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Having thus grasped in his mind the requirements of the survey in 

 its mere practical character, Major Colby felt, as a man of science, 

 that so great a national work ought not to fall short of the excellence 

 of Continental works in any of its operations, and that some scien- 

 tific advance should be made in the mode of measuring its first base 

 line. With the beautiful differential rods of the French philosophers 

 he was not perfectly satisfied, nor would he adopt the mode, proposed 

 by the late Captain Drummond, of measuring with broad bands, or 

 ribands formed of mica ; but feeling a preference for the principle of 

 compensation, he gave it a nevv' application, by inventing those ad- 

 mirable compensation bars, which stamped on the Irish Survey a 

 character of novelty, and inseparably' connected the name of their 

 author with the history of geodetic science. It is not to be supposed 

 that so great a work could have been carried on successfully without 

 the cooperation of many most able and zealous officers ; but when it 

 is considered that their efforts were all directed and regulated on the 

 system planned by General Colby, it must be felt that the Irish Sur- 

 vey, in its beginning and in its end, was eminently his own work. 



Were this narrative now to end, it would fail to do full justice to the 

 comprehensive mind of General Colby. When asked by Sir Henry 

 Hardinge, then Clerk of the Ordnance, to state the advantages of a 

 survey, he did not content himself by describing its ordinary useful- 

 ness, but nobly represented it as the proper basis for geological, sta- 

 tistical and antiquarian surveys. These views were acted upon at 

 the commencement of the Survey, and to General Colby must there- 

 fore be ascribed the merit of having first originated a national 

 Geological Survey, and, connected with it, a museum of Economic 

 Geology. He did indeed more, as his scheme com.prised natural 

 history and antiquities; and the museum at Mountjoy contained not 

 only a most valuable collection of minerals and fossils, but also an 

 equally important one of the plants and animals of Ireland. It is 

 true, that subsequently General Colby shrank from that responsibility 

 which at first had seemed so light to him ; that the Ordnance 

 abandoned these collateral works ; and that the Geological Survey 

 passed into the hands of the Woods and Forests, there to acquire a 

 full development under the able guidance of Sir Henry De la Beche; 

 but let us recognize in the Memoir of Londonderry, published in 

 1835, — in the Report of the Geology of Londonderry and Tyrone, 

 by Captain now Lieut. -CoL Portlock, R.E., published in 1843, — and 

 in the Statistical Papers of the Census Commission drawn up by 

 A-Iajor Larcom, and founded on the Statistical Section of the Memoir 

 of Londonderry, to which that officer had so largely contributed, 

 proofs that the scheme proposed by General Colby in 1824, would, 

 if it had been followed up, have led to the publication of a national 

 work, which, both in the grandeur of its conception and the import- 

 ance of its results, would have been unrivalled by any such national 

 work in Europe. 



In 1825 Major Colby became Lieutenant- Colonel ; in 1837 

 Colonel ; and in 1846 Major- General. It is greatly to be regretted 

 that his attainment of the last-named rank should have required that 



