256 NUMERICAL RELATIONS BETWEEN THE ATOMIC 'WEIGHTS. 



EXPLANATION OF THE TABLE, 



The formula at the head of each series is a general expression for the atomic weights 

 of that series. The names of the series are derived from the " Common Differences," 

 which are the numbers multiplied by n in the general fonnulte. In the columns 

 headed " Theoretical " are given the atomic weights calculated from these formulce and 

 the values of n given in the last columns at the right of each division of the table. 

 In the columns headed " Observed " will be found the observed values of the same 

 atomic weights. These have been taken from the table of atomic weights given in the 

 last volume of Liebig and Kopp's Jahresbericht (for 1852), with the exception of those 

 against which are placed the initials of the observers. The last were taken from 

 Weber's Atomgetcichts Tahellen. In some cases the atomic weight is taken at twice its 

 received values, but it is then underlined. The compounds in any one column at the 

 right of the names of the elements are homologous. In the same way, those in any 

 one at the left are isomorphous. The numbers at the head of these last columns 

 indicate crystalline systems as follows: 1. Monometric; 2. Dimetric ; 3. Trimetric; 

 4. Monoclinic ; 5. Triclinic ; 6. Ehombic. The data from which the table was com- 

 piled were drawn from numerous sources, but especially from the following works : 

 Gmelin's Handbook of Chemistry, Graham's Elements of Chemistry, Phillips's Miner- 

 alogy by Brooke and Miller, and Gustav Eose's Krystallo-chetniscke Mineralsystem. 

 References have been given only in a few cases, to avoid crowding the tables. For 

 authorities in other cases, the author would refer to the above-mentioned works. 



