NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Leap seconds at Big Ben.
From: Bill Morris
Date: 2009 Jan 6, 00:30 -0800
From: Bill Morris
Date: 2009 Jan 6, 00:30 -0800
I think I knew the answer in advance, but was thrown by George's learned use of the word "centroid" which is, informally, what I call centre of mass. It would need an exceptionally weighty pendulum rod to bring the centre of mass above the top of the bob (let's not go into Captain Kater's pendulum). I added 50 grams to the top of my regulator's pendulum and it gained over a period of 12 hours. As Matthys' book points out, you can hang a small adjusting nut below the bob to raise or lower the centre of mass of the pendulum. Lowering the nut slows the clock, but you have to stop it to make the adjustment, whereas adding weights to a pan 2/3rds up the pendulum is easier. Bill --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---