Letter from Edward Sabine, Woolwich to Humphrey Lloyd Sabine discusses the observations at Melville Island. Discussion on the needle’s poles being reversed and error of the dip. Sabine would like Mr [Henry] Barrow to adjust the needle, and discusses the total force achieved. Sabine discusses Lloyd’s suggestions of deflection distances at Melville Island and asks if 14 inches will be too small a deflection. Discussion of the earth’s force and the coefficient for the fourth term. Sabine is grateful that Lloyd has considered the values of p and q in the perpendicular plane. Sabine discusses [Thomas] Grubb’s nine inch bars and the 3,67 magnets used to obtain the coefficient by [John Henry] Lefroy. The earth’s horizontal force at Melville Island. 22 April 1848