34 THE ATOMIC WEIGHTS. 



(9.) Ag : NaCl : : lOO : 54.2076, dr .0002 

 (10.) Ag : KCl : : lOO : 69.1032, d= .0002 

 (11.) Ag : KBr : : 100 : 110.3459, zfc .0019 

 (12.) Ag : KI : : 100 : 153.6994, zb .0178 

 (13.) Ag : CI : : loo : 32.8418, dz .0006 

 (14.) Ag : Br : : lOO : 74.0809, ± .0006 

 (15.) Ag : I : : 100 : 117.5345, ± .0009 

 (16.) Ag : AgjS : : 100 : 1 14.8581, ± .0006 

 (17.) KCl : AgCl : : 100 : 192.294, zb .0029 

 (18.) AgCl : AgBr : : 100 : 131.030, d= .023 

 (19.) AgCl : Agl : : 100 : 163.733, ± .0076 

 (20.) AgCl : Ag2S : : 100 : 86.4733, ;+: .0011 



Now, from ratios 1 to 7 inclusive, we can at once, by 

 applying the known atomic weight of oxygen, deduce the 

 molecular weights of seven haloid salts. Let us consider 

 the first calculation somewhat in detail. 



Potassium chlorate yields 39.154 per cent, of oxygen and 

 60.846 per cent, of residual chloride. For each of these 

 quantities the probable error is zb .00038. The atomic 

 weight of oxygen is 15.9633, ± .0035, so that the value for 

 three atoms becomes 47.8899, =t .0105. We have now the 

 following simple proportion: 39.154 : 60.846 : : 47.8899 : x, = 

 the molecular weight of potassium chloride, = 74.4217. 

 The probable error being known for the first, second, and 

 third term of this proportion, we can easily find that of the 

 fourth term by the formula given in our introduction. It 

 comes out d= .0164. By this method we obtain the follow- 

 ing series of values, which may conveniently be numbered 

 consecutively with the foregoing ratios : 



With the help of these molecular weights we are now 

 able to calculate eight independent values for the atomic 



weight of silver : 



