446 
The corrections are: 
9 
dt = 2 (<*. dx'. + /3. dy'. ) 
. I 1 1 1 1 7 
1=1 
(11 = 2 (y. dx'. T 8. dy'i ) 
(10) 
i=l 
The weight coefficients are: 
Q tt = 3.168 
Q a - 3.090 
(H) 
The sum [vV] and the standard error of unit weight are: 
[dx'] 2 + [dy'] 2 N 91 2 + N 92 2 
[vV] - [dx' 2 ] [dy' 2 ] 
(N os [dx']) 2 (N„4 §-[<ly']) : 
4.72 
3.44 
s' -1 |vV1 
S ° V IQ - 
8.16 
0.316 dt 2 — 0.324 dl 2 
(12) 
The definitions are: 
N 91 =0.6 (dx'! — dx' 3 + dx' 4 — dx' 6 + dx' 7 — dx' 9 ) + dy'! 
+ dy' 2 + dy'o — dy' 7 — dv' 8 — dy' 9 
N 92 — + dx'! dx' 2 + dx' 3 — dx' 7 — dx' 8 — dx' 9 + 
+ 0.6 (— dy'i + dy' 3 — dy' 4 + dy'o — dy' 7 + dy' 0 ) 
N 93 = 0.6 (dx' 4 + dx' 3 + dx' 4 + dx'g + dx' 7 + dx' 9 ) + 
dy'i — dy' 3 — dy' 7 + dy' 9 
N 94 = 0.6 (dx' 4 — dx' s — dx' 7 + dx' 9 ) + dy' 4 + dv' 2 + 
+ dy' 3 + dy' 7 + dy' 8 + dy' 9 
The coefficients for computing the x-obliquity and the width-error 
are given in the table No. 2. 
3.1 Practical experiments. 
There is obviously a very important problem, namely how great the 
x-obliquity and the width-error are allowed to be, before they must be