356 
Independently of whether the amounts of the disturbances for all 
the threads be equal or not, they are now given by 4 ([Aly + [4] ) 
and not as in the previous supposition by the sums themselves, so 
that smaller, i.e. less improbable values may now be ascribed to 
them, but we may go farther and conclude that it is most probable, 
that an abnormality in the observation of the middle thread has been 
the main cause of the anomaly found. This we may perhaps imagine 
as having oceurred in the following manner. With eye- and ear- 
observations the observer forms a mental image of the position 
occupied by the star at the last preceding second. While his attention 
is now partly occupied by the bisection, it is possible that this image 
is derived from too late a moment and this would lead to too early 
an estimate of the time of transit. 
If the abnormal observation of the transit over the middle thread is the 
only source of disturbance, the expression + hel must give us 
the true values of the thread-intervals with the bisected stars also. 
This may first be tested with the stars in the same period VI, which 
were also observed in declination. 
Corrections to the preliminary thread-intervals VI according to the bisected stars. 
= KAM v. HENNEKELER | 
5 4 K+H 
= ae 
in 1866 —67 1867—68 | Mean 1866—67 1867—68 Mean 
I = Ye nad ita 4.16 4.24 493 +424 | +20 
II 30 <4 OT AF ld AAE 
Ill —56 96 —41 —44 ld 20 NEER 
V +28 +24 +26 04 8 6 [ooo 
VI +53 +38 +46 Dye 197 TA En 
VII 4-58 +40 +49 +42 +20 431), |SEEA0 
Here and there (with threads V and VI) it might look as if 
systematic differences exist between A and H/, but on comparing 
the results obtained with those derived from the non-bisected stars, 
this becomes very doubtful and the final results from the two series 
are in very good agreement with each other. 
