Seventeen volumes recording 'Apparent errors of the Sidereal Standard Clock, and adopted clock rates and clock errors at 0h Sidereal'. Handwritten entries on printed Forms No. 8 and 8*. From 1931, Form No. 8 has the new title, 'Transit Circle. Observed correction to Sidereal Standard Clock, and adopted clock correction and rate at 0h Sidereal'. There are many gaps in the book sequence with only the following date ranges covered: 1806-1813, 1899-1911, 1919-1921, 1929-1940.