MEMOIR

OF THE

16631-

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

University
MICHIGAN

OF THE ORDNANCE SURVEY OF GREAT BRITAIN

AND IRELAND;

A WORK WITH WHICH GENERAL COLBY WAS CONNECTED FOR
FORTY-FIVE YEARS.

BY

LIEUTENANT-COLONEL JEAN

R.E., F.R.G.S. & M.R.I.A., ETC.

PORTLOCK,

SEELEY, JACKSON, & HALLIDAY, 54, FLEET STREET.

LONDON, MDCCCLXIX.

Captain Colby's remarks on Edinburgh Observatory.

Comparison of Base Lines. Instruments used on the

Continent. French and English Arcs: observations in

Shetland

Pendulum Experiments. Instantaneous Signals

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60-84

84-92

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