Before 1864, in running random and true section lines, it was required to make the record of courses on the ancient plan shown by this example: East on a random line between sections 1 and 12. Variation 13° 15′ E. (falling perhaps 42 links north of objective. corner). West on true line between sections 1 and 12. Variation 13° 33′ E., etc., thus representing the "corrected " course by a nominal change of variation; whereas, after the instructions of 1864, the record would truly show the change to have been, not in the variation, but in the course, thus: N. 89° 42′ W. on a true line, etc. Therefore, in a large portion of the early records, the words "east ” and "west" in such connection were only approximate, while by the present system the true course is intended. 38. Terrestrial magnetism, the cause of "variation," is a fluctuating quantity, subject to unexplained changes. But since all qualified surveyors and engineers of this day are competent to make the requisite astronomical observations to determine true courses, surveying by the needle is not recommended. MARKS ON MONUMENTS OF SURVEY. 39. Inquiries are often made to learn the meaning of the marks on corner stones. It is not practicable here to give an abstract of all the markings used in full compliance with the manual; but the following notes will suffice to explain ordinary cases: Notches made on the east and south angles of an interior section corner indicate how many miles it is from the east and south lines of a full township; and by using the plan of a township plat, the numbers of the sections about the given corner stone will be known. In fractional townships, marks show the sections the same as if the boundaries were complete. 40. Observe that there are cases of irregular subdivision, where the stone or post is a corner of two townships or two sections only; also that stones may have been sometimes overthrown or turned around to a new and improper position. 41. On township and range lines grooves cut in the stone or post on opposite sides show distances to exterior corners of the township. Thus, two grooves on the south and four on the north indicate a corner of sections 19, 24, 25, and 30. 42. W C" upon a monument means a witness corner, placed not at the true corner point (which may be in water or otherwise impracticable), but established elsewhere on safe ground at a distance and course shown by the official field notes and plats. "MC" shows a meander corner, placed either on an exterior or section line at any certain distance from a section corner as shown by the plat. 43. "SC" denotes a standard corner-that is, a regular corner on a standard parallel-belonging to two sections on the north side, with a closing corner (marked C C) somewhere east or west of it, belonging to two sections on the south side of the parallel. The letters C C are also used in many other situations, where a regular line closed upon a boundary of a State, a reservation, or a private land claim. 44. Post corners and bearing trees (B T) have marks that are selfexplanatory. Two chops or notches on the two opposite sides of a tree indicate that it stood upon the original line when surveyed. Such are called "line trees," and are thus distinguished from trees merely blazed near the line. Full instructions as to the construction, marking, and differentiation of the 108 kinds of corner monuments are given in the Manual of Surveying Instructions. These should be consulted, in connection with a correct copy of the original field notes, in case of difficulty. TO RESTORE LOST OR OBLITERATED CORNERS. 45. To restore corners on base lines and standard parallels.-Lost or obliterated standard corners will be restored to their original positions on a base line, standard parallel, or correction line, by proportionate measurements on the line, conforming as nearly as practicable to the original field notes and joining the nearest identified original standard corners on opposite sides of the missing corner or corners, as the case may be. 46. The term "standard corners" will be understood to designate standard township, section, quarter section, and meander corners; and, in addition, closing corners, in the following cases: Closing corners used in the original survey to determine the position of a standard parallel, or established during the survey of the same, will, with the standard corners, govern the alinement and measurements made to restore lost or obliterated standard corners; but no other closing corners will control in any manner the restoration of standard corners on a base line or standard parallel. 47. A lost or obliterated closing corner from which a standard parallel has been initiated or to which it has been directed will be reestablished in its original place by proportionate measurement from the corners used in the original survey to determine its position. Measurements from corners on the opposite side of the parallel will not control in any manner the relocation of said corner. 48. A missing closing corner originally established during the survey of a standard parallel as a corner from which to project surveys south will be restored to its original position by considering it a standard corner and treating it accordingly. 49. Therefore, paying attention to the preceding explanations, we have for the restoration of one or several corners on a standard par allel, and for general application to all other surveyed lines, the following proportion: As the original field-note distance between the selected known corners is to the new measure of said distance so is the original fieldnote length of any part of the line to the required new measure thereof. The sum of the computed lengths of the several parts of a line must be equal to the new measure of the whole distance. 50. As has ben observed, existing original corners can not be disturbed; consequently discrepancies between the new and the original field-note measurements of the line joining the selected original corners will not in any manner affect measurements beyond said corners, but the differences will be distributed proportionately to the several intervals embraced in the line in question. After having checked each new location by measurement to the nearest known corners, new corners will be established permanently and new bearings and measurements taken to prominent objects, which should be of as permanent a character as possible, and the same recorded for future reference. 51. Restoration of township corners common to four townships.— Two cases should be clearly recognized: First, where the position of the original township corner has been made to depend upon measurements on two lines at right angles to each other. Second, where the original corner has been located by measurements on one line only; for example, on a guide meridian. 52. For restoration of a township corner originally subject to the first condition: A line will first be run connecting the nearest identified original corners on the meridional township lines, north and south of the missing corner, and a temporary corner will be placed at the proper proportionate distance. This will determine the corner in a north and south direction only. Next, the nearest original corners on the latitudinal township lines will be connected and a point thereon will be determined in a similar manner, independent of the temporary corner on the meridional line. Then through the first temporary corner run a line east (or west) and through the second temporary corner a line north (or south), as relative situations may suggest. The intersection of the two lines last run will define the position of the restored township corner, which may be permanently established. 53. The restoration of a lost or obliterated township corner established under the second condition, i. e., by measurements, on a single line, will be effected by proportionate measurements on said line, between the nearest identified original corners on opposite sides of the missing township corner, as before described. 54. Reestablishment of corners common to two townships.-The two nearest known corners on the township line, the same not being a base or a correction line, will be connected, as shown in sections 45 to 50, by a right line, and the missing corner established by proportionate distance as directed in that case; the location thus found will be checked upon by measurements to nearest known section or quarter-section corners north and south, or east and west, of the township line, as the case may be, to obtain approximate though probably not exact verification of original distances. 55. Reestablishment of closing corners.-Measure from the quartersection, section, or township corner east or west, as the case may be. to the next preceding or succeeding corner in the order of original establishment, and reestablish the missing closing corner by proportionate measurement. The line upon which the closing corner was originally established should always be remeasured, in order to check upon the correctness of the new location. (See secs. 29 to 34 and 64 to 66 for details.) 56. Reestablishment of interior section corners.-This class of corners should be reestablished in the same manner as corners common to four townships. In such cases, when a number of corners are missing on all sides of the one sought to be reestablished, the entire distance must, of course, be remeasured between the nearest existing recognized corners both north and south, and east and west, in accordance with the rule laid down, and the new corner reestablished by proportionate measurement. The mere measurement in any one of the required directions will not suffice, since the direction of the several section lines running northward through a township, or running east and west, are only in the most exceptional cases true prolongations of the alinement of the section lines initiated on the south boundary of the township; while the east and west lines running through the township, and theoretically supposed to be at right angles with the former, are seldom in that condition, and the alinements of the closing lines on the east and west boundaries of the township, in connection with the interior section lines, are even less often in accord. Moreover, the alinement of the section line itself from corner to corner, in point of fact, also very frequently diverges from a right line, although presumed to be such from the record contained in the field. notes and so designated on the plats, and becomes either a broken or a curved line. This fact will be determined, in a timbered country, by the blazes which may be found upon trees on either side of the line, and although such blazed line will not strictly govern as to the absolute direction assumed by such line, it will assist very materially in determining its approximate direction, and should never be neglected in retracements for the reestablishment of lost corners of any description. Sight or line trees described in the field notes, together with the recorded distances to same, when fully identified, will, it has been held in one or more States, govern the line itself, even when not in a direct or straight line between established corners, which line is then necessarily a broken line by passing through said sight trees. Such trees, when in existence and properly identified beyond a question of doubt, will very materially assist in evidencing the correct relocation of a missing corner. It is greatly to be regretted that the earlier field notes of survey are so very meager in the notation of the topography found on the original line, which might in very many instances materially lessen a surveyor's labors in retracement of lines and reestablishment of the required missing corner. In the absence of such sight trees and other evidence regarding the line, as in an open country, or where such evidence has been destroyed by time, the elements, or the progress of improvement, the line connecting the known corners should be run straight from corner to corner. 57. Reestablishment of quarter-section corners on township boundaries. Only one set of quarter-section corners are actually marked in the field on township lines, and they are established at the time when the township exteriors are run. When double section corners are found, the quarter-section corners are considered generally as standing midway between the corners of their respective sections, and when required to be established or reestablished, as the case may be, they should be generally so placed; but great care should be exercised not to mistake the corners belonging to one township for those of another. After determining the proper section corners marking the line upon which the missing quarter-section corner is to be reestablished and measuring said line, the missing quarter-section corner will be reestablished in accordance with the requirements of the original field notes of survey, by proportionate measurement between the section corners marking the line. 58. Where there are double sets of section corners on township and range lines and the quarter-section corners for sections south of the township or east of the range lines are required to be established in the field, the said quarter-section corners should be so placed as to suit the calculation of areas of the quarter sections adjoining the township boundaries as expressed upon the official township plat, adopting proportionate measurements when the present measurement of the north and west boundaries of the sections differs from the original meas urement. 59. Reestablishment of quarter-section corners on closing section lines between fractional sections.-This class of corners must be reestablished proportionately, according to the original measurement of 40 chains from the last interior section corner. If the whole measurement does not agree with the original survey, the excess or deficiency must be divided proportionately between the two distances expressed |