Molad based on a constant interval cycle that is widely but incorrectly regarded as an approximation of the time in Jerusalem of the mean lunar conjunction. Each "molad" moment occurs exactly 29 days 12 hours 44 minutes and 3+/ seconds (or, equivalently, 29 days 12 hours and 44+/ minutes) after the previous "molad" moment. This interval is numerically exactly the same as the length of the mean synodic month that was published by Ptolemy in the Almagest, who cited Hipparchus as its source. Although in the era of Hipparchus (2nd century BC) this interval was equal to the average time between
1920 Isle of Man TT 44 minutes and 6 seconds, an average speed of 51.36 mph. A mechanical retirement for Eric Williams allowed Cyril Williams also riding an AJS to build up an impressive lead of 20 minutes. However, Cyril Williams hit transmission problems at Creg-ny-Baa and free-wheeled and pushed it for the last five miles to win by a margin of 9 minutes and 50 seconds from J.A.Watson-Bourne, riding for Blackburne motorcycles in 4 hours, 37 minutes and 57 seconds, at an average race speed of 40.74 mph. The Lightweight class within Junior race was won by R.O Clarke riding a Levis and he