Page:Economic History of Virginia Vol 1.djvu/565

 was, therefore, untrustworthy for a survey in which the nicest accuracy in measurement was required. The subdivision of the surveyor&#8217;s compass did not extend further than two degrees and forty-nine seconds, and in consequence the bearing of all objects must have been shifted not less than one degree and twenty-five minutes from their real positions. This important difference was not recorded in the survey, either because the surveyors themselves were unaware of it, or because they were too careless to take it into account in their calculations. The second defect arose from a cause which could easily have been prevented if they had shown strict integrity in the execution of their work. In laying off the perpendicular lines of a plat, that is to say, the lines drawn at right angles to the base line, some object of a permanent nature to serve as a terminus was always selected. If, for instance, there was a watercourse, road, or hill, it was customary to abridge or extend the line, as the case required, to reach this object, and when the plat of the survey was made up, the line was represented as ending there although its length was stated to be a mile. In reality it may have exceeded or fallen short of this distance by a hundred yards more or less. In the survey also, a stretch of inferior land, over which the line was drawn, was frequently left out of account in fixing the mile limit, being excluded from consideration as if it had no existence in the area of the plat. The divergence from the straight line, which was sometimes rendered necessary by the thickness of the forest growth, also