SILVER. . 107 



vacuum. If CI = 35.42 (Turner) the value follows. {Phil. 

 Trans., 1^3, 1833, 586.) 



F. Penny : 107.97 (0 = 16). 



Penny made six experiments on the conversion of silver 

 into nitrate. The silver was dissolved in cold nitric acid, 

 the solution evaporated, and the nitrate fused all in one 

 flask and with precautions against loss by spiriting. He 

 found 100 Ag = 157.441 nitrate ; extreme difi:erence, 0.028. 

 In five experiments the nitrate from the preceding determi- 

 nations was converted into chloride, by means of chlorhy- 

 dric acid, in the same flask, dried, fused, and weighed. 

 Penny could detect no decomposition in fusion. He found 

 100 Ag = 132.8372 chloride ; extreme difference, 0.01. In 

 two experiments silver was dissolved in nitric acid, precipi- 

 tated with chlorhydric acid, evaporated and fused, giving 

 132.830 and 132.838. The mean of all seven experiments 

 is 132.836. Penny takes 132.837. From the relations of 

 the chlorides, chlorates, and nitrates of potassium and 

 sodium, Penny had determined the difference between the 

 atomic weights of a chloride and a nitrate at 26.565. This 

 gives the molecular weight of argentic chloride at 143.424 

 and Ag = 107.97. The silver used, as well as the water 

 and the acids, were carefully tested for impurities and a 

 minute amount of solid residue in the twice distilled water 

 and in the acids was allowed for. The weighings were all 

 reduced to vacuum. [Phil Trans., W9, 1839, 27.) 



C. Marignac : 108 (O = 16) ; 675 (O = 100). 



Silver was dissolved in nitric acid and precipitated with 

 chlorhydric acid. One experiment, reduced to vacuum, 

 gave 100 silver =: 132.74 chloride, which Marignac consid- 

 ered confirmatory of Berzelius' value, 132.75. He therefore 

 adopted the latter number, 100 potassic chloride were 

 found to produce 192.26 argentic chloride, in two experi- 

 ments, the difference between which was 0.01. By analysis, 

 by means of heat, of potassic chlorate, Marignac had found 

 the molecular weight of the chloride 932.14, these relations 

 give the molecular weight of argentic chloride at 1792.13 

 and the atomic weight of silver at 1350. The potassic 

 chloride was prepared by heating the chlorate and cooling 

 the resulting chloride over sulphuric acid. {Liebig's Ami., 

 U, 1842, 23.) 



