PROCEEDINGS OF THE SECTIONS. 387 
eas ace of observation. This R.A. has been deduced from 
the ta’ tabulated positions at the upper and lower Greenwich transits, 
ing been taken o sere of the third an nd 
_ meridian. Column 6 gives the resulting longitudes. At the foot 
of this paper the tiean of the six culminations is shown to be 9h. 
‘9m. 56-86s. ; by telegraph from Sydney it is 58-99s,, and by the 
oo occultation of Antares, 60°49s. 
Paper is the computation of the longitude from an 
observation of the occultation of Antares. Both phases of this 
omenon, immersion and emersion, were observed, and the 
results differ from each other, as shown at the foot of page 2, by | 
1508 seconds. The instants ‘of disappearance and re-appearance 
Were recorded by pressing the connecting key of an electric chrono- 
gph in the usual manner ; and (as mentioned in my notes of the 
ieee 1 was distinctly sensible of the existence of a small 
al of time between the actual impression conveyed to the 
¥.- 
Gite alock error. On more delvberkts reflection I am ot opini 
: enon of emersion from the illuminated part of the moon’s 
although it was predicted by preliminary computation with 
se ble care, would not be noticed quite so instantaneously as 
He disappearance behind the dark part of the moon. If thisisin  — 
ecord with the facts of the case, the observations of the 
e 
the two phenomena of the occultation. ppeared t 
interesting gveres test of the precision to be obtained 
hone of the two kinds of observations, occultations or’ 
As stage reeulting values of the eeaiade only differ 
very little can be inferred in favour of either system . 
mple. I prefer the method of culminations, because i 
id being both prepared beforehand by noting the 
ch of the object to t read, a practical observer 
ntact with the thread in e ae 
of ‘ving an of wr re ad of ee 
