Atomic Weight of Radium. 283 
15°4, 112, 826°4, 2213°2, and 7794-2 respectively, we obtain 
the formula 
atomic weight =log-!(0°47185 + 0°4773327 log wz), 
which gives for 
GROW aac (ss = 10°83 instead of 11 
Aluminium ... 27°69 e pay alk 
Gallidme 0.0... (aa i 70 
SCH ae 113-54 eg pe a [2h 
Phadiramy 32... 206045"... 204°1 
In the group Be, Zn, Cd, and He, taking the formula 
already given, we obtain for 
ery lum 7 ...... 88 instead of 9-1 
TANG: «6 re 604 a 654 
Cadmium......... 1124 fe a4 
Meneuny) ..)...... 222°5 Ag 200 
If we include radium under this formula with the difference 
4858:5, we obtain for the atomic weight 227°75. 
If we take the differences between the first two lines of the 
triplet-series in Mg, Ca, and Sr, viz. 40-7, 102°6, and 394-0, 
we obtain the formula 
atomic weight =log—!(0°45705 + 0'57223 log 2), 
which gives for 
Beryllium ...... 8°43 instead of 9-1 
Magnesium ... 23°89 4s 24°36 
Caleta... 2 40°58 A 40-1 
Strontium ...... 87°56 es 87°6 
The lines of Mg, Ca, and Sr now employed by Runge and 
Precht for calculating the atomic weight of radium are pairs 
of lines not belonging to the triplet-series. 
If we calculate a formula for the group containing copper 
and silver from the differences 248 and 920°8, we obtain 
atomic weight =log—!(6°83405 + 0°4378 log a). 
Taking the differences for Li, Na, Au, and Hg as 0, 17:2, 
3817, and 4633:2 respectively, we obtain the following atomic 
weights :— | 
Lithiams 42),). 6°82 instead of 7:03 
Soditmi......' 0: 21°52 be 3°05 
Copper. 84 63°6 Re 63° 
Dilver 080) * 107°93 x! 107°93 
Gokiee a SLO } 197-2 
Mercia, . 206'2 - 200 
