122 ATOMIC WEIGHT DETERMINATIONS. 



analyses of the oxalate he got 233.97 ; extreme difference, 

 0.6. {Kopp's Jahresbericht, 1874, 261; Bull. Soc. Chim., 

 (2,) ^i, 116.) 



TIN. 



Regnault and Kopp have each determined the specific 

 heat of tin. It agrees with an atomic weight of about 118. 

 Dumas, Cahours and others have determined the vapor 

 density of volatile tin compounds with a similar result. 

 {Gmelin-Kraut^ I. c. ; L. Meyer, I. c.) 



J. J. Berzelius; 117.64-7 (0 = 16); 735.294(0 = 

 100). 



Berzelius determined this value by oxidizingi^ure tin foil 

 by means of nitric acid and weighing the oxide. He found 

 100 tin = 127.2 stannic acid. [Poggend. Ann., 8, 1826, 184.) 



G.J.Mulder: 116.112 (0 = 16); 725.7 (0 = 100). 



Two experiments were made by oxidizing tin with nitric 

 acid, evaporating, drying, and heating to redness. They 

 gave each 100 tin =: 127.56 stannic aci^; whence the value. 

 All possible precautions are said to have been taken. The 

 metal was prepared by the reduction of pure oxide with 

 soot and a flux. {Erdmann's Journ. fur Prak. Chem., 48, 

 1849, 35 ; Seheikundige Onderzoek., 5. J)eel, 260.) 



C. L. Vlaanderen: about 118. (O = 16). 



Determined from experiments on the oxidation and re- 

 duction of tin and stannic acid in vessels of various ma- 

 terials. The experiments regarded as the most accurate 

 were made on the reduction of the acid in a current of 

 hydrogen in porcelain vessels. The acid had been heated 

 in platinum. These experiments gave 59.04 and 59.12. 

 Stannic acid heated in glass or porcelain was found to 

 retain nitric acid. {Kopp's Jahresbericht, 11, 1858, 138 ; 

 Midder, Seheikundige Verh. en Onderzoek., 2. Deel, 150.) 



J. Dumas: 118.08 (0 = 16). 



Two experiments were made on the oxidation of pure 

 tin by nitric acid. The stannic acid being heated white 



