(S*S) 
A Method 
For finding the Number of the Julian Period for any year af 
fignd, the Number of the Cycle of the Sun, the Cycle of 
the Moon, Md ofthe Indi&ions, for the fame year, being 
given: together with the Demonftration of that Method. 
I N thefe Transactions, N\ iS. f.324, Isa Theorems fa finding 
the Year of the Julian Period , by a new and very eafie Me- 
thod, which was taken out of the Journal des Scavans 
as it had been propofed and communicated by the Learned Jefuite 
Be Bill 
Multiply the 
Lunar | by ^4200.^ Then divide 
■6916; 
^ Indiffiion 
The fumof the Produ&s by 7980 (the Julian Period) the Re- 
mainder of theDivifion, without having regard to the Qgotienr* 
fliall be the Year inquired after. 
Some Learned Mathematicians of Paris , to whom the faid 
P. de Billy did propofe this Probleme, have found the Demon- 
firation thereof, as the fame Journal intimates. 
There being no further Elucidation of the faid Theoremefmce 
publifht , Mr. John Collins, now a Member of the B. Society, 
communicated what follows, viz. 
That the Julian Period is a Bafis, whereon to found Chrono- 
logy not lyable to Controverfie, as the Age of the World is : And 
*tis the Number abovefaid , to wit 7^80 , which is the Pro- 
dud of iRthef Solar Cycle, 
ipthe> Lunar, 
1 5 the > Indiction, 
Concerning this Julian Period , the late Arch-bifhop o&Armach, 
Mft)cr s in the Preface to his learned hnnak , advertifeth, that 
Robert Lotharing, Biihop of Hereford, firftobferved the Conve- 
niencies thereof: 500 years after whom it was fitted/or Chrono- 
logical ufes by Jofeph Scaliger , and is now embraced by the 
Learned, as fuch a limit to Chronology 0 that within the Jpace of 
7980. years, the Number of tfaSun s Cycle , the Prime , and the: 
Year ofthe Roman Indiction Q which related to their ancient Laws 
and 
