 170. Mean in high. 



It is apparent that the results from the selenate would 

 raise the atomic weight as much as those from the sulphate 

 would lower it, namely, 0.5. We, therefore, leave it at 90. 



ADDENDA TO PART SECOND. 



I. REDUCTION TO AIR. 



The Reduction to Vacuum was condemned by Berzelius. 

 H-e considered it a mere "gnat" in comparison to the 

 unavoidable errors of all other operations involved. 



We have found this opinion of Berzelius to be exactly true. 



Besides, we have shown that this pretended " correction " 



