Determination of the day of the week determined for the latter part of the analysis. By using a given day August 13, 2009 which was a Thursday as a reference, with "Base" and "n" being the number of days and weeks it has been since 01/01/0001 to the given day, respectively and "k" the day into the given week which must be less than 7, "Base" is expressed as Knowing that a year divisible by 4 or 400 is a leap year while a year divisible by 100 and not 400 is not a leap year, a software program can be written to find the number of
Ogof Dydd Byraf Ogof Dydd Byraf Ogof Dydd Byraf is a cave which extends under Esclusham Mountain in north-east Wales from its entrance in the south face of the Minera Limeworks quarry. It was originally discovered and explored in 1964 by the Wrexham Caving Club, before they were merged into the North Wales Caving Club. After a short series of mined passages there is a narrow 10 metre pitch into the main levels consisting of a series of well-decorated galleries. Some of the passages come very close to the cave Ogof Llyn Du whose access is blocked by a deep and difficult sump.