MEMOIR OF THE 1663J- LIFE OF MAJOR-GENERAL COLBY. R.E., LL.D., F.R.S.L. & E., F.R.A.S., F.G.S., M.R.I.A., ETC. TOGETHER WITH A SKETCH OF THE ORIGIN AND PROGRESS GENERAL LIBR University OF THE ORDNANCE SURVEY OF GREAT BRITAIN AND IRELAND; A WORK WITH WHICH GENERAL COLBY WAS CONNECTED FOR ли BY LIEUTENANT-COLONEL J. E/PORTLOCK, R.E., F.R.G.S. & M.B.I.A., ETC. SEELEY, JACKSON, & HALLIDAY, 54, FLEET STREET. Difficulty of determining Latitudes. Soldiers employed on the Survey. Comparison of Standards and Meridional Arcs... 40-59 ... Captain Colby's remarks on Edinburgh Observatory. Comparison of Base Lines. Instruments used on the Continent. French and English Arcs: observations in Pendulum Experiments. Instantaneous Signals ... ... ... ... 60-84 |