This was clearly a wide and most important departure from the original intention of the six inch survey in Ireland, and it is not to be doubted that General Colby, who would not trust to paper measurements for the areas of entire townlands, would have adopted at the very outset, for his manuscript plans of these minute subdivisions, a scale much larger than that of six inches to one mile. The engraving of the six inch survey appears to have resulted from a demand for six copies of one sheet for valuation purposes when it was found that it would be as cheap to engrave it as to make that number of copies. So valuable did the six inch map of Ireland prove for many purposes over and above that for which it had been originally designed, that, in 1840, when the Irish survey was completed, and that of England resumed, the Government gave their consent to the adoption of the same scale for the unsurveyed parts of Great Britain. By 1851, Yorkshire, Lancashire, the Isle of Lewis, and several counties in the south of Scotland were finished on the six inch scale. Then began that long controversy which has been well termed the "battle of the scales" and which for eleven or twelve years retarded the progress of the survey and led to a large waste of public money. During the time that the Ordnance Surveyors were engaged in making their six inch map of Lancashire and Yorkshire they were called upon and employed to make, at the expense of the land owners, twenty-three plans of parishes and townships on the scale of twenty-six and 2/3 inches to one mile for tithe commutation. It was even found that the plan of London, made for the Metropolitan Commissioners of Sewers, on the scale of sixty inches or five feet to one mile was inapplicable to house drainage within the area. Between 1851 and 1852 no fewer than three select committees and one royal commission deliberated on the scale for the survey, and fourteen blue books were presented to Parliament. The main point of the controversy was whether the six inch or some larger scale was best fitted for the national map. A host of persons eminent in science were consulted on the subject, and a great diversity of opinion was found to exist, the weight of evidence, however, inclining by a majority of four to one, to a scale of from 20 to 26-2/3 inches to a mile. In 1853 a statistical conference held at Brussels and attended by twenty-six delegates from the chief States of Europe considered the question of national maps or cadastres, and pronounced unanimously in favor of a scale of 1/2500th of nature equivalent to about 25-1/3 inches to a mile, recommending at the same time that the cadastre on this scale should be accompanied by a more general map on the scale of 1/10,000 equivalent to about six 1/3 inches to a mile, and thus very nearly corresponding to the six inch scale of the Ordnance Survey.