[ 1 69 ] 
Obfcrvations are too inaccurate to determine any 
thing from them in this Affair. 
The EcJipfcs recorded by ‘Ptolemy in h : s Alma- 
geji, are mod of them fo loofely described, that, if 
they fhew us the Moon's mean Motion has been 
accelerated in the long Interval of Time fince they 
happened, they are wholly incapable ot fhewing us, 
how much that Acceleration has been. There are 
indeed two or three of them attended with (uch 
lucky Circumftances as not only plainly prove that 
there has been fuch an Acceleration, but alfo help 
us to guels at its Quantity. One ot thefe is the Ec- 
lipfe, laid by Hipparchus to have been obferved at 
Babylon, in the 366th Year of Nalonaflar , the Night 
between the 26th and 27th Days oi'Thoth, when a 
Email Part of the Moon’s Disk was eclipfed from the 
North Eaft, half an Hour before the End of the Night, 
and the Moon fet eclipfed. This was in the Year before 
Chrift 313, P)ecemh. 22. The Middle of this Ec- 
liple at Babylon ( fuppofing with Ptolemy the Me- 
ridian of that Place to be 50' in Time Eall of the 
Meridian of Alexandria ), by my Tables was P)ec. 
22. 4* 4 ' apparent Time; the Duration was i h 37', 
Ptolemy makes it i h 30' nearly j whence the Be- 
ginning fhould have been about 8 h 1 y' after Mid- 
night: According to Ptolemy , the Night at Baby- 
lon was at that Time i4 h 24' long, and therefore 
Sun rife at y b 12 ' after Midnight; and as the Moon 
.had then South Latitude, and was not quite come 
to the Sun’s Oppofition, her apparent Setting mull 
have been fomething fooner, i. e. more than an 
Hour before tha Beginning of the Eclipfe, accord- 
ing to the Tables } whereas the Moon was feen 
Y eclipfed 
