234 
MR. J. J. MANLEY ON THE APPARENT 
Table III. 
Date. 
Differences in the 
weights of A and B. 
Maximum 
variations. 
Approximate degree 
of accuracy. 
1 
1 
mgr. 
mgr. 
July 14,1910. . 
0 • 265 
+ -033 
± 1 in 3^8 millions 
•338 
•005 
25-4 
„ IG „ . . 
•285 
•016 
„ 8-0 „ 
„ 18 „ . . 
•268 
•007 
„ 17-0 „ 
„ 19 „ . . 
•223 
•009 
„ 14-0 „ 
„ 20 „ . . 
•260 
•020 
.. 6-4 „ 
i „ 21 „ . . 
•360 
•038 
)) 3 ■ 3 ,, 
„ 22 „ . . 
•350 
■035 
3-6 „ 
,, 23 „ . . 
•280 
•042 
„ 3-0 „ 
i 
j Mean . . . 
•292 
± -023 
± 1 in 9^4 millions 
We may here mention that the maximum variations in the daily mean values, and 
also the degfrees of accuracy Indicated, were of the same order as those shown in 
Table III. 
The final result of all the experiments of Series I. may now be stated thus :— 
Before mixing the contents of A, the difference A —B = +0'292 mgr. 
After „ „ „ „ „ A-B = + '325 „ 
Apparent change in mass = + '033 ,, 
It is curious that the apparent change in mass here shown is almost exactly equal 
to the limit given by Landolt for accurate weighing. 
Series II .—After the observations and experiments which have been dealt with in 
the immediately preceding section had been completed, various circumstances arose 
which for a time prevented me from continuing this research; but in April, 1911, 
opportunity was again afiorded for resuming the work. 
Adopting, with slight modifications, the method of procedure followed in Series I., 
the weight of A in terms of B was again determined, the number of independent 
values obtained being 36. The final mean value deduced from tlie whole of the 
observations for the difierence in the weights of the two vessels and their contents 
AV8jS a TY r\ r\C\r* 
A —B = +0 026 mgr. 
In this set, the maximum and minimum values found for the difierence A —B were 
respectively +‘042 mgr. and +'005 mgr. Of the 36 determinations, 20 exhibited an 
average variation from the mean value = +'007 mgr. ; for the remaining 16 determina¬ 
tions the average variation was = — '008 mgr. ; for any one determination the 
average deviation from the final mean value may therefore be taken as approximately 
= ±’008 mgr. 
