264 
Period. An error of circumstance in this computation is cor- 
rected, in a comparison of it with that of the proper epoch, and 
the same result is established ; from which it appears that the 
order of the quadrienniums in the Egyptian cycle is precisely 
that which is assigned to those of the forementioned period. 
In proceeding to consider the usage of the Greeks, the 
author commences with disposing of a difficulty which arises 
in identifying the Olympic years with the Julian, in conse- 
quence of the one having commenced in July, and the other 
in January. After pointing out the manner in which this 
difficulty admits of correction, he proceeds to show how the 
Olympiads are thus reducible, in their order, to the Julian 
quadrienniums, to which they in effect conformed. Commenc- 
ing with the first year of the firstOlympiad, he thence concludes 
that what is true of it necessarily applies to all those Olympiads 
which succeeded. From the solar distribution of the year 
he thence turns to the lunar, and shows that the cycles in 
which the latter was equated were accommodated to the Olym- 
piads. Having exemplified this point, in the oldest cycle 
composed of two quadrienniums, he proceeds to the cycles of 
Cleostratus and Harpalus, which he shows had their first year 
coincident with the first year of the Olympiad. The same 
observation is shown to extend to Meton’s celebrated cycle, 
although its distribution into quadrienniums was disregarded 
by that astronomer with a view to its accommodation to the 
lunar revolutions. By Calippus, however, in his improve- 
ment upon Meton, the principle for which the author contends 
is fully recognised, his celebrated cycle of 76 years having 
been distributed into complete quadrienniums, and having its 
first year coincident with the first year of the Olympiad. 
From the reformation of the Roman Calendar by Cesar, a 
correspondent result is deduced ; the quadrienniums, as deter- 
mined by him, having been necessarily identical with those of 
the Julian Period. This point is established from an investi- 
gation of the first year, which commenced with the epoch of — 
