256 THE ATOMIC WEIGHTS. 



Closely agreeing with these figures are those of Marchand,* published 

 in the following year : 



Reduction Series. 



79.307 

 79.302 



Mean, 79.3045 



Oxidation Series. 

 79.321 

 79.35 2 



Mean, 79.3365 

 Mean of all, 79.3205, =b .0073 



The figures obtained by v. Borch f agree in mean tolerably well with 

 the foregoing. They are as follows : 



Reduction Series. 

 79.310 

 79.212 

 79.289 



79.313 

 79.225 



79-290 

 79.302 



Mean, 79- 2 77 

 Oxidation Series. 



79-359 

 79-339 



Mean, 79.349 

 Mean of all, 79.293, .0108 



Dumas J gives only a reduction series, based upon trioxide obtained 

 by the ignition of a pure ammonium tungstate. The reduction was 

 effected in a porcelain boat, platinum being objectionable on account of 

 the tendency of tungsten to alloy with it. Dumas publishes only 

 weighings, from which I have calculated the percentages : 



* Ann. Cheni. Pharni., 77, 261. 1851. 



t Journ. fur Prakt. Chem., 54, 254. 1851. 



JAnn. Chem. Pharni. , 113, 23. 1860. 



