Unidad documental simple 168 - Letter from George Airy

2 pp.

GA has fallen behind in his official observatory work: 'I have to work well in order to bring it to a respectable state'. He has been going through the Horizontal Magnetic Forces from ten years photographic self-registration, and has found that 'twice in every lunar day, the needles N.pole is drawn vertically, and twice returns easterly. But the vertically is not true W. but, as far as our numbers can be trusted, about 20 [degrees] N. of W. It may be, among these small quantities that there is sufficient uncertainty to allow us to take the direction as truly W.'