a asd 
ED ES Sree eS SSE FS BL ae eee 
Sh. 15m : é : - > 31°84.08" 
Sir NEP atin aet AE RM 
ce “ce ig Es . x “ 55.64" 
sewer : - - oe 55007 
aoe - - - b «- 54.89" 
“2% * 54.95" 
M8 tones ; 
the mean of which is 31’ 54. 81". It abiiald a be remarked, that 
a more perfect judgment can be formed of the exactness of contact of 
sharply termmated points, such as were the cusps during the eclipse, than. 
can be the case with edges or limbs, as tremulous as that of the sun, 
where an alternate overlapping and recession leaves something to estima- 
tion. On this account, an attempt to obtain several measures of greatest 
distance of limbs was relinquished, both because greater inaccuracy was 
apprehended from the above source; and the measures of the cusps af- 
forded a more advantageous method of arriving at the same results. 
The maximum distance of the cusps, which may be obtained by inter- 
polation from those nearest in point of time, will give the observed diame- _ 
ter of the moon, free, it is believed, from the effects of irradiation. The 
minimum  distanice will be a greatly magnified measure of the error of 
the moon’s assumed latitude, the ratio of increase of the distance of the 
cusps at that pont to the corresponding difference of the latitude being 
about as 25.7 : 
“At 5h. 20m. the measures of distance were relinquished, as the sun’s 
proximity to the horizon would soon render = further. observation of 
this kind of little value. 
At the end of the eclipse, the sun was scarcely 3 degrees above the 
horizon, and the extreme undulation of his limb rendered much accuracy 
in the time of the observation impossible; and being, therefore, deemed 
phen se “it was not carefully noted, and may possibly be in 
“The sidereal. ack Shi which the abdve determinations of time were 
taken and reduced, had been compared frequently during the months of 
August and September with transits of stars, and the deviations of the 
transit instrument, the value of the divisions of its level, and the irregu- 
of the clock’s rate, carefully registered and applied. ~ From a 
comparison of these observations, it appears, that the error of or 
-* The moon's latitude, as assumed for the calculation of the eclipse in the 
Alm 
American , is by the observation of the nearest approach of cusps, 10.05’ 
too large; a determination which, if the calculated semidiameters of the sun and 
moon correct, is-in error by only one hineteenth part of the error of obser- 
vation. 
Vou. XXXV_No. 1 23 
* 
