8 
GIOVANNA TOGLIATTI 
Table 2 
Mean Residual parallaxes (Mj) 
them the columns of the mean M x have been selected and they are shown in table 2. 
Then we have computed a further summary of all the values obtained for parallaxes 
and deviations by averaging the 10 values of the means M x for each strip ; the 
resulting figures are indicated in the last column of table 2 as M 2 . The values M 2 
have been collected in table 3 in order to make more evident the final results. Let 
us now make some considerations about them. 
Table 3 
GENERAL MEANS (in cm) 
Parallaxes 
8 X 
S Y 
8 Z 
6-1 
3 
5 
26 
47 
6-3 
8 
3 
18 
32 
18-1 
9 
4 
24 
44 
18-6 
10 
3 
15 
27 
The value of 3 cm we obtain for mean residual parallax in computation 6-1 
is nearly meaningless, since there is only one redundant equation in respect to the 
minimum number of 5, which would have brought null residual parallaxes indepen