On the Atomic Weights of the Elements of Six Chemical Families. 
By Joun Mercer, #.R.S. 
128. Atomic Parallels. 128. 
124, 124. 
120 120. 
116 116. 
112 112. 
108 108. 
104 104. 
100 100. 
96 96. 
92 92. 
88. 88. 
84 84. 
80. 80. 
76. 76. 
a2: 72. 
68. 68. 
64. 64, 
60. 60. 
56. 56. 
52. 52, 
48, 48. 
44 44, 
40. 40. 
36. 36. 
32 32. 
28 28. 
24, 24, 
20 20. 
16. 16. 
12. 12, 
8. 
4, | 4. 
0. 0. 
7OMe* i N Clr a ae N CI§ 
* Oxygen and Magnesian Groups, showing the steps or difference between each member ; 
they are parallel, except that Mg is raised up 4°. + This pair, Nitrogen and Chlorine 
Groups, are the same, but Cl is raised up 5°. { Oxygen and Magnesian, full lengths, 
Mg 4° longer. § Nitrogen and Chlorine Groups, full lengths, Chlorine 5° longer. 
