Airy 
Phil. Trams. MD CC CLXK. RateHM. 
Curves representing the Diurnal Change in Mougnitade anti Direction of the Maxjnetin Forces in 
Die Horizontal Plane anting on the Forth Fnti of the Ffeetile , at the. Hoy al Observatory, Oreenvrich, for 
the Years 1858 to 1868, from the Means of the Observations at corresponding Hours through each Year. 
The minerals on the Curves represent 
Honrs of Greenwich Mean Solar Time. 
"WiH.'WesieylrttL 
