Dr. Crakelt, an able master. The General often pointed out the grey tower of Northfleet church, and spoke with much feeling of his connection with its school. From Northfleet he was transferred to the Royal Military Academy at Woolwich, and obtained his first commission as Second Lieutenant of Engineers on the 21st December, 1801.

On the 12th of January, 1802, Captain Mudge, R.A., then Superintendent of the Survey, applied to the Earl of Chatham, requesting that Lieutenant Colby might be attached to that work, and his appointment took place the same day. Captain Mudge's letter, referring to Lieutenant Colby, as a young gentleman who has just got his commission, proceeds thus "I find him, on examination, well grounded in the rudiments of mathematics, and in other respects perfectly calculated to be employed in this business. I beg to point out to your Lordship the expediency of Lieutenant Colby being attached to me with some degree of permanency, and to request you will assign him to my orders on that principle." It is certainly possible that the name of Lieutenant Colby may have been brought before General Mudge by his uncle, General Hadden, then Surveyor-General of the Ordnance, through the Master-General's Secretary, General Neville, who was a very near relative of Captain Mudge, but there cannot be a doubt that the selection was made from the motive assigned in the above letter; and that it was wise and just, and never regretted by General Mudge, may be gathered from his subsequent letter

of September 9th, 1813, in which he thus feelingly expresses himself:-"This brings to my mind how happy I am to account myself, that Providence has placed to my hand so able and firm a friend as you are. You have served without fee and reward; but find the greatest satisfaction for your actions in not having served in vain."

Under the authority of the Duke of Richmond, Master-General of the Ordnance, a corps of draftsmen (or surveyors and draftsmen) had been formed, and, as will be shown hereafter, employed to complete the topographical part of the Survey, by filling in the details required for a map. The establishment of this corps was a wise measure, and a necessary step towards the attainment of that harmony and perfection which ought to characterise a great national work. Mr. James Gardner, who was for many years chief draftsman, not only superintended the drawing and publication of the first maps, especially that of Kent, but also shared in the labours of much of the triangulation. To General Morse, then Chief Engineer, was due the very judicious idea of rendering this corps useful in instructing the young Engineer officers in sketching and surveying, and thus supplying one of the practical elements then wanting in the course of study. At his request, General Mudge allowed Mr. Stanley and Mr. Dawson, two of the most able surveyors and draftsmen of the corps, to undertake this task. In 1803, Mr. Dawson was engaged in the survey of Cornwall, nd stationed at Liskeard, having then under him his three first

pupils, Lieutenant Williams, Boothby, and Boteler. Whilst there, Lieutenant Colby visited him on a tour of inspection, and when trying an old pair of pistols, and about to discharge one of them as he held the other by the barrel with his left hand, the latter exploded and burst, shattering his left hand, whilst one of the fragments made a fearful indent in his skull, the mark of which on his forehead was never obliterated. Almost dying, Lieutenant Colby was carried to the house of Mr. Dawson, when the local surgeons at once amputated the hand; and it was also proposed to resort to the hazardous operation of trepanning, but this design was abandoned. A constitution of unusual strength at length enabled him to triumph over the effects of this appalling accident, and he was mercifully restored once more to health; but it is impossible not to recognise in the injury inflicted on his skull, a sufficient cause both for subsequent bodily ailments, and for a reluctance to enter on long-continued mental exertion. At this point it seems desirable to pause, and to take a brief retrospect of the Ordnance Survey before General Colby succeeded Major-General Mudge as its superintendent.

Major-General William Roy, R.A., F.R.S., A.S., remarks that "Accurate surveys of a country are invariably admitted to be works of great public utility, by affording the surest foundation for almost every kind of internal improvement in time of peace, and the best means of forming judicious plans of defence against the invasions of an enemy in time of

war." And hence it is that the difficulties experienced in war from a want of accurate maps, and a consequent defective knowledge of the country to be included within a chain of military operations, has often led to the commencement of such works. The Scotch Rebellion of 1745, which was finally suppressed by His Royal Highness the Duke of Cumberland at the Battle of Culloden, pointed out the propriety of exploring and mapping the wild Highland districts, with a view to the establishment of military posts and roads of communication. In 1747 a body of infantry was encamped at Fort Augustus for this purpose under Major-General Lord Blakeney; and the plan of a Survey suggested by Lieutenant-General Watson, then Deputy QuarterMaster General in North Britain, was undertaken by General Roy, R.A., then Assistant QuarterMaster General, and the work was at length extended from the Highlands over the whole mainland of Scotland. This work was never published, and having been carried on with inferior instruments, was merely considered by General Roy" a magnificent military sketch." The war of 1755 put a stop to these works of peace; but at the peace of 1763 the subject of a General Survey of Great Britain, which would have included the work already done in Scotland, again engaged the attention of Government, and was again thrown into the shade by the. troubles which preceded, and ended in, the American War. The peace of 1783 again restored that tranquillity which is equally necessary for the consider

ation as for the execution of such works: and at this critical period (October, 1783) a memoir of M. Cassini de Thury, on the great advantages which would be derived by astronomy from the connexion through trigonometrical measurements of the two great observatories of Greenwich and Paris, and the consequent determination of the exact differences between their latitudes and longitudes, was submitted to the British Government by Count d'Adhemar, the French ambassador. The French had already carried a series of triangles from Paris to Calais, and it was only necessary that the English should complete the work by carrying a similar series from Greenwich to Dover. Mr. Fox, by the King's command, transmitted this memoir to Sir Joseph Banks, President of the Royal Society, and at his request General Roy charged himself with the undertaking, his Majesty George III. having expressed his warm approbation of the scheme, and supplied the funds necessary for the operation. The site of the initial base of this work, which must be considered the germ of all future scientific surveys of the United Kingdom, was fixed at Hounslow Heath; and, in this case also, soldiers--a party of the 12th Regiment-were employed to clear the ground, to protect the instruments, and to assist in the operations generally. Several modes of measuring this base were proposed and tried the first was a steel chain, 100 feet long, constructed by Mr. Ramsden, on the principle of a watch chain, each link being one foot long, and constructed of three

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