56 ATOMIC WEIGHT DETERMINATIONS. 



L. DE BOISBAUDRAN : 69.9 (0 = 16). 



This chemist " has prepared several chlorides, [^samples 

 of chloride ?] several bromides, and several anhydrous iodides 

 of gallium. He has determined the atomic weight of gal- 

 lium, and found it 69.9, (mean of two experiments.) " {Paris 

 Comptes Bend., 86, 1878, 756.) 



GOLD. 



Dulong and Petit and Regnault have determined the 

 specific heat of gold. It corresponds to an atomic weight of 

 about 200. {Gmelin-Kraut, I. c.) 



J. J. Berzelius : 1964 (0 = 16). 



Determined by the amount of mercury necessary to pre- 

 cipitate a known weight of gold from solution of chloride. 

 142.9 mercury were found equivalent to 93.55 gold. [If 

 Hg = 200, this gives Au = 196.397.1 (Poggend. AnnaL, 8, 

 1826, 178.) 



T. Thomson : 200 (0 = 16). 



This value is derived from a somewhat inaccurate experi- 

 ment on the reduction of auric chloride by ferrous sulphate. 

 {Edinh. Trans. Roy. Soc, 11, 1831, 26.) 



J. J. Berzelius : 196.73 (O = 16). 



Determined by five experiments on the relative amount, 

 of gold and of potassic chloride in the residue obtained by 

 heating the double chloride of the two metals in an atmos- 

 phere of hydrogen. [Calculated for KCl = 74.594, (Stas,) 

 these experiments give a maximum of 196.79, minimum of 

 196.63 and a mean of 196.727. The atomic weight derived 

 from the first experiment is misprinted in the Lehrbuch, as 

 is the mean in the Jahresbericht.] {Berzelius' Jahresbericht,. 

 25, 1846, 41 ; and Lehrbuch, 3, 1845, 1212.) 



A. Levol : 196.26 (O = 16). 



_A known weight of gold was converted into chloride, and 

 this salt decomposed in boiling solution by a current of 

 pure, washed sulphurous acid. "The sulphuric acid formed 



