190 S. Newcomb on the apparent inequalities 
fore his observation agrees well with that of Flamstead. The 
discordance between the observed and computed times, of this 
second occultation indicates a correction of about 4.39” to 
Hansen’s mean longitude at the epoch 1680, and the first may 
be considered as confirming this correction in direction, if not 
in amount. 
For the rea = May 38, 1715 we have the following com- 
puted and observed times. I have assumed Halley’s station to 
be in latitude 51° 31’ and Mebiate 25% west. Pound’s is taken 
in accordance with his own statement to be in latitude 51° 34’, 
and. lo: ag 8° west. These agree pretty well with Flam- 
stead’s statements that Wanstead is seven or eight miles N. by 
. from Greenwich,* and that Crane Court is half a minute of 
time West of Greenwich. 
Halley at London. 
Computed. | Observed. o-0 
m 8 | h m 8 8 
| First contact, 20 2 35 20 2 37 — 2 
| Beginning of Totality, 21 5 52 21 5 39 +13 
| Endo 21 9 ST 2 9 +1 
| End of Eclipse, 22 16 55 | 22 16 37 +18 
Pouna at Wanstead. 
Computed. Observed. C—O 
d . m 8 h s 8 
Eclipse first perceived, 20 Bas oe 20 + epee? + 8 
The total immersion, 21 $e 6 6 | +32 
emersion, 91 9 48 21 9 7 +22 
The justend of the eclipse,| 22 Bays 42 22 17 +32 
The only information I have respecting Flamstead’s observa- 
tions is contained in a letter of his found in Baily’s ‘ Life and 
Correspondence of Flamstead, p. 315, from which it cppeare that 
his times differ only a few seconds from Halley’s, instead of 
differing by the half minute required by the difference of meri- 
dians. An obvious slip of the pen, (/ater being written instead 
of earlier) makes it doubtful in which way the “few seconds” 
are to be counted. It can, however, be fairly inferred from his 
statement that his observations diverge from the tabular times 
as much or more than Pound’s. 
The discordance of the results of first and last contact may 
be attributed to this cause: that with their imperfect telescopes 
the observers did not begin to see the moon until several seconds 
after the actual ee of tee: eclipse, and lost sight of 
it a few seconds before t The 4 iscordance in the 
— of totality sadinde sar a “high srobability that sae | 
computed shadow path falls a few miles too far north. 
_ case the mean of the results for beginning and end of eee 
* Baily’s Flamstead, p. 316, p. 328. 
Ute ee re 
