# Dictionary of National Biography, 1885-1900/Colby, Thomas Frederick

​COLBY, THOMAS FREDERICK, LL.D. (1784–1852), major-general, and director of the ordnance survey, belonged to a family of property in South Wales. He was the eldest child of Major Thomas Colby, royal marines (d. 1813), by his wife, Cornelia Hadden, sister of Major-general Hadden, royal artillery, sometime surveyor-general of the ordnance. He was born at St. Margaret's-next-Rochester on 1 Sept. 1784. His boyhood was passed in charge of his father's sisters at the family place, Rhosygilwen, near Newcastle Emlyn, South Wales, and at school at Northfleet, Kent, under the Rev. W. Crakelt, M.A., translator of Manduit's 'Spherical Trigonometry,' and adapter of various educational works. Thence he was transferred to the Royal Military Academy, Woolwich, and passed out for the royal engineers before attaining the age of seventeen. His commissions were as follows: second lieutenant royal engineers, 2 July 1801; first lieutenant, 6 Aug. 1802; captain (second), 1 July 1807; brevet major, 19 July 1821; regimental lieutenant-colonel, 29 July 1825; regimental colonel, 10 Jan. 1837; major-general, 9 Nov. 1846.
At the beginning of the present century the system of triangulation carried on in 1784 and 1787 by General Roy, under the auspices of the Royal Society, for the geodetic connection of Greenwich and Paris observatories, and resumed after Roy's death by the board of ordnance for a survey of South Britain, had extended over the southern counties into Devonshire and Cornwall. It was becoming the custom to attach young engineer officers to the survey for a time to learn topographical drawing under the ordnance draughtsmen. Either in this way or through the good offices of his uncle, Colonel Hadden, royal artillery, at that time secretary to the master-general, young Colby attracted the notice of Major Mudge, director of the ordnance survey, who asked that he should be attached in some permanent manner to that duty. The request was granted the same day, 12 Jan. 1802, on which date commenced the future General Colby's connection with the ordnance survey, which ultimately extended over a period of forty-five years. Up to that date the British ordnance survey had helped little towards the solution of the great astronomical problem of the earth's figure, but the tardy completion of a new zenith-sector, a noble instrument, ordered by the board of ordnance from the famous maker, Ramsden, years before, induced Major Mudge to apply the projected extension northwards of the ordnance triangulation to the measurement of an arc of the meridian between Dunnose, Isle of Wight, and a station near the mouth of the Tees, and the young lieutenant's first services appear to have been in connection with the sector observations made at Dunnose in the summer of 1802. In December 1803, when on duty at Liskeard, Colby met with a fearful accident through the bursting of a pistol loaded with small shot with which he was practising, his left hand being so shattered as to necessitate amputation at the wrist, and part of the barrel or charge being permanently lodged in the skull, so as to seriously affect his health through life, and eventually to cause his death. Youth, a vigorous constitution, and the kind care of friends carried him through this trial, and he recovered sufficiently to resume his survey duties, and in the face of lifelong difficulties, which would have daunted any ordinary man, he persevered in his profession. In 1804 he was observing the pole star for azimuths at Beaumaris; in 1806 he was assisting Colonel Mudge in the measurement of a base-line on Rhuddlan Marsh, near St. Asaph, and in astronomical observations in Delamere Forest, Cheshire, and on the Yorkshire moors; later, again, he was selecting trigonometrical stations on the mountains in South Wales. The intervals were spent in the ordnance map office, in the Tower of London, in computing results and superintending the construction and engraving of the ordnance ​maps, the publication of which was, however, suspended during the continuance of the war. In 1811 appeared the third volume of 'Trigonometrical Survey of England—An Account of the Trigonometrical Survey extending over the period 1800-1809. By Lieut.-colonel Mudge, Royal Artillery, and Capt. Colby, Royal Engineers,' the first two volumes of the work containing accounts of the previous surveys reprinted from 'Philosophical Transactions.' Meanwhile, in July 1809, Colonel Mudge had been appointed lieutenant governor of the Royal Military Academy, Woolwich, and Colby became the chief executive officer of the survey.
In 1813 it was decided to extend the measurement of the meridional line between Dunnose and the mouth of the Tees into Scotland, in combination with a mineralogical survey entrusted to Dr. McCulloch. In that and the following year Colby and his chief assistant, James Gardner, were busily engaged in selecting stations in the south-west of Scotland, and observing from them with the great theodolite belonging to the survey. The Waterloo year brought extra work at the Tower map office, and the Scottish observations, completing the connection between Cumberland, Isle of Man, part of the north coast of Ireland and the south-west of Scotland as far as Ayr, were carried out by Gardner, but in 1816-17 Colby was again in the field carrying the triangulation round the eastern coast towards the Orkneys and Shetland, and in the latter year, in conjunction with Gardner, measured the base-line of Belhelvie Links, near Aberdeen, the only base-line in Scotland. He was also engaged in observations in Shetland with M. Biot, who had been deputed by the French Institute to make pendulum and other observations there in connection with the prolongation of the arc of the meridian, the measurement of which had been carried from the Balearic Isles, through France, to Dunkirk. Unfortunately, owing to petty causes, which have been discussed at some length by Colby's biographer (Portlock, Mem. of Colby, pp. 73-84), there was an utter want of harmony between the two observers. Colby, however, afterwards accompanied General Mudge to Dunkirk, and took part in the observations made, in conjunction with MM. Biot and Arago, with Ramsden's sector, which was set up in Dunkirk arsenal. In 1819 Colby was again engaged in Scotland, the season's work commencing, early in May, on Corrie Habbie, Banff, and ending in Caithness at the end of September. One of his subalterns, the late Lieutenant-colonel Dawson, has left some reminiscences of Colby's extraordinary activity and of the arduous character of the survey duties in the highlands (ib. pp. 131-53). During the summer, when exploring the eastern side of Inverness, Ross, and Caithness, and the mainland of Orkney, with a party of artillerymen, and afterwards the western sides of Ross and Skye with a fresh party, Colby traversed on foot 1,099 miles in forty-five consecutive days, including Sundays and other rest days, besides scaling many heights, as in the Coolin range in Skye, the ascent of which involved some mountaineering skill. While thus employed in Scotland Colby was made LL.D. of the university of Aberdeen and F.R.S. Edinburgh.
Early in 1820 General Mudge died, and the Duke of Wellington, then master-general of the ordnance, after consulting Sir Joseph Banks and other scientific authorities, appointed Colby to succeed him at the head of the survey (Mem. of Colby, pp. 106-7). On 13 April 1820 Colby became a fellow of the Royal Society of London. Later in the same year Lord Melville nominated him to a seat on the board of longitude, which he retained until the board was dissolved by act of parliament in 1828. He also became an associate and afterwards an honorary member of the Institution of Civil Engineers, in the proceedings of which he always continued to manifest active interest. Living constantly in London, then the headquarters of the survey, and possessing, in addition to his pay, moderate private means, he was a most untiring worker in the cause of science. His name appears among the proprietors of the London Institute, in Finsbury Circus, as early as 1818. He was one of the founders of the Royal Astronomical Society, and with Colonel Mark Beaufoy, Dr. Olinthus Gregory, Troughton, the mathematical instrument maker, and one or two more fellows of the Royal Society, was charged with the task of framing rules and regulations for its government. He was also one of the early members of the Athenaeum Club. After General Mudge's death there was a cessation of the mountain work of the survey; but in 1821 Colby was employed in making observations in Orkney and Shetland, and on the two lone islets of Faira and Foula; and in 1821-3 he was deputed by the Royal Society, in conjunction with Captain H. Kater, late of 12th foot, an Indian geodesist of great experience, to cooperate with MM. Arago and Matthieu, acting on behalf of the French Institute, in verifying the observations made forty years previously for connecting the observations of Greenwich and Paris. The results are given in 'Philosophical Transactions,' 1828. To facilitate the observations across the Channel ​between Folkestone and Calais, Fresnel's compound lenses, then new to science, were used at night, and to Colby's notes thereupon, communicated to his friend Robert Stevenson, the engineer of the Bell Rock lighthouse, we owe the adoption of these lenses in British lighthouses (A. Stevenson, Treatise on Lighthouses, ii. 5, in Weale's series).
In 1824 a survey of Ireland was ordered after a very careful consideration of the subject before a select committee of the House of Commons, which recommended that the work should be entrusted to the ordnance (Parl. Reports, 1824, viii. 77, 79). The Duke of Wellington, as master-general, selected Colby to plan and execute the survey, and left the number and selection of persons to be employed thereon entirely to him (Wellington Supp. Despatches, iv. 219, 333). Into this, the great work of his life, Colby forthwith entered with all his energy and skill. Being intended to facilitate a general valuation of property throughout Ireland, with a view to secure a more equal distribution of local taxation, the survey was required to be so precise that the accuracy of the details should be unquestioned, while yet the cost was to be kept within reasonable limits. Colby determined to make it dependent on chain measurement, controlled by a very complete system of primary, secondary, and minor triangulation, allowing of the fixation of a trigonometrical point for each four hundred statute acres. He also decided to have the work carried on under direct official supervision, instead of by contracts with civil practitioners, a practice then largely followed in the ordnance survey of England. For this reason he adopted a military plan of organisation, and obtained the Duke of Wellington's approval of a plan for raising three companies of sappers and miners to be trained in survey duties. The cost of these three companies of 105 men each, who could at any time be made available for the ordinary service of the country, was defrayed out of the annual parliamentary grants for the survey. Later, as the work progressed, he subdivided the duties into so many different branches, serving as mutual checks, that he was enabled to avail himself of the natural aptitude of the lower orders of Irish, large numbers of whom were employed on the survey. The Irish survey was begun by Colby with a small party of sappers on Divis mountain, near Belfast, in 1825. Not approving of the appliances used or proposed for base-line measurements, Colby instituted a series of experiments on the expansion and contraction of metal bars under variations of temperature, guided by which he eventually devised a dual arrangement of brass and iron, called by him a 'compensation bar,' which, with an ingenious arrangement of connecting microscopes, forms the beautiful apparatus known by his name, and since used in base-measurements in all parts of the world (Mem. of Colby, pp. 268-72). With this apparatus a base-line, eight miles long, was measured under Colby's personal superintendence, on the southern side of Lough Foyle, in 1827-8, an account of which was published long afterwards by order of the board of ordnance (An Account of the Measurement of the Lough Foyle Base, 1847). Colby ordered two ten-foot iron standard bars to be constructed, to serve as a permanent record of the length of the compensation bars and of the base-measurements therewith at a temperature of 62 Fahr.; likewise two three-foot bars, which in March 1834 he caused to be compared by a committee of experts with the parliamentary standard yard, and which bars formed part of the evidence on which the parliamentary committee had to rely for the restoration of the standard yard, after the latter was destroyed by the fire which burned down the houses of parliament in the autumn of the same year. Colby's biographer also claims for him that he was the first to point out the collateral advantages to be derived from combining with the national survey researches and collections illustrative of the geology, natural history, statistics, and antiquities, especially as regards local names, of the country. His ideas on this subject were overruled by financial considerations, but have since borne rich fruit in many quarters.
The great difficulty at the outset was the want of a trained staff, training in such duties being a work of time. Hence the progress made was slow and unsatisfactory, and an idea arose that the methods adopted were too refined for the particular purpose in view (Wellington Supp. Despatches, iv. 331, 333). These representations led to the appointment of an engineer committee, with Sir James Carmichael Smyth at its head, which, after vexatious inquiry, recommended the adoption of more rapid but less accurate methods than those in use.
In 1828 Colby married Elizabeth Hester Boyd, second daughter of Archibald Boyd of Londonderry, sometime treasurer of that county. By this lady, who was a descendant of the Errol and Kilmarnock families, and on her mother's side of the Earls of Angus, he had a family of four sons and three daughters. After his marriage Colby removed from London to Dublin, residing at first in Merrion Square, and afterwards at Knockmaroon Lodge, at the gates of Phoenix Park, within ​easy distance of the survey office, which was established in the old Mountjoy barracks.
Under Colby's personal superintendence the organisation of the survey steadily developed, and the attempt to substitute speed for accuracy having been finally abandoned in 1832, the work began to progress more satisfactorily. In May 1833 the publication of the first Irish county— Londonderry—in fifty sheets, took place. Other counties followed in quick succession, so that on the completion of the map in 1847 there had been issued 1,939 sheets, surveyed and plotted on a scale of six inches to the statute mile, and which in the completeness of the details, the elaborate system of check and counter-check applied to them, and in harmony of artistic style and finish, far surpassed anything of the kind before produced. The amount of work involved in their preparation is indicated by the fact that from 1828 to the completion of the Irish survey in 1846, the average force employed thereon was twenty officers, two hundred sappers and miners, and two thousand civilian assistants, the expenditure during that time amounting to 720,000l. After he had got his system into working order, and finished maps were annually completed to the extent of two million to three million acres, Colby, as the ordnance records prove, did not hesitate year after year to take upon himself the responsibility of exceeding by large sums the votes sanctioned by parliament, rather than diminish the rates of expenditure and progress by discharging qualified assistants. To keep down the current expenditure, Colby for some time did not draw his own salary. When he subsequently applied for the arrears, they were refused and never paid. That the scientific accuracy on which Colby so strongly insisted was, in the highest sense, utilitarian and economical in its results, is shown by the following passage in the 'Annual Report of the Royal Astronomical Society' for 1852-3 (p. 16): 'It (the Irish map) has formed the basis of the poor-law boundaries in detail, determining the localities called electoral divisions, according to which the poor-law assessment is made; it has served for the poor-law valuation, which includes tenements, and which is distinct from the town-land or general valuation of all Ireland; it has been used as a means of obtaining an accurate annual return, at a very small cost, of every variety of agricultural produce in Ireland; it has been made the basis of the Irish census, and employed in the sale of property, the boundaries of fields and farms sold being laid down on the map and accurately coloured, and each map subsequently "enrolled," so that at any future time the property sold can be traced on the map, and from it identified on the ground; it has further been employed in carrying out the provisions of the Land Improvements Act; and last, but not least, it has greatly facilitated the task of carrying on in the most economical manner the various engineering works executed in the country.'
To these results thus achieved must be added a very complete series of tidal observations, made under Colby's direction during the progress of the survey, at twenty-two different stations round Ireland, and extending over a period of two months. The astronomer royal, in a paper on the 'Law of the Tides on the Coasts of Ireland,' based on them, observed: 'The circumstances of place, simultaneity, extent of plan, and conformity of plan appear to give them extraordinary value, and extent of time alone appears wanting to render them the most important series of tide observations that has ever been made' (Philos. Trans. 1845, p. 1). When Colby commenced the Irish survey, there was, strictly speaking, no topographical staff. At the close of the survey all branches of the work had been organised in one harmonious whole, and the country was in possession of a topographic corps composed of engineer officers, sappers, and civilians, which was, and has continued, second to none in the world. Among other improvements introduced by Colby during its progress may be mentioned the now familiar process of electrotyping, whereby the maps can be reproduced from duplicate plates without wearing out the originals; the introduction of contours or equi-distant level lines on the six-inch maps, the feasibility of such an undertaking at moderate cost having been previously ascertained by experiment in the barony of Ennishowen; and the training of picked men of the sappers and miners (now royal engineers) in the use of the larger instruments, whereby the services of an extra number of good geodesical observers (with whom strong sight and steadiness of hand are the chief essentials) were secured to the country at small cost. In 1833 Sir Henry, then Mr. De la Beche, suggested the preparation of a geological map of the west of England, which, after some deliberation, was entrusted by the government to Colby in conjunction with the projector, the ordnance finding the funds and engraving the maps, and Mr. De la Beche being answerable for the accuracy of the geological details placed on them. The arrangement continued in force until 1845, when the geological survey was transferred to the department of woods and forests. With this exception, and the publication of the sheets of the one-inch ​ordnance map of England and Wales, which had been resumed, the operations of the British survey were at a standstill after the death of General Mudge until 1838, when the survey of Scotland was resumed, and Colby removed from Dublin to London. In that year he made his last appearance as an observer in the field on Ben Hutig in Sutherlandshire. Two years later, on the urgent representations of various scientific bodies in England and Scotland of the advantages which had attended the publication of the ordnance maps of Ireland, the government consented to extend these advantages to the six counties in England remaining unsurveyed, viz. Lancashire, Yorkshire, Cumberland, Westmoreland, Durham, and Northumberland, and to the whole of Scotland, the survey of which was ordered to be conducted and the maps engraved on the six-inch scale, while the publication of the one-inch map was continued for the rest of England. The assistants employed on the Irish survey, as they completed their work, were successively transferred to England, part, after a while, being removed to Scotland. The work was proceeding very slowly when, in November 1846, just as the sheets of the last Irish county were preparing for issue, Colby attained the rank of major-general, and in accordance with the rule of the service was retired from the post he had so long held. Thenceforward he devoted himself to the education of his sons, residing for some time at Bonn, on the Rhine. He died at New Brighton, near Birkenhead, in the midst of his tenderly attached home circle, on 9 Oct. 1852, in the sixty-ninth year of his age. A monument was erected to him in St. James's cemetery, Liverpool.
Colby was a knight of Denmark, a distinction conferred in recognition of aid afforded by the ordnance survey to the Danish geodesists under Professor Schumacher; a LL.D. of the university of Aberdeen, a member of the Royal Irish Academy, fellow of the Royal Societies of London and Edinburgh, and of various learned societies of London and Dublin, and a member of the Institution of Civil Engineers. While living he received no mark of distinction from his own country; but after his death his eminent public services were recognised by the grant of a life pension to his widow. The only entry of authorship under his name in the 'Brit. Mus. Cat. of Printed Books' is a reprint of an address delivered before the Irish Geological Society, the 'Survey of the County of Londonderry' (Dublin, 1837, 4to), which appears under his name in most catalogues, being there assigned, by cross reference, to one of his assistants, Sir E. Larcom.
In person Colby was rather short, with a wiry active frame. The best likeness of him is considered to be a bust in the ordnance map office, Southampton. Notwithstanding the loss of one hand, his dexterity as an instrumental observer was remarkable. His brother officers have testified to his single-mindedness, his kindly and unselfish nature. His administrative qualifications are shown in his apt choice of assistants as well as in the scope and results of their united labours.
[General Colby's family claims to be of Norfolk descent. A pedigree of two or three generations of Colby of South Wales is given in T. F. Colby's Addenda to Colby of Great Torrington, Devonshire, with notices of families of the same name in other counties, a pamphlet privately printed in 1880, of which there is a copy in the British Museum. A memoir of General Colby, by the late Major-general J. E. Portlock, at one time his most trusted subaltern, appears in Papers on Subjects connected with the Royal Engineers, vols. iii. iv. v., and was afterwards published as Memoirs of the Life of General Colby (London, 1869). Obituary notices appeared in Abstracts Roy. Soc. 1853, Annual Report R. Astronom. Soc. 1852–3, Annual Report Institution of Civil Engineers, 1852–3; the two last, which are the best, were subsequently issued as separate reprints. The art. ‘Trigonometrical Surveying’ in Encyc. Brit. 8th ed., and one on the Irish survey in Brit. Almanac and Companion, 1849, may be consulted; also the chapters on the ‘survey companies’ in Captain and Quartermaster Connolly's Hist. Roy. Sappers and Miners; also Accounts and Papers, 1844, xxx. 527; also the Reports on Ordnance expenditure in Sessional Papers of various dates up to 1849; also the various publications of the Ordnance Survey relating to the period in question, and the Records of the Board of Ordnance (Ordnance In-Papers) now in the Public Record Office, London.]
H. M. C.