OF THE ATOMIC WEIGHT OF ALUMINUM. 
1031 
present and that assumed in such calculation, instead of leaving the whole resulting 
from using Stas’ numbers uncorrected, my silver having had the oxygen removed, 
while his had not been so treated. The atomic weights adopted then for these two 
elements are— 
Ag= 107-649 Br= 79754 
Calculated results .—The following are the values obtained for the atomic weight of 
aluminum from the different series of experiments, with the probable (mean) value 
resulting from each set, the difference from this mean of each individual experiment, 
and the probable error of the mean itself calculated in the usual way by the method 
of least squares : 
First series. 
A. 
Experiment. 
Diff. from mean. 
I. 
Al= 27-029 
-•oil 
II. 
„ 27-043 
+ •003 
III. 
„ 27-055 
+ •015 
IV. 
„ 27-068 
+ •028 
Y. 
„ 27-005 
-•035 
Mean 
„ 27-040 
Probable 
error of mean result +-0073 
A. 
Second 
Experiment. 
Diff. from mean. 
I. 
Al=27-035 
+ •001 
II.' 
„ 27-021 
— •013 
III. 
„ 27-046 
+ •012 
Mean 
„ 27-034 
Probable 
error of mean result +"0049 
Experiment 
( 
IX. 
Al = 26 
X. 
„ 27 
XI. 
„ 27 
Experiment. 
B. 
Diff. from mean. 
VI. 
Al=27 , 114 
+ •018 
VII. 
„ 27-095 
— •001 
VIII. 
„ 27T07 
+ •011 
IX. 
„ 27-067 
— •029 
X. 
„ 27-096 
•ooo 
Mean 
„ 27-096 
Probable 
error of mean result +"0054 
series. 
Experiment. 
B. 
Diff. from mean. 
IY. 
Al=27'028 
+ •005 
Y. 
„ 26-993 
— •030 
YI. 
„ 27-036 
+ •013 
VII. 
„ 27-028 
+ •005 
VIII. 
„ 27-030 
+ •007 
Mean 
„ 27-023 
Probable 
error of mean result + ’0052 
I)iff. from mean. 
•999 —-019 
•034 +'016 
021 +-003 
Mean ,, 27'Of 8 
Probable error of mean result +‘0069. 
