JEPARTMENT OF THE INTERIOR GENERAL LAND OFFICE T A ADVANCE SHEETS of Chapters I to VI, inclusive, of a revision of the MANUAL OF INSTRUCTIONS FOR THE SURVEY OF THE PUBLIC LAND^ OF THE UNITED STATES Prepared and published under the direction of the Commissioner of the General Land Office WASHINGTON GOVERNMENT PRINTING OFFICE 1919 GIFT OF DEPARTMENT OF THE INTERIOR GENERAL LAND OFFICE ADVANCE SHEETS of Chapters I to VI, inclusive, of a revision of the MANUAL OF INSTRUCTIONS FOR THE SURVEY OF THE PUBLIC LANDS OF THE UNITED STATES Prepared and published cinder the direction of the Commissioner of the General Land Office WASHINGTON GOVERNMENT PRINTING OFFICE 1919 3HT r DEPARTMENT OF THE INTERIOR GENERAL LAND OFFICE WASHINGTON, June 16, 1919. GENTLEMEN: It has been deemed advisable to publish advance sheets of six chapters of a new edition of the Manual of Surveying Instructions, as follows: (I) Regulations Imposed by Law; (II) Instruments and Methods; (III) System of Rectangular Surveys; (IV) Corner Monuments; (V) Restoration of Lost Corners; and, (VI) Resurveys. These advance sheets will immediately supersede the related provisions of the Manual of 1902, except as may be found impracticable in the case of surveys already in process of execution, or in the instance of returns of surveys now in course of preparation, otherwise the provisions of the Manual of 1902 will remain in full force and effect. Every member of the surveying service is requested to report to the undersigned any typographical errors which may be detected, to the end that the same may be removed from the completed edition. Very respectfully, CLAY TALLMAN, Commissioner. To the SURVEYING SERVICE OF THE GENERAL LAND OFFICE. CONTENTS. CHAPTER I. REGULATIONS IMPOSED BY LAW. Page. The Public Domain 1 lews Relating to Surveys 5 General Rules 18 The Manual 19 The Standard Field Tables 20 Ephemeris of the Sun and Polaris, and Tables of A zimuths of Polaris 21 CHAPTER II. INSTRUMENTS AND METHODS. Measurements 23 The long steel tape 24 Stadia measurements 29 Triangulations 35 Instruments and requirements as to their adjustment 39 General statement, time, latitude and azimuth 42 Analytical notation, declination and refraction 43 Time 51 Time in its relation to Polaris observations 53 Altitude observation of the sun for apparent time 62 Meridian observation of the sun for apparent noon 64 Time from the solar attachment 66 Latitude 66 Meridian altitude observation of the sun for latitude 60 Altitude observation of Polaris for latitude 69 Azimuth 71 The solar attachment 71 Description. 72 Adjustment 75 U so 80 Test 82 The solar compass 83 Errors in azimuth, due to small errors in declination or latitude 85 Polaris at elongation 86 Azimuth of Polaris at an}' hour angle ; 93 Polaris at sunset or sunrise 100 Altitude observation of the sun for azimuth 102 Equal altitude observations of the sun for meridian .'. 114 The true parallel of latitude 121 Solar method. 122 Tangent method 122 Secant method 124 Convergency of meridians 12t> Lengths of arcs of the earth's surface 128 VI M AN UAL OF S I" X \ J : Y I A G IN STKUC TION S. CHAPTER III. SYSTEM OF RECTANGULAR SURVEYS. Page. General scheme 131 Initial points 132 Principal meridian '. 133 Meridians and base lines of the United States Rectangular Surveys 134 Base line 135 Standard parallels 136 Guide meridians 137 Township exteriors 138 Regular order 138 Irregular order and partial surveys 143 General exceptions 143 Completion of partially surveyed exteriors 148 Retraccments before subdividing 150 Rectangular limits 150 Rectification of defective exteriors before subdividing and method o es- tablishing new governing boundaries where the previously surveyed ex- teriors are found to be defective 152 Tables of latitudes and departures and closing errors 159 Subdivision of townships 160 Regular boundaries 160 Irregular boundaries 166 Sectional guide meridian 166 Sectional correction line . . 166 Closing section lines , , . .... 170 Subdivision of sections - 173 Subdivision by protraction 175 Subdivision by survey 180 Fragmentary subdivision of townships , . 184 Fractional townships .- 184 Retracements ,. 188 Completion of partially surveyed sections 190 Subdivision of fractional sections resulting from fragmentary surveys.,. . . 205 Completing the subdivision of a partial township resulting from fragmen- tary surveys ; . . 209 Meandering 212 Rivers 215 Lakes 216 Islands 217 Limits of closure 218 Marking lines between corners 219 Summary of objects to be noted, and sketches ; 221 CHAPTER IV. CORNER MONUMENTS. The legal significance of a corner monument 227 Corner material .....: 229 Witness corners 230 CONTENTS. VH Page. Marking corners 231 Marks on iron post monuments 232 Marks on stone monuments 240 Marks on tree monuments 244 Corner accessories 249 Bearing trees, bearing objects, and memorials 250 Mound of stone 251 Pits 252 Arrangement and marking of corner accessories 252 CHAPTER V. RESTORATION OF LOST CORNERS. Identification of existent corners 259 Restoration of lost corners 263 Primary methods 265 (a) Double proportionate measurement 265 (ft) Single proportionate measurement 268 (c) Closing comers 269 Secondary methods 270 (d ) Broken boundaries 270 () Original control 271 (/) Index correction for average error in alinement and measurement . 271 Special cases 271 (<7) Miscellaneous control 272 CHAPTER VI. RESURVEYS. Jurisdiction 275 Limit of authority of surveyor 276 Bona fide rights of claimants 277 General field methods 280 The Dependent Resurvey , 282 General control 282 Reestablishment of true lines 287 Additional methods for the protection of bona fide rights 239 Example v 289 The Independent Resurvey 294 Reestablishment of outboundaries 295 Metes-and-bounds survey of private claims 296 The projection of new lines 303 Additional chapter subjects to be included in a mbsequent edition of the completed Manual. VTI. Special surveys and instructions. VIII. Field notes. IX. Plats. X. Mineral surveys. CHAPTER I. REGULATIONS IMPOSED BY LAW. THE PUBLIC DOMAIN. 1. The survey of the public lands of the United States is insep- arably associated with questions relating to the acquisition and dis- posal of proprietary title to the lands which have been added to the area included in the original thirteen States. The term "public domain" has been applied broadly to the entire aforementioned area in so far as the lands have been subject to survey and disposal by the United States, and of interest herein may be mentioned the twenty-nine States and the District of Alaska surveyed or in progress of survey under the United States rectangular system, as follows: Alabama. Included in the territory of the original thirteen States, and admitted into the Union December 14, 1819 (3 Stat. ? 608) ; surveys practically completed and original records transferred to the Secretary of State at Montgomery. Arizona. Included in the lands ceded by Mexico, in 1848, and the Gadsden purchase, in 1853, and admitted into the Union Feb- ruary 14, 1912 (36 Stat., 557 and 37 Stat., 1728); surveys in progress; United States Surveyor General at Phoenix. Arkansas. Acquired under the Louisiana Purchase, in 1803, and admitted into the Union June 15, 1836 (5 Stat., 50); surveys practi- cally completed and original records transferred to the Commissioner of State Lands at Little Rock. California. Ceded by Mexico, in 1848, and admitted into the Union September 9, 1850 (9 Stat., 452); surveys in progress; United States Surveyor General at San Francisco. Colorado. Acquired largely under the Louisiana Purchase, in 1803, but including additional land, title to which was quieted through treaty with Spain, in 1819, with other lands annexed with Texas, in 1845, and lands ceded by Mexico, in 1848, and admitted into the Union August 1, 1876 (18 Stat., 474, and 19 Stat., 665); surveys in progress; United States Surveyor General at Denver. Florida. Ceded by Spain in 1819, and admitted into the Union March 3, 1845 (5 Stat., 742); surveys practically completed and original records transferred to the CommiBsioner of Agriculture at Tallahassee. 2 MAM AL OF SLKVi,riNG INSTRUCTIONS. Idaht. Acquired with the Oregon Territory, title to which, was established in 1846, and admitted into the Union July 3, 1890 (26 Stat., 215); surveys in progress; United States Surveyor General at Boise. Illinois. Included in the territory of the original thirteen States and admitted into the Union December 3, 1818 (3 Stat., 536); sur- veys practically completed and original records transferred to the Auditor of State at Springfield. Indiana. Included in the territory of the original thirteen States and admitted into the Union December 11, 1816 (3 Stat., 399); sur- veys practically completed and original records transferred to the Auditor of State at Indianapolis. Iowa. Acquired under the Louisiana Purchase, in 1803, and ad- mitted into the Union December 28, 1846 (9 Stat., 117); surveys practically completed and original records transferred to the Sec- retary of State at Des Moines. Kansas. Acquired under the Louisiana Purchase, in 1803, and with lands annexed with Texas, in 1845, and admitted into the Union January 29, 1861 (12 Stat., 126); surveys practically com- pleted and original records transferred to the Auditor of State and Register of State Lands at Topeka. Louisiana. Included in the Louisiana Purchase, in 1803, and boundary extended to include additional lands, title to which was quieted through treaty with Spain in 1819, and admitted into the Union April 30, 1812 (2 Stat., 701); surveys practically completed and original records transferred to the Register of State Lands at Baton Rouge. Michigan. Included in the territory of the original thirteen States and admitted into the Union January 26, 1837 (5 Stat., 144); surveys practically completed and original records transferred to the Commissioner of State Land Office at Lansing. Minnesota. Included in the territory of the original thirteen States, and with lands acquired under the Louisiana Purchase, in 1803, and admitted into the Union May 11, 1858 (11 Stat., 285); surveys practically completed and original records transferred to the Secretary of State at St. Paul. Mississippi. Included in the territory of the original thirteen States and admitted into the Union December 10, 1817 (3 Stat., 472); surveys practically completed and original records transferred to the Commissioner of State Lands at Jackson. REGULATIONS IMPOSED BY LAW. 3 Missouri. Acquired under the Louisiana Purchase, in 1803, and admitted into the Union August 10, 1821 (3 Stat., 645, and 3 Stat,, Appendix II); surveys practically completed and original records transferred to the Secretary of State at Jefferson City. Montana. Acquired under the Louisiana Purchase, in 1803, and with the Oregon Territory, title to which was established in 1846, and admitted into the Union November 8, 1889 (25 Stat., 676, and 26 Stat., 1551); surveys in progress; United States Surveyor General at Helena. Nebraslca. Acquired under the Louisiana Purchase, in 1803, and admitted into the Union March 1, 1867 (14 Stat.. 391, and 14 Stat., 820) ; surveys practically completed and original records transferred to the Commissioner of Public Lands and Buildings at Lincoln. Nevada. Ceded by Mexico in 1848 and admitted into the Union October 13, 1864 (13 Stat, 30, and 13 Stat., 749); surveys in progress; United States Surveyor General at Reno. New Mexico. Included with lands annexed with Texas, in 1845, with lands ceded by Mexico, in 1848, and the Gadsden Purchase, in 1853, and admitted into the Union January 6, 1912 (36 Stat., 557, and 37 Stat., 1723); surveys in progress; United States Surveyor General at Santa Fe. North Dakota. Included in the territory of the original thirteen States, and with lands acquired under the Louisiana Purchase, in 1803, and admitted into the Union November 2, 1889 (25 Stat., 676, and 26 Stat., 1548); surveys practically completed and original rec- ords transferred to the State Engineer at Bismarck. Oklahoma. Acquired under the Louisiana Purchase, in 1803, and with lands annexed with Texas, in 1845, and admitted into the Union November 16, 1907 : (34 Stat., 267, and 35 Stat., 2160); surveys practically completed and original records filed with the Commis- sioner of the General Land Office at Washington, D. C. Ohio. Included in the territory of the original thirteen States, and admitted into the Union April 30, 1802 (2 Stat., 173); surveys practically completed and original records transferred to the Auditor of State at Columbus. Oregon. Included in the Oregon Territory, title to which .was established in 184.6, and admitted into the Union February 14, 1859 (11 Stat., 383); surveys in progress; United States Surveyor General at Portland. , , South Dakota. Included in the territory of the original thirteen States, and with lands acquired under the Louisiana Purchase, in 4 MANUAL OF SURVEYING INSTRUCTIONS. 1803, and admitted into the Union November 2, 1889 (25 Stat., 676, and 26 Stat., 1549); surveys in progress; United States Surveyor General at Huron. Utah. Ceded by Mexico in 1848, and admitted into the Union January 4, 1896 (28 Stat.. 107, and 29 Stat., 876); surveys in progreas; United States Surveyor General at Salt Lake City. Washington. Included in the Oregon Territory, title to which was established in 1846, and admitted into the Union November 11, 1889 (25 Stat., 676, and 26 Stat., 1552); surveys in progress; United States Surveyor General at Olympia. Wisconsin. Included in the territory of the original thirteen States, and admitted into the Union May 29, 1848 (9 Stat., 233); surveys practically completed and original records transferred to the Commissioners of Public Lands at Madison. Wyoming. Included with lands acquired under the Louisiana Purchase, in 1803, with lands annexed with Texas, in 1845, with lands included in the Oregon Territory, title to which was estab- lished in 1846, and with lands ceded by Mexico, in 1848, and admitted into the Union July 10, 1890 (26 Stat., 222); surveys in progress; United States Surveyor General at Cheyenne. District of Alaska. Ceded by Russia in 1867; surveys in progress; United States Surveyor General at Juneau. 2. After the admission of the States into the Union the United States continued to hold title to the unappropriated lands and to administer its public-land laws with reference thereto, and it is ex- pressly provided, as one of the conditions set forth in the various enabling acts, that the title to unappropriated lands within the State shall remain in the United States. The lands in the Territo- ries not appropriated by competent authority before they were acquired are in the first instance the exclusive property of the United States, to be disposed of to such persons, at such times, in such modes, and by such titles as the Government may deem most advantageous to the public. Congress alone has the power, derived from Article IV, section 3, of the Constitution, of disposing of the public domain and making all needful rules and regulations in respect thereto. 3. Under the laws of the United States the navigable waters have always been and shall forever remain common highways, and below mean high water the same are not subject to survey and disposal. This reservation includes all tidewater streams, and other important permanent bodies of water whose natural and normal condition at REGULATIONS IMPOSED BY L.AW. & the date of the admission of a State into the Union was such as to classify the same as navigable water. 4. The act of Congress approved March 2, 1849 (9 Stat., 352), granted to the State of Louisiana all the swamp and overflowed lands within the limits of the State for the purpose of aiding in the reclamation of said lands, and the act of Congress approved Sep- tember 28, 1850 (9 Stat., 519), extended the grant to the other public land States then in the Union. The grant was also extended to the States of Minnesota and Oregon by the act of Congress approved March 12, 1860 (12 Stats., 3). The provisions of the aforementioned grants apply to the zone situated below the uplands wherein the lands are of such a character that without the construction of suit- able levees and artificial drainage systems the same would be wet and unfit for agricultural purposes. The swamp-land grants apply to all swamp and overflowed lands within the beneficiary States which were unappropriated at the dates of the acts of Congress and whose character at that tune, would bring them within the provi- sions of said grants. A notable exception to the swamp-land laws is found in the Arkansas Compromise Act approved April 29, 1898 (30 Stat., 367), by virtue of which all right, title, and interest to the remaining unappropriated swamp and overflowed lands within the State of Arkansas reverted to the United States. 5. It comes within the province of the Department of the Inte- rior to consider and determine what are public lands, what lands have been surveyed, what are to be surveyed, what have been dis- posed of, % what remain to be disposed of, and what are reserved, and it is a well-settled principle of law that the United States, through the Department of the Interior, has the right to extend the surveys as may be necessary to include lands omitted from earlier surveys. It is an important duty of the surveyor in the field to discriminate between what are and what are not public lands of the United States and to subdivide the former in accordance* with the regula- tions imposed by law. TAWS RELATING TO SURVEYS. 6. The rectangular surveying system is based upon existing law and was devised with the object of marking upon the ground and fixing for all time legal subdivisions for purposes of description and disposal of the public domain under the general land laws of the United States. 7. The rectangular system of survey of the public lands was inau^ gurated by a committee appointed by the Continental Congress. 6 MANUAL OF SURVEYING INSTRUCTIONS. On the 7th of May, 1784, this committee reported "An ordinance for ascertaining the mode of locating and disposing of lands in the western territory, and for other purposes therein mentioned." The ordinance as finally passed on the 20th of May, 1785, provided for townships 6 miles square, containing 36 sections of 1 mile square. The first public surveys were made under this ordinance. The townships, 6 miles square, were laid out in ranges extending north- ward from the Ohio River, the townships being numbered from south to north, and the ranges from east to west. The region em- braced by the surveys under this law forms a part of the State of Ohio. In these initial surveys only the exterior lines of the town- ehips were surveyed, but the plats were marked by subdivisions into sections of 1 mile square, and mile corners were established on 6 5 4 3 '2 \ 7 8 9 JO 11 12 18 17 16 15 14 \3 19 20 2! 22 23 24 30 29 28 27 26 25 31 32 33 34 35 36 the township lines. The sections were numbered from 1 to 36, and the surveys were made under the direction of the Geographer of the United. States. The act of Congress approved May 18, 1796, provided for the appointment of a surveyor general and directed the survey of the lands northwest of the Ohio River and above the mouth of the Ken- tucky River, "in which the titles of the Indian tribes have been extinguished." Under this law it was provided that "the sections shall be numbered, respectively, beginning with the number one in the northeast section and proceeding west and east alternately through the township, with progressive numbers till the thirty-sixth be completed." This method of numbering sections, as shown by the accompanying diagram, is still in use. REGULATIONS IMPOSED BY LAW. 7 The act of Congress approved May 10, 1800, required the "town- ships west of the Muskingum, which * * * are directed to be sold in quarter townships, to be subdivided into half sections of three hundred and twenty acres each, as nearly as may be, by run- ning parallel lines through the same from east to west and from south to north at the distance of one mile from each other, and marking 1 corners at the distance of each half mile on the lines running from east to west and at the distance of each mile on those running from south to north. * * * And the interior lines of townships inter- sected by the Muskingum, and of all the townships lying east of that river, which have not been heretofore actually subdivided into sections shall also be run and marked. * * * And in all cases where the exterior lines of the townships thus to be subdivided into sections or half sections shall exceed, or shall not extend, six miles, the excess or deficiency shall be specially noted and added to or deducted from the western and northern ranges of sections or half sections in such townships, according as the error may be in run- ning the lines from east to west or from south to north." The act of Congress approved February 11, 1805, directs the sub- division of the public lands into quarter sections and provides that all the corners marked in the public surveys shall be established as the proper corners of sections, or subdivisions of sections, which they were intended to designate, and that corners of half and quar- ter sections not marked shall be placed as nearly as possible "equi- distant from those two corners which stand on the same line." This act further provides that ' ' The boundary lines actually run and marked * * * shall be established as the proper boundary lines of the sections or subdivisions for which they were intended; and the length of such lines as returned by * * * the survey- ors * * * shall be held and considered as the true length thereof, and the boundary lines which shall not have been actually run and marked as aforesaid shall be ascertained by running straight lines from the established corners to the opposite corresponding corners; but in those portions of the fractional townships where no such oppo- site or corresponding corners have been or can be fixed, the said boundary lines shall be ascertained by running from the established corners due north and south or east and west lines, as the case may be, to the * * * external boundary of such fractional town- ship." : The,, act of Congress approved April 25, 1812, provided "That there shall be established in the Department of the Treasury an 8 MANUAL OF SURVEYING INSTRUCTIONS. office to be denominated the General Land Office, the chief officer of which shall be called the Commissioner of the General Land Office, whose duty it shall be, under the direction of the head of the department, to superintend, execute, and perform all such acts and things touching or respecting the public lands of the United States, and other lands patented or granted by the United States, as have heretofore been directed by law to be done or performed in the office of the Secretary of State, of the Secretary and Register of the Treasury, and of the Secretary of War, or which shall hereafter by law be assigned to the said office." The act of Congreas approved April 24, 1820, provides for the sale of public lands in half-quarter sections, and requires that "in every case of the division of a quarter section the line for the division thereof shall run north and south * * * and fractional sections, containing one hundred and sixty acres and upward, shall, in like manner, as nearly as practicable, be subdivided into half-quarter sections, under such rules and regulations as may be prescribed by the Secretary of the Treasury; but fractional sections containing less than one hundred and sixty acres shall not be divided." The act of Congress approved May 29, 1830 (sees. 2412, 2413, R. S.), provides for the fine and imprisonment of any person obstructing the survey of the public lands, and for the protection of surveyors, in the discharge of their official duties, by the United States marshal, with sufficient force, whenever necessary. The act of Congress approved April 5, 1832, directed the sub- division of the public lands into quarter quarters; that in every ease of the division of a half-quarter section the dividing line should run east and west; and that fractional sections should be subdivided under rules and regulations prescribed by the Secretary of tha Treasury. Under the latter provision the Secretary directed that fractional sections containing less than 160 acres, or the residuary portion of a fractional section, after the subdivision into as many quarter-quarter sections as it is susceptible of, may be subdivided into lots, each containing the quantity of a quarter-quarter section as nearly as practicable, by so laying down the line of subdivision that they shall be 20 chains wide, which distances are to be marked on the plat of subdivision, as are also the areas of the quarter quarters and residuary fractions. The last two acts above mentioned provided that the corners and contents of half-quarter and quarter-quarter sections should be ascer- REGULATIONS IMPOSED BY LAW. 9 tained, as nearly as possible, in the manner and on the principles directed and prescribed in the act of Congress approved February 11, 1805. The act of Congress approved July 4, 1836, provided for the re- organization of the General Land Office, and that the executive duties of said office "shall be subject to the supervision and control of the Commissioner of the General Land Office under the direction of the President of the United States." The repealing clause is, "That such provisions of the act of the twenty-fifth of April, in the year one thousand eight hundred and twelve, entitled 'An act for the establishment of a General Land Office in the Department of the Treasury,' and of all acts amendatory thereof, as are incon- sistent with the provisions of this act, be, and the same are hereby, repealed. " From the wording of this act it would appear that the control of the General Land Office was removed from the Treasury Depart- ment, and that the commissioner reported directly to the President; but, as a matter of fact, the Secretary of the Treasury still had supervisory control, for the act of Congress approved March 3, 1849, by which the Department of the Interior was established, provided, "That the Secretary of the Interior shall perform all the duties in relation to the General Land Office, of supervision and appeal, now discharged by the Secretary of the Treasury * * *." By this act the General Land Office was transferred to the Department of the Interior, where it still remains. 8. The following comprises so much of the general laws relating to the survey of the public domain as it is deemed necessary to incor- porate in this volume, reference being made by chapter and section to the codification of the Public Land Laws, prepared pursuant to acts of Congress approved March 3, 1879, and June 16, 1880, and by section number to the Revised Statutes of the United States. SEC. 32. The Commissioner of the General Land Office shall per- form, under the direction of the Secretary of the C m Interior a11 executive duties appertaining to the surveying and sale of the public lands of the United States, or in anywise respecting such public lands; and, also, such as relate to private claims of lands, and the issuing of patents for all grants of land under the authority of the Govern- ment. (R. S., 453.) 66466~19 2 10 MANUAL OF SURVEYING INSTRUCTIONS. SEC. 61. The Commissioner, under the direction of the Secretary of the Interior, is authorized to enforce and carry Power of Com- -^ execution every part of the public j d j missioner to make . f f regulations. not otherwise specially provided for. (R. S., 2478.) SEC. 77. There shall be appointed by the President, by and with the advice and consent of the Senate, a surveyor Surveyor general, genera i f or fa e states and Territories herein named, how and where ap- , pointed. embracing, respectively, one surveying district, namely: Louisiana, Florida, Minnesota, Kansas, California, Nevada, Oregon, Nebraska and Iowa, Dakota, Colorado, New Mexico, Idaho, Washington, Montana, Utah, Wyoming, Arizona. (R.S.,2207.) SEC. 83. Every surveyor general, while in the discharge of the Residence of sur- duties of his office, shall reside in the district for veyor general. which he is appointed. (R. S. 2214.) SEC. 84. Every surveyor general shall, before entering on the duties of his office, execute and deliver to the eneraf ' ^^^ Secretary of the Interior a bond, with good and sufficient security, for the penal sum of thirty thousand dollars, conditioned for the faithful disbursement, ac- cording to law, of all public money placed in his hands, and for the faithful performance of the duties of his office; and the Presi- dent has discretionary authority to require a new bond and additional security, under the direction of the Secretary of the Interior, for the lawful disbursement of public moneys. (R. S., 2215, 2216.) SEC. 85. The commission of each surveyor general shall cease and expire in four years from the date thereof, unless Duration of office. sooner vacated by death, resignation, or removal from office. (R. S., 2217.) SEC. 86. Every surveyor general, except where the President sees Continuance of cause otherwise to determine, is authorized to con- duties and bond tinue in the uninterrupted discharge of his regular after expiration of official duties after the day of expiration of hie commission. commission and until a new commission is issued to him for the same office, or until the day when a successor enters upon the duties of such office; and the existing official bond of any officer eo acting shall be deemed good and sufficient and in force until the date of the approval of the new bond to be given by him, if recom- missioned, or otherwise, for the additional time he may so continue KEGULAT1ONS IMPOSED BY JLA\\ '. 11 officially to act, pursuant to the authority of this section. (R. S., 2222.) SEC. 87. Whenever the surveys and records of any surveying die- Transfer of papers tr * ct are completed the surveyor general thereof and discontinuance shall be required to deliver over to the secretary of office in case of of state of the respective States, including such completed surveys. surveys> or to 8Uch other officer as may be authorized to receive them, all the field notes, maps, records, and other papers appertaining to land titles within the name ; and the office of surveyor general in every such district shall thereafter cease and be discon- tinued. (R.S.,2218.) SEC. 88. In all cases of discontinuance, as provided in the preced- ing section, the authority, powers, and duties of Devolution of ^ surve yor general in relation to the survey, re- powers upon Com- ..... ., ,' . . ' missioner in case of aurve y> or subdivision of the lands therein, and all discontinuance. matters and things connected therewith, shall be vested in and devolved upon the Commissioner of the General Land Office. (R. S., 2219.) SEC. 89. Under the authority and direction of the Commis- sioner of the General Land Office any deputy Free access to surveyor or other agent of the United States shall public records de- have free accega to h field ^ livered to States, and condition of records, and other papers for the purpose of such delivery. takin g extracts therefrom or making copies thereof without charge of any kind; but no transfer of such public records shall be made to the authorities of any State until such State has provided by law for the reception and safe- keeping of such public records, and for the allowance of free access thereto by the authorities of the United States. (R. S., 2220, 2221.) SEC. 99. First. The public lands shall be divided by north and R south lines run according to the trur; meridian, and by others crossing them at right angles, so as to form townships of six miles square, unless where the line of an In- dian reservation, or of tracts of land heretofore surveyed or pat- ented, or the course of navigable rivers, may render this impracti- cable ; and in that case this rule must be departed from no further than such particular circumstances require. Second. The corners of the townships must be marked with pro- gressive numbers from the beginning; each distance of a mile between such corners must be also distinctly marked with marks different from those of the corners. ] 2 MANUAL OF SURVEYING INSTRUCTIONS. Third. The township shall be subdivided into sections, containing as nearly as may be, six hundred and forty acres each, by running; through the same, each way, parallel lines at the end of every two miles 1 ; and by making a corner on each of such lines at the end of every mile. The sections shall be numbered, respectively, begin- ning with the number one in the northeast section, and proceeding west and east alternately through the township with progressive numbers till the thirty-six be completed. Fourth. The deputy surveyors, respectively, shall cause to be marked on a tree near each corner established in the manner de- scribed, and within the section, the number of such section, and over it the number of the township within which such section may be; and the deputy surveyors shall carefully note, in their respective field books, the names of the corner trees marked and the numbers so made. Fifth. Where the exterior lines of the townships which may be subdivided into sections or half sections exceed, or do not extend six miles, the excess or deficiency shall be specially noted, and added to or deducted from the western and northern ranges of sections or half sections in such townships, according as the error may be in running the lines from east to west, or from south to north ; the sec- tions and half sections bounded on the northern and western lines of such townships shall be sold as containing only the quantity expressed in the returns and plats, respectively, and all others as containing the complete legal quantity. Sixth. All lines shall be plainly marked upon trees, and measured with chains, containing two perches of sixteen and one-half feet each, subdivided into twenty-five equal links; and the chain shall be adjusted to a standard to be kept for that purpose. 2 Seventh. Every surveyor shall note in h}s field book the true situations of all mines, salt licks, salt springs, and mill seats which come to his knowledge; all water courses over which the line he runs may pass ; and also the quality of the lands. Eighth. These field books shall be returned to the surveyor gen- eral, who shall cause therefrom a description of the whole lands sur- 1 Authority for the establishment of section lines at intervals of 1 mile is found in the act of Congress approved May 10, 1800, previously quoted. 2 The superior results obtained by the use of modern steel ribbon tapes, in con- trast with the obsolete link chain, have led to the abandonment of the latter, except that the "chain unit," which is peculiarly adapted to land surveying, has always been employed. REGULATIONS IMPOSED BY LAW. 13 veyed to be made out and transmitted to the officers who may superintend the sales. He shall also cause a fair plat to be made of the townships and fractional parts of townships contained in the lands, describing the subdivisions thereof, and the marks of the corners. This plat shall be recorded in books to be kept for that purpose; and a copy thereof shall be kept open at the surveyor general's office for public information, and other copies shall be sent to the places of the sale and to the General Land Office. (Acts of May 18, 1796, and May 10, 1800, and R. S., 2395.) SEC. 100. The boundaries and contents of the several sections, half Boundaries and sect i ns > an( * quarter sections of the public lands contents of public shall be ascertained in conformity with the follow- lands, how ascer- ing principles : tained - First. All the corners marked in the surveys returned by the surveyor general shall be established as the proper corners of sections, or subdivisions of sections, which they were intended to designate, and the corners of half and quarter sections, not marked on the surveys, shall be placed as nearly as possible equidistant from two corners which stand on the same line. Second. The boundary lines, actually run and marked in the surveys returned by the surveyor general, shall be established as the proper boundary lines of the sections or subdivisions for which they were intended, and the length of such lines as returned shall be held and considered as the true length thereof. And the boundary lines which have not been actually run and marked shall be ascer- tained by running straight lines from the established corners to the opposite corresponding corners; but in those portions of the fractional townships, where no such opposite corresponding corners have been or can be fixed, the boundary lines shall be ascertained by running from the established corners due north and south or east and west lines, as the case may be, to the water course, Indian boundary line, or other external boundary of such fractional township. Third. Each section or subdivision of section, the contents whereof have been returned, by the surveyor general, shall be held and considered as containing the exact quantity expressed in such return; and the half sections and quarter sections, the contents whereof shall hot have been thus returned, shall be held and considered as containing the one-half or the one-fourth part, respectively, of the returned contents of the section of which they may make part. (Act of Feb. 11, 1805, and K. S., 2396.) 14 MANUAL OF SURVEYING INSTRUCTIONS. BBS. '101. In every case of the division of a quarter section the line for the division thereof shall run north and r^ U w f ^ ivision south, and the corners and contents of half-quarter of half-quarter sec- , . , tiom, how ran. sections which may thereafter be sold shall be ascertained in the manner and on the principles directed and prescribed by the section preceding, and fractional sections containing one hundred and sixty acres or upwards shall in like mariner, as nearly as practicable, be subdivided into half- quarter sections, under such rules and regulations as may be pre- scribed by the Secretary of the Interior, and in every case of a division of a half-quarter section, the line for the division thereof shall run east and west, and the corners and contents of quarter-quarter sec- tions, which may thereafter be sold, shall be ascertained, as nearly as may be. in the manner and on the principles directed and pre- scribed by the section preceding; and fractional sections containing fewer or more than one hundred and sixty acres shall in like manner, as noaiiy as may be practicable, be subdivided into quarter-quarter sections, under such rules and regulations as may be prescribed by the Secretary of the Interior. (R. S., 2397.) SEC. 106. The public surveys shall extend over all mineral lauds, and all subdividing of surveyed lands into lots less Extension of pub- t j ian one hundred and sixty acres may be done by county and local surveyors at the expense of claimants; but nothing in this section contained shall require the survey of waste or useless lands. (R. S., 2406.) SEC. 118. Each surveyor general, when thereunto duly authorized by law, shall cause all confirmed private land Surveyors general claims within his district to be accurately siir- to surve ^ s pr ^^ veyed, and shall transmit plats and field notes confirmed, etc. thereof to the Commissioner of the General Land Office for his approval . When publication of such surveys is authorized by law, the proof thereof, together with any objections properly filed, and all evidence submitted either in sup- port of or in opposition to the approval of any such survey, shall also be transmitted to said Commissioner. (R. S., 2447.) SEC. 120. Every person who in any manner, by threat or force, * interrupts, hinders, or prevents the surveying of Penalty for inter- ^ public lan( j s? or o f any private land claim which has been or may be confirmed by the United Slates, by the persons authorized to survey the same, in conformitv with the instructions of the Commissioner of the Gen- REGULATIONS IMPOSED BY LAW. 15 eral Land Office, shall be fined not less than fifty dollars, nor more than three thousand dollars, and be imprisoned not less than one nor more than three years. (R.S.,2412.) SEC. 121. Whenever the President is satisfied that forcible oppo- sition has been offered, or is likely to be offered, Protection of sur- to any 8Urve y Or or deputy surveyor in the dis- veyor by marshal of , ,. , . , , ,. . ,, , .. , , district charge of his duties in surveying the public lands, it may be lawful for the President to order the marshal of the State or district, by himself or deputy, to attend such surveyor or deputy surveyor with sufficient force to protect such officer in the execution of his duty, and to remove force should any be offered. (R. S., 2413.) 9. More recent legislation has brought about (a) provision for the appointment of a United States Surveyor General for the District of Alaska; (6) authority for the purchase of durable monuments, to be employed in place of native material to mark public land corners; (c) penalty for the destruction of monuments of the public land surveys; (d) authority for necessary resurveys; and (e) change of survey system from contract to direct with authority for the em- ployment of a permanent corps of United States surveyors; all as indicated by the following quotations from the United States Statutes: The act of Congress approved May 17, 1884, providing a civil government for Alaska, provides "That the said Surveyor general District of Alaska is hereby created a land dis- for the District of,.,.,.,,, ... * i -jj/u Ai as k a tnct, r and the marshal provided for by this act shall be ex officio surveyor general of said district." (23 Stat., 24, sec. 8.) The act of Congress approved July 24, 1897, amends the act approved May 17, 1884, and provides "That there shall be appointed by the President, by and with the advice and consent of the Senate, a surveyor generarfor the District of Alaska, embracing one surveying district. ' ' (30 Stat. , 215, sec . 2. ) The act of Congress approved May 27, 1908, provided "for the purchase of metal monuments to be used for public land survey corners wherever practicable. >r (35 Stat., 347.) This authority was amplified by the act of Congress approved June 25, 1910, making appropriation for sundry civil expenses for the fiscal year ended June 30,1911, and has been continued from year to year to the present time; The act approved July 1, 1918, provided, under "Surveying the Public Lands." as follows: 16 MANUAL OF SURVEYING INSTRUCTIONS. ''That the sum of not exceeding 10 per centum of the amount hereby appropriated may be expended by the Commissioner of the General Land Office, with the approval of the Secretary of the Interior, for the purchase of metal or other equally durable monu- ments to be used for public land survey corners wherever practi- cable: * * *." (40 Stat., 668.) The act of Congress approved March 4. 1909, entitled "An act to penalty for the c d^y> revise, and amend the penal laws of the destruction of sur- United States," provides punishment for offenses vey monuments. against the operation of the surveying service of the Government, as follows: "Whoever shall willfully destroy, deface, change, or remove to another place any section corner, quarter-section corner, or meander post, on any Government line of survey, or shall willfully cut down any witness tree or any tree blazed to mark the line of a Government survey, or shall willfully deface, change, or remove any monument or bench mark of any Government survey, shall be fined not more than $250, or imprisoned not more than six months, or both." (35 Stat., 1088, sec. 57.) The act of Congress approved March 3, 1909, entitled "An act authorizing the necessary resurvey of public " lands," as amended by joint resolution approved June 25, 1910, provides as follows: "That the Secretary of the Interior may, in his discretion, cause to be made, as he may deem wise under the rectangular system now provided by law, such resurvey s or retracements of the surveys of public lands as, after full investigation, he may deem essential to properly mark the boundaries of the public lands remaining undis- posed of: Provided, That no such resurvey or retracement shall be so executed as to impair the bona fide rights or claims of any claimant, entryman, or owner of lands affected by such resurvey or retracement: Provided further, That not to exceed 20 per centum of the total annual appropriation for surveys and resurveys of the public lands shall be used for the resurveys and retracements authorized here- by." (35 Stat., 845, and 36 Stat., 884.) The act of Congress approved September 21, 1918, entitled ' l An act authorizing the resurvey or retracement of lands heretofore re- turned as surveyed public lands of the United States under certain conditions", provides authority for the resurvey by the Govern- ment of townships heretofore held to be ineligible for resurvey REGULATIONS IMPOSED BY LAW. 17 under existing regulations of the Department of the Interior by reason of disposals in excess of fifty per centum of the total area thereof. The act provides: " That upon the application of the owners of three-fourths of the privately owned lands in any township covered by public-land surveys, more than fifty per centum of the area of which townships is privately owned, accompanied by a deposit with the United States surveyor general for the proper State, or if there be no sur- veyor general of such State, then with the Commissioner of the General Land Office, of the proportionate estimated cost, inclusive of the necessary (office) work, of the resurvey or retrace ment of all the privately owned lands in said township, the Commissioner of the General Land Office, subject to the supervisory authority of the Secretary of the Interior, shall be authorized in his discretion to cause to be made a resurvey or retracement of the lines of said township and to set permanent corners and monuments in accord- ance with the laws and regulations governing surveys and resurveys of public lands; that the sum so deposited shall be held by the surveyor general or commissioner when ex officio surveyor general and may be expended in payment of the cost of such survey, in- cluding field and office work, and any excess over the cost of such survey and the expenses incident thereto shall be repaid pro rata to the persons making said deposits or their legal representatives; that the proportionate cost of the field and office work for the re- survey or retracement of any public lands in such township shall be paid from the current appropriation for the survey and resurvey of public lands, in addition to the portion of such appropriation otherwise allowed by law for resurveys and retracements; that similar resurveys and retracements may be made on the applica- tion, accompanied by the requisite deposit, of any court of compe- tent jurisdiction, the returns of such resurvey or retracement to be submitted to the court; that the Secretary of the Interior is author- ized to make all necessary rules and regulations to carry this act into full force and effect." (40 Stat., 965.) The act of Congress approved June 25, 1910 (36 Stat., 703, 740), making appropriation for sundry civil expenses * '" for the fiscal year ended June 30, 1911, provided, under "Surveying the Public Lands": " The sur- veys and resurveys to be made by such competent surveyors as the Secretary of the Interior may select, * * * . " This provision of law. 18 MANUAL OF SURVEYING INSTRUCTIONS. brought to a close the contract system which had theretofore been adhered to since the beginning of the public land surveys, and the authority for the employment of a permanent corps of United States surveyors has been continued from year to year to the pres- ent time. The following comprises that part of the act of Congress approved July 1, 1918, under " Surveying the Public Lands," re- lating directly to the administrative control of the surveying service: "For surveys and resurveys of public lands, under the supervision of the Commissioner of the General Land Office and direction of the Secretary of the Interior, * * *. The surveys and resurveys provided for in this appropriation to be made by such competent surveyors as the Secretary of the Interior may select, * * *. " (40Stat., 668.) GENERAL RULES. 10. From the foregoing synopsis of congressional legislation it is evident First. That the boundaries of the public lands established and returned by the duly appointed surveyors, when approved by the surveyors general and accepted by the Commissioner of the General Land Office, are unchangeable. Second. That the original township, section, and quarter-section corners established by the surveyors must stand as the true corners which they were intended to represent, whether in the place shown by the field notes or not. Third. That quarter-quarter-section corners not established in the process of the original survey shall be placed on the line connecting the section and quarter-section corners, and midway between them, except on the last half mile of section lines closing on the north and west boundaries of the township, or on other lines between fractional or irregular sections. Fourth. That the center lines of a regular section are to be straight, running from the quarter-section corner on one boundary of the sec- tion to the corresponding corner on the opposite section line. Fifth. That in a fractional section where no opposite corresponding quarter-section corner has been or can be established, the center line of such section must be run from the proper quarter-section corner as nearly in a cardinal direction to the meander line, reservation or other boundary of such fractional section, as due parallelism with section lines will permit. REGULATIONS IMPOSED BY LAW. 19 Sixth. That lost or obliterated corners of the approved surveys must be restored to their original locations whenever it is possible to do so. Actions or decisions by surveyors which may result in changes of boundaries of patented lands and disturb questions of ownership in connection therewith are subject to review by the courts. THE MANUAL. 11. Various regions of the United States have been surveyed under different sets of instructions issued at periods ranging from 1785 to the present time. The earliest rules were given to surveyors in manuscript or in printed circulars. Regulations more in detail, improving the system for greater accuracy, permanency and uni- formity, were issued in book form in editions of 1855, 1881, 1890, 1894 and 1902. The Manual of Surveying Instructions has been again revised with a view to harmonizing the printed instructions furnished to the sur- veyors with recent legislation and current surveying practice. The use of iron-post corner monuments adds much to the permanency of the evidence of the surveys, but this calls for little change in rules except to outline the standard practice. A growing necessity for resurveys to identify and restore original surveys actually made, but poorly monumented, or to supersede grossly erroneous or fraudulent original surveys "to properly mark the boundaries of the public land remaining undisposed of" has demanded a full discussion of the subject in this revision of the Manual. The change from the contract system to the present system under which the public-land surveys are executed by a permanent corps of surveyors employed by the General Land Office has involved changes in the administra- tive control without departing from previous technical procedure, and hereafter throughout the Manual all reference to administrative questions will be found to be stated in general terms in order to avoid confusing that matter with the purely technical subjects. Modern surveying practice has been introduced into the public-land surveys as far as legally consistent and efficient, which has prompted a rather full instructive treatment of the subjects of measurements with long steel tapes, stadia method and triangulations, and field observations for the determination of time, latitude and azimuth, to afford versatility on the part of the surveyor in adopting methods beet suited to the ever-changing conditions under which his work must be accomplished. 20 3IANTJAL OF SURVEYING INSTRUCTIONS. The instructions contained in this Manual are to be observed by every surveyor engaged in the execution of the public-land surveys. All other surveyors, including those who have at times been em- ployed in the surveying service of the General Land Office, should bear in mind that in their private capacities they are acting under somewhat different rules of law from those governing original sur- veys, and surveyors should discriminate between the provisions of the statute which control original surveys and those which apply to the retracement of lines that have been officially established and approved. THE STANDARD FIELD TABLES. 12. There has been published by the General Land Office, in the shape of a pocket field book, a compendium of tables and formulae entitled "Standard Field Tables." The volume embraces the data peculiarly useful to surveyors engaged in subdividing the public lands. The Standard Field Tables are issued as a supplement to the Manual, and as such the former are apart of the latter, with con- tents as follows: 1. Units of linear measure, units of area, expansion of steel tapes, and conversion tables; chains to feet and feet to chains. 2. Reduction in latitude to south boundary of township, and cor- rections for convergency within a township. 3. Traverse table, for the correction of random lines. 4. Traverse tables. 5. Correction of error in stadia wire interval. 6. Stadia coefficients, vertical rod. 7. Natural sines and cosines. 8. Natiiral tangents and cotangents. 9. Logarithmic sines, cosines, tangents and cotangents. 10. Logarithms of numbers. 11. Convergency of meridians, and differences of latitude and longi- tude. 12. Azimuths of the tangent to the parallel. 13. Offsets from the tangent to the parallel. 14. Azimuths of the secant. 15. Offsets from the secant to the parallel. 16. Lengths of arcs of the earth's surface. 17. Apparent time of sunrise and sunset. 18. Conversion tables, degrees to time, and time to degrees. 19. Sidereal conversions, and reductions to the local mean time of upper culmination of Polaris. REGULATIONS IMPOSED BY LAW. 21 20. Mean refractions in zenith distance. 21. Coefficients to apply to mean refractions for variations in ba- rometer and temperature. 22. Coefficients for computing errors in azimuth due to small errors in declination or latitude. 23. Mean refractions in polar distance. 24. Trigonometric formulas for the solution of plane triangles. 25. Trigonometric formulas for the solution of stadia measurements, observations for time, latitude and azimuth, and problems in convergency. EPHEMERIS OF THE SUN AND POLARIS, AND TABLES OF AZI- MUTHS OF POLARIS. 13. The above title has been given to a second supplement to the Manual which is published each year, a convenience which serves to supply the surveyors with all necessary data relating to the daily positions of the sun and Polaris without requiring frequent revision of the text of the Manual or the Standard Field Tables. As a supple- ment to the Manual the data contained in the Ephemeris will be adopted in preference to that contained in other publications over which the General Land Office has no control either as to accuracy or fitness for use in the public-land surveys. CHAPTER II. INSTRUMENTS AND METHODS. MEASUREMENTS. 14. The law prescribes the chain as the unit of linear measure for the survey of the public lands, and all returns of measurements are to be made in true horizontal distances, in miles, chains and links. The chain unit is known as the invention of Edmund Gunter, an English astronomer of the seventeenth century, and is especially convenient in computing areas in the unit of acres, one acre being equal to 10 square chains. Units of linear measure. 1 chain ==100 links. =66 feet. 1 mile =80 chains. =5,280 feet. Units of area. 1 acre=10 square chains. =43,560 square feet. 1 square mile =640 acres. 15. Each surveyor will be provided with a standard and an assortment of 1, 2, 5 or 8-chain steel tapes. The standard tape will be employed for comparison with the field tapes, in order that errors in the latter may be noted and corrected. Before chainmen are intrusted with their actual duties they should be instructed by the chief of party, and required to measure over one or more trial lines of level and mountainous surface, to secure accuracy and uniformity of results. 16. It is essential to the record of a survey to state briefly at the beginning of the iield notes, with every set of returns, the general manner of making measurements in the survey, and as topographical 23 24 MANUAL OF SURVEYING INSTRUCTIONS. difficulties are encountered making it necessary to depart from the stated general method, it is desirable to record the plan of special measurement adopted. The field notes thus exhibit the manner of making all measurements, and the record should be such that another surveyor retracing any line can substantially duplicate the exact procedure adopted in the original survey. The following paragraphs are illustrative of the record to be made in the field notes: "Unless otherwise specified all measurements are made with a Chicago 1 -chain steel tape compared with a Chesterman standard steel tape and found correct." " Unless otherwise specified all measurements are made with a Lallie 2-chain steel tape found correct by comparison with a Luf kin standard steel tape." " Unless otherwise specified all measurements are made with a Lufkin steel tape 8 chains in length compared with a Chesterman standard steel tape and found correct. The measurements are made on the slope, the vertical angle determined, and the slope measure- ments properly reduced to true horizontal distances." THE LONG STEEL TAPE. 17. The most approved method of measurement involves the use of steel ribbon tapes from 2 to 8 chains in length; in its use in the public-land surveys the tape is properly alined and stretched, and the measurements are made on the slope at any convenient dis- tance up to the length of the tape as limited by the topography . The vertical angles of the lesser slopes are determined by the use of clinometers in the hands of the chainmen, while the vertical angles of the particularly sharp slopes are determined with the transit oper- ated by the surveyor. The slope distances are then reduced to true horizontal distances and the entire operation suitably recorded. It is not considered necessary to exhibit in the official field notes any but the true horizontal distances, omitting details, except where precise measurements are made of various bases for special use. 18. The following is an example of both field and final record for the use of the long steel tape and clinometer, and reductions by the use of the traverse tables (see Table 4, Standard Field Tables): INSTRUMENTS AND METHODS. Field record. Final field notes. Mean verti- cal angle. Dis- tance on slope. True horizon- tal dis- tance. Inter- mediate meas- ure- ment. Differ- ence in eleva- tion. -12** -17 + 8T +19 *7f1 -6J- -ioi - -1 4 o Chains. 4.50 2.20 Chains. 4.398 2.098 Chains. 3.80 0.00 1.20 1.90 1.15 Chains. -0.95 - .66 - .75 Chains. 10.30 23.50 24.70 25.40 32.0 40.00 North, bet. sees. 19 and 24. Desc. 155 ft. over NW. slope, through scattering timber and dense undergrowth. Dry gulch, course W.; asc. 295 ft. over SW. slope. Spur, slopes W.; desc. 185 ft. to 1/4 sec. cor., over NW.slope. Wagon road, bears E. and W. Leave undergrowth. Enter heavy timber, bears N W . and SE. Set an iron post, etc. 6.70 8.00 6.496 7.917 + .75 4-1-15 +2.10 + .44 14.70 6.20 14. 413 5.835 20.90 3.30 20.248 3.270 24.20 8.00 23.518 7.949 -0.91 - .66 -1.21 32.20 3.70 31.467 3.641 35.90 5.00 35.108 4.851 40.90 .04 39. 959 .04 40.94 40.00 40.00 40.00 19. A simplification of the reduction of measurements on the slope is obtained by the use of two diagrams constructed on cross- section paper, as follows: The first with the vertical lines repre- senting intervals of 20 links measurement on the slope to 2, 5 or 8 chains to suit the length of tape used ; the horizontal lines repre- senting the correction in links to be made from the measurement on the slope to obtain the true horizontal distance; slanting lines are drawn to represent various degrees of slope scaled to the proper 55465 19 3 26 Slope MANUAL OF SURVEYING INSTRUCTIONS. 5670 Measurement in Chains. I Z 3 Fig. I. INSTRUMENTS AND METHODS. 27 Slope Measurement in 01 3 Chains. A. $ e WOttOn in Feet. B 1^" II || 5; > ; = Jj! ;s ^~^ = ; -si - _- _ *^, .. s~ = :- = "^^ = =: \" 2* 3 nee //> / IN - --N \ ^ ^ ^ W* ;|| Is ^ ^> ^ \ sN S; > N \ s s S % S s x s s, " ^; :>; ^E ^fc^ - Is -. ~~- ~J "J := 5' 6* g ^ S *> v NT v*V" is N v- - ^ ^ v ^ ^ fr" -: ** N ^ i x^ ^\ '^ ^ ^ N^; ' ^ . IT " kr _._ i> ^ k \ S S v N, -.. i \ K ^ L^ "s * ^ y" r ,\ S \ ^ \ p^ -T^ i ^ ^> "^ \o e V '"*\S k^ S H s ^ X, " - v N ^ S 5 , \ s^ s^ "^ 5^ '^ : N \s ^ , S -^ N S^ s X ' x >! 12 \ S \ ^ ^ 4 ^ \ v^ r^ JJ x. ^v., S l^s > ^ \ N k^ V 'v \ ^ ! 13 v ^ ^ N s k r V, ^ ^ R k \ S- s^ s ' A \ [S^ " k s \ K s^ V \ $ ^ ' \ "\ > \ ^ \ ""s. ^k \S s^ sj ^ X N \ . N ^ s N \ \ ^ \ N r\ "^ k 17^ -^S s ^KC x\ X k s ^ \ ^\ \T? ; \ ^c \\ k \ v \ IR N \ \ \ \ S v SJ k, > x l\T\ \ , \ ^ \K N 4 N ( \r\ ^ \ X ^> \ 21* ^ C! ^ N ^ ^\ s v \ S X s^^ \ 22 \j\ ^ x^ a s \ ^ \ 23 k. ^ -^ S^ V 24* s \ N > s 22R S, N 1^ ?*>" \ l\ N \ \ . \ s 26 N N s ^ \ V S 2d" * s \ B 23 V 30 275 j ,_ Fig. 2. Reduction for difference of elevation. 28 MANUAL OF SURVEYING INSTRUCTIONS. points for the correction for the full length of the tape. The second diagram is constructed with the vertical lines representing similarly the measurement on the slope in the chain unit; the horizontal lines in this diagram representing the difference in elevation in feel, at intervals of 5 feet; slanting lines are drawn to represent various degrees of slope scaled to the proper points for the differences of elevation for the full length of the tape. (See figs. 1 and 2.) 20. The following is ?.n example of record for the use of the long steel tape and clinometer, r.nd reductions by the use of the reduction diagrams: Field record. Mean vertical angle. Dis- tance on slope. Correo- iiou to hori- zontal. Chains. 0.10 .10 Inter- mediate meas- ure- ment. Differ- ence in eleva- tion. Final field notes. -12^ -17^ + SJ -H9f + 7f> -6T Chains. 4.50 2.20 Chains. 3.80 0.00 1.20 1.90 1.15 Peft, - 60 - 45 - 50 Chain*, 10. 30 23.50 24.70 25.40 32.60 40.00 North, bet. sees. 19 and 24. Desc. 155 ft. over NW. slope, through scattering timber and dense undergrowth. Dry gulch, course W.; asc. 295 ft. over SW. slope. Spur, slopes W.; dose. 185 ft. to % sec. cor., over NW. slope. Wagon road, bears E. tmd W. Leave undergrowth. Enter heavy timber, bears NW. and SE. Set an iron post, etc. C.70 S.OO 0.20 .08 + 50 -f 75 -f 140 + 30 14.70 6. 20 0.28 .37 20.90 3.30 0.65 .03 24.20 8.00 0.68 .05 - 60 - 45 - 80 -101 14 6 32.20 3.70 0.73 .06 35.90 5.00 0.79 .15 40.90 .04 0.94 .00 40.64 40. JO i 0.94 0.00 INSTRUMENTS AND METHODS. 21. By a skillful use of the long steel tape on the slope, with cor- rect determinations of the vertical angle, and proper reductions from the slope to the true horizontal distance, the surveyor obtains one of the most rapid and reliable methods of measurement. It IP essential to make all reductions for distance as the work progresses, but the additional information regarding the amount of the ascents and descents is readily obtainable from the record at the conven- ience of the surveyor. STADIA MEASUREMENTS. 22. Under proper safeguards the stadia method of measurement affords a useful and reliable means of overcoming the difficulties of obtaining correct distances across water and over precipitous slopes that can not be reached with the tape. It is required that the wire interval or ratio be determined in the field by frequent tests under working conditions in comparison with steel tape measurement, solving the formula given in the Standard Field Tables (p. 221) for the value of the wire ratio with the horizontal distance known. The record of the stadia tests should be given in the field notes. It is essential to accurate stadia work that rods of approved construction be used, together with two targets and a properly adjusted rod level to secure true vertical readings; the readings at all times must be restricted to suitable atmospheric conditions and to distances per- mitting exact bisections of the targets. Possible criticism of the use of the stadia method is found in the failure to observe proper details and not in the reliability of the method if skillfully followed. 23* It is desirable to state briefly at the beginning of the field notes, with every set of returns, the general plan of making stadia measurements. The following paragraphs are illustrative of the character of such record: "All stadia measurements are made with fixed stadia wires with' a ratio of 1 : 132 , as exhibited by the tests shown in the field notes; the focal constant of the instrument is 1. 2 links; the rod used is a standard Philadelphia level rod graduated to feet and equipped with two targets and a rod level; all readings are made with a vertical rod." ''All stadia measurements are made with fixed stadia wires with a ratio of 1 : 100 , as exhibited by the tests shown in the field notes; the focal constant of the instrument is 1. 2 links; the rod used is a standard Troy level rod graduated to feet and equipped with two targets and a rod level: all readings are made with a vertical rod." 30 MANUAL OF SURVEYING INSTRUCTIONS. 24. Notation used in stadia measurements: Hor. dist.: The true horizontal distance from the center of the in- strument to the rod. Diff. elev.: The true vertical distance from the height of the instru- ment to the center point between the two targets of the rod. " r " : Vertical rod reading . " v " : Observed vertical angle . "K": The wire interval or ratio. "c": Distance from the center of the instrument to the object glass. "/": Distance from the plane of the cross-wires to the object glass. Hor. dist.=.> cos 2 ^-f-(c+/) cos v. Diff. elev.=J> % sin 2v-f(c-f/) sin r. } Diff. elev. & 9 .3 25. In Table 6, Standard Field Tables, the natural functions "cos 2 !'" and " sin 2u" are tabulated by intervals of 2' for all angles from 0' to 28 0'; these values become natural coefficients of the rod reading in the use of the vertical rod. In the same table are tabulated the natural products " (c-f-/) cos v " and " (c+/) sin v, " for three values of "( c +/)" which may be considered as expressed in either the link or foot unit as convenient. 26. In public-land surveying it is convenient to have fixed stadia wires with a ratio of 1:132, so that the sum of two rod readings in feet will be equivalent to a ratio of 1:66, or a reduced distance in chains; it is also convenient to reduce the error in the wire interval to the error in 10 chains, and to eliminate the error by applying to the reduced distance the proper correction taken from the table of proportional parts (Table 5, Standard Field Tables). INSTRUMENTS AND METHODS. . oi 27. Example of test of stadia wire interval, the approximate ratio being 1:132. and the focal constant 1.2 links: Field record. Final field notes. Measurement of base by steel tape and clinometer. Vertical rod reading. W 2W True horizontal distance. Chains. -4r 3.90 -l-j 8.00 4-7-1 1 2.20 Total base Focal constant Chains. 3. 888 7. 998 2. 180 Feet. 6.992 6.998 7.002 6.995 7.003 7.004 6.997 6.995 7.001 6.998 June 11, 1911, 1 make the follow- ing test of the stadia wire inter- val: Horizontal length of base =14. 066 chs. Mean of 10 rod readings - 6.9985ft. Vertical angle of of test - -O ^ ^=132.551 Reduced error in 10 chs. -4.1 Iks. All corrections to be added to the distances given by the stadia. - 14.066 = .012 Stadia base = 14. 054 chs. " " -927. 504 ft. Mean rod reading = Coefficient for 10' 0.9999; 0.0001X6.9985 r 0082 r = _ 927.564 T - ~6TWTO~ 132 * 5pl Measured base 6'.9985H mean rod readin *- 6.9985 .0007 6.9978 -14. 066 chs. 14. 008 chs. 13.997 ^equivalent 1:66. 13.997 X 0.9999- 13. 9961 (c+/)- .012/ Error in 14. 008 chs. Error in 10.00 chs. by stadia - 0.058 chs. by stadia = 0.041 chs. 28. The error of the wire interval having been determined for a distance of 10 chains, the proportional error for any distance from 1 to 20 chains may be taken from Table 5, Standard Field Tables, thus eliminating all complex steps from the ordinary reductions of field observations. Emphasis is placed upon the necessity for the above tests for accurate stadia work, and attention is directed to the probability that successive tasts will show slightly increasing or decreasing values of the wire interval. It is not considered necessary to record in the official field notes any but the basic elements of stadia obser- vations, omitting the details of the reductions. 29. The following example of record, with reductions added, is 32 MANUAL OF SURVEYING INSTRUCTIONS. val, ratio 1:132 with an error of 4.1 links in 10 chains, and focal con- stant 1.2 links. Field record. Final field notes. Chains. N. 02' W., bet. sees. 15 and 16. Descend gradually over mountainous land. 3.194 3. 212 12.60 Rim of canon, bears NW. and BE.; precipitous descent of 170 ft. Stadia to left bank of creek: 3.194 and 3.212ft, 26 44'. Stadia to right bank of creek: 3.448 and 3.432ft., 24 10'. Stadia to right rim of canon: 4.914 and 4.895ft., -f458'. 6.406X0.79765.109 Error + . 021 (C4-/) cos v -1- .011 12.60 -f-5.14 chs. 6. 406X0. 4018=2. 574 chs. Diff. elev. =170 ft. = 17.74 Left bank of creek, 62 Iks. wide, worse NW. 3.448 3. 432 ' 6.880X0.8324=5.727 Error -f . 024 (c-f/) cos v + .011 12.60 +5.76 chs. 5.14 chs. 18.36 Right bank of creek; precipitous aspect of 225 ft. to rim of canon. Width of creek 4.914 4.895 =0.62 chs. 9.809X0.9925=9.735 Error -f . 040 (c-f-/) cos v . 012 12.60 4-9.79 chs. 9. 809X0. 0863=0. 847 chs. - 56 ft. -H70 ft. Diflf. elev. = 226 ft. -=22.30 Rim of canon, bears NW, and SE.; asc. gradually. 30. Attention is directed to the fact that in making the above reductions in the chain unit, wire ratio 1:132, the process is at once resolved into taking the sum of the two rod readings in feet mul- tiplied by the proper coefficient for vertical angle, to which product are applied the corrections for the error in the wire interval and for the horizontal value of the focal constant. As two rod readings should alwavs be taken, one as a check urxm the other, the entire INSTRUMENTS AND METHODS. 33 operation becomes very simple. It should also be noted that in computing the difference of elevation no correction has been made for the height of the instrument above the ground, nor for the mean height of the rod reading; these corrections are compensating and ordinarily may be neglected, but in precise reductions must be considered. Therefore, in ordinary work in computing differences of elevation by the stadia method it is permissible to neglect the height of the instrument above the ground, the mean height of the rod reading, the error in the wire interval, and the term "(c-f/) ein V." 31. Many surveyors prefer the conventional stadia wire ratio 1:100 generally adopted in miscellaneous surveying practice, using a rod graduated to feet. With an instrument so fitted for public- land surveys, in which the chain unit of horizontal distance is stipulated by law, the reduction is simplified by ascertaining the logarithm of "IT" -gg-, rod in feet and horizontal distance in chains, accomplishing the reduction of ll Kr cos 2 D" by logarithmic functions. 32. Example of test of stadia wire interval, the approximate ratio being 1:100, and the focal constant 1.2 links: Field record. Vertical rod reading. i Final field notes. Measurement of base by steel tape and clinometer. if? 1 sw True horizontal distance. Chains. - 3| 6.40 - 4|* 2.70 + 12J 5.20 Total base (+/) Chains. 6. 386 chs. 2.692 5.082 Feet. 9.515 9.518 9.522 9.519 9.527 9.513 9.521 9.524 9.521 9.520 July 7, 1915, I made the following test of the stadia wire interval: Horizontal length of base= 14. 160 chs. Mean of ten rod readings = 9.5200ft. Vertical angle of test . = -H54' #=98. 193 log ^>rodinfect 66 and horizon- tal distance in chains = 0.172637 - 14.160 = .012 Stadia base - 14.148chs. -933.768ft. Mean rod reading = Coefficient for 154' =0.9989; 0.0011X9.5200 - r cos 2 v= 'JWfe-f log 1T= 1.992081 9. 76 81.96 Dist. by return meas. = 2. 84 11 415 =2.617831 Diff. elev.=415 ft. 79.12 1.75 6.92 79.12 Intersect W. bay. of Tp., 14 Iks. S. of the cor. of sees. 19, 24, 25 and 30. Thence S. 89 58' E., on a true line bet. sees. 19 and 30. Ascend gradually in valley. Base of bad-land bluff, bears N. and S.: precipitous ascent of about 400 ft. Top of bad-land bluff, bears N. and S.; thence over level prairie. INSTRUMENTS AND METHODS. 37 (6) Field record. Final field notes. NOTE. Stadia wire ratio, 1:132.551; e+/)=1.2 Iks. 9.827 9.839 19.666 Error=-f.082 .012 =19.76 79 11' 33 03 67 46 ISO W loe; 19.76 " sin 67 46' ' sin 33 03' " 33.54 Dist. by tri. 1.295787 9.966447 1. 262^34 9. 736692 - 1.525542 - 33.54 chs. At the meander cor. at 57.30 chs. bet. sees. 16 and 17. a flag on Indian Island bears N. 18 41' W.; a point on a rock in the lake bears S. 82 08' W., stadia base to this point: 9.827 and 9. 839 ft., level, measured base impracticable; from point on island, flag on rock in lake bears S. 14 22' Vv r .; all bearings checked by direct reading of the solar, and all angles checked by deflection: Length of base =19.76 chs. From meander cor. to island=- 33.54 chs. At the above point on Indian Island from which the meander cor. at 57.30 chs. bet- sees. 16 and 17, bears S. 18 41' E. f 33.54 chs. dist.: I Set a limestone, 28 x 10 x 6 ins. , 21 ins. in the grour d, for auxiliary meander cor. in sec. 8, mkd. A M C on S. face; from which A spruce, 14 ins. d'am.. bears N. 42* E., 69 Iks. dist., mkd. T67NR43WS8 A V C B T. A fir-balsam, 9 ins. diam., bears N. 14J W.. 38 Iks. dist., mkd. T 67 N R 43 W S 8 A M C B T. *M8. 65 0' 0" 25 20' 0" i Rev. Mean 3 58 48 64 45 25 31 * 3i>5753> 64 52' 30" | 25 25' 30" v = 25 25' 30" Refraction^ 2' 0" Parallax- -f- V 8" Ji = 25 23' 38" f - 64 36' 22" 90 0' 0" Final field notes. Mar. 18, 1910, I make an altitude obser- vation upon the sun for time and azi- muth, making two observations, one each with the tele- scope in direct and reversed positions, observing opposite limbs of the sun. Mean watch time of observation, 3h 57m 53s p. m. Mean horizontal an- gle from flag S. to sun SW., 64 52' 30". Mean observed verti- cal angle 25 25' 30". Example of vertical reduction to the sun's center. Field record. Final field notes. Sun's lower limb Redaction to sun's center Sun's center, =25 20' 0" - +16' 6" r =25 36' 6" Refraction = - 2' 0" Parallax = -f O 7 8" =25 34' 14" =.64 25' 46" 90 9 : Phi: Latitude of the station of observation. 53. X: Lambda: Longitude of the station of observation. 54. 6: Delta: Declination of the sun or Polaris; to be taken from the Ephemeris for the date of observation; the declination of the sun is to be corrected in hourly difference to the longitude of the station and to the time of observation; north declinations are treated as positive and south declinations as negative; a northerly hourly motion is treated as positive and a southerly hourly motion is treated as negative; in the use of the solar attachment the decimation of the sun is to be corrected for refraction in polar distance, always north. Examples of computation of the sun's declination. (a) It is desired to compute the value of the sun's declination for the above altitude observation upon the sun for time and azimuth. Longitude of the station of observation, 5 11 8 m W.; apparent time of observation, 3 h 42 m p. m.: Declination of the sun at Greenwich apparent noon Mar. 18, 1910 =1 IV 3" S. Difference in time from Greenwich apparent noon to apparent time of observation: For longitude == 5 h 8 m Fortune, p. m. = -f3 42 8.83 h = 8 h 50 m Hourly difference in declination=-f-59 // .28 Difference in declination from Greenwich apparent noon to apparent time of observation: 8.83X59.28=523" = 8' 43" N. True declination of the sun . 1 2' 20" S. (6) It is desired to prepare, by computation, a table of hourly declinations of the sun, corrected for refraction in polar distance, for use with the solar attachment, for a date March 14, 1912, and for a station in latitude 33 HX N., and longitude 7 h 47 m W. 46 MANUAL OF SURVEYING INSTRUCTIONS. 2 33' 28".6 S. =Declination of the sun at Greenwich apparent noon, Mar. 14, 1912. Difference in time from Greenwich apparent noon to 7 a. m., local app. time: For longitude = 7 h 47 m For time, a. m., 12 h ~7 h O m = (-) j> _ 0_ 2.78 h = 2 h 47 m Hourly difference in declinations =-f-59 // . 2. 2' 44".5 N.== Difference in declination from Greenwich apparent noon to 7 a. m., local apparent time: 2.78X59.2= 164".5. 2 30' 44". 1 S. =True declination of the sun, 7 a. m., local apparent time. Local apparent time. True declina- tion. Refraction. Declination setting. 7 a in 2 30' 44" S 2' 41" N. 2 28' 3" S 7i... 2 30 14 1 48 2 28 26 S. . 2 29 45 1 22 2 28 23 9 2 23 46 58 2 27 48 10 2 27 47 47 2 27 11 a m 2 25 48 43 2 26 5 Noon 2 25 49 41 2 25 8 1 D. m . . 2 24 50 43 2 24 7 2. ... 2 23 51 47 2 23 4 3 .. . 2 22 52 58 2 21 54 4 2 21 53 1 22 2 20 31 4-K. .... 2 21 23 1 48 2 19 35 5 p. m 2 20 54 2 41 2 18 13 (c) It is desired to prepare, by computation, a table of hourly declinations of the sun, corrected for refraction in polar distance, for use with the solar attachment, for a date August 12, 1912, and for a station in latitude 47 1(X N., and longitude 7 h 24 m W. 15 1' 6" N.= Declination of the sun at Greenwich apparent noon, Aug. 12, 1912. Difference in time from Greenwich apparent noon to 6 a. m., local app. time: For longitude= 7 h 24 m Fortune a.m., 12 h -6 h Qm == (_)6 Q 1.4 h = l h 24 m Hourly difference in declination 45". 1. l x 3" S.= Difference in declination from Greenwich apparent noon to 6 a. m., local apparent time: 1.4X45.1=63 // . 15 0' 3" N.=True declination of the sun, 6 a. m., local apparent time. INSTRUMENTS AND METHODS. 47 Local apparent time. True declina- tion. Refrac- tion. Declination setting. 6 a m 15 0' 3"N 3' 29" N 15 3' 32" N 6i. . 14 59 40 2 22 15 2 2 Y" 14 59 18 1 46 15 1 4 8 . 14 58 33 1 9 14 59 42 9 14 57 48 5'! 14 58 40 10.. 14 57 3 42 14 57 45 11 a m 14 56 18 39 14 56 57 Noon.... 14 55 33 37 14 56 10 1 p rn. 14 54 48 39 14 55 27 14 54 3 42 14 54 45 3 14 53 18 52 14 54 10 4 14 52 33 1 9 14 53 42 5 14 51 48 1 46 14 53 34 5V . . . 14 51 26 2 22 14 53 48 6 p. nu. 14 51 3 3 29 14 54 32 (d) A graphic method for ascertaining the changing declinations of the sun, corrected for refraction in polar distance, for use with the solar attachment, is obtained by the use of a diagram constructed on cross-section paper for each date, as follows: The horizontal lines may be used to represent each hour of the day, and the vertical lines may represent intervals of V in declination. It is convenient to use the right-hand side of the sheet to represent N., and the left-hand side of the sheet to represent S., or to have N. declinations increase numerically to the right-hand side of the sheet, and S. declinations increase numerically to the left-hand side of the sheet. The vertical lines are numbered to suit the range of declination of the sun for the date. Two points are marked on the diagram to agree with the true declination of the sun; the first point is marked with the argument of declination agreeing with the declination of the sun taken from the Ephemeris for Greenwich apparent noon and with the argument of time agreeing with the local apparent time corresponding to Greenwich noon ; the second point is marked agreeing with the proper declination and time 10 hours later; the straight line determined by the two points agrees with the sun's true declination for the date for the local apparent time . The proper refractions in polar distance are then scaled from the straight line to the N. for each tabulated refraction, a. m. and p. m., taken from Table 23, Standard Field Tables, appropriate to the latitude of observation and declination of the sun; the locus of the latter points is a smooth curve representing graphically the declinations of the sun, corrected for refraction in polar distance, for use with the solar attachment. The scale of the refractions must equal the scale of the intervals of l x in declination, and the refractions are laid off along or parallel to the horizontal lines and not normal to the line of 48 MANUAL OF SURVEYING INSTRUCTIONS. true declination. At any time throughout the day the proper declination for use with the solar attachment is obtained by reference to the curve at the point corresponding to the time of observation. To obtain any true value of the sun's declination for use in the reduction of altitude observations reference may be made to the straight line of true declination at the point corresponding to the time of observation. The advantage of the diagram method is found in the practical elimination of errors of computation, and the ease with which it is checked, together with the fact that in the use of the diagram actual values are obtained at any time without any process of interpolation . The following diagrams have been prepared to illustrate the method: DIAGRAM OF THE SUN'S DECLINATIONS. Date, Mar. 20, 1912. Station: Lat.=37 30 7 N. Long.=7 h 30" 1 W. Declination. Greenwich noon=0 11' 14" S.=4 h 30 a. m. Diff. 10 h , +593"= Q9 53 N. 001 / 21 // S.=2 h 30 m p. m. 5 6 7 8 9 10 II Noon 1 2 3 S PM 3 \ \ \ I \ \ \ \ N \ \ S \ \ \ \ -^ \ \ X s \ \ \ INSTRUMENTS AND METHODS. DIAGRAM OF THE SUN'S DECLINATIONS. Date, Sept. 23, 1913. Station: Lat.=47 3(K N. Long.==6 h 18* W. Greenwich noon=0 03' 55" N.=5 h 42 a, m. Diff. 10 h , -585"= 9 45 S. Q05 / 50 // S.=3 h 42 p. m. ^ : S * iCO^^OiO^ COo Mar. 18, 1910, apparent time of altitude observa- tion upon sun =3 h 42 m 11 s p. m. Equation of time, Greenwich ap- parent noon +8 m 23.4" Interpolation for longitude of station 5 h 08 m W., and time of observation 3 h 42 m , p. m., 8 h 50 m after Green- wich noon, or 8.83/24 of change (17.64 s ) in 24 hours = 6. 5 9 Equation of time -j-8 m 16. 9 s -f 8 m 17 s Local mean time of observation 3 h 50 m 28 s Watch time of observation =3 h 57 m 53 s Watch fast of local moan time = 7 m 25 s TIME IN ITS RELATION TO POLARIS OBSERVATIONS. 60. Polaris, a star of the second magnitude, occupies a position in the northern heavens a little more than 1 from a line defined by the axis of the earth's rotation, and on account of its brightness and proximity to the polar axis it ranks to the surveyor as the most useful circtimpolar star. It will be assumed that the surveyor has learned how to identify the north star among its associates in the clear starlit heavens, especially with reference to the * ' pointers ' ' in the con- stellation of the " Great Bear," which is popularly called the " Dip- per." Polaris (ex Ursse Minoris) is nearly on a line (or great circle) determined by the pole and the star ' ' 6 Cassiopeiae, ' ' and both stars are located in the same direction from the pole. The same line (or great circle) passes near the star " f Ursse Majoris " (another star of the "Dipper"), but the latter star is located on the opposite side of the pole. The surveyor may note the relative position of the three stars aforementioned, if it is a clear night, and this will give an im- mediate indication of the approximate position of Polaris in its di- urnal circle at such time of observation. The novice should secure field demonstration in these details from an experienced observer. The three stars named are all of about the same brightness. In- structions will follow (sec. 99) regarding the positive identification of Polaris by instrumental methods during the twilight period, be- fore the star is visible to the naked eye, and the same process may 54 MANUAL, OF suK\i:ri:\G J.N> 'i iu"< .TIONS. f Star Magnitudes i* * * * I? 3 4 S ^Meridian *'' \ / v rt ^ .v. Polaris & x- 'JSPC X' ' ' 5 /> rra e A'or/A Po/e / \ NAKED-EYE IDENTIFICATION OF POLAKIS. About noon March 23rd. About 6 a. m. June 22nd. About midnight September 22nd. About 6 p. m. December 22nd. INSTRUMENTS AND METHODS. 55 be employed for verification of night observations, if there should be any doubt as in case the neighboring constellations are obscured by clouds. A skillful surveyor can readily observe Polaris at sunset or sunrise without artificial illumination, and with a very clear atmosphere can perform the observation when the sun is as much as 20 or 30 minutes above the horizon . At any time that Polaris is visible any one of the various methods of Polaris observation for meridian, properly followed, is superior to any form of observation upon the sun for the same purpose. In general, in public-land surveying, the best of all practices is found in the proper use of a solar instru- ment adjusted to the true meridian as established by Polaris obser- vation. Polaris has a diurnal circle about the earth's polar axis similar to the diurnal circle of other stars, though Polaris has the smallest circle of any naked-eye star. The daily circuit of Polaris is covered in one sidereal day of 24 sidereal hours, or an equivalent of 23 hours 56 minutes 4.09 seconds of mean solar time. In its diurnal circle Polaris crosses the meridian twice, once at upper culmination, or above the polar axis, and once at lower culmination, or below the polar axis. The direction of the apparent motion of Polaris is suggested by the following diagram: w. f . The pointings of the arrows on the above circle indicate the direc- tion of the apparent motion of Polaris in its diurnal path, while the pointings of the arrows on the lines tangent to the circle show the direction of travel at the epochs of culmination and elongation. If the surveyor has any doubt in regard to the quadrant occupied by Polaris in its diurnal circle at the time of an observation, he may set the intersection of the telescope cross-wires exactly upon the star, then, without moving the instrument, note the direction of the star's motion and compare with the diagram. 56 MANUAL OF SURVEYING INSTRUCTIONS. The position of Polaris in its diurnal circle at any time may be determined by reference to the mean time interval from upper cul- mination to any observed position west of the meridian, or by refer- ence to the mean time interval from any observed position east of the meridian to the succeeding upper culmination. 61. The Greenwich mean time of upper culmination of Polaris is tabulated in the Epheraeris for every day in the year, arranged for the ordinary civil date, a. m. or p. m. 62. Local mean time of upper culmination of Polaris: the Green- wich mean time of upper culmination of Polaris is to be taken from the Ephemeris for the date of observation; the amount to be subtracted from the Greenwich mean time of upper culmination of Polaris to obtain the local mean time of upper culmination, in which the argument is the longitude west from Greenwich, is obtained from the table of sidereal conversions without computation; see Table 19, Standard Field Tables. Example of reduction from the Greenwich mean time of upper culmination of Polaris to the local mean time of upper culmination of Polaris, longitude 111 15' W.: Aug. 12, 1910, Gr. U. C. of Polaris=4 h 08.3 m a. m. Red. to long. 111 15' W., l m 33 s = - 1.2 L. M. T. of U. C. of Polaris =4 h 07. l m a. m. 63. The Greenwich mean time of elongation of Polaris, latitude 40, is tabulated in the Ephemeris for every day in the year, arranged for the ordinary civil date, a. m. or p. m. 64. Local mean time of elongation of Polaris: the mea'n time of elongation of Polaris, Greenwich meridian, latitude 40, is to be taken from the Ephemeris for the date of observation: the amount to be subtracted from the mean time of elongation of Polaris, Green- wich meridian, latitude 40, to obtain the mean time of elongation of Polaris, local meridian, latitude 40, in which the argument is the longitude west from Greenwich, is obtained from the table of side- real conversions (Table 19, Standard Field Tables) without compu- tation. The amount to apply to the local mean time of elongation of Polaris latitude 40 to obtain the local mean time of elongation of Polaris at the latitude of observation is tabulated in the Ephemeris in connection with the table of azimuths of Polaris at elongation. Examples of reduction from the Greenwich mean time of elonga- tion of Polaris, latitude 40, to the local mean time of elongation of Polaris, latitude 64 30 7 N., and longitude 146 30' W.: INSTRUMENTS AND METHODS. 57 EASTERN ELONGATION. Sepfc. 9, 1910, Gr. E. E. of Polaris, Lat. 40=8 h 19.6 m p. m. Red. to long. 146 3(X W., l m 36 s = - 1.6 Red. to lat. 64 3(X N. = + 5.8 L. M. T. of E. E. of Polaris 8 h 23.8 m p. m. WESTEEN ELONGATION, SAME STATION. Oct. 16, 1910, Gr. W.E. of Polaris, lat. 40=5 h 48. 5 m a. m. Red. to long. 146 30' W., l m 36 8 - 1. 6 Red. to lat. 64 30' N. = - 5. 8 L. M. T. of W. E. of Polaris *=& 41. l m a. m. 65. Conversion of a mean time interval into a sidereal time inter- val, or vice versa: The amount to apply tp one time interval to obtain the other time interval is found in the table of sidereal conversions (Table 19, Standard Field Tables) without computation. Example of conversion of a mean time interval into a sidereal time interval: Mean time hour angle of Polaris for an assumed obser- vation in Alaska = 7 h 32. 6 m 7 h 32 m 36" Conversion into equivalent sidereal hour angle = 4- . 1 . 14? Sidereal hour angle 7 h S3 8 50" 7 h =105 33 m = 8 15' 50" = 12 X 30 // ' =11327 / 30 // 66. Hour angles of Polaris: a mean time hour angle of Polaris west of the meridian is the mean time interval from the local mean time of the last preceding upper culmination to the local mean time of observation of Polaris; a mean time hour angle of Polaris east of the meridian is the mean time interval from the local mean time of obr servation to the local mean time of the next succeeding upper cul- mination of Polaris. The above application of the term "hour angle" is a departure from conventional usage, which has been employed in order to sim- 55465 19 5 58 MANUAL OF SURVEYING INSTRUCTIONS. plify the text. By this means one confusing step in the problem relating to hour angles for positions of Polaris east of the meridian is avoided. Polaris crosses the meridian at lower culmination at an hour angle of ll h 58 m 02 s , and in the arrangement of the various examples, the observations west of the meridian have been referred to the last preceding upper culmination, and those east of the merid- ian have been referred to the next succeeding upper culmination, thus avoiding the introduction of any hour angles exceeding 1 l h 58 m 02". Examples of computing hour aiiglos of Polaris; all taken out for longitude 117 15' W.: West of the meridian, p. in. obsn., U. C. -in p. m. L. M. T. of obsn., Feb. 18, 1911 =5 h 20. l m p. m. Gr. U. C. same date =3 h 36. 5 m p. m. Red. to long. 117 15' W.= - 1.3 =3 35.2 p. m. Hour angle of Polaris, west =l h 44. 9 m West of the meridian, p. m. obsn., U. C. in a. m. L. M. T. of obsn., May 14, 1911 , I 7 h 12. 4 m p. m. Gr. U. C. same date =10* 02. l m a. m. Red. to long. 117 W W.= -1. 3 = 10 0. 8 a. m. Hour angle of Polaris, west = 9* 11. C m INSTRUMENTS AND METHODS. West of the meridian, a. w. obsn., U. C. in p. m. L. M. T. of obsn., Nov. 3, 1911 Gr. U. C., Nov. 2 ^IG* 43.9 m p. m. Red. to long. 117 15' W. -1.3 Hour angle of Polaris, west 14-12 |= 6 h 31. 6 m a. m. =10 42.6 p. m. = 7 h 49.0 m West of the meridian, a. m. obsn., U. C. in a. m. L. M. T. of obsn., Aug. 11, 1911 = 5 h 05.9 m a. m. Gr. U. C., same date 4 h 13. 6 m a. m. Red. to long. 117 15' W. ~1.3 =4 12.3 a. m. Hour angle of Polaris, west O h 53.6 m East of the meridian, p. m. obsn., U. C. in p. m. Gr. U. C., Dec. 20, 1911 Red. to long. 117 15' W. L. M. T. of U. C., Dec. 20 L. M. T. of obsn., same date Hour angle of Polaris, east 7 h 34.8 m p. m. -1.3 7 33.5 p. m. 4 35.1 p. m. 60 MANUAL OF SURVEYING INSTRUCTIONS. East of the meridian, p. m. obsn., U. C. in a. TO. Gr. U. C., Sept. 2, 1911 Ued. to long. 117 15' W. L. M. T. of U. C., Sept. 2 L. M. T. of obsn., Sept. 1 Hour angle of Polaris, east = 2 h 47.4 m a. m. = -1.3 j= 2 46.1 a. m. 1+12 = 6 34.0 p. m. East of the meridian, a. m. obsn., U. C. in p. m. Gr. U. C., Mar. 19, 1911 Red. to long. 117 15' W. L. M. T. of U. C., Mar. 19 L. M. T. of obsn., same date Hour angle of Polaris, east I h 42.1 m p. m. -1.3 |= 1 40.8 p. in. 1+12 = 6 06.6 a. m. ~ 7 h 34.2 m INSTRUMENTS AND METHOD*:. 61 East of the meridian, a. m. obsn., U. C. in a. m. = 9* 46.4 m a. m. = -1.3 = 9 45.1 a. m. = 4 42.9 a. m. = 5 h 02.2 m Gr. U. C., May 18, 1911 Red. to long. 117 15' W. L. M. T. of U. C., May 18 L. M. T. of obsn. Hour angle of Polaris, east 67. By reference to the preceding diagram showing the direction of motion of Polaris in its diurnal circle, Zenith the motion at western elongation is shown to be vertically downward, and at eastern elongation the motion is shown to be ver- tically upward. At the epoch of either western or eastern elongation the motion of Polaris in azimuth is zero. At the equator, if Polaris could be ob- served; the hour angle of Polaris at elon- gation would be 90 0' 0"=6 h O m s sidereal hour angle^S 11 59 m 1.02" mean time hour angle, but as stations of ob- servation are occupied in the higher latitudes the hour angle of Polaris at elongation decreases progressively. The reason for this is found in the fact that all vertical planes intersect at the ze- nith, and the point of tangency of a vertical plane with the diurnal circle of Polaris occurs at points corresponding to decreasing hour angles with the higher latitudes. The "spread" of the two vertical planes intersecting Polaris at eastern and western elongation increases with the higher latitudes, giving in- celestial sphere. creasing azimuths at elongation with the more northern latitudes. N Horizon FIG. 8. The meridian and vertical planes tangent to the diurnal circle of Polaris as viewed from inside of the 62 :\f ANUAL OF SURVEYING INSTRUCTIONS. 68. Mean time hour angle of Polaris at elongation: the sidereal hour angle in angular measure; this converted into time measure, and this in turn converted from a sidereal time interval into a mean time interval gives the mean time hour angle of Polaris at elongation: Cos Z=cotan 5 tan < Example of computing the mean time hour angle of Polaris at elongation, April 3, 1915, in latitude 65 0' N., on which date the declination of Polaris=88 5V 20" N.: ^,=65 0'; log tan <*> =0. 331327 6=88 51' 20"; " cotan 6 =8. 300530 " coat = 8.631857 Sidereal hour angle =87 32' 41" 87=5 h 48 m 32'= 2 m 08' 41"= 3- =5 h 50 m ll s Reduction to mean time hour angle = O m 57* Mean time hour angle at elongation =5 h 49 m 14 s ALTITUDE OBSERVATION OF THE SUN TOR APPARENT TIME. 69. Altitude observation of the sun for apparent time: Z=hour angle from apparent noon in angular measure: reverse the signs of 8 for south declinations: T i / /si V co cos 1 (r+-5) 70. An altitude observation of the sun for time is made by deter- mining the correct altitude of the sun's center and recording the watch time at the epoch of observation. The following order of procedure is recommended for the elimination of instrumental errors, reduction to the sun's center, and practical elimination of differen- tial refraction : A. M. OBSERVATION. Thoroughly level the transit. Observe the sun's upper limb, recording the watch time of observa- tion and vertical angle . Reverse the transit. INSTRUMENTS AND METHODS. 63 Observe the sun's lower limb, recording the watch time of observa- tion and vertical angle. The mean vertical angle is equivalent to the vertical angle to the sun's center corresponding to the mean epoch of the watch readings. P. M. OBSERVATION. Thoroughly level the transit. Observe the sun's lower limb, recording the watch time of observa- tion and vertical angle. Reverse the transit. ) Observe the sun's upper limb, recording the watch time of observa- tion and vertical angle. The mean vertical angle is equivalent to the vertical angle to the sun's center corresponding to the mean epoch of the watch readings. Example of altitude observation of the sun for apparent time: Final field notes. August 24, 1909, in latitude 37 16' 50" N., and longitude 102 12' W., I make an altitude observation upon the sun for time, making two observations, one each with the telescope in direct and reversed positions, observing opposite limbs of the sun: Mean observed vertical angle =19 39' 30" Mean watch time of observation = 4 h 56 m 04 s p. m. Watch slow of local mean time = O m 56 1 Field record. Telescope. Sim's limbs. Watch time. Vertical angle. Direct J$L . 4h55m22 19 33' 00" Reversed.. . i TJr 4 56 46 19 46 00 Mean . . 4h,56m04B 19 39 / 30"=t> Refraction . Parallax. .- - 2 40 ...= 4- 003 h 19 36' 58" 64 MANUAL OF SURVEYING INSTRUCTIONS. True vertical angle=&=1937' Zenith distance =f =7023' Sun's declination =5=1105 / N. =* 7023 / r f=7023' 0= 37 17 0=37 17 <+ ) values= 5922 / 30 // 2205 / 30 // (r-0-H)=44ll' (f-j-0)=107 40' (f-0) 5= 11 05 (+) 5=11 05 (4-) 5)= 9635 / 48 17'30" 1100 / 30 // (r-0-S) log sin i(r+0-5)= 9. 873054 9. 575291 cos 4(r+04- 5)=9. 707073 9. 448345 cos i(r-0-S)=9. 991934 9. 699007 9. 699007 ======== 73=4 h 52 : tan 2 \t 9. 749338 41' = tan it = 9.874669 24"= i=7341 / 24 // t Apparent time of observation =4 h 54 m 46 s p. m. Equation of time -f-2 14 Local mean time of observation =4 h 57 m 00 8 p. m. Watch time of observation =4 56 04 p. m. Watch slow of local mean time = O m 56 8 MERIDIAN OBSERVATION OF THE SUN FOR APPARENT NOON. 71. Meridian observation of the sun for apparent noon. With the telescope in the meridian elevated to the sun's altitude, the watch times of transit of the sun's west and east limbs are noted, the mean of which is the watch time of apparent noon; if the observation fails for either limb the reduction to the sun's center is accomplished by adding or subtracting 68 seconds; a refinement in the amount of thie time is hfl/1 hv referrim* to the "Rnhemeris for the time of the siin'p INSTRUMENTS AND METHODS. 65 semi-diameter passing the meridian for the date of observation; the setting for the approximate altitude of the sun's center is: OBSERVING PROGRAM. Determine the meridian by the best means at hand and compute the altitude setting for the sun. Level the transit, place the instrument in the meridian, and ele- vate the telescope to the altitude of the sun's center. Note the watch time of the sun's west limb tangent to the vertical wire. Note the watch time of the sun's east limb tangent to the vertical wire. Take the mean of the readings for the watch time of apparent noon from which to compute the watch error local mean time. Example of meridian observation of the sun for apparent noon: Final field notes. August 14, 1909, in latitude 37 16' N., and longitude 102 16' W., with the telescope in the meridian and elevated to the sun's altitude, T observe the sun's transit for time, noting the watch time of transit of each limb: Mean watch time of apparent noon=12 h 00 m 27* Watch slow of local mean time = 4 m 06 Field record. Setting: 90 00' 4, ^ (~)37 16' N. 3 ^ (-f) 14 2^ N. v ^ 67 09' J- Watch time of transit, W. limb =11^ 59 m 22 ~> Watch time of transit, E- limb =12 01 32 Watch time of apparent noon =12 h 00 27* Apparent noon =12 h 00 m 00" Equation of time= + 4 33 Local mean time of apparent noon=12 04 33 Watch slow of local mean time = 4 m 06 The above form of meridian observation of the sun for apparent noon is by far the most convenient reliable method of time observation. ()6 MANUAL, OF SUKVEYING INSTRUCTIONS. TIME FROM THE SOLAR ATTACHMENT. 72. Several of the approved forms of solar apparatus, including principally the Smith solar attachment and the Burt solar compass, have a graduated arc or circle mounted normal to the polar axis to indicate the apparent time of observation. The reading of the time arc is most conveniently checked by comparison with the above form of meridian observation of the sun for apparent noon. An eiTor in the reading of the time arc or hour circle may be corrected by adjusting the circle, or allowed for as an index error. The reading of the hour circle may then be safely accepted as giving correct apparent time for use in computing or taking out required declina- tions of the sun for the various forms of solar observations. A proper reading of the hour circle may be safely accepted to indicate apparent time at which moment the watch reading may be noted, and the watch error local mean time determined as shown in the preceding example of conversion of apparent time into local mean time; this result derived for the ivatch error local mean time may then be safely used in observations on Polaris at elongation, but for observations upon Polaris by the hour angle method the time should be determined by one of the more refined methods already given. LATITUDE. 73. It is absolutely necessary in the operation of any solar attach- ment to employ the correct latitude of the station, and in general in altitude observations upon the sun for azimuth or time the latitude must be well determined. In the public-land surveying practice all determinations of either time or latitude are an important part of the program of operations only so far as these functions finally enter into the establishment of the true meridian; all classes of observations given in the Manual have been arranged to facilitate the performance of solar instruments, and for this purpose a definite knowledge of the true latitude is highly important. No lack of reasonable precision should be allowed in the accepted latitude. The various forms of observations for latitude are very simple and a considerable series should be taken in every group of surveys, all reduced to the township boundaries for comparison, until a satis- factory mean has been obtained. MERIDIAN ALTITUDE OBSERVATION OF THE SUN FOR LATITUDE. 74. Meridian altitude observation of the sun for latitude. Reverse the sign of 5 for south declinations: <*=90 -f ~h INSTRUMENTS AND METHODS. 67 The following observing program is recommended: Thoroughly level the transit and place the telescope in the merid- ian elevated to the sun's approximate altitude at noon. Observe the altitude of the sun's lower limb with the sun slightly east of the meridian. He verse the transit. Observe the altitude of the sun's upper limb with the sun slightly west of the meridian. Take the mean observed vertical angle for the altitude of the sun's center at apparent noon. The following is an example of meridian altitude observation of the sun for latitude: Final field notes. October 5, 1909, in approximate latitude 37 2CK N., and longitude 102 04' W., I make a meridian altitude observation of the sun for latitude, observing the altitude of the sun's lower limb with the telescope in direct posit ion, reversing the transit and observing the sun's upper limb : Apparent time of observation, noon=12 h 00 m 00 s Mean observed altitude =47 59' 45" Reduced latitude =37 19'.3 N. Field record. Setting: 90 0(X <(> ^ (-)3720'N. 5 ^ (-) 442 / S. v ^ 47 58' Lower limb 47 42' Upper limb 48 14' f- Observed alt., lower limb, tel. dir.=47 43' 00" ~b Observed alt., upper limb, tel. rev. =48 W 30" Mean observed altitude, v =47 59' 45" Refraction - 52 Parallax -f 06 /*=47 58' 59" 5= 4 41 42 S. d-A=37 19 19 90 00' 00" 68 MANUAL OF SURVEYING I> > Si RUCTIONS. 75. The above-described observation is conveniently combined with the meridian observation of the sun for time, by observing simultaneously the sun's lower and west limbs, recording the watch time and the vertical angle and reversing the transit in the interval of about 2 minutes, and then observing simultaneously the sun ? s upper and east limbs. The settings for the approximate altitudes of the sun's lower and upper limbs, respectively, are: Example of meridian observation of the sun for time and latitude: Final field notes. June 8, 1910, in approximate latitude 38 54' N., and longitude 77 Ol x .6 W., I make a meridian observation of the sun for time and latitude, observing simultaneously the altitude of the sun's lower limb and the transit of the sun's west limb, reversing the telescope and observing simultaneously the altitude of the sun's upper limb and the transit of the sun's east limb: Mean observed altitude =73 55' 30" Reduced latitude =38 53'.7 N. Mean watch time of observation =12 h OG m 40" Watch fast of local mean time = 7 m 58* Field record. Setting: 90 (XX #g 4>^ (-)3854'N. 5= (-f).2249'N. Lower limb Upper limb 73 5$' 73 39' 74 11'. Position of telescope. Position of sun. Watch time transit. Observed ver- tical angle. Direct n 12h OS* 37* 73 42' 30" Reversed "b 12 07 42 74 08 30 Mean... 12h 06m 40 73 55' 30" Refrac^'on. Parallax. -16 H-02 h : = 73 55' 16" 5= 22 4y 00"; 90 +5 ..,..;..., =112 49 00 0=38 53'.7N.90-fS-fc =* 38 53' 44" INSTRUMENTS AND METHODS. 69 Watch time of apparent noon = 12 h 06 m 40* Apparent noon = 12 h 00 m 00 s Equation oi time . . = 1 18 Local mean time of apparent noon. =11 58 42 Watch fast of local mean time = 7 m 58 s The known latitude of the above station is 38 53' 40",- but it can not be assumed that any one altitude observation of the sun will always give a result so close to the true latitude. In general a better determination of the latitude by this method is possible only by making a series of observations on successive days, or by combining the result with Polaris observations for latitude. For the purpose of a test as to the accuracy of the above time observation, the same watch was compared with a Western Union telegraph clock as follows: 75th meridian time of comparison. 12 h 00 m 00 Correction for longitude 77 1.6'.. . = -08 06 Local mean time of comparison. . .=ll h 51 m 54* Watch time of comparison =11 59 56 Watch fast of local mean time ..... = 8 m 02* ALTITUDE OBSERVATION OF POLARIS FOR LATITUDE. 76. Altitude observation of Polaris at upper culmination for latitude: Altitude observation of Polaris at lower culmination for latitude: The mean time hour angle of Polaris at lower culmination is 11 hours 58 minutes 2 seconds: The settings for the approximate altitude of Polaris at upper and lower culminations, respectively, are: The following program is recommended in altitude observations of Polaris at culmination for latitude. Compute the local mean time and watch time of culmination. Thoroughly level the transit. About four minutes before culmination observe the altitude of Polaris with the telescope in direct position. 70 MANUAL OF SURVEYING INSTRUCTIONS. Reverse the transit and observe the altitude of Polaris. Again level the transit. Observe the altitude of Polaris with the telescope in the reversed position. Reverse the transit to the direct position of the telescope and again observe the altitude of Polaris. Take the mean observed altitude to use in the reduction. Example of altitude observation of Polaris at lower culmination for latitude: Final field notes. June 19, 1910, in approximate latitude 38 54' N., and longitude 77 01'. 6 W., I make an altitude observation on Polaris at lower culmination for latitude, making four observations, two each with the telescope in direct and reversed positions: Watch fast of 75th meridian standard time by comparison = O m 24 s Mean watch time of observation = 7 b 44 m 37 s p. m. Mean observed vertical angle = 37 44' 00" Reduced latitude 38 53'. 4 N. Field record. Setting: 90 00' 6^88 49 / 90-$^ 1 11' 54' Gr. U. C. of Polaris, June 19, 1910 = 7 h 39.7 m a. m. Reduction to longitude 77 1.6' W. = -0.8 Reduction to lower culmination =4-11 58.0 7 h 36.9 m p. in. L. M. T. of L. C. of Polaris, June 19 = 7 h 36 m 54- p. m. Watch fast of 75th meridian standard time by comparison with a Western Union telegraph clock f 24 Correction for longitude 77 Ol x .6 W. =-f 8 06 Computed watch time of lower culmination == 7 h 45 m 24" p.m. INSTRUMENTS AND METHODS. 71 . Telescope. Watch time. Vertical angle. Direct 7h 4Qm HB 37 42' 20" Reversed . 7 42 45 37 44 30 Reversed 7 46 39 37 45 30 Direct . . . 7 48 50 37 43 30 MeftTi . . . . 7h 4401 378 37 44' 00" Refraction. . . -1 15 S88 49' 20"; 90 -/; ft=37 42' 45" = 1 10 40 38 53' 25" AZIMUTH. THE SOLAR ATTACHMENT. 77. The solar attachment to the engineer's transit has been designed f or instrumentally setting off the sides of the " pole-zenith- sun" triangle in agreement with their angular values at the station and time of observation. The sun's image may be brought into the line of collimation of an auxiliary telescope by orientation of the transit to the position where the instrumental parts are made parallel to the respective sides of the celestial triangle, whereupon the verti- cal plane of the " pole-zenith " arc of the solar attachment will coincide with the true meridian. Skillfully handled, the solar at- tachment will give at once close approximations to the true meridian comparing favorably for accuracy with direct observations. The advantage in the proper use of the solar attachment is found in its rapid and close determinations of the meridian in heavy timber, dense undergrowth, and strong wind, in low swamp or on high mountain ascents, and under nearly all other difficult physical situations encountered in the field, avoiding in its proper use accumu- lative errors incident to the prolongation and deflection of transit lines, and deviations in the azimuth of latitudinal lines. Several ingenious instruments have been devised for this purpose, but the Smith solar attachment, invented by Benjamin II. Smith, of Colo- rado, in 1880, has given the most general satisfaction of any solar instrument in meeting the special requirements of the surveying service of the General Land Office wherein it has been developed to a state of efficiency which has fully warranted the adoption of this model as a standard instrument for use in the public-land surveys. 72 MANUAL OF SURVEYING INSTRUCTIONS. Owing to the different details in the design of the J3mith solar attachment as constructed by various instrument makers it is impossible to discuss fully the test and adjustment of each without giving a complete description of the several models, and this would lead away from the purpose of the Manual. The standard model, embracing the most recent improvements, is therefore selected for description, and discussion of the theory, adjustment and use of the Smith solar attachment. The supervising officers will furnish the surveyors with suitable instructions relative to the test and adjust- ment of any other special instruments supplied to them, published in circular form as deemed expedient. DESCRIPTION. 78. The working parts of the Smith solar attachment consist of five fundamental features, each performing its own distinctive function. The principles involved have been adapted to various types of construction, and the efficiency of the different designs is related directly to the perfection which may be attained in making a proper adjustment in the field, the stability of the adjustments when made, and the compactness of the design, considering protect tion to the working parts and proper distribution of weight. The five fundamental working parts consist of: 1. An auxiliary telescope whose line of collirnation is the polar axis of the solar attachment; the telescope may be revolved in col- lar bearings which are securely mounted on a vertical limb. 2. The vertical limb is mounted on a horizontal axis and has a graduated latitude arc in its vertical plane. 3. A plane mirror at the objective end of the auxiliary telescope with an axis normal to the line of collimation, and an arm leading to a graduated declination arc. 4. An hour circle on the auxiliary telescope mounted normal to the line of collimation. 5. A set of equatorial wires parallel to the axis of the reflector. In all the forms of construction of the Smith solar attachment the auxiliary telescope is mounted in a vertical plane parallel to the transit telescope. Thus, if the instrument is in proper adjustment and oriented to the true meridian, the polar axis of the solar attach-^ ment may be made parallel to the earth's polar axis by. setting off the true latitude of the station. The sun's rays are brought into the auxiliary telescope by means of the mirror, due allowance being INSTRUMENTS AND METHODS. 73 FIG. 9. The solar transit as it appears in use. 55465 19 6 74 MANUAL OF SURVEYING INSTRUCTIONS. made for the sun's declination north or south of the equator, but to bring the sun's image into the auxiliary telescope the latter must be revolved in its collar bearings until the reading of the hour circle agrees with the sun's apparent time. When the auxiliary telescope is thus revolved the sun's image will traverse the field of the eye- piece parallel to the equatorial wires with the limbs of the disk tan- gent to the same. If the transit is turned in azimuth the sun's image will immediately depart from the equatorial wires, except at noon when the image will follow the equatorial wires whether the transit be turned slightly in azimuth or the auxiliary telescope be revolved in hour angle. At apparent noon the declination arc is in a ver- tical plane and at this time an absolute determination may be made of the correctness of the reading of this arc. In the modern construction the solar attachment is mounted upon the east standard of a regular light mountain model full engi- neer's transit, the horizontal circle of which has a diameter of 4J inches, with a vertical circle of 4 inches diameter. The horizontal distance between the vertical planes of the transit and auxiliary tele- scopes is a trifle less than 4 inches. The auxiliary telescope has a focal length of 4| inches and a magnifying power of about 10 diam- eters. The latitude arc has a radius of 3 inches, and the declination arc has a radius of 3J inches. Upon the latter arc the graduations read the true declination and, as the mirror needs to be turned only 5 to correspond to a change of 10 in the sun's declination, the gradu- ations are made in one-half space, i. e., an interval of 10 on the arc as graduated occupies a segment of only 5. At zero declination the plane of the mirror is at 45 to the line of sight of the auxiliary telescope. Both telescopes are fitted with the necessary colored glass shades for observing the sun. The base plate of the solar is mounted upon three foot posts, adjustable by means of opposing capstan nuts. This three-point base forms a right-angled triangle, with one side horizontal and one side vertical, thereby permitting adjustment in either of two directions: (a) One about a horizontal axis, and (b) one about a vertical axis. Suitable capstan nuts are also placed at one end of the auxiliary telescope to provide for its proper adjustment with respect to the axis of the latitude arc. Good solar work must depend first of all upon the proper adjust- ment of the transit upon which it is mounted, with great care in keep- ing every working part cleaned, suitably oiled to work smoothly, and INSTRUMENTS AND METHODS. 75 protected from adverse weather and injury. The same precautions are due the solar attachment. It will give very efficient meridional performance if properly adjusted and operated; nothing less can be conceded. Before starting in with the adjustments it should be determined that the auxiliary telescope revolves smoothly in its collar bearings, neither too tight nor too loose ; that there is free and smooth motion to the latitude and declination arcs; that the clamps are positive and the tangent motions smooth and free in either direction; that the eye-piece is carefully focused upon the cross wires; and that the objective is carefully focused upon any quite distant object, then secured in this position. The eye-piece turns freely and has a pin- which travels in a guide slot; this pin is not a clamp. The objective may be moved by first loosening, then pushing the screw, which will be found to travel in a guide slot near the lower (or left hand) collar bearing. ADJUSTMENT. 79. The field adjustments of the solar attachment should be con- sidered in the following order: 1. The equatorial wires must be made parallel to the axis of the reflector. 2. The line of sight of the auxiliary telescope must lie in its true turning axis. 3. The polar axis, or line of sight of the auxiliary telescope, must be normal to the axis of the latitude arc, describe a true vertical plane when turning on said axis, and said vertical plane must be parallel to the vertical plane of the transit telescope. 4. The latitude arc should read zero when the auxiliary telescope is horizontal. 5. The declination arc should at all times read the true declina- tion of the sun plus the refraction in polar distance. 6. The hour circle should read the sun's apparent time. There are two or more methods of testing each and every adjust- ment, but those stated below are without doubt the simplest, and most rapid and reliable of all field methods. The true meridian should be established by Polaris or other independent observation, upon which to test the solar, but otherwise it plays only a small part in the adjustments of the solar attachment. The true latitude of the station must be definitely known. There should be a clear view to a 76 MANUAL OF SURVEYING INSTRUCTIONS. distant object in the horizon, but if an object less than a mile away must be utilized due allowance may be made for the horizontal dis- tance between the vertical planes of the transit and auxiliary tele- scopes. 1. The equatorial wires. Set up the instrument as in a regular solar observation, setting off the known latitude, declination and apparent time, and bring the sun's image accurately between the equatorial wires by orienting the transit approximately to the meri- dian, in which position the instrument should be clamped. (See fig. 9.) Turn the auxiliary telescope in hour angle, causing the sun's image to travel across the field from side to side. If the image follows the equatorial wires accurately the latter are parallel to the axis of the reflector as required. If the sun's image departs materially from the equatorial wires, the capstan screws which hold the diaphragm should be loosened and the reticle may be rotated until the equa- torial wires are made to agree with the path of the sun's image across the field, then return each capstan screw to a proper seat. 2. Collimation of the auxiliary telescope. Swing the mirror to give a direct view through the auxiliary telescope. (See fig. 10.) Set the line of sight on a distant point and clamp the instrument. Revolve the auxiliary telescope 12 hours in hour angle. If the line of sight remains fixed on the distant point it agrees with the turning axis as required. If after revolution, the line of sight appears to be above or below, or to the right or left, of the distant point, one-half of the differences should be taken up with the capstan screws which control the diaphragm. The test should be repeated until the auxili- ary telescope is in perfect collimation. 3. The polar axis. Carefully level the transit and then sight the main telescope to the distant point and clamp the instrument; sight toward the same point with the auxiliary telescope, and place the striding level on the latitude axis. (See fig. 10.) The striding level should be reversed to see if there is any error in the level itself, and if so take the mean position for the true indication of the level. If the latitude axis is not horizontal it may be made so by adjusting the lower pair of capstan nuts on the base frame of the solar attachment. If the line of sight of the auxiliary telescope is not parallel to that oi; the main telescope it may be made parallel by means of the left- hand upper pair of capstan nuts on the base frame of the solar. After fulfilling the foregoing conditions turn the transit 180 in azimuth and reverse both telescopes so as to sight again to the same distant object, INSTRUMENTS AND METHODS. 77, FIG. 10. Direct sighting through the auxiliary telescope, with the mirror swung to a central position, and showing the striding level on the latitude axis. 78 MANUAL OF SURVEYING INSTRUCTIONS. setting the main telescope upon the object. (See fig. 11.) If the auxiliary telescope does not again sight upon the distant object, one- half the error is due to its line of sight not being at right angles to the axis of the latitude arc. Take up half of the amount of the error by means of the pair of capstan nuts at one end of the auxiliary telescope, and take up half of the error by again correcting the left-hand upper pair of capstan nuts on the base frame of the solar. The line of sight of the auxiliary telescope should now be normal to the axis of the latitude arc, should describe a vertical plane when turning on said axis, and said vertical plane should be parallel to the vertical plane of the transit telescope. The tests should be carefully repeated until the adjustments are perfected. 4. The latitude vernier. Carefully level the transit, clamp the latitude arc at zero, and place the striding level in position on the auxiliary telescope. (See fig. 12.) The striding level should be reversed to see if there is any error in the level itself, and if so take the mean position for the true indication of the level. If the aux- iliary telescope is not horizontal it may be made so by means of the tangent motion of the latitude arc. When the auxiliary telescope has been made truly horizontal the reading will indicate the index error of the vernier of the latitude arc. The vernier is held in posi- tion by two screws passing through elongated holes, and by loosening the screws the vernier may be shifted to read zero, or the difference from zero may be carried as an index error. 5. The declination vernier. A few minutes before apparent noon set the instrument in the established meridian. Set off the known true latitude, allowing for any index error in the vernier of the lati- tude arc. Carefully level the transit and clamp the instrument with the main telescope in the meridian. Bring the sun's image into the field of the auxiliary telescope by turning this telescope in hour angle. At apparent noon bring the sun's image accurately between the equatorial wires by means of the tangent motion of the declination arc. The difference between the reading of the declina- tion arc and the calculated declination (corrected for refraction) will indicate the index error of the vernier of the declination arc. This vernier is also held in position by two screws passing through elongated holes, and by loosening the screws the vernier may be shifted to read the calculated declination for apparent noon of that date, or the difference may be carried as an index error. This test should be made every day the instrument is used. If by some INSTRUMENTS AND METHODS. FIG. 11. The auxiliary telescope in reversed position. 80 MANUAL, OF SURVEYING INSTRUCTIONS. failure in the adjustments of the solar attachment a difference of as much as 30" from previous tests should be discovered in the noon observation, the new error will generally be found in one of three places: (a) The auxiliary telescope may be out of collimation; (6) the vernier of the latitude arc may have become loose and shifted; or (c) the vernier of the declination arc may have become loose and shifted. Any slight error in the other adjustments, or in the determination of the established meridian, will not appear in the noon test of the declination arc. 6. The hour circle. A few minutes before apparent noon set the instrument in the established meridian . Level the transit and clamp the instrument with the main telescope in the meridian and elevated to the sun's altitude. Set your watch to read 12 o'clock as the sun's center crosses the vertical wire of the main telescope. At any convenient time thereafter set off the proper readings on the latitude and declination arcs, and with the instrument in the meridian, bring the sun's image to the center of the field of the auxiliary telescope and observe the watch time. If the reading of the hour circle agrees with the watch it is in adjustment; if not, it may be made to read apparent time by loosening the set screw which holds the hour circle in position and shifting the circle until the reading agrees with the watch, care being taken not to move the auxiliary telescope in hour angle until after the set screw is again seated. The test may then be repeated as often as desirable. USE. 80. Before using the solar attachment the latitude of the station and the sun's declination (properly corrected for refraction in polar distance) must be l:nown and accurately set off on the respective arcs. The instrument is carefully leveled and the apparent time set off on the hour circle. The transit is then oriented to the meri- dian. The plates are generally first set at zero and the sun's image brought into the field of the solar telescope before setting the lower clamp; thereupon the sun's image is brought accurately between the equatorial wires with the lower tangent motion; this gives the solar meridian. The transit may then be used for any normal func- tion. The solar meridian may be tested as many times as may be desirable by simply setting the plates back to zero and turning the auxiliary telescope in hour angle to the apparent time; this brings the sun's image again to the center of the field. The sun's declina- tion is constantly changing at a very slow rate, so that it is necessary INSTRUMENTS AND METHODS. 81 FIG. 12. The striding level on the auxiliary telescope. 82 MANUAL, OF SURVEYING INSTRUCTIONS. to correct the reading on the declination arc with its tangent motion to agree with the declination of the sun for the apparent time of observation. The great advantage of the Smith solar over all other forms of solar attachment is found in the fact that the latitude and declina- tion arcs remain clamped while the transit is being used in any nor- mal function. Upon setting up at a second station it is necessary merely to correct the latitude and declination arcs with their tangent motions to agree with any change from the previous station. For this reason it may be operated more rapidly than any other form of solar attachment. In fact, the solar meridian is so quickly deter- mined that the observation is usually repeated at every station. The same restrictions which must be recognized in making direct observations on the sun operate in the same way as a prohibition in the use of any solar instrument. There are only two such limita- tions: (1) When the sun is within two hours, or possibly an hour and one-half of the meridian; and (2) when the sun is low in the horizon. In the first instance, the sun's relative rate of change in azimuth is much greater than the rate of change in altitude, and a small error in adjustment or in setting the arcs is greatly multiplied. In the second case the refractions are great, more or less uncertain, and changing rapidly. The latitude of the station should always be determined with great care. Altogether too many maps are unreliable in this respect. If the latitude has been determined by competent observers, well and good, it may be free from error, but the direct altitude observa- tion upon the sun for latitude is so simple and the reduction so easy that every operator of a solar transit should make it a practice to accomplish direct observations on the sun for latitude on as many successive days as may be necessary to give a reliable determination of the true latitude of any unknown station. TEST. 81. When the solar attachment has been put in good adjustment it is proper to test it frequently on a true meridian established by Polaris observation or other approved method. The test consists merely in determining a meridian with the solar and comparing this indication with the true meridian established by other reliable method. The test should be repeated in a. m. and p. m. hours at INSTRUMENTS AND METHODS. 83 frequent intervals, and the noon observation should most certainly be taken every day that the solar is used . The selection of the method of observation to establish the true meridian will be made by the surveyor, the facts relative to which are to appear in the final field notes, and the solar attachment may be considered in satisfactory adjustment when all meridional tests during the usual hours of solar work are found to come within V 30" of the true meridian, whereupon the certificate of the surveyor's examination of the adjustments of his instrument will take the following form: Field record. Final field notes. Buff Solar Transit No. 8028. Sun's declination at Greenwich noon =5h58ma. m., localapp.t. =18 32' 04" S. Dtff. IQh, 382" = 6 22 S. 3h,58 ra p.m. = 18 38' 26" S. /8S. 6 7 8 9 10 II Noon 1 2 3 4 / / / N 0*0. ,/ /30 r* / ^ / /~ Nor <-h / /- Non h / /. Dec/. arc O.K. / 1 / / Av o'oi / ffi f - A rth nrrh / \7V orth P.M. 5 Y * Adjust auxiliary telescope forcollimation, Nov. 16, 1911, at my station in Sec. 35, T. 11 N., R. 6 E., 5th Prin. Mer., Arkansas, in latitude 35 32.9' N., as determined by the mean of altitude observations on the sun on Sept. 26 and 29, 1911, heretofore described, and longitude 90 25' W.,I examine the ad- justments of the instrument and cor- rect all errors. I then test the solar apparatus by comparing its indications hourly with the true meridian estab- lished by Polaris observation Sept. 26, 1911, heretofore described. At9h20>a. m.,app.t., I set off 3533'N., on the lat.arc; 18 32'. 5 S., onthedecl. arc; and determine a meridian with the solar which I find to agree with the true meridian. At app. noon, with the lat. arc un- changed, I observe the sun on the meridian; the resulting reading of the decl. arc is 18 34 '.5 S., which agrees with the computed decimation of the sun. At 3 h O m p. m.. app.t., with the lat. arc unchanged, I set off 18 36' S. , on the decl. arc; and determine a meridian with the solar which I find to agree with the true meridian. As all of the solar observations during the usual hours of solar work come within 1' 30" of the true meridian, I conclude that the adjustments of the instrument are satisfactory. THE SOLAR COMPASS. 82. The Burt solar compass, invented by William A. Burt, of Michigan, in 1836, was the first solar instrument, and since its intro- 84 MANUAL, OF SURVEYING INSTRUCTIONS. duction the instrument has been extensively used in public-land surveying; the solar compass has given general satisfaction and is still used to some extent in the public-land surveys, but in recent years it has been largely superseded by the more complete instru- ment already described. The Burt solar apparatus is designed for mounting upon an open-sight compass, commonly used in the early public-land surveys. A polar axis is fitted in line with the terrestrial sights when the plate verniers are set at zero. The in- clination of the polar axis is controlled by a latitude arc mounted in the same vertical plane. Normal to the polar axis there is a revolv- ing arm upon which is mounted a declination arc and two solar lines of collimation, one for north declination of the sun, and one for south declination. Each line of collimation consists of a lens and silver plate or disk mounted upon opposite ends of the revolving arm; parallel equatorial lines are drawn upon each disk symmetrical with the axis of the opposite lens. Two adjustments are peculiar to the Burt solar compass, which are here given for the surveyor's reference in the field; these adjustments should be made when the sun is within an hour of the meridian. (1) To make the solar lines of collimation parallel. The declination arm will be detached and replaced by an auxiliary frame upon which the arm will be laid. Set the latitude and declination arcs approx- imately correct for the hour, date and station, and bring the sun's image upon either disk as in an orientation to the meridian. Now turn the arm over, without reversing from end to end, and see if the sun's image again comes between the equatorial lines; if not, adjust the disk for half the difference and repeat the test until satisfactory. When this has been accomplished, reverse the arm from end to end for the purpose of adjusting the second disk with respect to the opposite lens. Remove the auxiliary frame and attach the declina- tion arm in place. (2) To set the vernier of the declination arc. Set the declination vernier to read approximately zero, and bring the sun's image upon either disk as in an orientation to the meridian, changing the eleva- tion of the polar axis as may be necessary to bring the solar line of collimation upon the sun. With the sun's image accurately between the equatorial lines, clamp all other motions and reverse the declina- tion arm on the polar axis, thus bringing into use the second line of collimation. Note if the image of the sun is now squarely between the second pair of equatorial lines; if not, correct half the differ- INSTRUMENTS AND METHODS. 85 ence by movement of the tangent screw of the declination arc. Again orient in azimuth to bring the sun's image accurately between the equatorial lines, clamp and reverse as before, repeating the test until satisfactory. When the lines of collimation have thus been made truly at right angles to the polar axis, the vernier may be shifted to read zero in this position. The general test of the Burt solar compass, by comparing its indica- tions, resulting from solar observations made during a. m. and p.m. hours, with the true meridian determined Ly independent method, is similar to the test of the Smith solar attachment except in respect to the test of the latitude arc. No provision is made for independent adjustment of the latitude arc, and in the operation of the Burt solar compass the latitude is used as given by the instrument resulting from a meridian observation on the sun. In this respect therefore the noon observation with the Burt solar compass differs from the noon observation with the Smith solar attachment. Example of noon observation with the Burt solar compass, in lati- tude 38 53' 40" N., and longtitude 77 01. V W.: "May 6, 1910: At this station I set off 16 26' N., on the decl. arc; and, at apparent noon, observe the sun on the meridian; the result- ing latitude is 38 54' N." ERRORS IN AZIMUTH, DUE TO SMALL ERRORS IN DECLINATION OR LATITUDE. 83. It may frequently happen with a solar transit, especially at the beginning of a new survey or with an instrument insufficiently tested, that the first meridional trials are made with slight errors in the settings of the latitude and declination arcs, resulting in small errors in azimuth. This may be particularly true with a solar compass prior to a determination of the instrumental latitude. The correction of such errors has been provided for in Table 22, Standard Field Tables, which may be applied to results of single observations with considerable certainty, .but not so well to a series of observations as in ordinary line work owing to the changing values (for hours from noon) of the correction coefficients. The explanation with the table gives a key to the direction of the azimuth errors on account of small errors in setting the latitude and declination arcs. For example, at 9 h 40 m a. m., app. t., at a station in latitude assumed to be 46 20 X N., a test was made with a solar transit whereby the trial indication was found to fall 05 X west of the true meridian. Sub- 86 MANUAL OF SURVEYING INSTRUCTIONS. sequent determinations of the true latitude of the station and of the correctness of the vernier of the declination arc showed that the actual latitude of the station was 46 21/.5 N., and that the vernier of the declination arc had an index error which gave readings OCK.5 S. of the calculated declination (i. e. reading 15 19'.5 N. for a calculated declination of 15 2(X N.). Thus in the test the latitude arc was set l x .5 S. of the correct latitude of the station, and the declination arc was actually set 0'.5 N. of the value that would have been set had the index error been known. Table 22 is entered to obtain the correction coefficients: Latitude. Hours from noon. 2 h O m . 2h 20^. 8*1K 45 00' 46 21.5 50 00 2.83 2.55 2 62 2.00 Declination coeffi- cient. 3.11 2.81 2.20 45 00 46 21.5 50 00 2.45 2.10 2.16 1.41 Latitude coefficient. 2.69 2.31 1.56 The corrections are then applied as follows: Indication of solar in test =S. OS'.O W. Correction for declination = 01 .3 E.=(2.62X0.5) Correction for latitude = 03 .2 E. =(2.16X1-5) Corrected indication of solar=S. OCX.5 W. The above corrections will often serve to explain the apparent errors of the solar, but these are not intended for use in line work, and can not be accepted in lieu of satisfactory subsequent tests based on correct values. In the above connection it should be explained that it is not deemed desirable to burden the official record with evidence of correction for index errors found in the verniers of the latitude and declination arcs, "other than to state, when such are determined, that the same are forthwith removed or are allowed for in subsequent observations. POLARIS AT ELONGATION. 84. The surveyor having thoroughly considered the theory and use of the solar instrument in its relation to the public-land surveys, INSTRUMENTS AND METHODS. 87 and presumably mastered its operation, his attention is now directed to the approved methods of observation to establish the true meridian with which to make comparisons of the indications of the solar apparatus as a necessary test of such an instrument, or without a solar instrument, the establishment of the true meridian from which to project transit lines and to test the calculated course thereof. Of the various independent methods of observation to establish the true meridian, the simplest and most reliable is found in the observation upon Polaris at eastern or western elongation. Azimuth of Polaris at elongation: Sin _COS 5 ~cos $ Zenith Observing station Diurnal circle of Polaris / / / / // fig. 13. 1 The meridian and vertical planes tangent to the diurnal circle of Polaris as viewed from outside of the celestial sphere. 88 MANUAL, OF SURVEYING INSTRUCTIONS. Example of computing the azimuth of Polaris at elongation, Octo- ber 20, 1910, in latitude 46 20 X N., on which date the declination of Polaris=8849 / 4S // N.: log cos 6=8.310033 " cos 0=9.839140 " sin J.=8.470893 A= Azimuth of Polaris at elongation=l 41 X 41 X/ . 85. A table of azimuths of Polaris at elongation for latitudes from 25 to 70 N., appears in the Ephemeris, arguments: declination of Polaris, and latitude of station. Example in the use of the table of azimuths of Polaris at elongation, same date and station as above, showing the method of interpolation: Latitude. Declination. 88 49' 40" 88 49' 48" 88 49' 50". Azimuths at elongation. 46 00' 46 20 47 00 1 41' 15" 1 43 08 1 41' 04" 1 41 42 1 42 57 1 41' 01" 1 42 54 By interpolation in the table the required azimuth of Polaris at elongation is therefore found to be 1 41' 42". 86. An observation upon Polaris at elongation for azimuth con- sists in marking upon the ground a point to define the true line of sight to Polaris at the epoch of elongation, from which to lay off the true meridian. An equivalent process is to determine the true horizontal angle by deflection from a fixed reference point to Polaris at the epoch of elongation, by which to determine the true bearing of the reference point. POLARIS AT ELONGATION, OBSERVING PROGRAM "a." 87. Select the observing station and make suitable provision to mark the line defining the direction of Polaris at elongation; the flag point should be from 5 to 10 chains N. of the transit point, and should be cleared of all obstruction before dark. Determine the local mean and watch time of elongation of Polaris, provide suitable INSTRUMENTS AND METHODS. 89 illumination for both the transit and flag point, and have every- thing in readiness as much as 15 minutes before the time of elonga- tion. Thoroughly level the transit. About six minutes before elongation, with the telescope in direct position, bisect Polaris, note the watch time, and mark the direction of sight. Reverse the transit, bisect Polaris, note the watch time, and mark the direction of sight. Again level the transit. With the telescope in the reverse position bisect Polaris, note the watch time, and mark the direction of sight. Reverse the transit to the direct position of the telescope, bisect Polaris, note the watch time, and mark the direction of sight. By daylight determine the mean (a) of the first and fourth sights, and (6) the mean of the second and third sights; then take the mean of points "a" and "6" to define the true direction of Polaris at elongation. The mean of the four watch readings may be taken as the watch time of observation, which if within four or five minutes of correct watch time of elongation, the mean position of Polaris during the observation will be within 1" or 2" of true elongation. The proper value of the azimuth of Polaris at elongation having been taken from the table is then used to lay off the true meridian to the east for west- ern elongation or to the west for eastern elongation. The above program practically eliminates instrumental errors in observation. In laying off the azimuth of Polaris, the angle may be laid off directly, if desired, checked by the method of repetitions, and corrected if necessary; or the azimuth angle may be laid off by the natural tangent method; this should then be checked by reading the angle on the plates. Example of observation of Polaris at elongation, observing pro- gram "a:" 55465 19 7 90 MANUAL OF SURVEYING INSTRUCTIONS. Field record. Final field notes. Sept. 10, 191 of Polaris, Red. to long Red. to lat. L. M. T. of 3 Watch slow Watch time I, Gr. E. E. lat. 40 . 111 45' W. i322'30"N. u. E. of Polaris. = 8 h 17.0 m p. m. = -1.2 = +0.5 86] s 1 i 1 8 c e s t r t t (] 5 Az e f a d 8 5 ...--8*] 16. 3 p.m. 1.7 ofl.m.t. ofE. E. 4. 6 m p. m. Telescope. Watch Time. Direct- .. 8*>OS 26" p. m. 20 34 46 Reversed 8 11 Reversed . 8 14 Direct . . .. 8 16 Mean 8M2< 46" p. m. Declination of Polaris=88 49' 54" N. Latitude. Declination. 88 49' 50" 88" 49' 54" 88 49' 60" Azimuth. 43 C 00' 00" 43 22 30 44 00 00 1 35' 57" 1 1 1 37 33 1 35' 51" 36 27 37 27 1 35' 43" 1 37 19 Sept. 10, 1911, in camp at the standard cor. of Tps. 1 N., Rs. 39 and 40 E., Boise Her., in latitude 43 22' 30" N., ancf longitude 111 45' W., at 8h 16.3m p. m . f i. m . t>> i observe Polaris at eastern elongation, making four ob- servations, two each with the telescope in direct and reversed positions, and mark the mean point in the line thus determined, on a peg driven firmly in the ground, 5chs.N. Azimuth of Polaris at eastern elongtion=l 36' 27". Sept. 11: I lay off the azimuth of Polaris, 1 36' 30", to the west, and mark the meridian thus determined, by a tack in a peg driven firmly in the ground> 5 chs. N. The above program of observatipn of Polaris at elongation is the most convenient method where there is an opportunity to mark the direction of the line of sight. Occasionally conditions obtain where it is impossible to define or mark the direction of the observation ; the program may then be altered to the reading of deflection angles as shown in the next method. POLARIS AT ELONGATION, OBSERVING PEOGRAM "b." 88. Select the observing station and mark a point by driving a tack in a peg driven firmly in the ground approximately in the true meridian as determined by the solar before sunset, or choose other suitable reference mark in. any direction. The reference point should not be nearer to the transit than 5 chains distant. Deter- INSTRUMENTS AND METHODS. 91 mine the local mean and watch time of elongation of Polaris, pro- vide suitable illumination for both the transit and flag point, and have everything in readiness as much as 10 minutes before the time of elongation. Thoroughly level the transit. About 6 minutes before elongation with the transit in direct position, read and note the deflection angle from the reference point to Polaris, noting ajso the watch time of observation. Reverse the transit and read and note the deflection angle from the reference point to Polaris, noting also the watch time of observa- tion. Again level the transit. With the transit in the reverse position again read and note the deflection angle from the reference point to Polaris and note the watch time of observation. Reverse the transit to the direct position and again read and note the deflection angle from the reference point to Polaris, and note the watch time of observation. As the position of Polaris remains within about OCX 01" of true elongation for a period of about five or six minutes either side of the time of exact elongation, the observation may be considered satis- factory if all of the watch readings fall within the stated period. The mean of the four horizontal deflection angles may be taken to which must be applied the value of the azimuth of Polaris at Elongation taken from the table, to obtain the true bearing of the reference flag, from which the true meridian may be laid off, or the flag may be used as a reference point. A 'reference point in any direction may be used in the above method ; the direction of the deflection from the reference point to Polaris should always be clearly stated. The insignificant figures of the final result may be discarded if the value of the bearing angle does not enter into another determination that demands great pre- cision. In the example below the true meridian may be laid off by accurately measuring a distance from the reference point, at right angles to the line of sight, found by multiplying the distance from the instrument to the reference point (660 ft.) by the tangent of the bearing angle (nat tan 00' 44" =--0.00021) which gives 0.14 ft. After laying off the true meridian the angle from the reference point may be checked by the method of repetitions. 92 MANUAL OF SURVEYING INSTRUCTIONS. Example of observation of Polaris at elongation, observing pro- gram < <6": Field record. =6^ 46. l m p. m. = - 1.1 - - 1.0 Apr. 1, 1911, Gr. W. E. of Polaris, lat. 40 Tied, to long. 104 39' W. " " lat. 46 13' N. L. M. T. of W. E. of Polaris. =6* 44.0">p. m. Watch slow of L. M. T. =-2.9 Watch time of W. E Telescope. Direct Reversed . Reversed . Direct Mean. Watch time. 6h 37m 22 6 39 40 6 43 14 6 45 30 6k 4im Deflection angle. 141'00' 1 40 30 1 40 00 1 40 30 1 40' 30' Declinationof Polaris- 88 49' 58" N. Latitude. 40 00' 46 13 47 00 Declination. 88 49' 50" 88 49' 58" 88 49' 60" Azimuth. 1 41' 01" 1 42 54 1 40' 50" 1 41 14 1 42 42 1 40' 47' 1 42 39 Final field notes. April 1, 1911, in camp at the cor. of Tps. 5 and 6 N., Us. 56 and 57 E., Prin. Mer., Montana, in latitude 46 13' N., and longi- tude 104 39' W., at 6h 44.0 p. m., 1. m. t., I observe Polar- is at western elongation, mak- ing four observations, two each with the telescope in direct and reversed positions, reading the deflection angle from a tack in a peg driven firmly in the ground, 10 chs. N., west to Polaris: Azimuth of Po- laris at west- em elonga- tion = 1 41'14" Mean deflec- tion angle = 1 40 30 True bearing of mark 89 . Both of the above observing programs require the surveyor to compute in advance the correct watch time of elongation, and in so conducting the observation the minimum period is consumed in the observing program; every opportunity is also thus afforded for re- versals to eliminate instrumental errors and otherwise to introduce creditable refinement. However, should the watch error be unknown , the observation may be conducted by following the motion of Polaris in azimuth during an ample period preceding elongation to insure that the epoch of the vertical motion of Polaris in its diurnal circle, INS'lUUMENTH AND METHODS. 93 or zero motion in azimuth, is taking place, when the surveyor marks the direction of sight thus defined. The rate of horizontal motion for the hour preceding elongation rapidly diminishes, the change in azimuth being to the west for western elongation, or to the east for eastern elongation, when Polaris will follow the vertical cross- wire, after which the motion is reversed at an accelerating rate. This suggests a third, but less refined, ob- serving program . POLARIS AT ELONGATION, OBSERVING PROGRAM "C." 00. Select the observing station and make suitable provision to mark the line defining the direction of Polaris at elongation; provide suitable illumination for both the transit and flag point, and have everything in readiness as much as an hour before the time of elonga- tion. Thoroughly level the transit. Bisect Polaris and note that the motion of the star carries it away, from the vertical wire in the proper direction. As long as this motion is discernible continue the bisection of Polaris by the tangent move- ment. When it can not be discerned in a period of several minutes that the least lateral motion is taking place mark the direction of sight upon the ground. Reverse and level the transit. Again bisect Polaris and mark the direction of sight upon the. ground. Verify the position of Polaris in its diurnal circle by again bisect- ing the star and without changing the tangent motion note the move- ment of Polaris; the motion should still be nearly vertical, with a scarcely discernible movement in the opposite horizontal direction. By daylight determine the mean of the sights, and establish the meridian by properly laying off the correct azimuth as described in observing program "a." AZIMUTH OP POLARIS AT ANY HOUR ANGLE. 01. AVhile no more reliable method is at the command of the sur- veyor for the establishment of the true meridian than the observa- tion upon Polaris at elongation, yet the epoch of elongation may occur at a very inconvenient tune and should Polaris be obscured by clouds at the time of elongation the observation must fail. The, "hour angle 7 ' method admits of observation upon Polaris for azi- muth at any time that the star is visible; the precise watch error local mean time must be known, but if this has been determined, 94 MANUAL OF SURVEYING INSTRUCTIONS. the hour angle method becomes at once the most convenient. The possible accuracy of the result compares favorably in every way with the refinement to be obtained in an observation at elongation. The determination of the watch error local mean time and the cal- culation of hour angles having been fully treated on previous pages, it remains only to state that the record of the time observation should appear in the field notes with the record of all observations upon Polaris for azimuth by the hour angle method, as the azimuth observation is incomplete without the time determination. With the meridian observation of the sun for apparent noon, and the use of the azimuth tables contained in the Ephemeris, the entire process becomes so simple and yet so highly refined that the surveyor should early become thoroughly familiar with the hour angle method. 92. Azimuth of Polaris at any hour angle. ""=sidereal hour angle in angular measure; in hoar angles exceeding 90 the function " sin cos V becomes positive by virtue of the cosine of an angle between 90 and 270 being treated as negative in analytical reduc- tions: sin t Tun ^1 i cos < tan 5 sin cos t Example of computing the azimuth of Polaris, February 23, 1911, at a mean time hour angle of 2 h 37 .4 m , in latitude 33 2(X N., on which date the declination of Polaris=88 50' 08" N.: Mean time hour angle =2 h 37.4 m =2 h 37 m 24 8 2 h =30 37 m = 9 15' Bed. to sidereal hour angle= +26* 50* = 12' 30" Sidereal hour angle =2 h 37 m 5Q s =3927 / 30" [ log cos 9. 921940 log sin $ =9. 739975 " tan 5 =1. 691944 " cos t =9. 887666 " cos < tan 5= 1. 613884 " sin < cos =9. 62764] nat cos < tan 5=41. 104 nat sin cos t=0. 424 nat sin < cos t 0.424 ( ) log sin * =9. 803127 Algebraic sum=40. 680 " 40.680 =1. 609381 " tan -4 =8. 193746 Azimuth of Polaris at above hour angle, J.=0 53 X 42" I N STRU AIEX TS A N D METHODS . 95 98. A table of azimuths of Polaris at all hour angles, for latitudes from 30 to 50 N., appears in the Ephemeris, arguments: declina- tion of Polaris, mean time hour angle, and latitude of station. For other than the latitudes given in the table the surveyor will be required to solve the above equation. Example in the use of the table of azimuths of Polaris at any hour angle, same date, hour angle and station as above, showing the method of interpolation: Declination. Latitude. 88 60' 0" 88 5 " tan 5 =9.864833 =1. 690496 log sin " COS* =9 =9 .832969 . 565596 " cos < tan 6 =1. 555329 " sin cos t =9 .398565 nat cos < tan 5 =35. 919 nat sin cos 5 - .250(+) log sin t =9 .968441 Algebraic sum =36.169 11 36.169 =1 .558337 " tan A =8 . 410104 Azimuth of Polaris at above hour angle, A 96 MANUAL OF SURVEYING INSTRUCTIONS. 95. Example in the use of the table of azimuths of Polaris at any hour angle, same date, hour angle and station as above: Declination. Latitude. 88 49' 50" 88 49' 54" 88 49' 60" 42 (XX 42 54' 44 00 / Mean time hour angles. Azimuths of Polaris. 7* 15. 7m 29.3 7* 15.1m 25.1 28.8 7fc 14.2^ 28.0 88'. 6 86. 6 89 '.9 88. 4 87. 8 91 '.5 89. 4 By interpolation in the table the required azimuth of Polaris is therefore found to be 88 X .4=1 28' 24". 96. An observation upon Polaris for azimuth by the hour angle method consists in marking upon the ground a point to define the true line of sight to Polaris at any convenient epoch, the watch error local mean time being known, from which line to lay off the true meridian. An equivalent process is to determine the true hori- zontal angle by deflection from a fixed reference point to Polaris at any convenient epoch, the watch error local mean time being known, by which to determine the true bearing of the reference point. HOUR ANGLE OBSERVATION OF POLARIS, OBSERVING PROGRAM u tt. M 97. Select the observing station and make suitable provision to mark the line defining the direction of Polaris; the flag point should be from 5 to 10 chains north of the transit point; provide suitable illumination for both the transit and flag point. Thoroughly level the transit. With the telescope in the direct position, bisect Polaris, note the watch time, and mark the direction of sight. Reverse the transit, bisect Polaris, note the watch time, and mark the direction of sight. Again level the transit. With the telescope in the reverse position bisect Polaris, note the watch time, and mark the direction of sight. Reverse the transit to the direct position of the telescope, bisect Polaris, note the watch time, and mark the direction of sight. By daylight determine the mean (a) of the first and fourth sights, and (6) of the second and third sights; then take the mean of I N STK U ME N TS A !N D METHODS. 97 points "a" and "6" to define the true direction of Polaris at the epoch of the average of the watch times of observation. Treat the reduction as one observation, applying the watch error to the average watch time of observation to obtain the correct local mean time of observation. Enter the table in the Ephemeris or make the computation to determine the value of the azimuth of Polaris at the epoch of the observation with the stated arguments: declination of Polaris, mean time hour angle and latitude ; this value is then used to lay off the true meridian to the east if Polaris is observed west of the meri- dian or to the west if Polaris is observed east of the meridian. Example of hour angle observation of Polaris, observing program "a": Field record. Meridian observation of the sun for apparent noon: 0=37 18' N. 90 00' 5= 4 36 S. 41 54 y=48 06' Watch time. = 12* 00<" IS* = 12 02 26 0+6=41 54' Sun's W. limb O - Watch time of app. noon App. noon = 12^ 00" 00 s Equation of time = 11 25 L. M. T. of apparent noon Watch fast ofl. m. t. Hour angle observation of Polaris: 22 12oi 47" Telescope. Watch time. Direct Reversed. Reversed. Direct Mean Watch fast ofl. m. t.. L. M. T. of obsn. 5*i 48^40" p. m. 5 49 49 5 51 36 5 52 54 5i 50^ 45 p. m. - 12 47 37^ 58* p. m. 38. 0^ p. m. Final field notes. Oct. 5, 1910, in camp at the cor. of sees. 5, 6. 31, and 32, on the S. bdy. of T. 31 S., K. 42 W.. 6th Prin. Mer., Colo., in lati- tude 37 17'.6 N.. and longi- tude 102 11' W., I make a meridian observation of the sun for apparent noon: Watch time of obsn.=12h 01 22^. Watch fast of 1. m. t.=12 47*. At the same station, at 5* 38.0 m p. in., 1. m. t., I make an hour angle observation on Polaris east of the meridian, making four observations, two each' with the telescope in direct and reversed positions, and mark the mean point in the line thus determined, on a peg driven firmly in the ground, Schs.N. 98 MANUAL OF SURVEYING INSTRUCTIONS. Field record, con. Gr. U. C. of Polaris, Oct. 6, 1910 =0^ 32.7' a. m. lied, to long. 102 11' W. 1.1 L. M. T., U. C. of Polaris, Oct. 6= 0^ 31.6 a. m. +12 L. M. T. of obsn., Oct. 5 =5 38.0 p. m. Hour angle of Polaris east of the meridian -= 6& 53.6^ Declination of Polaris=S8 49' 42" N. Final lield notes, con. Declination. +88 49' 40" 42" 50* Mean time hour angles. 6^51. 6 61.5 53.6 61.1 6M9.5 59.6 Latitude. 36 00' 37 18' 38 00' Azimuth of Polaris. 84'. 3 83. 3 85'. 7 85. 5 84. 8 86'. 5 85. 6 Watch time of obsn., mean of four readings= 5> 50 45 p. m. Oct. 6, 1 lay oft the azimuth of Polaris, 1 25' 30", to the west, and mark the meridian thus determined, by a tack in a peg driven firmly in the ground, 8 chs. N. HOUR ANGLE OBSERVATION OF POLARIS, OBSERVING PROGRAM "6." 98. Select the observing station and choose a suitable reference mark in any direction. The reference point should be at least 5 chains distant. Thoroughly level the transit. With the telescope in the direct position, read and note the hori- zontal angle from the reference point to Polaris, noting the watch time at the moment Polaris is properly bisected. Reverse the transit and read and note the horizontal angle from the reference point to Polaris, noting the watch time at the moment Polaris is properly bisected. Again level the transit. With the telescope in the reverse position again read and note the horizontal angle from the reference point to Polaris, noting the watch time at the moment Polaris is properly bisected. Reverse the transit to the direct position of the telescope and again read and note the horizontal angle from the reference point to Polaris, noting the watch time at the moment Polaris is properly bisected. Treat the reduction as one observation, applying the watch error to the average watch time of observation to obtain the correct local INSTRUMENTS AND METHODS. 99 The mean of the four horizontal deflection angles may be taken, to which must be applied the proper value of the azimuth of Polaris at the mean epoch of the observation, to give the true bearing of the reference flag, from which the true meridian may be laid off, or the flag may be used for a reference point. Example of hour angle observation of Polaris, observing program Field record. Final field notes. Hour angle observation on Polaris: March 21 , 1910, at a transit point in Washington. D. C., hi lati- tude 38 53 7 40' 'N. f and longi- tude 77 1'.6 W., I find by comparison with a Western Union telegraph clock that my watch is 1m 22* slow of 75th meridian standard time. At the same station at 6** 19.9m p. m., 1. m. t., I make an hour angle observation on Polaris, west of the meridian, two each with the telescope in direct and reversed posi- tions, reading the horizontal deflection angle from a flag pole about 20 chs. S., in the direction S-W-N to Polaris. Watch time of obsn.=-6* 26 40 3 p. m. Mean horizontal angle from Polaris to flag =177 34' 15" N-W-S Azimuth of Polaris- 1 26 24 W. Horizontal angle Telescope. from flag to Polaris. Watch time. Direct... 177 3 4' 30" 4 30 4 00 4 00 6^ 22m 373 p. m . 6 25 29 6 28 17 6 30 17 Reverse* Reversed Direct... 177 3 177 3 177 3 Me Watch si ard tirr Correctio L. M. T. Gr. U. C same Bed. to 1 77 1 Hour an theme Declinati an. . . 177 34' 15" ow of 75th mer. stand- le n for longitude Qh 26m 4Q3 p. m . -f 1 22 -86 of obsn. Mar. 21, of Polaris, date =1*33 ong. 6' W - 1910- 6h 19m 56a 6 h 19. 9 01 p. m. .Qmp. m. .0=1 32.1 p.m. ?le of Polaris west of idian = on of Polaris 4* 47.8m 88* 49' 41" N. True bear- ing of flag f* N. 179* OO; 3d^ W. Declination, Latitude. 88 49' 38 00' 38*54' 40*00' 40" 11" 50" Mean time hour angles. Azimuths of Polaris. & 33. o m 49.0 33. 7 35. 0<* 47.8 49. 2 50. 8 83'. 6 85.5 84'. 7 86'. 80.4 86 . 6 88 . 100 MANUAL or SURVEYING INSTRUCTIONS. POLARIS AT SUNSET OR SUNRISE. 99. Polaris is conveniently observed for azimuth by the hour angle method at sunset or sunrise without artificial illumination. The preparation for the observation consists in computing in advance the approximate settings in azimuth and altitude in order to find Polaris, and the plan contemplates an approximate reference meridian: With the time of sunset or sunrise assumed as the time of observation, the hour angle "t" and azimuth "A" are ascertained in order to find the position of Polaris in azimuth; the position in altitude is found by the following approximation, the positive sign being used for hour angles less than 6 hours and the negative sign for hour angles exceeding 6 hours: ?'^4>70 / cos t Example of computation of the position of Polaris at sunset, May 6, 1911, at a station in latitude 47 20' N., and longitude 10240 / W. : From the Ephemeris the declination of the sun is found to be 16 18' X., and by entering Table 17, of the Standard Field Tables, the apparent time of sunset is found to be 7M5 m p. m. Assumed time of obsn., May 6, 1911 7 h 15 m p. m. Gr. U. C. of Polaris, May 6 = 10 h 33. 5 m a. m. +12 Red. to long. 102 W W. -1.1 = 10 32. 4 a. m. Assumed hour angle of Po- laris west of the meridian = 8 h 42. 6 m Hour angle, angular measure = 130 39' Azimuth of Polaris, W. ^ 1 17' Latitude of station =47 20' ===== 70' cos =70 cos 130 39 X = 46(-) 34' Example of computation of the position of Polaris at sunset, Nov. 6, 1911, at a station in latitude 47 20' N., and longitude 102 4(K W. : From the Ephemeris the declination of the sun is found to be 15 44' S., and by entering Table 17, of the Standard Field Tables, INSTRUMENTS 'AND MiyJ5l\2)S. 101 the apparent time of sunrise is fcand/tO be 4 h 48 m p. m. Gr. U. C. of Polaris, Nov. 6, 1911 Red. to long. 102 4(K W. L. M. T. of U. C. of Polaris Assumed time of observation ==l(^ 28. 2 - -1. 1 =10* 27. l =4 48 p. m. p. m. p. m. Assumed hour angle of Polaris east of the meridian= 5 h 39.1 m Hour angle, angular measure =84 46' Azimuth of Polaris, E. ^ 1 43' Latitude of station =47 2(X 70' cos f=*70 cos 84 46 X = 06 ( + ) 26 X Example of computation of the position of Polaris at sunrise, November 7, 1911, and same station as above: ( 7 h 12 m a m Assumed time of obsn., Nov. 7, 1911 ~< , 9 L. M. T. of U. C. of Polaris, Nov. 6 =10 27.1 p. m. Assumed hour angle of Polaris west of the meridian = 8 h 44. 9 m Hour angle, angular measure = 131 14 r Azimuth of Polaris, W. ^ 1 16 X Latitude of station =4720 / ===== 70 X cos =70 cos ISl !^^ 46(-) Thus at the above station in latitude 47 20 X N., and longitude 102 40 7 W., to observe Polaris by the daylight method an approxi- mate meridian should be established with the solar before sunset, then to find Polaris the following angles are set off: Horizontal angle. Vertical angle. SunmtMaye. 191 1 ., 117' W. 46 34' Sunset Nov. 6, 1911 143' E 47 26' Sunrise Nov. 7, 1911 .... 116' W 46* 34' 102 >jLANUA]L GF 3U&VJSYING INSTRUCTIONS. The abui o "/sorting^" are merely. approxiniations, but sufficiently close, however, to bring Polaris reasonably near the center of the field of the telescope where the star will be found in plain view; the telescope should be focused upon a distant object, otherwise, though Polaris may be practically at the center of the field, it might be out of focus and therefore not observable during daylight. When Polaris has been found the above settings have answered their purpose and the observation may proceed in accordance with either observing program "a" or "6" of the hour angle method, the final reductions to be based upon the precise details of the observation. During the reversals of the transit the settings should be made each time. The daylight hour angle method is particularly desirable be- cause the observation, including all instrumental work, marking of points upon the ground, etc., is accomplished without artificial illu- mination, and sunset is usually a convenient time to devote to this field duty. To recapitulate, the following general program will be found best adapted to the requirements of public-land surveying practice, and will be used most extensively: Time: By meridian observation of the sun for apparent noon. Latitude: By meridian altitude observation of the sun. Azimuth, true meridian upon which to test the solar apparatus: By hour angle observation on Polaris at sunset. Azimuth, on line: By the solar transit properly adjusted to the true meridian. ALTITUDE OBSERVATION OF THE SUN FOR AZIMUTH. % 100. While the methods of observation upon Polaris for azimuth are unquestionably the most desirable in their relation to the theory and practice of public-land surveying, yet a very efficient alternative is found in direct altitude observations upon the sun for azimuth, with a number of equations at the disposal of the surveyor to suit his convenience. During the shorter days of the year and even quite often at any season the surveyor finds himself at a loss for time and suitable daylight hours in which to make the required tests of his solar attachment; conditions obtain making the required tests impossible if limited to a Polaris meridian in camp, without involv- ing unreasonable delay. It is in such cases that a direct altitude observation upon the sun for azimuth, on the actual line of the survey, finds its most useful application. Presuming the surveyor INSTRUMENTS AND METHODS. 103 at .work with a standard instrument with solar attachment, the accuracy of its adjustments can, by this method, be readily tested at work on line at any suitable morning or afternoon hour, without appreciable loss of time. Under working conditions any line deter- mined with the solar attachment may be used for reference pur- poses, while vertical and horizontal angles are recorded to the sun to obtain the necessary data for computing the true bearing of the established solar line. A series of three altitude observations upon the sun, each with the telescope in direct and reversed positions, are required to guard against error; these are readily made in 10 or 12 minutes, while the reductions may be made in the evening without loss of time from the line work. Other difficulties in the nature of temporary disability of the solar attachment, and cloudy nights preventing Polaris observations, or other adverse conditions may sometimes obtain, during which periods, even for a few days, if the surveyor is familiar -with the method of direct altitude observation upon the sun for meridian. Le can thus establish his lines and possibly realize a saving of the entire time of his party until the trouble is removed. To the sur- veyors who have used this method little more needs to be said in its favor, but to those unfamiliar with it the suggestion is made to practice the observations and reductions until proficiency is attained, and in its application the reward will come many times during an average season's work. Referring to the description of the standard instrument adopted by the General Land Office it will be noted that it is equipped with a full vertical circle, a colored glass shade in the dust shutter of the eye-piece, and a prismatic eye-piece; these are essential to rapid and accurate altitude observations upon the sun. 101. An altitude observation of the sun for azimuth consists in the simultaneous determination of the true vertical and horizontal angles to the sun's center, the* horizontal angle being referred to a fixed point. With the true vertical angle to the sun's center, the declination of the sun, and the latitude of the station all known, one of the following equations is entered and a calculation made of the azimuth of the sun's center at the epoch of observation, as referred to the true meridian; the relation between the sun's calculated azimuth and the recorded angle to the sun's center gives the true bearing of the fixed reference point. 104 MANUAL OF SURVEYING INSTRUCTIONS. 102. Altitude observation of the sun for azimuth. Reverse the signs of " 5" for south declinations: l= / V cos \ (r-4>-5) sin \ (r- The spherical angles "f ", "0", and "6" appear in this equation combined as in the formula for the reduction of an altitude observa- tion of the sun for apparent time, and when it is desired to reduce for both time and azimuth, the above equation for azimuth is to be preferred to any that follow. 103. Altitude, observation of the sun for azimuth. For south declin- ations the function "sin 5" becomes negative by virtue of the sine of a negative angle being treated as negative in analytical reduc- tions: If the algebraic sign of the result is positive the azimuth "A" is referred to the north point, but if negative, the azimuth " A" is referred to the south point: Cos The above equation is very convenient in reducing for azimuth only. 104. Altitude observation of the sun for azimuth. To many sur- veyors the following equation is familiarly expressed directly in terms of the spherical triangle "pole-zenith-sun: " Reverse the sign of "5" for south declinations: Pole to zenith =90-<= colat.; Pole to sun =90 5= coded. ; Zenith to sun =90/& = coalt.; S$ sum of the three side?: r i A M n S g i n (-- coded.) ~ V sin colat. sin coalt. OBSERVING PROGRAM, MORNING. 105. Thoroughly level the transit. With the telescope in direct position observe and record the hori- zontal deflection angle from a fixed reference point to the sun's right limb, and the vertical angle to the sun 'supper limb; these observa- tions must be simultaneous, at the epoch of which the sun will appear as indicated; note the watch time at the epoch of the observation: tan h cos cos h log cos 0=9. 900674 log sin 6=9. 486493(+) log tan 0=9. 881708 11 cos 7i=9. 937897 " tan A=9. 759970 9.838571 9.838571 log 9.641678 log 9.647922 nat(-) .43821 nat (+) .44455 (-) .43821 cos^L=(+) .00634 -4=True bearing of sun =N. 89 38 X 12" E. Angle from sun to flag =(+) 2045 True bearing of flag ==N. 89 58 X 57" E. log cos 0=9. 900674 log sin 5=9. 486493(+) log tan 0=9. 881708 " cos /i=9. 933763 " tan A=9. 776132 9.834437 9.834437 log 9.657840 log 9.652056 nat(-) .45482 nat(+). 44880 (+) .44880 cos^=(-) .00602 4=True bearing of sun =S. 89 39 X 19" E. Angle from sun to flag =(-{-) 22 15 True bearing of flag =S. 90 Ol x 34" E. =N. 89 58' 26" E. 108 MANUAL OF SURVEYING INSTRUCTIONS. log cos <=9. 900674 log sin 5=9. 486493(-f ) log tan 0=9. 881708 =9. 923762 9. 824436 ' tan =9. 811941 9. 824436 log 9. 693649 nat (-) .49391 (+) .45926 log 9. 662057 nat (+). 45926 cos^=(-) .03465 ^l=True bearing of sun =S. 88 00' 52" E. Angle from sun to flag =(+)2 0030 True bearing of flag =S. 90 01' 22" E. =N. 8958 / 38 // E. The particular convenience of the above equation is noted in the fact that the functions "cos <", "tan <", and "sin 6" are constant throughout the entire reduction, the function "A" being the only variable. 109. The third of the above series is selected for an example of reduction by the equation: Co i A /-^ ^ sin (8 coded.) V sin colat. sin coalt. 90 -0=90 -37 17' 30" =52 42' 30"=colat. 90-S=90 -1751 / 04"(+)=72 08 56 =codecl. 90 -/}=90-3257 / 55" =57 02 05 =coalt. 2 =181 53' 31" = 90 56' 45" coded. =90 -5= 72 08 56 S- coded. = 18 log sin S " sin (S- coded. ) = " sin colat. =9.900674 " sin coalt, =9.923762 47/ 49// 9. 999941 9. 508146 9. 508087 9. 824436 9. 824436 < cos 2 JJ. = 9.683651 cos Lf = 9.841825 \A = 45 59 X 35" ^l=True bearing of sun =N. 91 59 X 10" E. Angle from sun to flag =( ) 2 00 30 True bearing of flag =N. 89 58 X 40" E. INSTRUMENTS AND METHODS. 109 The above equation is as good as any for the reduction of one obser- vation, but the reduction becomes laborious for a series of three observations. 110. The third of the above series is also selected for an example of reduction by the equation: Tan * A = / CQS 4 (f +4>+S) sin 4 (r+ 5)= 9. 791636 9. 538197 cos 4(f-0-5)=9. 999941 sin i-(f-0+5)=9. 508152 9. 508093 9. 50809$ log tan 2 4^4= 0.030104 " tan A= 0.015052 \A= 45 59 X 34" True bearing of sun =N. 91 W 08" E. Angle from sun to nag=(-)2 00 30 True bearing of flag =N. 89 58 X 38" E. 110 MANUAL OF SURVEYING INSTRUCTIONS. 111. The above equation is as good as any for the reduction of one observation, but the reduction becomes laborious for a series of three observations. However, the advantage in using the above equation is found when it becomes desirable to reduce the observations for both time and azimuth. Let it be required to reduce the third observation of the above series for time, making the reduction by the following equation: / /* <= Vc cos *(r+-5)=9. 999941 9. 746502 9. 746502 tan 2 i t = 9. 553286 tan 4 f = 9. 776643 i* =3052 / 34 // = * =61 45' 08 // =4 h 07 m 01 s Apparent time of observation =7 h 52 m 59 s a. m. Equation of time = +6 05 Local mean time of observation =7 h 59 m 04 s a. m. Watch time of observation =7 52 54 Watch slow of 1. m. t. = 6 m 10 s 112. Example of direct altitude observation of the sun for azimuth, eun south declination : Final field notes . March 18, 1910, at a transit point in Washington, D . C., in latitude 38 53 r 40" N., and longitude 77 01'.6 W., at3 h 42 m p. m., app. t., I make a series of three altitude observations upon the sun for azimuth, each with the telescope in direct and reversed positions, observing opposite limbs of the sun, and reading the horizontal deflection angle from a flag pole about 20 chs. to the S., SW. to the sun: INSTRUMENTS AND METHODS. Ill Obser- vation. Telescope. Sun. Watch time. Vertical angle. 9 Horizontal angle flag to sun. 1st Direct q- 3 h 56 58> 25 20' 65 00' to SW. Reversed -b 3 58 48 25 31 64 45 " " Mean 3h sym 533 25 25' 30" 64 52' 30" " " 2nd. . . Direct.. .. q_ 4h Olm 48s 24 28' 65 56' " " Reversed.... 1 -b 4 03 10 24 44 65 36 " " Mean . 24 36' 00" 65 46' 00" " " . 3rd Direct 9- 4 h Q&* 58s 23 44' 66 44' " " Reversed 43 4 07 30 23 57 66 26 " " Mean . 23 50' 30" 66 35' 00" " " By 1st obsn. flag bears S. 1 0(K 02" W. " 2nd " " " S. 1 00 20 W. " 3rd " " " S. 59 50 W. Mean true bearing of flag=S. 1 00' 04" W. Field record. The declination of the sun for the mean period of the three obser- vations=l 02 X 16 X/ S. The following reductions are made to obtain the true vertical angles of the above observations: 1st obsn. 2nd obsn. 3rd obsn. v=2b 25 X 30" 24 36 X 00" 23 5(K 30" Refraction= -2 00 -2 06 *-2 10 Parallax = +08 +08 +08 =25 23 X 38" 24 02" 23 28 A 112 MANUAL OF SURVEYING INSTRUCTIONS. 113. The* first of the above series is selected for an example of reduction by the equation : Tan \A= h= 25 23' 38" $= 64 36 X 22" r=64 36' 22' 0= 38 53 40 0=38 53 40 =103 30' 02" f-0=25 42' 42" i= 1 02 16 (-) ' 5= 1 02 16 (-) =102 27' 46" 0+6=24 40' 26" = 51 13' 53" 4(f-0+5)=12 20' 13 A 103 30 X 02" f 0=25 42 X 42" 5= 1 02 16 (-) 5= 1 02 16 (-) -5=104 32 X 18" ^-0-5=26 44 X 58 A 5 ;\ f\O ~\ f\/ nQ-'/ iff" A*. f\\ 1 QO OQ^ *?Q^< o) == tjZi _LO uy 2\ i ~~fy "~"O j ^^ J-O ^.z ^y log cos i(r+0+5)= 9. 796697 5)= 9.898118 9. 694815 " cos J(r-0-5)=9. 988058 " 'sin i(f-0+5)=9. 329724 9.317782 9.317782 log tan 2 i A = 0. 377033 " tan 4 4 = 0.188516 J A =57 03 X 44" bearing of sun=N. 114 07 X 28 X/ W. Angle from sun to flag= (+)64 52 30 True bearing of flag=N. 178 59 X 58 /x W. =S. 1 00 X 02" W. INSTRUMENTS AND METHODS. 1 13 114. Let it also be required to reduce the first observation of the above series for time, making the reduction by the following equa- tion: i / /si V co cos log sin J(M-<-5)= " sin l(r-0+5)= cosJ(M-0+)= cos i(r-4>-5)= cos i(f-0-6) 9. 898118 9. 329724 9. 227842 9.796697 9.988058 9. 784755 9. 784755 log tan 2 J t= 9.443087 " tan i = 9.721544 i =27 46' 29" = =55 32' 58"=3 h 42 m 12 s Apparent time of obsn. =3 h 42 m 12 s p. m. Equation of time = +8 17 Local mean time of obsn.=3 h 50 m 29 s p. m. Watch time of obsn. =3 57 53 Watch fast of 1. m. t. = 7 m 24 s 75th meridian time of comparison with a Western Union telegraph clock =4 h 30 m 00 s p. m. Correction for longitude = 08 06 L. M. T. of comparison 4 21 Watch time of comparison =4 29 Watch fast of 1. m. t 54 20 = 7 m 26 9 115. The second observation of the above series is selected for an example of reduction by the equation : sin 5 Cos A log cos $=9. 891149 " cos A=9. 958790 9&9939 - r cos cos h log sin 5=8. 257958 tan tan h ( -) log tan 0=9. 906733 " tan h =9. 660053 log nat(-) 9.J849939 8.408019 .02559 log nat(-) (-) cos.4=(-) 66 46 X 20" W. 9.566786 .36880 . 02559 .39439 ^=True bearing of sun =S. Angle from sun to flag=(-)65 46 00 True bearing of flag =S. 1 00 X 20 / W. 114 MANUAL OF SURVEYING INSTRUCTIONS. 116. The third observation of the above series is selected for an example of reduction by the equation: Cos J A= sn (S- sin colat. sin coalt. 90-4>=90-38 53' 40" = 51 06' 20"=colat. 90-5=90- 1 02 16 (-) = 91 02 16 =codecl. 90 -fc=90 -23 48 28 = 66 11 32 =coalt. 2 S=208 20' 08" S=104 10' 04 A coded. =90 -5 = 91 02 16 S-codecl.= 13 07' 48" log sin S =9. 986585 " sin (S-codecl.) = 9.356334 9.342919 " sin colat =9.891149 ~ The symmetry of the equal altitude observation is maintained by observing opposite limbs in azimuth in the a. m. and p. m. observations, in connection with the same limb in vertical angle in both observations. With "%d5" and "ife+ =9.891149 =38 10' 30" log sin J( 9.791034 9.682183 9.682183 log d ^5=2.367035 d As= Differential azimuth correction = 233" =3 X 53" INSTRUMENTS AND METHODS. 119 121. The following reduction to obtain the value of the differ- ential azimuth correction for the above series is made with the use of Table 22 of the Standard Field Tables: K*i+^)i or hours from noon. 2h 2*33 m 3k 35 00' 2.44 2.05 1.73 38 54 2.16 40 00 2.61 2.19 1.85 Declination coefficient =2.16 d ^U=2.16Xi = tan Example of computation of the convergency of two meridians 24 miles long and 24 miles apart in a mean latitude of 43 2(X: nat 1 log* 1. 0000000 sill 43 20' nat log' =8. 915 2515 =8. 915 2515 =9. 836 477 =9. 836 477 =7. 503 457 9.998 614 0. 0031875 0. 9968125 T^ 2 ~sin 2 l> =9.999 307 tan 43 20 7 =9. 974 720 " 24 , u a " 80* u product ."3963.3 nat =1. 380 211 =1. 380 211 =1. 903 090 =4. 637 539 =3. 598 057 =1. 039 482 10. 9517 chs. The convergency, measured on the parallel, of two meridians 24 miles apart and 24 miles long, in a mean latitude of 43 20 7 , is there- fore found to be 10.95 chains. The convergency of the east and west boundaries of a regular township in the same latitude would be equal to one-sixteenth of the convergency of the east and west boundaries of the quadrangle as computed above, or 68.44 links, which agrees with the value taken from Table 11 of the Standard Field Tables. *This factor is introduced here for the purpose of conversion from the unit ex- pressed in miles to the unit expressed in chains. 128 MANUAL OF SURVEYING INSTRUCTIONS. 130. In Table 11, Standard Field Tables, are tabulated the linear amounts of the convergency of meridians, 6 miles long and 6 miles apart, for each degree of latitude from 25 to 70 N., together with the angle of convergency of the same meridians. These amounts of linear convergency are at once the proper corrections to apply to the north boundary of a regular township in the computation of the closing error around a township, or other computation by which a theoretical length of a north or south boundary of a township is com- pared with the length of the opposite boundary; the tabulated linear amounts of convergency are equal to double the amounts of the offsets from a tangent to the parallel at 6 miles for the same latitudes. Simple interpolation may be made for any intermediate latitude, and the amount of the convergency for a fractional township or other figure may be taken in proportion to the tabulated convergency as the fractional area is to 36 square miles. The tabulated angle of convergency represents at once the devia- tion in azimuth of the tangent from the parallel at 6 miles; and %, HJ M> %> an( i 6 /e f the tabulated angles of convergency represent at once the amounts of the correction in the bearing of meridional section lines to compensate for convergency within a township. In the same table are given the differences of longitude for 6 miles in both angular and time measure, also the differences of latitude, for 1 or 6 miles, in angular measure, in the various tabulated latitudes. 131. In the plan of subdivision of townships the meridional section lines are established parallel to the east boundary or other governing line; this necessitates a slight correction on account of the angular convergency of meridians. Meridional section lines west of the governing line are deflected to the left of the bearing of the governing line the amount shown in the second part of Table 2, Standard Field Tables, which is entered under two arguments: (1) Latitude, and (2) distance from the governing line. Meridional section lines east of a governing boundary are given the same amount of correction for bearing, but the deflection is made to the right. LENGTHS OF ARCS OF THE EARTH'S SURFACE. 132. All computations involving a difference of latitude for a given measurement along a meridian or the converse calculation, or other computations involving a difference of longitude for a given measurement along a parallel or a similar converse calculation, are readily accomplished by the use of the values given in Table 16, Standard Field Tables; this table gives the lengths in miles and INSTRUMENTS AND METHODS. 129 decimal part of a mile of one degree of longitude measured on the parallel, and the lengths in miles of one degree of latitude measured on the meridian, for any latitude from 25 to 70 N. The above tabulated values may be reduced to miles and chains, or to chains or feet, as convenient. In taking out lengths of degrees of longitude measured on the parallel an exact linear interpolation may be made, and in taking out lengths of degrees of latitude meas- ured on the meridian the value should be taken out for the mean position in latitude of that portion of the meridian whose length it is desired to compute. 133. The first part of Table 2, Standard Field Tables, has been arranged for the reference of the latitude of any point within a town- ship to the south boundary, the only argument being the miles and chains distant from the south boundary. Thus with the use of this table all observations for latitude within a township may be reduced to the south boundary; and conversely, given the latitude of the south boundary of a township, the latitude of any station within the township may readily be obtained by applying the difference given in the table for the known distance north. CHAPTER III. SYSTEM OF RECTANGULAR SURVEYS. GENERAL SCHEME. 134:. In the preceding chapters there has been outlined the sys- tem of nomenclature and procedure relating, in general terms, to the survey of the public domain. It is confidently assumed that the United States surveyor has become impressed with the purpose of his task and the stability and dignity which should be attached to a work so great and important, commensurate with its broad founda- tion in law and science. For the purpose of disposal of the public domain the law provides, in general terms, for its description, subdivision and identification in conformity with the following general scheme: 1st. The township, 6 miles square, containing 36 sections, each 1 mile square. 2d. The numbering of the townships meridionally into a range and latitudinally into a tier, from which the necessity at once appears for the selection of independent initial points, each to serve as an origin for the extension of surveys synchronously needed in somewhat widely separated localities, to provide for which, principal or gov- erning meridians and base lines have been established, to which might be related the surveys executed in each of such localities. 3d. The establishment of guide meridians and correction lines or standard parallels at intervals sufficiently near each other to main- tain a practical workable adherence to the legal definition of the primary unit, the township 6 miles square, and at the same time to reduce to a minimum the number of corners required. 4th. The placing of fractional sections on the north and west bound- aries of the township. 5th. The subdivision of the townships into 36 sections by running parallel lines through the township from south to north and from east to west at distances of 1 mile. 6th . The inflexible declaration of the integrity of the corners marked in the public surveys as the proper legal corners of the sections or of the subdivisions of the sections which they were intended to 131 132 MANUAL OF SURVEYING INSTRUCTIONS. designate, together with the equally important provisions (a) that the boundary lines actually run and marked shall be and remain the proper boundary lines of the sections or subdivisions for which they were intended; (6) that the length of such lines as returned by the surveyors shall be held as the true length thereof; and (c) that the sections shall be subdivided by running straight lines from the established quarter-section corners to the opposite estab- lished quarter-section corners. 135. The townships will be numbered to the north or south com- mencing with number 1 at the base line, and with range numbers to the east or west beginning with number 1 at the principal meridian. The 36 sections into which a township is subdivided are numbered commencing with number 1 in the northeast section of the township, proceeding thence west to section 6, thence south to section 7, thence east to section 12, and so on, alternately, to number 36 in the south- east section. In the case of fractional townships, the sections will bear the same numbers they would have had if the townships were full, that is to say the section numbers should be employed which are the proper section numbers relating to the sides which are the governing boundaries, leaving any deficiency to fall on the opposite sides. 136. The specimen field notes will serve to illustrate the method of running lines to form quadrangles 24 miles square; the method of running the exterior lines of townships; and the method of sub- dividing regular townships. The methods here presented are designed to insure a full compliance with every practicable require- ment, meaning and intent of the surveying laws. 137. By the terms of the original law and by general practice section lines are surveyed from south to north and from east to west, in order uniformly to place excess or deficiency of measurement on the north and west sides of the townships. For convenience the exterior lines on which subdivisions are based are called the govern- ing boundaries. In unusual cases the north and west boundaries may be employed to govern the subdivision of a township, and in extreme cases an irregular township may be without even a single governing boundary. INITIAL POINTS. 138. Initial points from which the lines of the public surveys are to be extended will be established whenever necessary, under such special instructions as may be prescribed in each case by the Com- SYSTEM OF RECTANGULAR SURVEYS. 133 missioner of the General Land Office. The initial points are to be selected with a view to their control of extensive agricultural areas within reasonable geographical limitations. Upon the establish- ment of an initial point, the position of the point in latitude and longi- tude is to be determined by accurate field astronomical methods. During the period since the organization of the system of rectan- gular surveys numbered and locally named principal meridians and base lines have been established as shown by the accompanying tabular exhibit. These bases and meridians may be found by examining the large wall map of the United States published by the General Land Office; they are also shown upon the various official State maps, and upon a special map entitled ' ' United States, Showing Principal Meridians, Base Lines and Areas Governed Thereby. " 139. The latitudes and longitudes given in the following table are based upon the best obtainable information, but in some cases the values shown are only approximately correct owing to the fact that many of the initial points were fixed in position and the surveys therefrom largely completed before the same importance was at- tached to the matter of accurate latitudes and longitudes as at the present time. It may also be noted, by way of explanation, that present-day facilities for accurate field astronomical determinations were not available to the early surveyors. It is not expected that the values of the latitudes given in the table will be used as the basis of the calculation of the latitude of an unknown station, in lieu of a field determination thereof, except as an approximate value may satisfy all requirements. The coordinates of the earliest sur- veys in Ohio can not be conveniently tabulated, but they are shown upon the maps as stated above. PRINCIPAL MERIDIAN. 140. This line shall conform to the true meridian and will be extended from the initial monument, either north or south, or in both directions, as the conditions may require; regular quarter- section and section corners will be established alternately at inter- vals of 40 chains, and regular township corners at intervals of 480 chains; meander corners will be established at the intersection of the line with all meanderable bodies of water. 141. In the survey of the principal meridian and the other standard lines (base lines, standard parallels and guide meridians), hereinafter described, two independent sets of measurements will 134 MANUAL OF SURVEYING INSTRUCTIONS. MERIDIANS AND BASE LINES OF THE UNITED STATES RECTANGULAR SURVEYS. Meridians. Governing surveys (wholly or in part) in States of Longitude of principal meridians west from Greenwich. Latitude of base lines north from Equator. BlackHills South Dakota 104 03 00 44 00 00 Boise Idaho 116 24 15 43 22 31 Chickasaw Mississippi 89 15 00 34 59 00 Choctaw .do 90 14 45 31 54 40 Cimarron Oklahoma 103 00 00 36 30 00 Copper River Alaska 145 18 42 61 49 11 Fairbanks .. Alaska 147 38 33 64 51 49 Fifth Principal Arkansas, Iowa, Minnesota 91 03 42 34 44 00 First Principal . . . . Missouri, North Dakota^ and South Dakota. Ohio . 84 48 50 41 00 00 Fourth Principal Illinois 90 28 45 40 00 30 Do . . Minnesota and Wisconsin 90 28 45 42 30 00 Gila and Salt River Arizona 112 17 25 33 22 40 TTuTTibolflt California 124 08 00 40 25 12 Huntsville Alabama 86 34 45 35 00 00 Indian Oklahoma Q7 14 30 34 30 00 Louisiana Louisiana 92 24 15 31 00 00 Michigan Michigan 84 22 24 42 26 30 Mount Diablo California and Nevada 121 54 48 37 51 30 Navajo Arizona and New Mexico 108 32 45 35 45 00 New Mexico Principal . . . Principal Colorado and New Mexico Montana 106 53 40 111 38 50 34 15 25 45 46 48 Salt Lake . . . Utah.... 111 54 00 40 46 04 San Bernardino California 116 56 15 34 07 10 Second Principal .... . Illinois and Indiana 86 28 00 38 28 20 Seward Alaska 149 21 53 60 07 26 Sixth Principal Colorado, Kansas, Nebraska, 97 23 00 40 00 00 St. Helena South Dakota, and Wyo- ming. Louisiana 91 09 15 31 00 00 St. Stephens Alabama and Mississippi. . 88 02 00 31 00 00 Tallahassee Florida 84 16 42 30 28 00 Third Principal Uintah Illinois Utah 89 10 15 109 57 30 38 28 20 40 26 20 Ute Colorado 108 33 20 39 06 40 Washington Mississippi 91 09 15 31 00 00 Willamette Oregon and Washington 122 44 20 45 31 00 Wind River Wyoming 108 48 40 43 01 20 SYSTEM OF RECTANGULAR SURVEYS. 135 be employed, unless subdivisional closings thereon are provided in the same assignment with the standard line, in which case the clos- ings will furnish a satisfactory verification of the length of the lines thus surveyed. Where such closings are not to be made during the progress of the same survey, the proper supervising officer will pro- vide suitable instructions for the employment of a second set of chainmen, or for the duplication of the measurement by the one set of chainmen. In either case, where two independent sets of measure- ments are employed, the distance to the mean point, and the differ- ence between the measurements to each corner established, will be shown in the field notes; a form of record is given in the specimen field notes. 142. Should the difference between the two sets of measurements of any standard line, as above provided, exceed 20 links per 80 chains, it is required that the line be remeasured to reduce the difference, the final measurement of the line only to be shown in the field notes. Should the successive independent tests of the alinement of any standard line, or the average tests of the solar attachment employed in the projection thereof, indicate that the line has deflected from the true cardinal course to exceed 3' 00 // , the necessary corrections will be made to reduce the deviation in azimuth, the field notes of the true line only being shown. Every reasonable effort will be exercised to insure the accuracy of both the alinement and the meas- urement of the standard lines, and the stated discrepancies are the maximum that will be allowed in new surveys; corrective steps will be required where the differences are beyond the maximum. BASE LINE. 143. From the initial monument the base line will be extended east and west on a true parallel of latitude; upon the* true line stand- ard quarter-section and section corners will be established alter- nately at intervals of 40 chains, and standard township corners at intervals of 480 chains; meander corners will be established at the intersection of the line with all meanderable bodies of water. The manner of making the measurement of the base line and the accuracy of both the alinement and measurement will be the same as required in the survey of the principal meridian. Any one of the methods heretofore set forth for the determination of the alinement of the true latitude curve may be used as existing conditions may require and the detailed process will be fully stated in the field notes. 13(5 MANUAL, OF SURVEYING INSTRUCTIONS. STANDARD PARALLELS. 144:. Standard parallels, which are also called correction lines, are extended east and west from the principal meridian, at intervals of 24 miles north and south of the base line, in the manner prescribed for the survey of the base line. Fi 3 .l6. 1 * 1 c CD TJ First Stanc ard Par S T.4N. illel North *- (A outh Illustrating the survey of quadrangles each embracing 16 townships bounded by standard lines, and showing the coordinate system of numbering the townships 145. Where standard parallels have been placed at intervals of 30 or 36 miles, under practice then permissible, and present con- ditions require additional standard lines from which to initiate new, or upon which to close the extension of old surveys, an intermediate SYSTEM OF RECTANGULAR SURVEYS. 137 correction line should be established to which a local name may be given, e. g., " Fifth Auxiliary Standard Parallel North," or " Cedar Creek Correction Line," etc., and the same will be run, in all respects, like a regular standard parallel. GUIDE MERIDIANS. 146. Guide meridians are extended north from the base line, or standard parallels, at intervals of 24 miles east and west from the principal meridian, in the manner prescribed for running the principal meridian. Under all conditions the guide meridians will be terminated at the points of their intersections with the stand- ard parallels; the guide meridian is to be projected on the true meri- dian and the fractional measurement is to be placed in the last half mile. At the true point of intersection of the guide meridian with the standard parallel a closing township corner is to be established; the parallel will be retraced between the first standard corners east and west of the point for the closing corner, in order to determine the exact alinement of the line closed upon, and the distance will be measured and recorded to the nearest corner on eaid standard parallel. 147. When existing conditions require that such guide meridians shall be run south from the base or correction lines, they will be ini- tiated at the theoretical point for the closing corner of the guide meridian, which will be calculated on the basis of the survey of the line from south to north initiated at the proper standard township corner. At the theoretical point of intersection a closing township corner will be established. 148. Where guide meridians have been placed at intervals ex- ceeding the distance of 24 miles, and new governing lines are re- quired in order to limit the errors of the old or to control new sur- veys, a new guide meridian will be established, and a local name may be assigned to the same, e. g., "Twelfth Auxiliary Guide Merid- ian West, " or " Grass Valley Guide Meridian, " e tc . These auxiliary guide meridians will be surveyed in all respects like regular guide meridians. 149. The above scheme covers the controlling lines contemplated under the rectangular system, and results regularly in the survey of quadrangles bounded on the north and south by true parallels of latitude, and on the east and west by true meridians, 24 miles apart. One exception may now be noted which will be found to depart 55465 19 10 138 MANUAL OF SURVEYING INSTRUCTIONS. from former practice, that is, where a guide meridian is carried forward at a time when uncertainty exists as to how the exterior and sub divisional surveys to the east may close upon it, the corners upon the same will be marked only for the surveys to the west. TOWNSHIP EXTERIORS. REGULAR ORDER. 150. The controlling factors to be recognized in the establishment of new township boundary lines are found in the relation of these lines to the new subdivisional surveys which are to be executed. The south and east boundaries are normally the governing lines of the subdivisional surveys. Defective conditions which may be found in previously Established exteriors can not be eliminated where subdivisional lines have been initiated from or closed upon an old boundary, but the errors of the former surveys are not to be incorporated into the new, and where the previously established south and east boundaries can not on that account be used to govern the subdivision of the adjoining township, other controlling lines known as the sectional correction line and the sectional guide meridian, hereinafter described, will be employed as expedient. A new meridional township exterior is normally the governing bound- ary of the township to the west, and a new latitudinal township exterior is normally the governing boundary of the township to the north; any new boundary should therefore be established with full consideration for its control ur>on the sub di visional surveys there- after to be executed. 151. Whenever practicable the township exteriors will be sur- veyed successively through a quadrangle in ranges of townships, beginning with the townships on the south. The meridional bound- aries of the townships will have precedence in the order of survey and will be run from south to north on true meridians; quarter- section and section corners will be established alternately at intervals of 40 chains, and meander corners at the intersection of the line with all meanderable bodies of water; a temporary township corner will be set at a distance of 480 chains, pending a determination of the controlling factor upon which its final position will be governed, whereupon the temporary point will be replaced by a permanent corner in proper latitudinal position. The latitudinal township boundary will be run first as a random line, setting temporary corners, on a cardinal course, from the old toward the new meridional boundary, and corrected back on a true line if ideal conditions are SYSTEM OF RECTA IsGULAK SURVEYS. 139 f.g.17. 1 West on random, correct to true /in e ""iT-f^ T- ^ n T7|Tn riT-M- ^^ P-~ i C. l K 1 A- O t o 1 i " "* 'JO <~" 3 ~ ~ ** ?Jj L ' ! ! ! ' 1 ' L |- J 1 I U-v-.-i oj r " , T I4M |4ir!l V -H | 1 ^ -4-|9 1 JM ! I 1 1 1 1 t 1 1 1 ' Q-' -1 1 ! 1 * ' \) 1 2 | i ^ii 1 n 1 l uU" 3 ' ~" ! L-i--L_ J tiiij n 1 1 l i i i : i i ! STANDARD PARALLEL Westonrandom,correct to true tir e. -T -r r- -.-4 ' ' _l_ r L.4_ JL_|_i_ I -|? ._5--|-4-- ; ' 1 ' -\ i i i i i I | ; L _ t ;^ i !- _i 4 & X) 1 :i|? ~i i "1 i J i ; i i 1 1 l i i - r~ i r T i -4-31 1 1 i 1 i I i t" t Fig.18. 140 MANUAL, OF SURVEYING INSTRUCTIONS. " Fig. 19. asf on random, correct fi ?f rue line. j .i^jT-njd" I 6 ' 5 - A i *a 1 I _ III 1 ; 1 j I , . 1 1 . . J -4 ' "i ;j -4 h.i -1 "1 r | _7__J T 1 1 ', 1 1 > i > ""' " i -L-7-I 1 :ii 4 ^ - - t *ctto trt -il-I H ! "i 1 v A m, corrt. --+ 1 -f- (- -H l 1 t . ^ "1 n rancfo :^o _j ' i i i_i i. i_ _ 1 -j i . i i _i3l i 1 _J ' I i i 1 l i i STANDARD PARALLEL _4-_|_l_|_i_ f-J-- . J. ^L. ui-j-L zrpr i^-H-j "j 1 "~]~*f~ ! i --2-- ~!" l i ' J ' . L Ji l 1 1 -1- -4 1 1 1 r 1 _ I \j 1 I . _ ' 1 ' 1 ! ! 1 > n i ^ ! \ -i J 4-- --/- I'l -Tl9--' ll -\ ' 1 / -h ' 4- L ^) J J ^ -i ; i -430 ' ^ 1 --J 1 1 1 -It-; 1 "1 _ j. 2i 1 j i 1 i r i l I _J oo Fig. 22. 142 MANUAL OF SURVEYING INSTRUCTIONS. found to obtain. Where both meridional boundaries are new lines or where both have been previously established, the random lati- tudinal boundary will be run from east to west. In either case, if defective conditions are not encountered, the random line will be corrected back on a true line, upon which will be established regu- lar quarter-section and section corners at intervals of 40 chains, alternately, counting from the east, and meander corners at the intersection of the true line with all meanderable bodies of water. The bearing of the true line will be calculated on the basis of the falling of the random, and the fractional measurement will be placed in the west half mile. A meridional township exterior will be terminated at the point of its intersection with a standard parallel, placing the excess or deficiency in measurement in the northern- most half mile. At the point of intersection of the meridional boundary with a standard parallel a closing township corner will be established; the parallel will be retraced between the first standard corners east and west of the point for the closing corner, in order to determine the exact alinement of the line closed upon, and the distance will be measured and recorded to the nearest corner on said standard parallel. 152. In order to complete the exteriors of a township it will often remain to establish a meridional boundary between previously estab- lished township corners; such boundaries will be run from south to north on random lines, with temporary corners set at intervals of 40 chains, and, if defective conditions are not encountered, the random will be corrected to a true line; by this plan the excess or deficiency of measurement will be placed in the north half mile, as required by law, and double sets of corners will be avoided where unnecessary. 153. The temporary points on any random exterior will be re- placed by permanent corners, in proper position, when the final true line adjustments for the latter have been fully determined; the true line will be properly blazed "through timber, and distances to important items of topography will be adjusted to correct true line measurements. 154. The field notes will embrace a full and complete record of the manner in which the township exteriors are run and established. The notes will show how the alinement of the random latitudinal curve was determined, the direction of the projection, the amount of the falling north or south oi the objective township corner, and the calculated return course or true line. SYSTEM OF RECTANGULAR SURVEYS. 143 IRREGULAR ORDER AN-D PARTIAL SURVEYS. 155. As the remaining unsurveyed public lands are found to con- tain less and less extensive areas surveyable under the law it becomes necessary to depart from the ideal procedure in order more directly to reach the areas authorized for survey. The many possible com- binations are entirely too numerous to state in detail, but where an irregular order appears to be necessary such departure from the ideal order of survey will be specifically outlined in the written special instructions. Such departure should always be based on the principle of accomplishing, by whatever plan, the same relation of one township boundary to another as would have resulted from regular establishment under ideal conditions. In authorizing surveys to be executed it will not usually be pro- vided that exteriors are to be carried forward until the township is to be subdivided ; thus where causes operate to prevent the establish- ment of the boundaries in full it is not imperative that the survey of the exterior lines be completed; under such conditions it may be found necessary to run section lines as offsets to township exteriors and such section lines will be run either on cardinal courses or parallel to the governing boundaries of such townships, or even established when subdividing, as existing conditions may require. GENERAL EXCEPTIONS. 156. The above rules accord with former practice, except that in certain instances the random latitudinal boundaries will be run from west to east, instead of invariably from east to west, as here- tofore required. It is also deemed advisable to incorporate other exceptions which will lessen the difficulties of subdivisional surveys frequently experienced in the past. It is especially desirable that the alinement of a new latitudinal boundary (which becomes the governing south boundary of the township to the north) shall not depart more than 14' from the true cardinal course; therefore the random line, run upon the cardinal course, may be made the true line where the falling would require a correction exceeding 14' of arc. Where the random latitudinal boundary thus closes on a new meridional exterior the temporary township corner may be adjusted to the latitude of the opposite township corner; but where both meridional boundaries have been previously surveyed a closing township corner will be established at the point of intersection of the random latitudinal line with the 144 MANUAL OF SURVEYING INSTRUCTIONS. "Ft- :|f Fig East on random, cc J__5_._l 4 _i. l i i .23. meet to true tine. rrTi'T.T^.TIT r-i-r- 1- -L ^ JL a. -L -j- -L 4- J- 4 - 1 -J --3--I--2 1 i ! 1 i.l 1 L i ! < 1 1 ! I 1 j 1 -1 ! 1 1 _! ^ _ . & N I L_ ^ \ \ -Tl9~! --. i -i- T i-- ~\ i i -t30 | :TL_' _ 3 ! [ I: 3 ,'-' -j_t_J Ca/c ' East on t rut i * T P^O i h r I i 1 1 j j///7e,//fe< : ; ___.L f L 1 jret/ca/ d is tan ce. ~~L' -1--5-- ' j LJL^._L_4._l_|.J._j_L -j-J-4 -f- - 1 -- - -4- -j- -3 - - r - 2- - - -r- - ; i i . i i .J. ' i i j_ . >Quth on random, return on same fine. rLL _j ] T r i i 1 l 1 i i . i \ I fib' _ ~1 I ? 1 ^ j f ; i in \C$ I 1 1 i 1 i j j -i r -4-31- -4 l ! ^ i r i ' ! i 1 1 i J. ^ . East on n T "I ' -' 1 1 1 1 1 ! , !__ 1 i -1 ?ndom f return on same fine. Fig.24. SYSTEM OF RECTANGULAR SURVEYS. 145 Fig.25. STANDARD PARALLEL r-H~c i--o-- - -. --|-- .--|-- -- L" 1 ' i ' L. ! ! ^ $-*-- 1 | } . C; "_' I 1 cA ' -1-^ IffUh-r \M ' i Sjjj-f.- v\xca i r r\ ' i ' 1 > i 3P I 1 1 ? i ' 1 ! | cif- I I 1 1 1 l<0 jsirzi j 1 J J 1 Cole. West on t rue 1, e, theoretical distance. * Exteriors initiated at a tlieoi | tical point for a closing corner. 1 * i i i i 1 i i i i i LJ , i --3 2 p- I-- T i i 6i_J_|_ |_ 1 I I ill 1 Jqff --- r^f - *v. I 1 *U |i L $$ ^ r~ ~ |9 ^ T 1 Idf 4 jjji i i |_ (^ r1"T 1" ' t- i i X.I . I -JL- I i _L MANUAL OF SURVEYING INSTRUCTIONS. Fig.27. West Fig.28. SYSTEM: OF RECTANGULAR SUR\ T EYS. 147 meridional boundary, or its projection to the north or south as the case may be. Likewise, where a meridional boundary is run as a random, the random will be made the true line if the adjustment for falling plus the usual correction to secure parallelism of the meridi- Fig.29. 7 | 30 ^I W 1 31 *1 32*i I i 25 36 7 13 30*1 Latitude 25N. 33*1 24 25 36 6 $' 5 !! 4 1 f cardinal will not be considered defective in alinement. Even in he case of new exteriors, where the surveyor who establishes such ine is also to subdivide the township of which such exterior is a ;overning boundary, the margin of 14 X may be exceeded to a limited ixtent if the surveyor is satisfied that existing conditions favor keep- ng within the 21' limit in the sub divisional survey. Thus it will be een that the purpose of the 14' limit is merely to facilitate the estab- ishment of all subdi visional lines within the prescribed definite imit of 2V from cardinal. 157. Another general exception may be noted where uncertainty sxists as to how unsurveyed exteriors and sub divisional lines will lose upon the newly established boundaries, in which case the cor- kers thereon may be marked only for the townships of which the lew exteriors control the subdivisions. COMPLETION OF PARTIALLY SURVEYED EXTERIORS. 158. Where the end portions of a township exterior have been xreviotisly surveyed and closed upon, the fractional unsurveyed ruddle part will be completed by random and true line, without >ffset regardless of the deviation from cardinal; the fractional meas- irements will be placed as a general rule in the north and west lalf miles, thereby permitting the sub divisional lines to be extended is usual from the south to the north and from the east to the west. [n the case of a fractional part of an exterior remaining unsurveyed SYSTEM OF RECTANGULAR SURVEYS. 149 at either end of the line, the boundary will be completed by random line, initiated at the previously, established terminal monument, which will be projected on a cardinal course in the direction of the objective township corner. The random will be corrected to a true line where the calculated bearing of any subdi visional line, governed by such exterior, comes within 14' from cardinal, and the West on randorrt.correcf totrue ( lins regard/ess of bearing. , i75^^ to intersection. L* Frac me as. of> West Frac. meas. on West. / I ''* A ^ fi -c ,e*' 5 |l / to ^ Q ir . > 1 | Tj si ./ , y. "5 ^d ^- e 6 We st on random, correct to true line 'ifreau/a-- Frac. Meas Off svsxr If / ^ fj I s - \ / e d- _ il / r ^ I! S 6 S ^ ^6 X ^ / 1 t S* ^ tf. 8 || / 1 11 PARALLEL F.g.30. fractional measurement will be placed generally in the north or west half miles. However, should irregularity be developed, or in the absence of a previously established objective township corner, the partially surveyed exteriors will be completed on cardinal courses beginning as above; and in either case the fractional meas- urements will generally be placed in the north and west half miles. 150 MANUAL OF SURVEYING INSTRUCTIONS. RETEACEMENTS BEFORE SUBDIVIDING. 159. If any part or all of the boundaries of a township which is to be subdivided have been previously surveyed, and the proper supervising officer has reason to question the accuracy of any portion of such exteriors, or the condition of the corner monuments thereon, the fact will be stated in the written special instructions, and the surveyor will be authorized and required, as a condition precedent to beginning the subdivisional survey of such township, to retrace such boundaries in order to determine the true alinement and lengths of the lines, to rebuild any corners found to be in a poor condition, and otherwise to accomplish the following purposes: (a) To locate all material errors, (6) to test every line as to what alterations may be required, and (c) to determine all data necessary for the computation of the areas of all fractional lots. 160. All data obtained in the retracements will be embodied in the field notes and shown upon the plat of the survey, unless the retracement results are in substantial agreement with the record of the original survey, in which case a general statement to that effect may be made in the field notes, and the original record may be per- mitted to govern the data to be placed upon the plat. RECTANGULAR LIMITS. 161. Before approaching the subject of 1 1 subdivision of townships " it is necessary to consider the requirement of law relative to rectan- gular surveys, wherein the square mile, or section, is the unit of subdivision. The normal township will include 36 sections in all, 25 of which are returned as containing 640 acres each; 10 sections (on the north and west boundaries) each contain regular aliquot parts totaling 480 acres with 4 additional fractional lets in each section, each lot containing 40 acres plus or minus definite differences to be determined in the survey; and, section 6 containing regular aliquot parts totaling 360 acres with 7 additional fractional lots each con- taining 40 acres plus or minus certain definite differences to be determined in the survey, all as contemplated by law. The afore- mentioned aliquot parts of 640 acres may be termed "regular or legal subdivisions of a section," as a quarter section, a half-quarter section, or a quarter-quarter section, the legal minimum of which, for purposes of disposal under the general land laws, is 40 acres. 162. In the administration of the surveying laws it has been necessary to establish a definite relation between rectangularity SYSTEM OF RECTANGULAR SURVEYS. Fig.31. 151 West to intersection. _ t _l_4_-^-i_J_._|-i- < L-i-6 \- 5 ? |_J i i 1 Q. h ' l l 1 "T . i i 1 | i rl A o - f- 7 1 sd ' t i " 1 \ --!-ieA j>j- 1 1 -i - - - 1 4 i--, j Jf" 1 ! i i i i r :j$ ) \>- - 1 i i - L r ' l c; |_^_|9_ J ^-TI i i I-f>H 5 l 1 1 Sectional i correction i > i ///7ffJ p- r , r l 1 i i ^ f- J I . 1 i 1 | > -J3I- -;- -32- -i - -3,3 , - - ^ l 1 ! 1 } aU-aU i r r i TT j --36-- "l ! ~! Weston rar tdorr), corf -ecttotrue/ine. "i T!~! "[_T ^f" ~ ' ~T T" l--'-6-- - |- - 5 - - f .1 ' i -B 3--I--2-- I- J ' , i i i . I _) ' j 1 I r 1 UT" 4 1 i 1 -J J I L4 ' _ 1 1 ! '* f ~ fU-j M : ' ^ 1 ^0 ' i ~ 6 |: up ! ~ ' L "1 ' . 1 i : H ill- West to intersection. ' i_ L j. _i ' "r r r r r r nn^T ri " r r 1 U6 ^ 1 Qf -5-- t_ f '_ ! _1 I--I 1 1 '_ i_ y | i i r -t -\ -) ' t- lt"i"L_T_"r_T-T- I 1 1 1 1 I 1 & 1 j r i i i) !_ IO _ I i) i ~| i i x L L _L ! ^1-iUj r |J ! \& ' 1 , >1\ I 1 <\ v ' t ' - - - - !~\>- - T ~ ' i 1 c* ' * v 1 ' l M ! J tTD - ~1 ~t" T ^0 i | :._.!_] ! ' i- rip . t--i i f"! ! i I i %j 1 1 1 i r: ^ A 154 MANUAL OF SURVEYING INSTRUCTIONS. railroad or canal right-of-way, reservoir site, etc., has been connected with any corner on an exterior which may be subject to rectification, the fact will be specifically stated in the written special instructions, and in case such exterior is found to be defective the surveyor will accurately connect the old corner by course and distance with the new monument. Such old corners will not be destroyed, but the letters "W P" (signifying "witness point") will be distinctly added to the original markings. A complete record of the connection from the new to the old monument, a description of the latter and its accessories, and the new markings, will be included in the field notes, and the position of the old monument will be shown on the plat of the survey. 164. If a boundary is defective in measurement or position and is not subject to rectification, the location of the original corners will not be changed, but the marks thereon, and the marks upon or position of the accessories, may be appropriately altered to stand only for the sections of the previously established surveys. New corners to control the surveys of the adjoining township may then be established on the old line, but at regular distances of 40 and 80 chains. Where new corners are placed on an oblique exterior (one whose bearing departs more than 1 from cardinal) the same will be so located for measurement that the oblique distance multiplied by the cosine or sine of the bearing angle,, as the case may be, will result in cardinal equivalents of 40 and 80 chains. 165. Where subdi visional lines have been initiated from or closed upon one side of a portion of a township boundary prior to the subdivision of the township on the opposite side, while upon the remaining portion of the same such conditions do not interfere, said remaining portion may be obliterated, if found defective, whereupon a new line will be projected in accordance with regular methods. 166.. The position of the new exteriors, or of new corners on defective township boundaries must be established by an actual rerunning of such lines; the data acquired in surveying subdivisional lines closing upon defective exteriors can not be accepted in lieu of such retracement or resurvey. 167. Instances will occur both in closing subdivisional surveys upon regular exteriors and in the retracement of defective bound- aries not subject to rectification where it will be developed that the original monuments have become lost or obliterated, or where such SYSTEM OF RECTANGULAR SURVEYS. Fig. 35. East on random, return on same line. \ "^6 "{" ^ "* T ^1 ^ ~! ' ' '2 I \ \ 1 i I i I i ' , T 1 1 \ i I j 1 i ' i 1 _ ' 1 -J . | i 1 i r l ' I I ' i 1 i ~F 1 i i I $ - 1 i 1 A- i 1 c; 1> 1 . i tfl- i o --i L A* i o <0 i V 1 -i j 1 1 i ysO j I ^> S" " t --i i 1 r ^ c\> i i l.'l ^ -1-19- i i &! i I ** ^ - -J ' 1_! \3 i i l^ -U- i ' ' KO ' -1 h \ 1 I i i l^ 1 -1-1- , Sectional correction fine. -j _j - |._ _j 1 _ _ I-T- J - - 1 II 1 i i f 1 1 *5 i ~i i ! ! i i r r i i i i i i i 1 South bdy. defective in alinement. ' F East on random, return on same fine. 1 T; ' ' ; ; ~ r i ' ' T T~ ' i '"1 T ' "^ ' ' ' 51) 1 _ 6 __j 5^.1.-4__|__3_^i--2 I--I , i i i i i < i i .11 V 1 f _ i . i j i 1 Q i ' 1 1 i 4T- "1 1 - j 1 1 \ ! L ll ! i 1 *" ' o C^ J" i I 6 1 -L|8- -! > -sJ N 1 1 5 I* n ! ! ^ 1 _| 1 1 J" ] r^ ' 1 p -{-19--' ll" ! ' -K |r ""i i " r T ~ i & J X) i _j| ~ i T" > J KO ! I 1 1 <0 i i | I I- 1 i 1 1 r i ~ ""i i T ___ r _ 1 ">- -f-3- -! 1 1 ^ -! ' ! 1 i 1 ! i ! 1 ! i I 156 MANUAL OF SURVEYING INSTRUCTIONS. corners may be identified in an advanced state of deterioration. All such exterior corners will be reestablished and remonumented in their correct original positions in strict accordance with the pro- visions of Chapters IV and V, and a complete record thereof will be embodied in the field notes. 188. The south boundary of a township is regularly the govern- ing latitudinal boundary and will be used as such unless defective in alinement: if defective in measurement, and not subject to rec- tification, the position of the original corners will not be changed, but the marks thereon and the accessories will be appropriately altered to stand only for the sections of the township to the south; new corners of two sections and quarter-section corners common to the sections of the township to the north will be established at reg- ular intervals of 40 chains, counting from the east, and the excess or deficiency in measurement placed in the west half mile. If the south boundary is defective in alinement, a sectional correction line will be required. 169. The east boundary of a township is regularly the governing meridional boundary and will be used as such unless defective in alinement; if defective in measurement, and not subject to rectifi- cation, the position of the original corners will not be changed, but the marks thereon and the accessories will be appropriately altered to stand only for the sections of the township to the east; new cor- ners of two sections and quarter-section corners common to the sec- tions of the township to the west will be established at regular inter- vals of 40 chains, counting from the south. If the east boundary is def ective in alinement a sectional guide meridian will be required . 170. New west and north boundaries of a township become the governing meridional and latitudinal boundaries of the townships to the west and north, respectively, and are required to be properly established as such. 171. New east and south boundaries of a township become the closing meridional and latitudinal boundaries of the townships to the east and south, respectively, and where by peculiar necessity the ideal plan must be modified and doubt exists as to how unsur- veyed lines may close upon same, the corners thereon may be estab- lished common only to the sections of the township of which the new lines are the governing boundaries. The corners appropriate to the sections upon the opposite side will be duly established as closing corners at the time of the survey of the subdivisional lines SYSTEM OF RECTANGULAR SURVKY 157 Fig. 3 7. _ we ~T T i j 1 1 T 1 'sr TO /rrrt _|_._j. A ?rsecr/o/7. _ F4"-L 1 j-6--,- -5 - 1 1 i 1 * ~\ \ I 1 _j l 4 : W^4ri ! , r J -'! ! ; r n t -j %* 1 t "" -^ r i r ~ -{-18--! 1 :F Yr i. u4 ;l -1-19--; Li i ' ^ i 'I -k30--i -> i 1 i i i i ~ i :i 3 iT 1 1 1 i i -i Double set of corners. . _,_j_ 1.4. j. _,_.._ }_1.4 _l_ -4-6--] I--5--I 4~ --i - j' j : j> ( j j i i i i j ^i j _l ._:_.:._!.. -J-t-M ::q Nqrth to intersection. :!!-- 1 I I ! i t i A. . , --I | - -J-!8- - __! I 1 1 !/ ^ 1 i __! ( - : ,9-- r j_l i ; i x>* & 1 ! L 1 _j N" '"' 1 \\ i 1 1 1 I -j! :1 3 ,'- I i T 1 1 I r" i ! i 5. bdy. defective in measurement. Double set of corners. IBS MANUAL OF SURVEYING INSTRUCTIONS. of the adjoining townships if the original corners are then found to be defective in position, and where regular connections can be made the marks upon the original corners will be appropriately altered to corners of maximum control. If^l a L,_^ L M --)--5--,--4 | 3 I- 2-r-J - ! -r-- "J-J-- 1 J_-i_l_i_L J_J__L ' '~J West on random, correct to true line regardless ^/f gjg rroc-measurcmentonWesr. JrTT^Vn-'f-rVr'i-n-r In HT East to intersection. i . -t- -*. -4. _f < <7^. 0/7 / . 1--| --24r-i --I 1 ' c ' _j r " |I| 'k. -T30--1 ^0 i 1 1 1" % ~ --T i i 11 L. I t "* t~ 1 \ ' West to in -1 o || tersection. --16-- - H 1 - J 1 LLialULiJ^-i^iUl-l-i-' 1 - rFrac. meas. on North. South to intersection. :!.].t- | -J-. $' H-L- / ;i'p- r ! * J -"-30- . j | l" if J m i - -i . L i i \ \ . 1 Stan. Par: defective in measurement. ' .Orig. cars, altered to angie points. Fig. 39. 172. \Yhere the previously established north or west bounda- ries are found to be defective in measurement or position and sub- divisional surveys in the adjoining townships have been initiated upon the same, thereby preventing rectification, the marks upon the original corners will be appropriately altered to corners of two sections and quarter-section corners common only to the sections of SYSTEM OF RECTANGULAR SURVEYS. l.'/J the townships to the north or west, respectively. Closing section corners will be established when subdividing and the distance meas- ured to an original corner; new quarter-section corners, common to the sections of the township which is being subdivided, will be placed on the old line at the mean distances between the closing section comers, or at 40 chains from one direction, depending upon the plan of the subdivision of the section. Where such previously established north and west boundaries are defective in alinement, but not in measurement or position, no changes are required, and the section lines of the township which is being subdivided will be connected regularly to the original corners; the resulting fractional measurements will be placed uniformly in the north and west half miles. 173c The diagrams which accompany the text illustrate the guid- ing principles involved in the method of establishing new govern- ing boundaries where the previously surveyed exteriors are found to be defective. Each diagram illustrates a simple condition affect- ing one boundary only, and the examples are taken only from the regular order of procedure. Combinations of two or more of the simple defective conditions are best solved by an analysis of the complex problem into its several parts of simple defective condi- tions. The same statement is applicable to the solution of complex defective conditions encountered in the establishment of township exteriors under an irregular order of procedure. The surveyor will be expected to exercise skill and judgment in dealing with similar field problems, but where extraordinary conditions are encountered which will not admit of analysis and solution in harmony with the principles herein set forth he will report the facts to the proper supervising officer for his counsel. TABLES OP LATITUDES AND DEPARTURES AND CLOSING ERRORS. 174. Upon the completion of the survey of one or more township exteriors closing the figure of either a full or fractional township, a table of latitudes and departures and closing errors will be prepared, wherein due allowance for convergency of meridians will be intro- duced. The closing errors will furnish an immediate guide to the accuracy of the lines included in the table and, in case the limit of closure (-^ of the perimeter, in either latitude or departure) is ex- ceeded, will serve to show what additional retracements or other corrective steps may be necessary in order to perfect the survey 160 MANUAL OF SURVEYING INSTRUCTIONS. before leaving the field. The table of latitudes and departures and closing errors, including every part of any closed figure embracing township exteriors, based upon final field determination after all necessary retracements and final true lines have been completed, will be incorporated in the field notes of the survey. The general subject of " limits of closure" will be amplified hereinafter. SUBDIVISION OF TOWNSHIPS. REGULAR BOUNDARIES. 175. The boundaries of a township will be considered within satisfactory governing limits from which to control the subdivisional survey when the calculated position of the latter lines may be theo- retically projected from said boundaries without invading the danger zone in respect to rectangular limits as previously described. The danger zone has already been placed at theoretical bearings exceed- ing 14 X from cardinal, and the corresponding zone in respect to lengths of lines may be placed at theoretical adjustments exceeding 33 links per mile. 176. The direction of the east boundary may qualify anywhere within the governing limits set forth under the subject of " township exteriors," and where this boundary is broken in alinement, but otherwise within the governing limits, its mean course will be adopted when considering the control upon the direction of the meridional subdivisional lines. 177. The subdivision of a township may proceed in the normal order, where the above conditions are satisfied, as follows: The meridional section lines will be initiated at the regularly established section corners on the south boundary of the township and will be run from south to north parallel to the governing east boundary, or, in case the east boundary is within limits, but has been found by retracement to be imperfect in alinement, the merid- ional section lines will be run parallel to the mean course of such east boundary. Regular quarter-section and section corners will be established alternately at intervals of 40 chains, as far as the northern- most interior section corner. The last miles of the meridional section lines will be continued as random lines, each successive line being run parallel to the true east boundary of the section to which it belongs; a temporary quarter-section corner will be set at 40 chains, the distances will be measured to the points of intersection of the random lines with the north boundary of the township, and the SYSTEM OF RECTANGULAR SURVEYS. 161 fallings of the random lines east or west of the objective section corners will be noted. The randoms will then be corrected to true lines by returning to accomplish the required markings between the section corners, including the permanent establishment of the quarter-section corners on the true lines at distances of 40 chains from the south, thus placing the fractional measurements in the north half miles. The bearings of the true lines will be calculated on the basis of the fallings of the randoms (see Table 3, Standard Field Tables) . Where the north boundary of the township is a base line or standard parallel, the last miles of the meridional section lines will be continued as true lines parallel to the east boundary of the town- ship, setting permanent quarter-section corners at 40 chains from the south and closing section corners at the points of intersection of the several lines with the base or standard or correction line, where the distances will be measured to the nearest corners on said line. The adjustment of the bearing of all meridional section lines on account of convergency of meridians has already been explained in Chapter II. 178. The latitudinal section lines, except in the west range of sections, will normally be run from west to east on random lines parallel to the south boundaries of the respective sections, setting temporary quarter-section corners at 40 chains; the distances will be measured to the points of intersection of the random lines with the north and south lines passing through the objective section corners, and the fallings of the random lines north or south of said corners will be noted. Each random will be corrected to a true line by returning to accomplish the required markings between the section corners, including the permanent establishment of quarter-section corners at the mid-points on the true lines. The bearings of the true lines will be calculated on the basis of the fallings or the randoms (see Table 3, Standard Field Tables) . In the west range of sections the random latitudinal section lines will be run from east to west, parallel to the south boundaries of the respective sections, and on the true lines the permanent quarter-section comers will be established at 40 chains from the east, thus placing the fractional measurements in the west half miles. 179. Meander corners will be established at the points of inter- section of the several true lines with all meanderable bodies of water. 180. The meridional section lines will have precedence in the order of execution, and these will be surveyed successively, begin- 162 MANUAL OF SURVEYING INSTRUCTIONS. ning with the first meridional section line counting from the east. A meridional section line will not be continued beyond a section corner until after the connecting latitudinal section line has been surveyed, and in the case of the fifth meridional section line, both latitudinal section lines connecting east and west will be surveyed before continuing with the meridional line beyond a section corner. The successive meridional lines may be taken up at the convenience of the surveyor at any time in order as previously stated, but none will be carried beyond uncompleted sections to the east. The field notes will be compiled in ranges of sections begin- ning with the easternmost, and the west two ranges will be compiled by alternating with the adjoining east and west sections. The specimen field notes exemplify the usual order of survey and the prescribed method of arranging the field notes. 181. Thus, to recapitulate, the subdi visional survey will be com- menced at the corner of sections 35 and 36, on the south boundary of the township, and the line between sections 35 and 36 will be run parallel to the east boundary of the township, or to the mean course thereof, if it is imperfect in alinement, but within limits, establish- ing the quarter-section corner at 40 chains, and at 80 chains, the corner of sections 25, 26, 35 and 36. From the last-named corner, a random line will be run eastward, without blazing, parallel to the south boundary of section 36, to its intersection with the east boundary of the township, placing at 40 chains from the point of beginning, a post for temporary quarter-section corner. If the random line intersects said township boundary exactly at the corner of sections 25 and 36, it will be blazed back and established as the true line, the permanent quarter-section corner being established thereon, midway between the initial and terminal section corners. If the random intersects said township boundary to the north or south of said corner, the falling will be carefully measured, and from the data thus obtained, the true return course will be calculated, and the true line blazed and established, and the position of the quarter-section corner determined, as directed above. The meridional section line will be continued on the same plan, likewise the successive latitudinal section lines except that each random will be run parallel to the true south boundary of the section to which it belongs. After having established the west and north boundaries of section 12, the line between sections 1 and 2 will be projected northward, on a random line, parallel to the east boundary of the township, or to its mean SYSTEM OF RECTANGULAR SURVEYS. 163 course, as the case may be, setting a post for temporary quarter-sec- tion corner at 40 chains, to its intersection with the north boundary of the township. If the random intersects said north boundary , exactly at the corner of sections 1 and 2, it will be blazed back and established as the true line, the quarter-section corner being estab- lished permanently in its original temporary position, and the frac- tional measurement thrown into that portion of the line between the J -4- ' ! i ! ^ [ ! : j ! ' ! t ' - 4-6 --6 1 rf i ! Q--S--4 , f-f> ,-4--3 M 1 T i 3 ~ - 3- -22 - -2 ~ - > 1 '--'-- \ ^3 -1 \ "1 j_ 7 8 4 f- c ? 9 3 .f / ' 10 ?'0 II .< > 12 --|-I8 s - J i _L' 4 17 4- ' ^ 16 7 9 IS IQ 14 : ' 13 -4- !p ^ 1 | I CiO V f 20 3 9 2! 2 3(3 i 7 22 /5 t S i-^_24-4 ^ ' i t E I "^ ' f - - I i T ~ "I I |i^-f-- -T 3 !-~l I "rp25-- "i ! r L 1 l 1 t ! """ 1 i i r :>H : ^t 1 1 1 | i'' iif 168 MANUAL OF SURVEYING INSTRUCTIONS. as a permanent line on a true latitudinal curve initiated at the first regular section corner on the east boundary and projected to an intersection with the west boundary of the township where a closing section corner will be established and the distance measured to the nearest regular corner. The intermediate quarter-section and sec- tion corners will be marked as temporary points at regular intervals of 40 chains, alternately, counting from the east. Where the west boundary is not defective in position (nor within the danger zone) with reference to the section corners on the east boundary (by reason of the errors in alinement of the south boundary being compensating) , the first latitudinal section line will be projected 5 miles as a per- manent line on a bearing calculated to intersect the objective section corner on the west boundary; temporary quarter-section and section corners will be marked at regular intervals of 40 chains, alternately, counting from the east. The section corners on the sectional correction line will be estab- lished at the several points of intersection of the meridional section lines alined in the normal manner. Thereafter the quarter-section corners on the sectional correction line will be established at the usual mid-point positions except in the east and west ranges of sections. The quarter-section corner between sections 25 and 36 will be established at 40 chains from the west if the east boundary is defective in alinement; otherwise it will be fixed at the usual mid- point position. The quarter-section corner between sections 30 and 31 will be placed at 40 chains from the east, and if the sectional cor- rection line has not been terminated at a closing section corner on the west boundary of the township (as previously provided), the line between sections 30 and 31 will be run random and true in the normal manner. The quarter-section corners on the meridional section lines in the south tier of sections will be permanently established at 40 chains south from the corners on the sectional correction line. The balance of the subdivisional lines will be continued from the sectional correction line in the usual manner. 186. Where the south part of the east boundary, or the east part of the south boundary, is regular, and the balance of the exterior is found to be defective in alinement and not subject to rectification, the subdivisional survey will be made regular as far as possible. The initial point for the sectional guide meridian, or for the sectional correction line, will be determined by existing conditions, and the subdivisional survey continued in harmony with the principles SYSTEM F RECTANGULAR SURVEYS. 169 Fig. 43. - --< i i " i i i ;_i r~r 1 ' i | i 1 1 1 J 1 I f T ! : : 1 1 1 1 _| _. ,,_ ,. 1 1 1 1 i 1 I 1 1 j l ' ' i ^ " i I I --K3J --j- -32--I- -33- J- -^4.- --js-J.-jg-- llLJ^n-d-i->-r rTT-i-i-rT-r-r-T-J-i-.'-r- S. bcty. defective in a/inement. (Xf Fi 3 .44. 55465 19 170 MANUAL OF SURVEYING INSTRUCTIONS. already outlined. Thus the first meridional section line would be continued as a sectional guide meridian if the north part of the east boundary is defective in alinement and the north boundary is thereby made defective in position, but if the north boundary is not defective in position (nor within the danger zone) the first meridional section line should be continued on a course calculated to intersect the objective section corner on the north boundary. The same prin- ciple would be observed if the west part of the south boundary is defective in alinement and the west boundary is not defective in position (nor within the danger zone), but if the west boundary is thus made defective in position the sectional correction line should be established on the true latitudinal curve. Under the provisions of the above paragraph it will be seen that the maximum number of normal sections are to be secured where the condition of the governing boundaries warrants a combination of the several general plans of subdi visional surveys. The sections adjoin- ing the east boundary may be considered regular to the full extent of their conformity with the usual rectangular limits, and where such agreement obtains the quarter-section corners on the latitudinal section lines will be placed at the normal mid-point position. The sections adjoining the south boundary of the township can not be considered regular unless the meridional lines are established at 80 chains in length, and the sections are otherwise in conformity with the usual rectangular limits; certain exceptions to this rigid require- ment will be noted under the subject of " fragmentary subdivision/* 187. The field notes of subdi visional surveys embracing either a sectional guide meridian, a sectional correction line, or other gov- erning section line, will be compiled in the same regular order heretofore described, but appropriate explanatory remarks will be added indicative of the method and order of procedure. CLOSING SECTION LINES. 188. In the event of defective north or west boundaries, not sub- ject to rectification, where the subdi visional lines can not be con- nected with the previously established exterior section corners, regularly by random and true lines not exceeding 21/ from cardinal and at the same time not deviating more than 21' from a line parallel to the opposite (regular) boundary of the section, the normal posi- tions of the randoms will be made the true lines; a closing section corner will then be established at the point of intersection of the SYSTEM OF RECTANGULAR SURVEYS. Fig. 45. N. bdy. defective in position. ^TT/rrrriTi-T-Ti | ""I ! r ' ' i ' ! r "I 7 ""! ! ! \ ' , I ^ ' ' ' | | "^ ! ' ' ' 1 i r .-M8--J * ] ^-13-+- ~ i ' ' _ ! . ll| ' |' 1 y. defect - "i ' i i <'& ' T "i r s i {> t ( .-[-I9-H J $r $- 24H L "1 ! ' i ^[^ 'i o t" ' ~ ' " ' "" ! " Si^ ' ' "1 ' ' T i i ( lls ! r - L 30--| | | V-25-f "-J i i r i i #! i - I \ Sectional correction fine. , ' JL t " 1 i West to intersection. ' 1 i ~~! 1 | '1 I 1 1 1 ill" .- T 3I ,--32--,- -331 34--!- -35 I--36-J 5. bdy. defective in olinement. bdy defective in measurement. Doub/e set of corners S 1 1 i i i' i i 1 ' < l 1 ' 1 l ' l , ' i i ' i i C 1 K A O O ^' i Q |. .6 -[ -5-- -4- | 3- 2- .^.| 1 j- J ! } 1 i ' ' 1 ^ | t- > \ 1 1 *>'" * ["" ^| ! r | rement. D i i i |!| i i- -|-ie-H j i lil"" 134 -1 j 1 1 1 5f j L 1 nsodui ui ~l 1 1 1 1 -t-19-H 1 1 , "1 1 ' ' ' I -i- -4- - -i J. * t T-T 1 1 " -iii i i -t30--l I I -\ ' l 'Sectional correction line \ t \West to intersection. ' "1 1 ' ' ' 1 -' -S 1 Lliii^j^ *-+ ^ -*l ' Port ofs bc/y ffefect - ve /n 172 MANUAL OF SURVEYING INSTRUCTIONS. section line with the original boundary, and the distance will be measured to the nearest original corner. The quarter-section cor- ners on the closing section lines will be placed uniformly at 40 chains from the south or east as the case may be. If not already accom- plished, the defective boundaries of the township will be retraced as may be necessary, and the marks upon the original corners appro- priately altered as previously provided under the subject of rectifi- cation of defective exteriors, whereupon new quarter-section cor- ners, common to the sections of the township which is being subdi- vided, will be established on the original defective boundaries at the mean distance between the closing section corners, or at 40 chains from one direction, depending upon the plan of the subdi- vision of the section to which a particular quarter-section corner belongs. 189. Corners of two sections on the governing south or east boun- daries of a township will not be established as closing section corners, but at regular distances by measurement on said boundaries as already provided under the subject of rectification of defective exteriors before subdividing; thereafter the position of said corners will control the sub divisional survey. 190. Where a section is invaded by a State or reservation or grant boundary, or by a private claim of any description, such as mineral claims, forest-homestead claims, small-holding claims, etc., whose boundaries are at variance with the lines of legal subdivision, the distance on the township boundary or section line to the point of intersection with the irregular boundary will be carefully measured, likewise the exact bearing of the irregular boundary will be deter- mined and the distance will be measured to the nearest corner on such irregular boundary. Where a private claim is located entirely within the limits of a section, a connection will be made from a regular corner on one of the boundaries of the section to a corner of the claim, and the bearing and length of the connecting line will be carefully determined. In the latter case a connecting traverse line will be recorded, if one is run, but it will also be reduced to the equivalent direct course and distance, all of which will be stated in the field notes, and the course and length of the direct connecting line will be shown upon the plat of the survey. 191. If a survey is to be concluded upon an irregular boundary at variance with the lines of legal subdivision, or if the survey is to be continued on a blank line to acquire a definite location upon the SYSTEM OF RECTANGULAR SURVEYS. 173 opposite irregular boundary, but without monumenting the rec- tangular survey between such irregular boundaries, a closing town- ship or section corner, as the case may be, will be required at the point of intersection of the regular with the irregular line. On the other hand, if the survey is not to be so concluded, but is to be con- tinued for the purpose of establishing a full complement of section and quarter-section corners for the control of the subdivision of a section so invaded by a private claim, no closing corner will be required. 192. In qvery case where a closing township or section corner is to be established upon a standard parallel, State, reservation, grant, or claim boundary, or upon an irregular section line or exterior, the line closed upon (if the latter was not established by the surveyor who runs the closing line, or if not already retraced by him), will be retraced between the first corners to the right and left of the point for the closing corner, in order to determine the exact alinement of the line closed upon, to the end that the closing corner may be established at the precise point of intersection of the two lines. The distance from the closing corner to the nearest corner on the line closed upon will always be measured and recorded. SUBDIVISION OF SECTIONS. 193. The acts of Congress approved February 11, 1805, and April 5, 1832, contain the fundamental provisions for the subdivision of sections into quarter sections and quarter-quarter sections; the prin- ciples recognized by law have already been stated in Chapter I. The sections are not subdivided in the field by the United States surveyors unless provision therefor is specifically mentioned in the written special instructions, but certain subdivision-of-section lines are always protracted upon the official plats, and the local surveyor who may be employed by entrymen to run said lines in the field is compelled to correlate the conditions as found upon the ground with those shown upon the approved plat. The United States sur- veyor is required to so establish the official monuments that a proper foundation is laid for the sub division of the section, whereby the officially surveyed lines may be identified and the subdivision of the section controlled as contemplated by law. 194. The rectangular system provides for the unit of disposal under the general land laws, broadly, the quarter-quarter section of 40 acres, upon a plan in which the square mile, or section of 640 174 MANUAL OF SURVEYING INSTRUCTIONS. acres, is the unit of subdivision, while the unit of survey is the town- ship of 36 sections. All agricultural entries are based upon descrip- tions in accordance with legal subdivisions shown upon the offi- cial plat. The plats are constructed in harmony with the official field notes returned by the surveyor. The land included in an entry is identified on the ground by fixed monuments established by the surveyor. A United States land patent grants to the entry- man a title of ownership to a tract defined by certain fixed monu- ments on the ground and related by description and outline to the official plat. The function of the United States surveyor has been fulfilled when he has properly executed and monumented his survey and returned an official record thereof in the shape of complete detailed field notes and a plat. The function of the local surveyor begins when he is employed as an expert to identify the lands which have passed into private ownership; this may be a simple or a most complex problem, depending largely upon the condition of the original monuments as affected principally by the lapse of time since the execution of the official survey. The work of the local surveyor usually includes the subdivision of the section, already mentioned as the official unit of subdivision, into the fractional parts shown upon the approved plat. In this capacity the local surveyor is per- forming a function contemplated by law, and he can not properly Berve his client or the public unless he is familiar with the legal requirements concerning the subdivision of sections. In the event that the original monuments have become lost the surveyor can not hope effectively to recover said corners without a full under- standing of the record concerning their original establishment, nor can the surveyor hope legally to restore the same until he has mastered not only the principles observed in the execution of the original survey, but the principles upon which the courts having jurisdiction over such matters have based their rulings. 195. The General Land Office assumes no control or direction .over the acts of local and county surveyors in the matters of sub- , division of sections and reestablishment of lost corners of original surveys where the lands have passed into private ownership, nor will it issue instructions in such cases. It follows the general rule that disputes, arising from uncertain or erroneous loca- tion of corners, originally established by the United States, are to be settled by the proper local authorities or by amicable adjustment, and the office desires that the rules controlling the acts of its own surveying service be considered by all other surveyors as merely SYSTEM OF RECTANGULAR SURVEYS. 175 advisory and explanatory of the principles which should prevail in performing such duties. The subject of restoration of lost corners will be treated in a later chapter, as the purpose here is to outline the principles con- cerning the subdivision of sections, which will be recognized alike by the General Land Office surveying service and by all local sur- veyors. SUBDIVISION BY PROTRACTION. 196. Upon the plat of all regular sections the boundaries of the quarter sections are shown by broken straight lines connecting the opposite quarter-section corners. The sections bordering the north and west boundaries of a normal township, excepting section 6, are further subdivided by protraction into parts containing two regu- lar half -quarter sections and four lots, the latter containing the frac- tional areas resulting from the plan of subdivision of normal town- ships; the lines of the half-quarter sections are protracted from three points 20 chains distant from the line connecting the opposite quarter section corners, two of s$id distances counting on the oppo- site section lines and one counting on the line between the fractional quarter sections; the lines subdividing the fractional half-quarter sections into the fractional lots are protracted from mid-points on the opposite boundaries of the fractional quarter section. The two interior sixteenth-section corners on the boundaries of the fractional northwest quarter of section 6 are similarly fixed at points 20 chains distant north and west from the center of the section, from which points lines are protracted to corresponding points on the west and north boundaries of the section, resulting in subdivisions containing one regular quarter-quarter section and three fractional lots. The fractional lots herein described will be numbered yi a regular series progressively from east to west or from north to south, in each sec- tion. As section 6 borders on both the north and west boundaries of the township, the fractional lots in the same will be numbered commencing with No. 1 in the northeast, thence progressively west to No. 4 in the northwest, and south to No. 7 in the southwest frac- tional quarter-quarter section. Entrymen are allowed, under the law, to acquire title to any regular quarter-quarter section, but as such subdivisions are aliquot parts of quarter sections based upon mid-point protraction, it is not deemed necessary to indicate these lines upon the official plat. 176 MANUAL OF SURVEYING INSTRUCTIONS. Fig.47. Frac. 2O.OO j 2000 20.00 20.00 \ 2O.OO 20.00 20.00 ^ 01 \ ^ vj 1 4 3 | 2 t 4 \ 3 { 1 ^ 2 ' | I j j _j 1 , <3 5 1 fs, , ft \ 1 $ - 3 | I 1 f - .. j _ . 0) I 5 s; ! | 4O.07 ' 4O.O7 20.04 _j 20.04 > 20.O7 \ 20.07 \ 1 * <*> ' O i 1 ^ oj ' O I Q | 1 1 i ' i?+^ Sj . * i ^>' 1 $ ! C5' I O "! ! 40./O , 40. t-3 20.08 , 2 0.0 a j 20.06 , 2006 /g.^9 , ^0.00 / ! ***#*' -J-4 1 re y /i- H ' i i 19 . _'_J ! ^Xi "*" ~ rt&^J ! // fJ-30-- _ j "~ --! --K3I-- -4 Subdivide Regularly. Fig. 53. 188 MANUAL OF SURVEYING INSTRUCTIONS. In the construction of new township plats the former practice of showing certain outlying areas of sections protracted as surveyed lias been abandoned as unsatisfactory and inconsistent with the surveying laws. RETRACEMENTS. 215. Practically all fragmentary surveys require more or less re- tracement of the original surveys in order to identify the initial and closing lines; such retracements will always be accompanied by the restoration of all lost corners adjacent to the sections embracing, in whole or in part, the areas to be included in the extension survey, in-so-far as the section or subdivision -of -section lines controlling the new areas may depend upon the position of the previously estab- lished corners. The surveyor will often be required, in order to de- termine properly the position of a lost corner, to retrace additional lines which are not the boundaries of sections containing the new areas to be surveyed, but no reestablishments on such lines are re- quired. The theoretical position of a lost corner may be at variance with an unofficial corner established by local survey, accepted and recognized by the owners of the private lands affected ; thus much trouble between landowners is avoided if the reestablishments are confined strictly to those corners which control the position of the section boundaries or the subdivision-of-section lines affecting the public lands to be surveyed. A general exception to the foregoing rule will be made in the case of identified original corners which are adopted as a basis from which to control the reestablishments bordering the public land sections; such original corners, if not in a good state of preservation, will be reconstructed in first-class order, a complete record of which will be embodied in the field notes. All restorations of lost corners will be made in strict accordance with the provisions of Chapter V of the Manual. In the instance of de- fective conditions contained in the previously established lines, ex- ceeding the rectangular limit, even though all original corners may be fully identified and in a good state of preservation, the necessary retracements of the section boundaries will be made in order to de- termine the factors entering into the closing error and to furnish suitable data for the calculation of the areas of the resulting fractional lots embraced in the extension survey. SYSTEM OF RECTANGULAR SURVEYS. 189 Fig. 54. 30.00 T r~ 6 5 4 --3 L_ 1 ! f" 7 8 9 --IO-- t ITS I i i 1 I t 1 ! 1 ! t 1 i t \ < \ I 1 i ! t 18 17 16 15 Subdivide from north to south, and from west to east. Froc. 14 Subdivide from north to south, and from east to west. 190 MANUAL OF SURVEYING INSTRUCTIONS. COMPLETION OF PARTIALLY SURVEYED SECTIONS. 216. Many assignments for fragmentary surveys require the com- pletion of the survey of portions of boundaries of sections heretofore unsurveyed, in which sections are contained areas fixed in position by less than the regular complement of corners usually established for the identification of the legal subdivisions of the section. In the completion of such partially surveyed sections, the surveyor will be expected to give full consideration to the manner of pro- tecting acquired rights based upon the former approved plats. The following ten principles are distinctly applicable to the sub- ject: 1st. The legal procedure governing the subdivision of any normal section into quarter sections is based broadly on the principle that the partition lines may be definitely fixed bv four opposite quarter-section corners established on its bound- aries; the intersection of the true center lines thus controlled is .the legal point for the interior quarter-section corner of a section. 2d. The legal procedure governing the subdivision of regular quarter sections into quarter-quarter sections is based broadly on the same principle of controlling lines projected between opposite sixteenth-section corners of the quarter section, the latter corners established at mid-points on the true lines bound- ing the quarter section; the intersection of the true center lines of the quarter section is the legal point for the interior sixteenth-section corner of such regular quarter section. 3d. The legal procedure governing the subdivision of sections containing fractional lots into their component regular quarter- quarter sections and fractional lots is based on the same principle with the simple modification that the sixteenth-section corners on the boundaries of such quarter sections are themselves established at distances conformable to the proportions shown on the official plat. 4th. The fact that the full complement of four section corners of the section and all of the four opposite quarter-section corners has not been established in an accepted survey does not impair the validity of any areas shown upon the approved plat, and the legal procedure to be adopted in the extension of the bound- aries of such sections must be such as to fix, within reasonable limits, the remaining (quarter-section corners in a position which will protect the integrity of the original areas by con- trolling center lines connecting the old and new quarter-section corners. 5th. In the rectangular system the section is recognized as the unit of subdivision, and in proceeding with the extension of fragmentary surveys first consideration must necessarily be SYSTEM OF RECTANGULAR SURVEYS. 191 Fig. 56. Parallel to S. bdy. . Mid-poin1 1 80 80 o 1 ' \ \ \ } 2 1 * 1 f ~^^, I \ \ - 1 \ & Shown 0s ~ r regular. I 7 \ 8 | \ (^ Para/tel fo S. bdy. Mid-p f 80 oirit 80 1 \ -v I o 1 ! 2 3 4 ,g . <~~s^^ I 6 | ^ $h o wn os ^^ regu/ar. Q _ Q / a East boundary of section out of limits in measurement; southeast quarter protracted as surveyed; and section to be completed 192 MANUAL OF SURVEYING INSTRUCTIONS. given to the completion of the survey of fractional sections. No invasion of the original unit is tolerable if any portion of such unit has been surveyed, or if outlying areas have been shown protracted as surveyed. 6th. "Reasonable limits" for the fixation of ^ the remaining quarter-section corners of a section in a position which will rtect the integrity of the original areas of such section may considered such as for alinement when not to exceed 21' from a cardinal course, and for measurement when not to exceed 25 links from 40 chains where the opposite portion of the section boundary is shown as 40 chains, or in proportion as a limiting difference when the opposite portion of the section^is more or less than 40 chains. This concession as to limits is made in the interest of simplicity, where by such concession rectangu- larity of both the old and new surveys may be maintained if so harmonized. 7th. The position of the new quarter-section corner which is to be established on the new opposite boundary of a fractional section will be controlled from one direction only if the old opposite distance has been made to count from one direction only, and the controlling measurement will be made to harmo- nize with the length of the opposite portion of the section, but if the old opposite distance has been made to count from two directions the position of the new quarter-section corner will be controlled from the two directions and the proportional lengths of the two portions of the new line will be made to harmonize with the proportional lengths of the two parts of the old opposite boundary, all as indicated by the distances and areas shown on the original approved plat. 8th. The underlying principles governing the rectangular surveying system are equally applicable to the completion of the survey of fractional sections, and given a condition in an original survey which in all its various elements is " within limits'' within the meaning of the rectangular surveys, the simple plan of continuing in the same manner and order as would have been adopted in the original survey, if the same had not been discontinued, will accomplish usually in its simplest form the completion of the survey of fractional sections; this becomes the first duty of the surveyor before proceeding with the survey of additional sections, so tnat should irregularity be developed, no invasion of partially surveyed sections can result from the irregularities of other sections. It follows in principle, when irregularity is developed, that the surveyor will be best prepared to determine the proper method of survey adapted to procure simplicity of correction of existing irregu- larities and an early resumption of regularity, when he is in possession of full data concerning the conditions of all the old lines limiting the fragmentary surveys and upon which the new lines are to be initiated or closed, his knowledge being based upon the results of actual retracement of such irregular SYSTEM OF RECTANGULAR SURVEYS. 193 Fig. 57. Ron dom and true. (20JOO) (Froc.) (20.OO) (20.00) 3 2 \ 80 J ' - 4 5 6 ' I 1 - ^ Shown as regular. 8 1 (20.00) (Froc.) | Random and true. (20.00) 1 80 (Frac.) (20.00) 3 2 (2O. OO) \ r " 4 5 6 1 80 (20.00) r - " ^p^Ss^^^^^ ' 1 _|| Show/7 as ' ~| regular. ' 1 (Frac.) ^ South boundary of section out of limits in measurement; southeast quarter protracted as surveyed; and section to be completed. 194 MANUAL OF SURVEYING INSTRUCTIONS. Fig. 58. Ron dom ond true. (20.00) (Frac.) \ i \ 3 2 \ | , \ ^1 80 ll \ 1 ^1 4 1 5 i e J 1 \ \ \ i 1 j^^V^W^ i 1 | 80 1 H'i ' i Shown as regular. Mid-point j Random and true. (20.00) (free.) i f 3 2 | .. SI g ^ 80 _ " " I i 4 5 ( 6 1 1 I I ^*J ^^^^^^^w^w^w^v???! I j 7 i | ^ Shown as ^ 80 "" | regular. 8 1 1 Mid-i ix Jl East boundary of section out of limits in alinement; southeast quarter protracted as surveyed; and section to be completed. SYSTEM OF RECTANGULAR SURVEYS. 195 old lines. It must be granted that a skillful exercise of judg- ment by the surveyor based upon his knowledge of the facts is far more desirable than to restrict him to the application of empirical rules ^devised to cover possible, but innumerable combinations of irregularity. 9th. The completion of the survey of the partially surveyed sections will be made as nearly as possible in accordance with the regular rules for subdividing when the original lines are found to be within limits, otherwise, such sections will be completed by surveying all lines in such a manner that each and every section (excepting in cases of unavoidable hiatus or overlap) shall have four regular boundaries without offsets, with four governing section corners and four controlling quarter- section corners in such positions as to maintain the integrity of the fractional areas already shown upon the original plat. The subdivision thereof may then be made by connecting the oppo- site quarter-section corners in the regular manner with resulting locations agreeable to the legal subdivisions shown upon the original plat. If an hiatus or overlap is unavoidable, the position of the new quarter-section corner or corners will be carefully determined for latitude on a meridional line or for departure on a latitudinal line on the same plan as would have resulted in the regular survey of a new boundary extending in full from the one or two directions which control the position of the new quarter-section corner or corners. 10th. Adjoining sections must be considered separately when placing the new quarter-section corners, and the new corner need not be common to the four quarters of the two adjoining sections unless the theoretical position for each section falls within 25 links of a common point in which case the differ- ence may be adjusted in such a manner as to secure maximum regularity. 217. Let it be assumed that adjacent to two established section lines, the meridional line of which is out of limits in measurement, an outlying regular quarter section has been protracted as surveyed; then to complete the section the new section lines will be extended from the previously established section corners, parallel to the opposite established boundaries, or mean course thereof, to a mutual intersection. The quarter-section corner on the new latitudinal section line would be established regularly at the mean point, and would ordinarily be marked to control the subdivision of two sections. On the new meridional boundary one or two quarter-section corners may be required; one marked to control the subdivision of the section under consideration will be established at 40 chains from the original section corner; the same quarter-section corner would be marked to control the subdivision of the adjoining section if the fractional 196 MANUAL, OF SURVEYING INSTRUCTIONS. Fig. 59. ** Wf>*z + Mid-point 80 80 1 jv Shown as | regular. I West t 80 Mid-point 80 .c o \ \i Q; \ ^ 5 I \ 2 34 ^5: ^ \ \ \ m ^ xm ^ ;\\^ \ |r^ 1 \ 6 } \ ; 1 1 \ -j- \ 7 \ _^ Shown OS regular. 8 1 \ ^ Mid-point 1 South boundary of section out of limits in alinement; southeast quarter protracted as surveyed; and section to be completed. SYSTEM OF RECTANGULAR SURVEYS. 197 measurement is to be thrown in the same direction in the two sec- tions, otherwise an additional quarter-section corner marked to control the subdivision of the adjoining section would ordinarily be placed at 40 chains from the new section corner. Again, let the same condition be assumed with the exception that the latitudinal section line instead of the meridional line is found to be defective in measurement. Then, to complete the section, the new meridional line would be surveyed as in regular subdivision, parallel to the opposite meridional line, or mean course thereof, ordinarily with quarter-section and section corners of maximum control at 40 and 80 chains, respectively. The new latitudinal section line would then be established on a true line between the section corners, and one or two quarter-section corners will be established as required; one marked to control the subdivision of the section under consideration will be established at 40 chains from the original section corner; the same quarter-section corner would be marked to control the sub- division of the adjoining section if the fractional measurement is to be thrown in the same direction in both sections, otherwise an additional quarter-section corner marked to control the subdivision of the adjoining section would ordinarily be placed at 40 chains from the new section corner. 218. Let another assumption be made that adjacent to two estab- lished section lines, the meridional line of which is out of limits in alinement, an outlying regular quarter section has been protracted as surveyed; then to complete the section, the new meridional line will be projected as a sectional guide meridian, in accordance with the usual rules, ordinarily with quarter-section and section corners of maximum control at 40 and 80 chains, respectively. The new latitudinal section line would then be established on a true line between the section corners, with one or two quarter-section corners as required; one marked to control the subdivision of the section under consideration will be required at 40 chains from the original section corner; the same quarter-section corner would be marked to control the subdivision of the adjoining section if the fractional measurement is to be thrown in the same direction in both sections; otherwise an additional quarter-section corner marked to control the subdivision of the adjoining section will ordinarily be established at 40 chains from the new section corner. On the other hand, if the same conditions be assumed with the exception that the original latitudinal section line instead of the meridional line is found to be 198 MANUAL OF SURVEYING INSTRUCTIONS. Fig. 60. Poratlel'to South bdy | f20.00J ' (Frac.) 40 3 \ f 2O.OO t \ ( 2O.OO j * \ S 1 2 1 ' 1 1 ** | | 4 5 9 8 10 11 Mid-point "t ~~1 ' "o 1 617? ' ', * 1 ^ Shown as ^ regular \ Parallel to South bdy. (20.00) \ 40 Vj (Frac) i (2000) 3 i 2 I (2O.OO) 1 S [_ - H 1 j 1 4 l * 7 c . i t 9 8 . _| Shown ^5- 7/7 Mid-i reguk " yor'nt ^. East boundary of section out of limits in alinement and measurement; quarter protracted as surveyed; and section to be completed. SYSTEM OF RECTANGULAR SURVEYS. Fiq.61. 199 ,y. West (ZO.OOI (froc.) ( 2O.OO J (2O.OO) I 40 3 2 1 -. - S I 4 5. ? 6 ; 7 i ! J 9 8 i ^ Shown os 1 'o . (20.00) II (froc.) \ 'i / (20.00) (Froc.) j (20.00J (20.OO) \ 40 3 \ * 1 4 1 I "^ "*N \ ^ ^ 4 5 j 6 7 ^: 1 f *N^$^$S5tf^^> X ^^^ 1 9 CM | (^ Shown os t ,0 <3 ^ (20.00) _(Frac.) \ . . 1 South boundary of section out of limits in alinement and measurement; southeast quarter protracted as surveyed; and section to be completed. 200 MANUAL OF SURVEYING INSTRUCTIONS. defective in alinement, then the new latitudinal section line will have to be established as a sectional correction line, exactly in accordance with the rules already given for running such lines, ordinarily with section corner of maximum control at its inter- section with the new meridional section line, and quarter-section corner of maximum control at mid-point. On the new meridional section line one or two quarter-section corners may be required; one marked. to control the subdivision of the section under consid- eration will be established at 40 chains from the original section corner; the same quarter-section corner may be marked to control the subdivision of the adjoining section if the fractional measure- ment is to be placed in the same direction in the two sections, but if the fractional measurement is to be thrown in the opposite direction in the adjoining section an additional quarter-section corner marked to control the subdivision of that section would ordinarily be re- quired at 40 chains from the new section corner. 219. Many cases will arise in the field involving combinations of two or more of the above simple examples, in which instance the surveyor is advised to prepare a diagram illustrating the con- ditions found in the original survey, whereupon the new section lines may be shown with alinement in accordance with the usual rules for subdividing townships, noting that the new section lines are to be initiated at the previously established original section corners, and that the length of the meridional boundary will depend both upon the regularity of the length of the opposite original merid- ional section line and upon the alinement of the previously estab- lished latitudinal section line; thereupon the surveyor may at once show upon his diagram the position of the necessary quarter-section corners on the new section lines, all in conformity with the simple rules already stated. 220. Other instances will be found where half sections are shown upon the original approved plat protracted as surveyed, in some cases where only the opposite section line has not been established and in other cases where parts of the adjacent as well as the opposite section lines have not been established. In case only one section line remains to be established, it will be located upon the true line connecting the original section corners, regardless of bearing; the new opposite quarter-section corner marked to control the subdi- vision of the stated section will be placed at mid-point, regardless of the length of the new section line; the position of the quarter- SYSTEM OF RECTANGULAR SURVEYS. 201 New Fig.62. Para//e/ to 5. bdy. 0/d M/d-point Mid-point Mid-point Shown as regular. Shown as regular. Old bdrs. defective in measurement. flew West 0/d Mid-point Mid-point Mid-point Shown as regulqr. Shown as regular. Old bdrs. defective in alinement South half protracted as surveyed, and section to be completed. 55465 19 14 202 MANUAL OF SURVEYING INSTRUCTIONS. C/Q- Old bdrs. defective in measurement. Random and true. . Olcf Mid-point Mid-point Mid-point Shown as regular Shown as reg> ulaf. Old bdrs. defective in afinement. South half protracted as surveyed, and section to be completed* SYSTEM OF RECTANGULAR SURVEYS. 203 Id Regular 64. /Vet V (Calc.) 1 20.00 (frac.) j ( 20.00) 5 ( i 4 3 I 40 i I 1 i 1 -~ - \ -v y ^ M l - i 5 ^ k .-I 1 ^ ^ i r 1 * i i "" Q ^ 1 5 \ i 1 12 ' l3 1 2 c \ \ fl i jf^L-^-- M N. bdy. of Tp. (20.00) -*N ^ 4 (Frac.) 3 \ 2 $ ^ Shown as fractional. L -j -- S 5 6 I ^ Shown --r 12--.. 2- -4 \\\ * Itol 1 i 3 ^J f 6~* 5 J T 8 J 7 ; 6 5 1 ^ ^ 1 ^--1 7 8 ^ 9 1 10 ' II 40 y. f! ' ' ' 2 ' 34* 3'2li L.-l 3 4 | j45| 40 80 _ _^ ec 12 I 6 "! ' 8 7 1 6 ' 5 f~ 80 160 , . 1 J 7 ' 4O i 9 ' 10 i II i 1 i 1 ---I 80 160 160 80 - 40 | 2 45ec 22 Sec 23 S ec 24 - 3 (60 160 160 80 | , 4 3 ,' 2 j 1 | 40 80 80 4 ' 5 1 6 | 7 _ _j J- , 1,2 3 ' 4 ^ Sec. 25 ^98 6 ! 5 i 7 ! 8 | ,-^.... o__ ?/? fractional sections, and the completion of the subdivisional lines of a partial township fragmentary surveys. 208 MANUAL OF SURVEYING INSTRUCTIONS. the position of the new quarter-section corners, established to con- trol the subdivision of a particular section in question, must be such as to permit the center lines from said points to the opposite original quarter-section corners to be connected in strict harmony with the conditions represented upon the original approved plat, disregard- ing the effect upon the subdivision of the newly surveyed public land. Likewise the lines connecting the sixteenth-section corners on the opposite boundaries of a quarter section must conform to the conditions represented upon the original plat. When the subdi- vision-of-section lines are thus platted the section may be considered satisfactory if the integrity of the original areas is in no way violated. When the subdivision-of-section lines are platted as suggested, the permanent conditions affecting the new areas may be considered, and should be harmonized with the following additional rules: 1st. The new areas should be complementary to the original areas by the extension of the subdivision-of-section lines as already pro- tracted upon the original plat, except as poorly shaped lots, or lots of too great or too little area, would result in violation of the regular rules for subdivision of sections. 2d. The same meridional limit may be permitted, in the interest of regularity and simplicity of platting, as is ordinarily allowed in latitudinal section lines; i. e., a section may be considered regular whose boundary lines are all for alinement when not to exceed 21/ from a cardinal course, and for measurement when not to exceed 25 links from 40 chains between the section and quarter-section corners. Such regular sections may be subdivided into regular quarter sec- tions and quarter-quarter sections as far as possible. A section having three regular boundary lines may be subdivided in accord- ance with the usual rules for subdividing sections along the north and west boundaries of a normal township. A section having two adjacent regular boundary lines may be subdivided similarly to the manner in which section 6 of a normal township is "treated. All other sections should be treated as irregular, with subdivision-of- section lines protracted to mid-points on the boundaries of the quarter sections, except as a calculated proportional position for a sixteenth-section corner is made necessary by reason of conditions relating to the complementary area shown upon the original plat. 3d. All new fractional lots will be numbered beginning with the next higher number in the series of the same section already begun upon the previously approved plat, and proceeding in the usual SYSTEM OF RECTANGULAR SURVEYS. 209 order in which fractional lots are normally numbered. The new series may begin with No. 1 in case the fractional parts of the original area are not designated by lot number. COMPLETING THE SUBDIVISION OF A PARTIAL TOWNSHIP RESULTING FROM FRAGMENTARY SURVEYS. 225. After the partially surveyed sections have been fully completed the surveyor may proceed with the subdivision of the remaining portions of the township. Every condition represents a separate problem, and few specific rules would serve any purpose in guiding the surveyor to a definite procedure. If no irregularities are to be found in the previously established lines the new survey may proceed normally, but if defective conditions are encountered the irregularities are not to be extended into unsurveyed sections any farther than necessary to incorporate the resulting fractional measurements into suitable fractional lots adjoining the former surveys. Preference should be given to extending all surveys from south to north and from east to west, but if a better control is available by reversing the procedure in one or both directions, thus resulting in a simpler and better survey in respect to mini- mizing the number of extra comers as well as fractional lots, such reversal of procedure is fully warranted. The principle relating to controlling coordinate measurements in two directions at right angles, as along the south and east boundaries of a township, may be applied to the subdivisional lines best suited to control the new surveys to be executed; and, if the selected bases are defective in alinement, in whole or in part, the new section lines may serve the function of a sectional guide meridian or a sectional correction line as required. The corners from which the new. surveys are to be initiated and controlled in latitude and departure will be termed corners of four sections, or of two sections as appropriate, and where the terminal lines can not be connected regularly with the pre- viously established section corners by random and true line not exceeding 2V from cardinal, a closing section corner will be established in full accord with the principle relating to the estab- lishment of closing section corners on the north or west boundaries of a township where the latter lines are found to be defective in measurement. The fractional measurements of the closing section lines will be placed adjacent to the old surveys, and the distance from the closing section corner to the nearest original corner will 210 MANUAL OF SURVEYING INSTRUCTIONS. Fig. 66 (West half ) <* i X 5 6 40 7 40 8 10 3 V* -d e .__ -Sec 7- Al II 12 \> 14 13 5 2 1 1 1 3 4 - -- Sec 18- 1 6 5 1 1 1 _ L_ 3 i. 2 L 4J 3 ^ 2 [ 1 5 > 6 7 ' 8 5 I 6 t 7 8 1 40 t 40_j 40 | 40 40 | 40 | 40 2 9 _ Sec 19 Sec 2O Sec 21- i 3 10 4 II 1 1 2 2 *?/?/- 0/5 /* ?A 3 3 4 i 5 6 ! 7 1 i 2 ! 3 i 4 4 1 5 6 7 i i 1 i i, I i 1 Previously Subdivided Exairmlfi sho-sriner tha nnrrmlp.tion of t.ho snhdivisional SYSTEM OF RECTANGULAR SURVEYS. Fig. 66 (East half) 211 4 ! 3 !"' 2 ! , 4 u 3 ; 2 ; i 4 _[ 3 J_ 2 i_ r 6 7 i 8 S 1 6 7 i 8 5 , 6 7 1 8 J 40 40 ' 40 40 i 40 40 ' 40 40 , 40 40 I 40 .1 -5tfc J Sec 2'- Sec, / *. 10 II .1. ? ") in the following diagram: Two pits, in a cardinal direction from the monument, aa shown (with symbol " D ") in the following diagram: p - u U W&S368T E^S36BT ~ 1 n a NIB i N Nw4 Nw,4 >cs. j jfi*. CN|g CNjg ,D , 5 35 1 S 36 S 36 S 36 S36 S36 S36 S36 ~~^3% BT D BT BT D BT BT D BT BT D BT BT C I x 1 1 1 1 t CWfsS36BT 04; ci CE4S36BT ^3, 1-1 -^flS>- r-i --336^g^. S36- CV/4S36BT BT BT a 1 1 1 1 1 1 i I S35 S 6 SW.6 SW(^ CS ( i CSft SEft SEfe S.-g S,i S36 S36 S36 S~36 S3S S36 S36 -XE> S36 S3I 8T p BT BT p BT BT D BT BT D BT BTDBT 1 . 1 r l" j 1 i ,W,^S36BT ; E^SSSOT 1 *J3&- r- . L . . _ r, -& . J 256 MANUAL OF SURVEYING INSTRUCTIONS. 34:8. Sixteenth-section corners of minimum control. Two bearing trees, both in the particular section which is con- cerned, each marked with a key letter (N, E, S or W) to indicate the position of the monument, and "A" and the section; as r V . n K c L V I J N &SI8BT. Key Mound of stone, in the particular section which is concerned, In a cardinal direction from the monument. Two pits, one in each direction on the section line passing through the monument. 344. Special and auxiliary meander corners. Two bearing trees, each marked "SMC"or"AMC,"as the case may be, and the section; as S 14 S M C B T, or S 14 A M C B T. Mound of stone, on the opposite side of the monument from the meanderable body of water. Two pits, one 3 feet and one 6 feet distant, on the opposite side of the monument from the meanderable body of water. 345. Closing subdivision-of-section corners. Two bearing trees, both in the particular section which is con- cerned, each marked "C C" and the section; as S9CCBT. Mound of stone, on the closing line. Three pits, one on the closing line and one each to the right and left on the line closed upon. 346. Miscellaneous angle points along irregular boundaries. (a) Two bearing trees, where the monuments are less than 1 mile apart, one on each side of the boundary; and (b) four bearing trees, where the monuments are 1 mile or more apart, two on each side of the boundary; each marked "A P" and a serial or section number, CORNER MONUMENTS. 257 or both, also the initials or abbreviation of the State, reservation, giant, private claim or public land, as appropriate; as A P 2 TR 37 B T, and A P S 14 B T (for " angle point No. 2" on the boundary of a private claim "Tract No. 37 " fall- ing on surveyed land). Mound of stone, on the medial line between the boundary lines intersecting at the monument, and in the direction toward the S'ate, reservation, grant or private claim. Two pits, one in each direction on the lines intersecting at the monument. 347. Intermediate corners along irregular "boundaries, (a) Two bearing trees, where the monuments are less than 1 mile apart, one on each side of the boundary; and (b) four bearing trees, where the monuments are 1 mile or more apart, two on each side of the boundary; each marked with the number of the mile or half- mile corner and the letter "M" (to indicate "mile corner"), and the initials or abbreviation of the State, reservation, grant, private claim or public land, as appropriate; as 47 M COLO BT, and 47 M OKLA BT (for "47th mile" corner on the boundary line between the States of "Colorado" and "Oklahoma"). Mound of stone, on a line at right angles to the boundary, and in direction toward the State, reservation, grant or private claim. Two pits, one in each direction on the boundary. CHAPTER V. RESTORATION OF LOST CORNERS. IDENTIFICATION OF EXISTENT CORNERS. 348. It is the purpose of this chapter of the Manual to outline the guiding principles which are to be observed in the identification of existent corners, and thereafter to set forth the particular rules which are to be applied in the recovery of the position of lost corners originally established in the execution of the United States rec- tangular surveys. All surveyors, whether employed by the United States or not, are cautioned to note the difference between the regulations per- taining to the establishment of the original surveys of the public lands and those relating to the subsequent identification of said official surveys and the replacement of missing monuments thereof. In the extension of the rectangular surveys it devolves upon the United 'States surveyor to identify the initial lines of his group and to replace all lost corners thereof. On the other hand in the sub- division of sections and in the location of property lines generally, it falls to the county or other local surveyor to identify the official corners, and where a required corner is missing the local surveyor will be called upon to recover the point. Thus it will be seen that local as well as United States surveyors are constantly called upon to search for existing evidence of original monuments, and in this work the surveyors will be guided by the same general methods. Should the search for a monument result in failure, the appropriate restorative surveying process to be observed by either surveyor will be based upon the same rules as hereinafter outlined. The text that follows draws no distinction between the duties of the two classes of surveyors. 349. The terms " corner" and " monument" are used largely in the same sense, though a distinction should be noted to clarify the subject matter of this chapter. The term " corner" is employed to denote a point determined by the surveying process, whereas the "monument" is the physical structure erected for the purpose of marking the corner point upon the earth's surface. 259 260 MANUAL OF SURVEYING INSTRUCTIONS. 350. An existent corner is one whose position can be identified by comparing the evidence of the monument or its accessories on the ground, with the record contained in the field notes of the original survey, or where the point can be determined otherwise by suitable testimony. 851. The process of again bringing to light the physical evidence of an original monument is founded on the principle of intelligent search for the calls of the field notes of the original survey, guided by the controlling influence of known points. The problems incident to the search are vastly simplified whenever a retracement may be projected from known points, and the final search for a monument should cover the zone surrounding one, two, three or four temporary points as may be determined by connections with known corners in one, two, three or four directions, according to the number of points which will ultimately control the relocation in case the corner in question should be declared lost. 352. The character of the original monument is the most impor- tant factor in regard to its lasting qualities, and the search should be directed to an examination for such evidence as may reasonably be expected to remain. The evidence is bound to range from that which is least conclusive to that which is unquestionable, and the requisite support of corroborative evidence is necessary in direct proportion to the uncertainty of any feature regarding whose authenticity there may be danger of dispute. A stone, wooden post, tree corner, deposit corner, and the modern iron post monument are all subject to more or less deteriorating changes through various influences, depending upon the character of the original monument, its local site conditions, and the lapse of time, and all such factors should be taken into consideration when comparing the particular evidence in question with the description contained in the original field notes. 353. If the evidence of the monument is not fully conclusive, the surveyor's attention will be directed at once to the record acces- sories; this step is so generally necessary that it should be considered simultaneously with the search for the monument; in fact, in their broader significance the accessories are a part of the monument. The underlying principles relating to the identification of the corner accessories, subject to the changes which may be expected in the period intervening after the date of the original survey, have already been fully outlined in Chapter IV. It will suffice to state RESTORATION OF LOST CORNERS. 261 that the evidence of the accessories should agree with the record contained in the field notes of the original survey, subject only to such changes as may reasonably be expected. 354. In case of material disagreement between the particular evidence in question and the record calls, the process of elimina- tion of those features regarding which there may be doubt, after making due allowance for natural changes, will serve a most useful purpose, as follows: (a) The character and dimensions of the monument in evidence should not be widely different from the record ; (b) The markings in evidence should not be inconsistent with the record; and, (c) The nature of the accessories in evidence, including size, position and markings, should not be greatly at variance with the record. A certain measure of allowance for ordinary discrepancies should enter into the consideration of the evidence of a monument and its accessories, and no definite rule can be laid down as to w r hat shall be sufficient evidence in such cases. Much must be left to the skill, fidelity and good judgment of the surveyor in the performance of his work, ever bearing in mind the relation of one monument to another, and the relation of all to the recorded natural objects and items of topography. 355. A corner will not be considered as lost if its position can be recovered satisfactorily by means of the testimony and acts of wit- nesses having positive knowledge of the precise location of the original monument. The expert testimony of surveyors who may have identified the original monument prior to its destruction and thereupon recorded new accessories or connections, etc., is by far the^most reliable, though landowners are often arjle to furnish valuable testimony. The greatest care is necessary in order to establish the bona fide character of the record intervening after the destine tion of an original monument. Full inquiry may often serve to bring to light various records relating to the original corners, and memoranda of private markings, etc., and the surveyor should make use of all such sources of information . The matter of boundary disputes should be carefully looked into in so far as adverse claimants may base their contentions upon evidence of the original survey, and if such disputes have resulted in a boundary suit, the record testimony and the court's decision should be carefully examined 262 MANUAL OF SURVEYING INSTRUCTIONS. relative to any information which may shed light upon the position, of an original monument. The testimony of individuals may relate to knowledge of the orig- inal monument or the accessories, prior to their destruction, or to any other marks fixing the locus of the original survey, and the value of such testimony may be weighted in proportion to its completeness and agreement with the calls of the field notes of the original survey, also upon the steps taken to preserve the location of the original marks. All such evidence should be put to the severest possible tests by confirmation relating to known original corners and other calls of the original field notes, particularly to line trees, blazed lines and items of topography. It is impossible to outline a definite rule for the acceptance or non-acceptance of the testimony of individuals. Corroborative evi- dence becomes necessary in direct proportion to the uncertainty of the particular statements advanced by the individual who testifies. It will be well for the surveyor to bear in mind that conflicting statements and contrary views of interested parties are fruitful of boundary disputes. 356. In those cases where witness corners were established in the original survey, the true point for the corner will be controlled by such witness corner, when the latter can be identified, by reference to the record in accordance with the general plan of the survey. The usual diligent search will be made for witness corners, but where the same can not be identified the position of the true point for the corner will usually be of major importance, rather than the point for the witness corner, and in such instances the surveyor will pro- ceed directly to the re-determination of the true corner position, adopting the particular methods which should govern the case in hand. Should it become necessary to restore a lost witness corner the general principles hereinafter outlined will be observed. 357. In the absence of an original monument, a line tree, or a defi- nite connection to natural objects, or to improvements, which can be identified, may each fix a point of the original survey for both latitude and departure. The mean position of a blazed line, when identified as the original line, may sometimes help to fix a meridional line for departure, or a latitudinal line for latitude. Other alls of the original field notes in relation to vaiious items of topogra- phy may assist materially in the recovery of the locus of the original survey. Such evidence may be developed in an infinite variety. RESTORATION OF LOST CORNERS. 263 It may be only such as to disprove other questionable t features, or it may guide the surveyor in a general way in arriving at the immediate vicinity of a line or corner, or in its best phases may be such as to fix the position of a line or corner beyond any doubt. 358. A certain measure of allowance should be made for ordinary discrepancies in the calls relating to items of topography. Such evidences should be considered more particularly in the aggregate, and when they are found to be corroborative an average may be secured to control the final adjustment, which will be governed largely by the evidences nearest the particular corner in question, giving the greatest weight to those features which agree most har- moniously with the record, and to such items as afford definite con- nection. A careful analysis will generally reveal the merits of au- thentic evidences as opposed to unreliable features bearing re- semblance to the calls of the field notes, and in this matter the sur- veyor will find an opportunity to exercise his skill to the fullest capacity. 359. It is a matter of utmost importance to determine where an identified call of the original field notes shall operate to control for both latitude and departure, or for either coordinate by itself, and finally as to the necessity for applying the rules for proportionate measurement where the distance between the identified points is considerable. RESTORATION OF LOST CORNERS. 360. A lost corner is a point of a survey whose position can not be determined, beyond reasonable doubt, either from original traces or from other reliable evidence relating to the position of the original monument, and whose restoration on the earth's surface can be accomplished only by means of a suitable surveying process with reference to inter-dependent existent corners. 361. The surveyor is not prepared to consider the restoration of a lost corner until he has exhausted every other means of identifying its original position, and at this stage of his work he should have determined upon an approximate position of the original monument based upon his findings resulting from retracements leading from known corners to the lost corner, from one, two, three or four direc- tions in accordance with the plan of the original survey. The prin- ciple of proportionate measurement, which most nearly harmonizes surveying practice with the legal and equitable considerations involved in controversies concerning lost land boundaries, enters 264 MANUAL OF SURVEYING INSTRUCTIONS. into the problem at this stage, and this plan of relocating a lost corner will always be employed unless outweighed to the contrary by physical evidence of the original survey. In cases where the relocated corner can not be made to harmonize with all the calls of the original field notes, due to unexplained discrepancy which is made apparent by the retracement, the surveyor is required to determine which calls will be given major control, and those which must be subordinated. 362. The preliminary retracements furnish the only possible means of arriving at the discrepancies of the courses and distances of the original survey as compared with those derived in the process of re-running the lines, and the whole problem of proportionate meas- urement is one involving the adjustment of said discrepancies. The restoration of the lost corners can not proceed until the retracement of the original survey has been completed. The retracement will be based upon the courses and distances returned in the field notes of the original survey, or the equivalent by calculation, initiated and closed upon known original corners. Temporary stakes for future use in the relocation of all lost corners may be set when making the retracements. 363. As has been observed, existing original corners can not be disturbed; consequently discrepancies between the new and the original record measurements of the line connecting the identified original corners will not in any manner affect measurements beyond said corners, but the differences will be distributed proportionally within the several intervals embraced in the line in question. 364. A proportionate measurement is one resulting in concordant Telation between all parts of an original record length of a line and the new distances given to the several parts as determined by the re-measurement, in such a manner that the new distance given to any part of a line shall bear the same relation to the original record length of that part of the line as the new measurement of the whole line bears to the original record length of said line. The ordinary field problem consists in distributing the excess or deficiency determined by comparing the new measurement with the record distance between two original existent monuments, in such a man- ner that the amount of excess or deficiency given to each interval shall bear the same proportion to the whole difference as the record length of the interval bears to the whole record distance. After having applied the proportionate difference to the record length of RESTORATION OF LOST CORNERS. 265 each interval the sum of the adjusted lengths will equal the new measurement of the whole distance. 365. The term "single proportionate measurement" is applied to a new measurement made on a single line to determine the posi- tion thereon for restoring a lost corner, for example, a quarter-section corner on line between two original section corners. The term "double proportionate measurement" is employed to signify new measurements made between four original corners on intersecting meridional and latitudinal lines for the purpose of fixing by relation to both lines the position of a lost corner, for example, a corner common to four sections or four townships. 366. It will almost invariably happen that discrepancies will be developed between the new measurements and the original measure- ments recorded in the field notes. When these differences occur the surveyor will generally be required to adopt a proportionate measurement based upon a process conforming to the method followed in the original survey. The principle of the preponder- ance of one line over another of less importance is recognized, in order to determine upon the procedure relative to single or double proportionate measurement, or other rule to be adopted in order to limit the control and at the same time harmonize the restorative process with the method followed in the original survey. Thus standard parallels will be given precedence over other township exteriors, and the latter will be given precedence over subdivisional lines; section corners will be relocated before the position of lost quarter-section corners can be determined. PRIMARY METHODS, (a) DOUBLE PROPORTIONATE MEASUREMENT. 367 . The method of double proportionate measurement is generally applicable to the restoration of lost corners of four townships and of lost interior corners of four sections. It is the best example of the basic principle that monuments north and south should control the latitudinal position of a lost corner, and monuments east and west should control the longitudinal position of a lost corner, upon a plan by which the influence of one identified original corner is balanced by the control of a corresponding original corner upon the opposite side of a particular missing corner which is to be restored, each identified original corner being given a controlling weight inversely proportional to its distance from the lost corner. 55465 19 18 266 MANUAL OF SURVEYING INSTRUCTIONS. 368. In order to restore a lost corner of four townships where all of the connecting lines have been established in the field, a retrace- ment will first be made between the nearest identified original corners on the meridional line, north and south of the missing corner, upon which line a temporary stake will be placed at the proper proportionate distance. This will determine the latitude of the lost corner. Next, the nearest original corners on the latitudinal line will be connected and a point thereon will be determined by pro- portionate measurement in a similar manner, independent of the temporary stake on the meridional line. The second temporary point will determine the position of the lost corner in departure. Then through the first temporary stake run a line east or west, and through the second temporary stake a line north or south, as relative situations may determine. The intersection of the two lines last run will define the position of the restored corner by "double propor- tionate measurement." 369. In the accompanying diagram the points "A, " "B," "C" and "D" (on the small scale) represent four original corners; and (on the large scale) "E" represents the proportional point between "A" and "B," for measurement only, and similarly, "F" represents the proportional point between "C" and "D." The point "X" satisfies the first control for latitude, and the second control for departure. 370. The plan of double proportionate measurement will be applied to the restoration of lost corners of four townships where all the lines therefrom have been run. Lost interior corners of four sections, where all the lines therefrom have been run, will also be reestablished by double proportionate measurement, after first relocating the required lost section corners on the township exteriors. When a number of corners of four sections, and the intermediate quarter-section corners, are missing on all sides of the one sought to be reestablished, the entire distance must, of course, be re- measured between the nearest identified corners both north and south, and east and west, in accordance with the rule laid down. 371. Where one of the connecting lines has not been established in one direction from the missing township or section corner, the record distance to the nearest identified corner in the opposite direction will prevail in lieu of a proportional measurement. Thus, in the same diagram, if the latitudinal line in the direction of the point "D" had not been established in the original survey, the' RESTORATION OF LOST CORNERS. I 267 r- 25 . -j. 1 30 1 29 1 1 36 "1 ^ 1 3! I 32 | X 1 # . 1 L- I 1 5 1 L. _J fig, 67. 268 MANUAL OF SURVEYING INSTRUCTIONS. position of the point "F" in departure would have been deter- mined by reference to the record distance from the point "C, " whereupon the point "X " would have been fixed by cardinal offsets from the points "E" and "F" as before. Again, in rare instances, where the intersecting lines have been originally established in only two of the directions, the record distances to the nearest iden- tified corners on the two lines will control the position of the tem- porary points from which the cardinal offsets are to be made. (&) SINGLE PROPORTIONATE MEASUREMENT. 372. The method of single proportionate measurement is gener- ally applicable to the restoration of lost corners on standard parallels and other lines established with reference to definite alinement in one direction only. Intermediate corners on township exteriors and other controlling boundary lines are to be included in this class. 373. In order to restore a lost corner by single proportionate measurement, a retracement will be made connecting the nearest identified regular corners upon the particular line in question, the record of which shows no deflection in alinement; a temporary stake will be set on the preliminary line at the original record distance; the total distance will be measured, also the falling at the objective corner. The temporary stake will then be adjusted for the pro- portional part of the difference between the record distance and the re-measurement, also for its proportional part of the falling. Thus the adjusted position will fall on the true line connecting the nearest identified corners, and at the same proportional interval from either as existed in the original survey. Any number of lost points, on the same straight line, may be recovered by the same plan, setting a temporary corner for each at the time when making the retracement. On the retracement of an east and west line, the proper adjustments to secure the true latitudinal curve should be allowed for as outlined in Chapter II. 374. Lost standard corners will be restored to their original positions on a* base line, standard parallel or correction line, by single proportionate measurement on the line connecting the nearest identified original standard corners on opposite sides of the missing corner or corners, as the case may be. The term "original standard corners " will be understood to designate standard township, section and quarter-section corners, meander corners terminating the survey of a standard parallel, and closing corners in those cases where they were originally established during the survey of a RESTORATION OF LOST CORNERS. 26D standard parallel as corners from which to project surveys to the south. No other meander or closing corners along a standard par- allel will control the restoration of lost standard corners. 375. All lost exterior section and quarter-section corners will be restored by single proportionate measurement between the nearest identified corners on opposite sides of the missing corner, north and south on a meridional line, or east and west on a latitudinal line, after the township corners have been identified or relocated. An exception to this rule will be noted in the case of any exterior the record of which shows irregularities in alinement between the ter- minal township corners. (See sec. 380.) 376. All lost interior quarter-section corners will be restored by single proportionate measurement between the adjoining section corners, after the section corners have been identified or relocated. 377. Lost meander corners, originally established on a line pro- jected across the meanderable body of water and marked upon the opposite side thereof will be relocated by single proportionate measurement, after the section or quarter-section corners upon the opposite sides of the missing meander corner have been duly identified or relocated. (C) CLOSING CORNERS. 378. In order to reestablish a lost closing corner on a standard parallel or other controlling boundary, the line closed upon will' be retraced, beginning at the corner on the standard parallel or other controlling boundary from which the connecting measurement was originally made, itself properly identified or relocated; a temporary stake will be set at the original record connecting distance, and the total distance and falling will be noted at the next regular corner on the opposite side of the missing closing corner. The temporary stake will then be adjusted as in single proportionate measurement, i. e., the closing corner will be reestablished on the true line closed upon at the proper proportional interval between the nearest regular cor- ners to the right and left. An identified closing corner not actually located in the line closed upon will determine the direction of the closing line, but not its legal terminus; the latter is bound to fall at the true point of intersection of the two lines. The position of a restored closing corner should be verified by a retracement of the line whose terminus it was designed to mark. (See sec. 384.) 270 MANUAL, OF SURVEYING INSTRUCTIONS. SECONDARY METHODS. 379. The following methods involve special applications of the general rules of proportionate measurement for adoption in unusual cases where the ordinary control can not be obtained. (d) BROKEN BOUNDARIES. 380. In order to restore one or more lost corners on a broken or irregular township exterior, or other controlling boundary, a retrace- Closirig error of retrocemerit- Fig. 68. ment will be initiated at the nearest identified original corner on the boundary, following out the record courses and distances, or the equivalent by calculation, setting a temporary stake for each missing corner or angle point, until the next identified original corner has been attained, where a final temporary stake will be set at the record distance of the last course of the retracement. The closing error will RESTORATION OF LOST CORNERS. 271 then be determined for course and distance from the last temporary stake to the objective original corner, and each temporary stake will thereafter be adjusted on the bearing of the closing error, a propor- tional amount of the length of the closing error equal to the propor- tional part of the distance of the temporary stake from the initial point of the retracement, i. e., the particular distance to be measured at any temporary stake, on the bearing of the closing error, is to the whole length of the closing error as the distance of the particular temporary stake from the initial original corner is to the whole length of the retracement. Angle points and intermediate corners will be treated alike. (e) ORIGINAL CONTROL. 381. Where a line has been terminated with reference to a meas- urement in one direction only, a lost corner will be restored by refer- ence to the original record bearing and distance, counting from the nearest regular corner, the latter having been duly identified or restored. Examples will be found where lines have been discon- tinued at the intersection with large meanderable bodies of water, or at the border of what was classed as impassable ground. (/) INDEX CORRECTION FOR AVERAGE ERROR IN ALINEMENT AND MEASUREMENT. 382. In unusual cases where a retracement has been made of many miles of the original lines, between identified original corners, and there has been developed a definite surplus or deficiency in measurement, or a definite variation in alinement, characterizing the original survey, it will be proper to make allowance for such average " index error." Such adjustment will be taken care of automatically in all cases where there exists a suitable basis for proportional measurement, but in any case where such control is lacking, an index error, if conclusive, will be made use of by applying the determined correction to the record courses and dis- tances. If there is not conclusive evidence of such index error the record courses and distances will be allowed to prevail. SPECIAL CASES. 383. Examples of special cases could be set forth almost indefi- nitely, but without bringing out important new principles. In some respects the treatment of a large number of special examples would serve to confuse the subject by seeming to warrant certain procedure as a general rule which in fact would not be proper were 272 MANUAL OF SURVEYING INSTRUCTIONS. the conditions altered; the latter occur in an infinite variety. Ample provision has been made for the United States surveyor to call upon a supervising officer for advice in difficult cases, and where necessary the latter is in a position to direct the surveyor to proceed with additional retracements in order to develop any data which should be considered before a decision is rendered. In trials of boundary suits the court will generally consider many additional questions besides those concerned in the technical problem, and in such instances an academic study of hypothetical examples might serve to cloud the real issue. It would be beyond the purpose of the Manual to invade the realm of non-technical matter while attempting to lay down the general principles involved in the restoration of lost corners. 384:. In all unusual instances, where on account of manifest distortion, or through extensive obliteration resulting in great distances between existing corners, or otherwise, the evidence of a survey can not be identified with sufficient certainty to enable a suitable application of the various rules relating to the restoration of lost corners, the surveyor is again advised to report the facts to the proper supervising officer. In the same connection, it is impor- tant that the surveyor should not be confused with the notion that he is required, or has any authority, to revert to the principles relating to the establishment of original surveys as an alternative in such cases. The methods incident to resurveys, as outlined in the next chapter, are designed to rectify unusual conditions which are widely at variance with the representations of the original approved plat and field notes. (0) MISCELLANEOUS CONTROL. 385. It will be apparent to the experienced surveyor that actual field conditions do not always furnish the basis for the application of the rules heretofore set forth, and while developing a consistent theory to apply in unusual cases the surveyor will at once note that the first consideration relates to a more or less arbitrary limitation of the control to be adopted. No definite rule can be laid down, except that there should be the closest possible adherence to the basic exam- ples already given in the text. The methods heretofore outlined readily harmonize surveying practice with legal decisions concerning the restoration of lost corners. A strictly consistent mathematical recovery of a lost corner, not based upon any known legal decision, may be obtained by allowing every known corner within a reason- RESTORATION OF LOST CORNERS. 273 able radius to enter into the control, each original corner being given a weight inversely proportional to its distance from the missing corner, and though the principle will lead to the same result in come cases as by the methods previously outlined, it will yield a slightly different result under other regular circumstances. For the latter reason a miscellaneous control based upon such mathematical principle will not be adopted except as specifically approved by the proper supervising officer after due consideration of the facts in regard to the applicability of the method in the absence of a suitable basis for a regular control. 386. Having thus safeguarded the application of the following method, the problem in the field will be developed by a series of re- tracements each beginning at an accepted corner, thence following out the record courses and distances, each retracement terminating at a temporary stake in the vicinity of the objective lost corner. Each stake will be given a weight inversely proportional to the dis- tance from the accepted corner to which it is related. The several temporary stakes will then be combined ; the first two to be resolved into a point on the line between them, dividing the whole distance into two parts that will make the interval from either stake inversely proportional to the weights previously assigned, and the latter point will be given their combined weights. The last point will then be correlated with the third temporary stake on a similar plan. Three or more original corners will thus exercise their influence upon the final resultant position for the corner which is to be restored. The result will be the same no matter what the order of connecting the temporary stakes may be, but the omission of any element of the control or the introduction of an additional original corner will alter the final position. The field of influence should ^accordingly be selected with a view to obtaining a resultant balanced position which can not be materially changed by the introduction of other known points of control. CHAPTER VI. RESURVEYS. JURISDICTION. 887. Certain important considerations are involved in the execu- tion of Government resurveys of an entirely different character from those relating strictly to the making of original surveys; these considerations present matters not referred to in Chapter V. There is a twofold object of a resurvey: First, the adequate protection of existing rights acquired under the original survey in the matter of their location on the earth's surface, and, second, the proper marking of the boundaries of the remaining public lands. 388. As already noted in Chapter I, the Congress has authorized, under certain conditions, the re-marking of the public-land surveys. The acts relating to resurveys contemplate a restoration of the corners of the original surveys in those townships, (a) where the obliteration of the original monuments or other evidence of the position of the original lines has become so advanced that the land boundaries can be identified only through extensive retracements by experienced surveyors of the General Land Office, and (6) where field investigation shows that conditions on the ground disagree with the representations upon the original plat to such an extent that the land boundaries can not be identified positively ifi one position to the exclusion of another, in consequence of which said plat should be disqualified as a basis for the disposal of remaining public land. While the Government may initiate a resurvey in the absence of any application therefor, as a rule, the steps preliminary to the authori- zation of a resurvey will be taken by the settlers interested in the land, through a showing of facts made to the proper supervising officer, setting forth the existing conditions with respect to the original survey and status of ownership of the lands. 1 iSee current circular governing applications for resurveys. 275 276 MANUAL OF SURVEYING INSTRUCTIONS. 389. The surveyor is advised to bear in mind the fact that in localities where resurveys are necessary the occasion for boundary disputes is ever present; he should accordingly exercise the greatest care in his technical work in the field and in the record thereof, so that the result of the resurvey shall relieve existing difficulties as far as possible without introducing new complications. As in the case of original surveys, the records of all resurveys must form an enduring basis upon which depends the security of the title to all lands acquired thereunder, and the field notes should be so prepared that under the test of the closest possible scrutiny at all times, present and future, the record can be regarded as conclusive in the matter of the location of such rights. 390. The General Land Office has exclusive jurisdiction over all matters pertaining to surveys and resurveys affecting the public lands; as between private owners of lands the title to which has passed out of the United States, final determination in the matter of fixing the position of disputed land boundaries rests with the local court of competent jurisdiction. The rules of procedure laid down by the General Land Office to guide its surveyors in the re-marking of lines of previous surveys are intended to be in harmony with the leading court decisions in suits involving boundary disputes, and said rules should be so applied that the courts may, with security, accept without question the boundaries thus determined in so fa r as they represent the true location of a particular tract intended to be conveyed by a patent. Government resurveys are under- taken only by duly appointed United States surveyors acting under the authority of the Secretary of the Interior through the Commissioner of the General Land Office and under the immediate direction of subordinate supervising officers. LIMIT OF AUTHORITY OF SURVEYOR. 391. There are certain questions of a purely judicial nature involved in resurveys of every description where the decision is to be reserved to the General Land Office, particularly those relating to compliance with the general laws in respect to the entry of the public lands. Thus it comes within the realm of the surveying process to identify and mark out on the ground the various legal subdivisions of the public domain, but it is a judicial question beyond the function of the surveyor to determine whether or not specified lands have been duly earned under a certain entry. In RESURVEYS. 277 the resurvey process the surveyor will determine whether or not lands embraced within a claim as occupied have been correctly related in position to the original survey, and where the demon- stration of this question may be one involving more or less uncer- tainty, as is often the case, the surveyor will examine and weigh the evidence relating strictly to the surveying problem involved, and he will interpret the evidence in respect to its effect upon the manner in which the resurvey shall be executed looking to the protection of the valid rights acquired under the original survey. The surveyor has no authority to enter into any agreements looking to the exchange of one subdivision for another, or to bind the General Land Office in this particular. BONA FIDE RIGHTS OF CLAIMANTS. 392. In order to carry out the provisions of the laws relating to resurveys, the surveyor should understand fully the meaning of the words "bona fide rights r and under what circumstances it will be held that such rights have been impaired by a resurvey. In this connection attention is again directed to the clause contained in the act of March 3, 1909 (35 Stat., 845), as amended by joint resolution approved June 25, 1910 (36 Stat., 884), which reads as follows: " That no such resurvey or retracement shall be so executed as to impair the bona fide rights or claims of any claimant, entryman, or owner of lands affected by such resurvey or retracement." The rights of claimants are to be given similar protection under the provisions of the act of September 21, 1918 (40 Stat., 965). 393. It will be understood that bona fide rights are those acquired in good faith under the law. Eights of this character can be affected by a resurvey only in the matter of POSITION or LOCATION on the earth's surface, and the surveyor will be concerned only with the question as to whether lands covered by such rights have been actually LOCATED in good faith. Other questions of good faith, such as priority of occupation, possession, continuous residence, value of improvements, and cultivation, when considered apart from the question of the position of the original survey, do not in any manner affect the problem of resurvey. It is evident that the resurvey must afford adequate protection to bona fide rights vested in both improved and unimproved lands. In the final determination of the true position of all lands, whether 278 MANUAL OF SURVEYING INSTRUCTIONS. improved or unimproved, in the absence of original corners, the necessity for more or less flexibility of method must be recognized, as the value of both of these classes of lands may be vitally affected by an arbitrary process of resurvey which is rigid in its application. Unimproved lands, however, where no apparent attempt has been made on the part of the owner to identify the same under their original descriptions (and where the inherent value of the lands in question is the same), are not necessarily affected in the same manner, and such unimproved lands may be adjusted to a position found by the surveyor to be conformable to adjoining or near-by tracts, where all may be held to qualify under the rule of acceptable loca- tion. 394. The question arises whether the technical rules for the restoration of lost corners are to be rigidly applied in all cases regard- less of their effect on the position of improvements, or whether the position of all improvements is to be accepted without question regardless of the relation or irrelation of such improvements to the existing evidence of the original survey and to the description contained in the entry. Manifestly these opposite extremes are equally unacceptable. Somewhere between them, therefore, will be found the basis for a determination of the question as to when lands so improved are to be regarded as having been LOCATED in good faith or otherwise. It is clear that no definite specific set of rules can be laid down in advance for the determination of this question. This is a problem the solution of which must be found on the ground by the surveyor; it is upon his judgment primarily that the responsibility for a determination of the question of good faith as to LOCATION must rest. The surveyor may err in his judg- ment, but once this question is settled to his own satisfaction, the procedure to be adopted in the matter of the application of resurvey rules is no longer in doubt. 395. It may be held generally that an entryman has located his lands in good faith (referred to herein as an acceptable location of a claim or of a local point), when it is evident that his interpretation of the record of the original survey as related to the nearest existing corners at the time the lands were located (as denned by his fencing, culture, or other improvements) is indicative of such a degree of care and diligence upon his part, or that of his surveyor, in the ascer- tainment of his boundaries, as might be expected in the exercise of ordinary intelligence under existing conditions. From this it RESURVEYS. 279 follows that lack of good faith is not necessarily chargeable against an entryman if he has not located himself according to a rigid appli- cation of the rules laid down for the restoration of lost corners, where complicated conditions involve a double set of corners, both of which may be regarded as authentic; or where the nearest existing corners in one or more directions are an excessive distance away; or are improperly related to each other to an extraordinary degree; or where all evidences of the original survey which had been adopted by the entryman as a basis for his location have been lost before the resurvey is undertaken. Furthermore, the extent of recognition given by neighboring claimants to a local point used for the control of the location of claims very often carries with it the necessity for a consideration by the surveyor of its influence in the matter of the acceptability of such locations under the foregoing rule of good faith. 396. In cases involving extensive obliteration at the date of entry, the entryman or his successors in interest may be charged with the knowledge that the boundaries of the claim will probably be subject to more or less adjustment in the event of a resurvey, and that in the process of fixing the boundaries of groups of claims a general control applied to all must be favored as far as possible in the interest of equal fairness to all and of simplicity of resurvey. Even in the presence of extensive obliteration of the original survey, a claim which manifestly shows that no attempt has been made to relate the same in some manner to the original survey can not gener- ally be regarded as having been located in good faith. 397. Cases will arise where it may be evident that lands have been OCCUPIED in good faith, but whose boundaries as occupied are clearly in disagreement with the demonstrated position of the legal subdivisions called for in the description. Obviously the rule of good faith as to location can not apply, and relief must be sought through the process of amended entry (act of Feb. 24, 1909, 35 Stat., 645) to cover the legal subdivisions actually earned, rather than through an alteration of the position of established lines. This is a process of adjudication rather than one of resurvey. A case of this character should be regarded as an "erroneous location, " in pre- cisely the same manner as would obtain if the question of resurvey were not involved. 398. The recognition of the principle that the restoration of a cor- ner may be influenced by the position of one or more existing claims 280 MANUAL OF SURVEYING INSTRUCTIONS. warrants, within suitable limits, the acceptance of an unofficial deter- mination, in the manner hereinafter stated, which would not neces- sarily agree with that resulting from a rigid application of arbitrary rules laid down for the restoration of lost corners. GENERAL FIELD METHODS. 399. There are two recognized methods of making Government resurveys DEPENDENT and INDEPENDENT and in general, any field condition that may arise can be taken care of by the applica- tion of one or the other method. 400. The DEPENDENT resurvey is designed to accomplish a restora- tion of what purports to be the original conditions according to the record, based, first, upon identified existing corners of the original survey and other recognized and acceptable points of control, and, second, upon the restoration of missing corners by proportionate meas- urement in harmony with the record of the original survey. This type of resurvey is applicable to those cases showing fairly concordant relation between conditions on the ground and the record of the origi- nal survey. Titles, areas and descriptions should remain abso- lutely unchanged in the typical dependent resurvey. 401. The INDEPENDENT resurvey provides methods adapted to con- siderable areas of public land where the original survey can not be identified with any degree of certainty in accordance with the repre- sentations of the approved plat and field notes, and where the pre- vailing conditions are such that strictly restorative processes, when applied as an inflexible rule between existing monuments or adopted corner positions, are either inadequate or lead to unsatisfactory re- sults. This type of resurvey provides for the segregation of indi- vidual tracts when necessary, or a conformation of individual tracts to the subdivisions of the resurvey if suitable. These processes are found to be more flexible in their application than those of the strictly dependent type, but at the same time they duly protect all private rights which have been acquired upon the basis of the origi- nal approved survey and plat. With respect to the identification and description of the public lands involved, the independent type of re- survey supersedes the record of the original survey. This will be made apparent by the representations of the approved resurvey plat. 402. The basic principle, with respect to the protection of bona fide rights, involved in one type of resurvey is identical with that of the other type, whether dependent or independent; they are both KESTJRVEYS. 281 to be regarded as a demonstration, on the part of the General Land Office, in the light of the best evidence available, by means of the legal subdivisions of a dependent resurvey or by the tract segrega- tions of an independent resurvey, of the original position of entered or patented legal subdivisions or lots included in the original de- scription when related to the original survey. 403. The necessity for both types of resurvey is encountered in the field; the applicability of one or the other method is altogether a question depending upon local conditions, such as extent of oblit- eration, relative harmony of identified and recognized points, and extent of disposals by the Government. These questions should not be judged in advance of a comprehensive field examination. 404:. In general, a preliminary field examination will be required and authorized before the resurvey is to be undertaken. The purpose of an investigation is to develop the extent of the obliteration of the evidence of the original survey, the extent of settlement, the agricultural possibilities of the township, and any other information from which the necessity for, and the propriety of, the proposed resurvey may be determined. A second purpose to be subserved by an investigation is the assembling of sufficient data concerning the local survey conditions to permit a proper type selection; and with this end in view the examining surveyor should investigate and report upon the relative position of the evidence of the original survey; the degree to which identified points are concordant or the reverse; the extent to which corners discordantly related have been made the basis of claim locations; the presence of one or more systems of unofficial local surveys which have been recognized and adopted by the claimants in fixing their boundaries; and the degree to which conflicts are to be anticipated. 405. The proper supervising officer will provide the examining surveyor Vith suitable instructions in which the scope of the exam- ination will be indicated and attention will be directed to the par- ticular considerations which should receive attention. During the progress of the investigation interested parties should be informed, upon inquiry, that the work then in progress is merely preliminary and only for the purpose of gaining information, and that if resurvey is ultimately authorized all valid rights will then be protected as required by law. 55465 19 19 282 MANUAL OF SURVEYING INSTRUCTIONS. 406. The examiner's report should contain definite recommenda- tions concerning the type of resurvey which, in his judgment, should properly be applied in view of the prevailing conditions. When the report and recommendations of the examiner, with those of the supervising officer, have been received by the General Land Office, the situation will be considered, the appropriate type of resurvey will bie determined, and the preparation of special instruc- tions for the resurvey will be authorized. 407. The special instructions, which must of necessity be based largely upon the data provided by the examination, will indicate the scope of the work, and, regardless of whether the lands are to be dependently or independently resurvey ed, the necessary retrace- ments will be made to fix the outboundaries of the township or townships designated for resurvey. With the limiting boundaries once restored so as to protect under the rules already laid down all existing property rights in the adjoining lands not to be resurvey ed, the plan of procedure outlined in the instructions should, under the known conditions, produce satisfactory results, and adherence thereto is expected. If, however, unforeseen conditions are devel- oped in the progress of the resurvey, which may apparently render the special instructions inapplicable or likely to produce incon- sistent or unsatisfactory results, it is of the utmost importance that the surveyor suspend further monumentation of the corners; and after such additional retracement and investigation as may be neces- sary to a proper understanding of the situation, he should report the facts to the proper supervising officer and request further instructions. 408. During the progress of the resurvey the surveyor should advise all interested parties, as occasion and opportunity may offer, that the resurvey is not to be regarded as official or binding upon the United States until duly accepted by the Commissioner of the Gen- eral Land Office, as provided by law, and that no contemplated alteration in the position of improvements or claim boundaries should be made in advance of the official acceptance of the resurvey. THE DEPENDENT RESURVEY. GENERAL CONTROL. 409. A dependent resurvey is an official re-marking of the original lines upon a plan whereby existing evidence of the original survey is given primary control over the position of the lines to be reestab- lished. A certain amount of flexibility (as hereinafter described) RESURVEYS. 283 is allowable in the dependent resurvey when necessary for the protection of bona fide rights of claimants, particularly in those cases where no objection is found to adopting a point acceptably located under the rule of good faith already laid down, when only slightly at variance with the theoretical position of the same. 410. In theory the process consists, first, in the retracement and reestablishment of the township exteriors; second, the identifica- tion of all existing interior corners or other evidence of the original survey; and, third, the determination, by a suitable field procedure, of the theoretical position of all missing corners as indicated by a proper interpretation of the record of the original survey in relation to such existing evidence. The actual field process may be varied to some extent in order to meet local conditions or to suit the con- venience of the surveyor, but the theoretical position finally deter- mined must be identical with that which would result from a strict application of the principles of proportional measurement. When this has been accomplished, attention should be given to the adop- tion, as an integral part of the resurvey system, of corner positions determined by the evidences, of whatever character, of acceptable claim location. Such evidences may, for convenience, be termed " collateral evidence" as distinguished from direct evidence of the original survey. 411. The process of the dependent resurvey differs in scope from that applied for the usual restoration of one or more lost corners, and the rules governing a resurvey bring into consideration in a more comprehensive manner the position of recognized land bound- aries, in the absence of evidence of the original corners. The sur- veyor has noted the detailed instructions set forth in Chapter V looking to the identification of existing evidence^ of the original survey and the application of the rules of proportionate measurement for the determination of the theoretical position of lost corners. These rules will be applied in the dependent resurvey generally with respect to the township as a unit, wherein the means of identi- fication of each and every existent corner will be exhausted and the theoretical position determined for each lost corner. The former are to be considered as fixed points (except in most unusual cases) and may be monumented at any time; the latter will be subjected to the possible influence of points which may afterwards be determined to be acceptably located under the same rule of good faith, and will be marked only as temporary points until this ques- tion has been disposed of. 284 MANUAL OF SURVEYING INSTRUCTIONS. 412. A complete retracement of the original survey will be made, based upon known corners, it being assumed that the exterior boundaries of the township to be resurveyed have been identified or restored under the rules already laid down in Chapter V, and under those relating to the acceptability of a local point or claim location. It is not usually possible to follow the method and order of procedure shown in the record of the original survey (owing to missing corners), but the complete system, of lines will be run out by preliminary retracement, usually beginning with the meridional lines between known corners, followed by the latitudinal lines between known corners, noting the intersections with the said meridional lines. The surveyor must be supplied with a complete copy of the record of the original survey, and temporary reference stakes may be set on the meridional lines at the record measurement for each corner point. 413. The preliminary retracernents will lead at once to the identification of the prominent evidence of the original survey and a trial calculation will follow as to the latitudinal and longitudinal adjustments at each missing corner, to suit the proportions which may be derived when based upon these known corners. A second and more exhaustive search will then follow within the zone of the probable location of each missing corner for the more obscure evi- dence of the original survey. At this stage of his field work the surveyor should exhaust every possible means of identifying the existent corners of the original survey. In many respects, the surveyor will be compelled to devise his own methods as the actual field conditions seem to warrant, and his skill and judgment as a surveyor should function to the fullest capacity. If additional evidences of the original survey are found by this process, a second trial calculation will then be made as to the lati. tudinal and longitudinal adjustments of the temporary reference stakes previously set at each missing corner, to suit the proportional measurements derived from all of the known original corners exactly as outlined in Chapter V. These calculated adjustments will determine the theoretical location of each lost corner vrith reference to all existing evidence of the original survey. In the absence of other considerations, the theoretical points thus determined by proportionate measurement, based upon existing original corners, are fixed to a mathematical certainty, and when these points have been determined,, the evidence of the original RESURVEYS. 285 survey and the record thereof have served their primary purpose. Then, and not until that time, is the surveyor prepared to consider the weight of such collateral evidence as may be available. 414. The question now to be determined is whether the position of the lands claimed, occupied or improved is to be adopted under the rule of good faith as to location, and whether, if so adopted, the claims thus acceptably located can all be properly protected by the dependent plan of resurvey. If the position of any claim 'fails to qualify under the said rule of good faith it may be disregarded as to the effect produced thereon by the plan of dependent resurvey. On the other hand, if these claims are held to be acceptably located under the same rule, they may be adopted as the determining factor in the position of the missing corner or corners; and if the claims are in such concordant relation to each other and to the identified evidences of the original survey as to receive full protection by the dependent plan of resurvey, the surveyor may proceed with ful assurance of the adequacy of the plan. Otherwise, the question of other processes analogous to those of an independent resurvey (as hereinafter explained) must be considered. If two or more claims are acceptably located, but are discordantly related to each other to a considerable degree (by virtue of irregu- larities in the original survey), it will be clear that the general plan of dependent resurvey may not afford protection to such claims; whereupon the influence thereof must be rejected in favor of the theoretical point previously determined by proportional measure- ment. In this case, as before stated, some other process must be adopted to protect the acceptably located claims, 415. These acceptably located points for the missing comers will receive all the authority and significance of an identified original corner, and when the influence thereof on the dependent plan of resurvey has been combined with that of the existing original corners previously identified, the latitudinal and longitudinal adjustments of the temporary points on the meridional lines may be made accordingly. 416. In cases of distortion, if the distorted lines are to be adopted in the plan of dependent resurvey, it should be remembered that the lengths of lines, when subject to double proportion, are comparable only when reduced to cardinal equivalents or to equivalents along the direct lines between the nearest existing corners. 286 MANUAL OF SURVEYING INSTRUCTIONS. 417. Many situations will arise where it will be manifest to the surveyor that it is better to accept a position based upon local improvements rather than to disturb satisfactory existing condi- tions. The surveyor will endeavor to avoid disturbing the posi- tion of locally recognized lines when such action may adversely affect improvements, and at the same time extreme caution will be exercised in the matter of adopting local points of control, which when accepted must be given, as above stated, a significance similar to that of an original corner and be allowed to function on an equality therewith. The acceptance of duly qualified and locally recognized points of control should aid materially in obtaining simplicity of resurvey and avoid the need for special metes-and-bounds surveys (as hereinafter described), which would differ only slightly in posi- tion from the regular lines of the resurvey. In this manner a flexi- bility will be introduced in the application of a dependent resurvey, at least to the point of protecting satisfactory local adjustments. 418. The surveyor should fully understand that the field of influence to be exercised by any acceptable location must be re- stricted to that already covered in a larger way by the existing evidences of the original survey, and that the adjustive process ia of more or less local application. In this connection, it should be noted that the record of the original survey can not be abandoned in favor of an indiscriminate adoption of property corners, all or a portion of which fail to qualify as aforestated, nor is it to be assumed that because a large number or all of the claims within a township are consistently related among themselves to an arbitrary system of control which is itself altogether unrelated to the original survey, that such system is necessarily to be adopted as the basis of a depend- ent resurvey. 419. Thus where bona fide rights, as defined hereinbefore, are found to have been definitely established with reference to the location of lands the position of which can not otherwise be fully demonstrated by existing evidence of the original survey, the surveyor engaged in the resurvey will reject the theoretical point determined by the primary control in favor of a near-by duly qualified corresponding point, the position of which has been agreed upon by the adjoining property owners. Such a point may be recognized as the best available evidence of the true position for a corner; as previously stated its acceptance by the surveyor confers upon the RESURVEYS. 287 point a significance similar to that of an original corner position, and thus avoids disturbing satisfactory local adjustments. Chief among this class of evidence forming the basis of the recognized position of land boundaries are recorded monuments established by local surveyors, duly agreed upon by the interested property owners; the position of boundary fences determined in the same manner; and the center lines of public roads and drainage or irriga- tion ditches, when intended to be located on the subdivisional lines of the public-land surveys. The local record in these cases, when available, may furnish the connecting link to the previously identified evidence of the original survey, but even in the absence of a conclusive record, if a point qualifies as above outlined, the presumption is strong that its position bears satisfactory relation to the original survey and that its correctness can not be success- fully disputed. Points which actually qualify as aforestated may be accepted as the best available evidence of the true position of the original survey. 420. The technical record of the resurvey should clearly set forth the reasons for the acceptance of a local point, where unofficial determinations of the above character do not represent actual marks of the original survey. Such recognized and acceptable local marks will be preserved, and described in the record of the resurvey. New monuments will be established as required, in addition to, but with- out destroying the evidence of, the local marks. REESTABLISHMENT OP TRUE LINES. 421. As already stated, with the combined control of the depend- ent resurvey fully determined, the final calculation will be made as to the latitudinal and Jongitudinal adjustments of the temporary reference stakes previously set at the remaining missing corners. The final calculations will be based upon the known position of the corners of the general control as thus adopted, upon the plan of proportionate measurement, all as provided in Chapter V. The result of this process balances in regular proportion the differences between the measurements shown in the record of the original sur- vey and those derived in the retracement. Thus the true lines of the dependent resurvey are finally determined through the influ- ence exercised by the identified existent corners of the original survey and every other identified call of the record thereof, and 288 MANUAL OF SURVEYING INSTRUCTIONS. such other collateral evidence of the position of recognized land boundaries as may be properly adopted for such influence. 4:22. The field procedure incident to the running and measure- ment of the true lines of the dependent resurvey will conform to the requirements of Chapter II, while the marking of lines between corners and the notation of objects to be recorded wi.ll conform to the provisions of Chapter III, and the monumentation of the survey will comply with Chapter IV. The technical record of the resur- vey will be broadened to show the relationship between the original survey and its reestablished lines. 428. The field note description of an identified or accepted corner will be introduced into the technical record of the resurvey at the place in the true line notes where the position for the corner is indi- cated as having been attained. The record will embrace: (a) A complete description of the remaining evidence of the origi- nal monument ; (6) A complete description of the new monument; (c) A complete description of the original accessories as identified; (d) A complete description of the new accessories; (e) A concise statement relating to the recovery of a corner based upon identified line trees, blazed lines, items of topography, or other calls of the field notes of the original survey, in the absence of evidence of the monument or its accessories; and, (/) A statement of fact relating to the relocation of an obliterated monument; or a statement of the determining features leading to the acceptance of a recognized local corner. 424. General titles (in addition to the regular page heading) will be inserted in the field notes of dependent resurveys to indicate the character of the resurvey, the technical record of which follows. Such titles will be inserted in the body of the field notes, as appro- priate, and will show the name of the original surveyor and the year in which the original survey was executed; as, for example: " Eeestablishment of the surveys executed by John B. Smith, U. S. Surveyor, in 1842," and additional memoranda will be added as appropriate, explana- tory of the method of control adopted in the restoration of one or more lost corners. 425. In addition to the usual showing of data upon the township plat, the plat of a dependent resurvey should carry a memorandum RESURVEYS. 289 for the information of the public to the effect (modified as special circumstances may warrant) that "This plat of the resurvey of T. , R. , delineates a retrace- ment and reestablishment of the lines of the original survey as shown upon the plat approved (date), in their true original position according to the best available evidence of the position of the orig- inal corners; all differences between the measurements shown on the original plat and those derived in the retracement have been distributed proportionally between accepted corners in accordance with surveying rules; reference will be made to the original plat for the showing of the areas and more detailed descriptions of the various smaller subdivisions." ADDITIONAL METHODS FOR THE PROTECTION OF BONA FIDE RIGHTS. 426. Referring to those cases where locally recognized corners are discordantly related to the original survey, it will be apparent that such corners can be employed only for the determination of the boundaries of claims where bona fide rights have been duly established which would otherwise be impaired by the resurvey under the same rule of good faith in the matter of location. Cases of this kind are found to be decidedly exceptional in the townships where dependent resurveys have been made, and such situations will be given particular attention in the preliminary examination and special instructions. In those instances when encountered, provi- sion will be made in the special instructions for a "metes-and- bounds " survey, as hereinafter outlined under the general subject of " independent " resurveys, unless an amendment of entry in con- formity with the lines of the resurvey will answer the particular requirements of the situation. In either case the surveyor will note the Manual text relating to metes-and-bounds surveys and amendment of entries (see sees. 434 to 452, inclusive). EXAMPLE. 427. A hypothetical example of a dependent resurvey follows in the text, wherein a showing of typical conditions will be presented. In this connection it will be observed that the application of the rules for the execution of a dependent resurvey is generally made with respect to the township as a unit. In this hypothetical case it is presumed that a sufficient number of original corners can be identified to enable the restoration of the township exteriors resulting in a satisfactory closure. Upon retracement of the interior lines, some evidence of the original survey is developed, also certain 290 MANUAL OF SURVEYING INSTRUCTIONS. recognized and acceptable corners. All claims are found to be conformable. The surveyor will proceed with the complete retracement of the interior section lines. In this process he will employ instrumental methods and make the measurements as provided in Chapter II. He will be guided by the suggestions given in Chapter V in regard to the search for evidence of the original survey, and beyond that he will devise his own methods in the search as the actual field conditions seem to warrant. Temporary reference stakes will be set where the original corners are not at once identified (though the use of local reference points will be unobjectionable). It will be assumed that a single system of reference stakes has been employ- ed, as this scheme lends itself more readily to theoretical discussion, as well as practical utility in the field, and allows the utmost freedom as to the order in which the retracements are made. Having completed the reestablishment of the township exteriors and the retracement of the interior lines, the surveyor will be con- cerned with the two primary considerations, heretofore discussed, which it is his duty to harmonize: First, the restoration of what the record purports to be original conditions; and, second, the protection of the bona fide rights of claimants in the matter of location. The first requirment must be fulfilled with reference to the evidence of the original survey, and the discovery and identification of actual original corners is paramount, bearing in mind that the development of a single additional original corner adds manifest conclusiveness to the work. These identified points when combined with those acceptably located constitute the general control. The second item, which does not directly affect the technical procedure, has been fully discussed hereinbefore. KEY TO DIAGRAM, FIG. 69. A. Identified original corner. B. Intersection of center lines of public crossroads, intended to be located at section corner and generally so recognized; accepted as best available evidence of corner. C and D. Identified original corners. E. Corner established by local surveyor; record shows proper application of the method of double proportionate measurement; generally recognized as correct posi- tion of corner; accepted on an equality with an identified original corner. F-M, inclusive. Identified original corners. N. Same as B. O. Identified original corner. P. Intersection of mean position of meridional and latitudinal blazed lines through virgin timber; age count on overgrowth qualifies for date of original survey. Q. Restored corner based upon control furnished by latitudinal position of blazed RESURVEYS. 291 S. Same as E. T. Position determined by location of improvements; point agrees approximately with the theoretical position and it is recognized by adjoining claimants; improve- ments would be adversely affected by change of point. U. Same as E. V and W. Same as T. A / j > ^ / 7 t f . . 19 IS to Q -)* ( P ' --4 U2-. J ) ---1 D>- ---I 2 - _ -. 14 9 7 3 1 J ---, /a 7- -- T 1 13 ( 5 1 U 5 1 1- < , >*--! A* 5--- 1 J 2 17 0- - - 2 /2 ^ I- < )? 2 2 ;...2 s 2 )_-,- ...i 16 9 2 3 ----? Q 7---- -r-2 ^ 6 : 1 8--- 3 | 3 2 3 3--- 3 \ 3 5 --.3 j k f O Employed forgenefo/ con fro/. + Theoretical position. Fig.69. X. Identified original corner. a. Duly restored by double porportionate measurement and thereafter employed for general control on an equality with an identified original corner. b-n, inclusive. Theoretical true line position, duly restored by single proportionate measurement. 292 MANUAL OF SURVEYING INSTRUCTIONS. METHOD. After completing all retracements and having determined upon the general control to be adopted, as indicated in the diagram and accom- panying key, the true lines of the dependent resurvey, beginning at the southeast corner of the township, will be reestablished as follows: SINGLE PROPORTIONATE MEASUREMENT. Lines: A-B, B-a, A-C, C-D, D-E, E-F, F-G, G-H, H-I, a-J, J-K, K-L, L-M, and M-I. DOUBLE PROPORTIONATE MEASUREMENT. Section corners: 1, f-N and b-F; 2, f-N and c-S; 3, O-P and d-X; 4, C-Q and b-F; 5, C-Q and c-S ; 6, C-Q and N-U; 7, C-Q and d-X ; 8, g-S and b-F; 9, U-n and d-X; 10, U-n and Q-G; 11, D-L and b-F; 12, D-L and V-i; 13, D-L and W-j; 14, D-L and d-X; 15, D-L and Q-G; 16, h-X and b-F; 17, h-X and V-i; 18, h-X and W-j; 19, X-M and Q-G. INTERIOR QUARTER-SECTION CORNERS. All missing interior quarter-section corners by single proportionate measurement on line between the adjoining section corners as above determined. FIELD DATA. The retracements develop the following data in regard to the relative position of certain points of control and the temporary stakes: Beginning at f, North, 40.00 chains, set temporary stake; 80.00 chains, set temporary stake; 120.00 chains, set temporary stake; 160.00 chains, set temporary stake; 200.00 chains, set temporary stake; 241.20 chains, fall 90 links W. of N.; meridional excess f-N= 1.20 chains=40 links per 80.00 chains. Beginning at b, West, 40.00 chains, set temporary stake; 80.46 chains, fall 20 links N. of temporary stake previously set; record of original survey shows length of line 80.22 chains; continue west, etc., to F; latitudinal deficiency b-F=84 links=14 links per 80.00 chains. Beginning at 2 (temporary stake), East, 40.00 chains, set tempo- rary stake; 80.82 chains, fall 44 links S. of c; record of original sur- vey shows length of line 79.90 chains; run west from temporary stake at 2 on similar plan; latitudinal excess c-S =66 links=22 links per 80.00 chains. CALCULATIONS. The adjustments of the temporary stakes to true line position, ' RESURVEYS. BETWEEN SECTIONS 35 AND 36. 293 Memo. Course. Dis- tance. N. s. E. W. Retracement f-1 North 80.00 80.00 Adjustment at 1 for meridional .40 excess. Adjustment at 1 fo'r latitudinal * * 0.38 deficiency, 80.46 (80.22-0. 14-). True line f-1 N 016' E. 80.40 80.40 .38 Adjustment at f Too" .00 Adjustment at 1 .40 .38 Adjustment at ^ sec. cor. (mean) . .20 .19 BETWEEN SECTIONS 25 AND 26. Adjustment at 1 from true to 0.40 0.38 temporary. Retracement 1-2., North. 80.00 80.00 Adjustment at 2 for meridional .80 excess. Adjustment at 2 for latitudinal 0.70 excess, 80. 82 (79.90 -fO.22). 80.80 .40 .70 .38 .40 .38 True line 1-2 N. 14' E. 80.40 80.40 .32 Adjustment at 1 .40 - .38 Adjustment at 2. . .80 .70 Adjustment at s&c. cor. (mean) . 1.20 .60 1.08 .54 BETWEEN SECTIONS 23 AND 24. Adjustment at 2 from true to 0.80 0.70 temporary. Retracement 2-N North. 81.20 81.20 Random line to N . . East .90 r 0.90 81.20 .80 .90 .70 .80 .70 True line 2 N N 9' E 80 40 80 40 .20 Adjustment at 2. .80 .70 Adjustment from 80.00 ch. point on random to N. 1.20 .90 2.00 1.60 Adjustment at i sec. cor. (mean) . 1.00 .80 294 MANUAL OF SURVEYING INSTRUCTIONS. BETWEEN SECTIONS 25 AND 36. Memo. Course. Dis- tance. N. S. E. W. Retracement b-1 West. 80.46 80 46 Random line to temporary stake 0.20 atl. Adjustment at 1 temporary to 0.40 0.38 true. .40 20 38 80.46 .20 .38 True line b-1 N. 89 51' W 80.08 .20 80.08 Adjustment at b .00 .00 Adjustment from 80.00 ch. point .20 .46 on random to temporary stake atl. Adjustment at 1 temporary to .40 .38 true. .40 .20 .38 .46 .20 .38 .20 .08 Adjustment at J sec. cor. (mean) . .10 .04 BETWEEN SECTIONS 24 AND 25. c to random line. 0.44 Retracennent c-2 (reversed) West. 80.82 80.82 Adjustment at 2 tpTnporp.ry to 0.80 0.70 true. .80 .44 .70 80.82 .44 .70 True line c-2 N. 89 45' W. 80.12 .36 80.12 Adjustment from 80.00 ch. point .44 .82 on random to c. Adjustment at 2 temporary to .80 .70 true. 1.24 1.52 Adjustment at ^ sec cor (mean) .62 .76 THE INDEPENDENT RESURVEY. 428. An independent resurvey is an official re-subdivision of the public lands distinct from the original survey which it is designed to supersede. The independent resurvey is accomplished by three distinct steps: (a) The reestablishment of the outboundaries of the lands subject to resurvey, following the method of a dependent resurvey; RESURVEYS. 295 (6) The segregation of lands embraced in any valid claim where the initial steps have been taken looking to the disposal of the title of the United States based upon the former approved plat; and, (c) New exterior, subdivisional and meander lines as necessary, established upon a new regular plan, which, for every purpose of identification and description of the public lands involved, becomes the prevailing survey. REESTABLISHMENT OF OUTBOUNDARIES. 429. The limiting boundaries of the lands subject to independent resurvey must agree with the previously established and identified exterior or subdivisional lines of the approved original surveys. In order to qualify as a suitable limiting boundary as aforementioned, a line of the accepted established surveys will be selected which can be conclusively identified (by existing original or properly re- stored corners) in one position to the exclusion of all others and which by its known position adequately protects all rights (located in good faith as hereinbefore defined) based upon any township plat showing subdivisions of the public lands adjacent to said boundary. Such outboundaries of the lands to be resurveyed by the independent process must necessarily be retraced and reestablished in their true original position. The lands upon one side of such outboundary are to be re-subdivided upon a new plan, while upon the opposite side of such line the original subdivisions are to be strictly maintained and none of the original conditions are to be disturbed. 430. The outboundaries are generally selected along the locus of the previously established township exteriors where the existing evidence gives positive proof of the location of the original survey, and where conditions on the ground are harmoniously related to the record of said original survey. In special cases certain section lines may fully qualify as suitable lines to mark the limit of the inde- pendent resurvey; such section lines will then be duly retraced and reestablished in their true original position. Particular attention will be given to this very important subject at the time when the field examination is made with a view to maintaining the original survey as far as consistent. 431. In those cases where a proper limiting boundary can not be secured without involving the necessity for the inclusion in the group of a greater number of townships than administratively prac- ticable to execute in one assignment, the necessity may arise for the 296 MANUAL OF SURVEYING INSTRUCTIONS. extension of tract segregations (as hereinafter outlined) into a town- ship ungrouped for resurvey. In such cases, under specific authority of the General Land Office, any tract found to extend across such group outboundary will be segregated in full, whether or not the tract was originally described as in the township to be resurveyed, and the necessary steps will thereupon be taken by the General Land Office in the matter of suspension of the lands in the adjoining township from further disposal and of additional investi- gations with a view to a resurvey of all or a portion of the said adjoining township. (See second rule, sec. 445.) 432. The special instructions will show specifically what lines have been selected to limit the independent resurvey, and the sur- veyor engaged in the execution of such resurvey will proceed with the retracement and reestablishment of said outboundaries as a con- dition precedent to beginning the independent resurvey. 433. Where the new lines of the independent resurvey are not to be initiated or closed upon the restored original corners of the rees- tablished outboundaries of the independent resurvey, said restored corners will be marked only with reference to the township, range and section to which they will thenceforth relate, and new regular corners of minimum control will be established as necessary to govern the lines of the independent resurvey, all as provided in sec. 164, Chapter III. During the preliminary stages of the resurvey there will often be more or less doubt as to whether an old corner will retain its former control or will have to be altered, and until this uncer- tainty has been removed the marking of a corner and its accessories should be deferred. The monumentation will follow the final deter- mination of the future significance of each point. Where an old point is to be perpetuated merely to control the former alinement, but not the corner of a subdivision, its future significance will be that of an "angle point" only and the monument and its accessories will be marked accordingly. METES- AND-BOUNDS SURVEY OF PRIVATE CLAIMS. 434. After the reestablishment of the outboundaries of the lands subject to independent resurvey has been accomplished in accord- ance with the requirements of the special instructions, the surveyor's attention will be directed to the segregation or marking out of all duly entered, selected, reserved (in certain cases), granted, or patented RESURVEYS. lands whose description may be based upon the former approved plat, and which can not be conformed to the lines of the resurvey. 435. A status diagram will be furnished to the surveyor showing all patented lands, valid entries, school sections, and other land grants, and all other disposals, reservations, or selections of lands whose position and description are based upon the original survey and plat, and whose boundaries can not legally be disturbed. In every case the various tracts shown upon the status diagram will be protected either by individual u metes-and-bounds" survey or by the assignment of appropriate subdivisions of the resurvey in case the latter lines (new section lines, or center lines of sections or quarter sections) are found to coincide or approximately agree with the boundaries of said tracts. 436. It is not to be understood that the metes-and-bounds survey of private claims must be completed before beginning the projection of the new lines of the independent resurvey. It has merely been deemed logical to consider the subject of the tract segregations in advance of the question of the establishment of new lines. The fact is that surveyors will find it expedient to carry both branches of the survey along together in the locality of the camp or other field head- quarters. 437. The jurisdiction of the General Land Office, the limit of the authority of the surveyor, and the bona fide rights of claimants, where entered or patented lands are involved, remain absolutely the same whether the resurvey is to be made upon the dependent or independent plan. Thus where the independent type of resurvey has been adopted as more feasible, identified corners of the original survey in the immediate vicinity of lands to be segregated will be employed for the control of the location of such lands? The question of the good faith of the entrymaii will in every case be fully con- sidered, as previously outlined in this chapter, and where the evi- dence of the original survey is so obliterated that a charge of a lack of good faith can not be brought against an entrymaii whose claim, boundaries may differ from a theoretical location determined by more rigid surveying rules, the position of the improvements is to be regarded as the best available evidence of the original position of the claim, and the same will be employed as far as consistent for the control of the location of the boundaries of such claim. 438. Where there is sufficient evidence of the original survey, the identification of the areas to be segregated, resulting from the sub- 55465 19 20. 298 MANUAL OF SURVEYING INSTRUCTIONS. division of the original sections, will proceed in accordance with the provisions of Chapters III and V, and every corner or angle point of each tract as thus located will be marked upon the ground. 489. Where the surveyor can not point out, by suitable identi- fication of the original surveys, the definite location of an entry "based upon the former approved plat, the claimant or owner of such lands will be consulted as to the position of his boundary lines. The boundaries of the private claim, so determined, will be fixed, as between the private and public lands, subject to the official accept- ance of the resurvey. Where dispute is encountered in regard to the adjustment of the line between adjoining patented tracts, each acceptably located under the rules already laid down, which can not be reconciled or suitably disposed of by surveying process, the tracts will be surveyed in conflict, as hereinafter provided, and so shown on the resurvey plat; the questions arising out of such conflict will be given administrative review with the field notes of the resurvey. 440. The owner of an unidentified claim will be called upon to indicate the boundary lines thereof if possible, and in this connec- tion, should occasion arise, the surveyor will explain the manner of adjusting differences between adjoining claims and what will con- stitute an acceptable location of a claim. The latter condition demands a form agreeing with the original entry, approximately regular boundaries, an area not widely inconsistent with that shown upon the original plat, and a location as nearly correct as may be expected from the existing evidence of the original survey, without overlapping into an adjoining township not subject to resurvey, except as provided in sec. 431. In every case where the out- boundaries of the lands subject to ''independent resurvey" have been reestablished by the "dependent" or "restorative" plan, the subdivisions of a tract situated and originally described as along or upon the opposite sides of such outboundary must agree with the line reestablished and harmonize in relative position. 441. In the execution of an independent resurvey, therefore, the identity of each tract to be segregated therein or indicated by conformation to the lines of the resurvey, whether patented or unpatented, must be maintained, and the surveyor will not be allowed to change materially the configuration of a tract as shown by its original description in order to indemnify the owner thereof against deficiencies in area, to eliminate conflicts between entries, RESURVEYS. 299 or for any other purpose. If improvements have been located in good faith, the segregation survey should be so executed, or the conformation to the lines of the resurvey so indicated, as to cover as nearly as possible these improvements and at the same time maintain substantially the form of the entry as originally described. No departure from this rule will be allowed. 442. The question of amendment of entries for the purpose of permitting adjustments in terms of the resurvey involving lands not included within the original tract is a matter for the adjudica- tion of the General Land Office after the resurvey has been accepted and the plats thereof filed in the local land office. 443. In case of absentee owners an attempt should be made to establish communication, if necessary, in order that the claimant may point out the lands subject to a rnetes-and-bounds survey. If the owner can not be found and thero is no visible indication, such as a boundary fence, of the location of the limits of a claim, the surveyor will exercise the alternative of locating the claim from the nearest original point of control or from a point of a neighboring claim, or of assigning to the entered or patented lands the appropri- ate subdivisions of the resurvey, all subject to the principles here- inbefore set forth. The controlling factors in such locations will be based upon the individual and neighborhood improvements (such as buildings, wells, springs of water, cultivated lands, public roads, fences, corners of recognized private surveys, etc.) which may indi- cate the evident intention of the entryman or patentee as to the position of his land. 444. Each non-conformable valid claim in a township will be given a serial tract number, commencing with No. 37 in the smallest numbered and entered section of the original plat, progressing through the township in the order in which lots and sections are numbered. A tract number will be used but once in a township, and if any tract lies partly in two or more townships subject to resurvey the number applied to the tract in the first township resurveyed will not be used for other tracts in the adjoining town- ship. 445. The following rules will be observed in the execution of the metes-and-bounds survey of all specially designated tracts: 1st. Each claim, acceptably located, but at variance with the lines of the resurvey, will be surveyed and monumented at each angle point. 300 MANUAL OF SURVEYING INSTRUCTIONS. 2d. Where a portion of a claim is originally described as in a town- ship not subject to resurvey, such portion of the claim will not be surveyed by metes and bounds, provided the limiting boundary is found to qualify as set forth in sec. 429. The portion of the claim originally described as in the township to be resurveyed should ordinarily be defined in a position (either by segregation or confor- mation to the lines of the resurvey) which is properly related to the identified or restored corners on the limiting boundary. (See sec. 431.) 3d. Where the boundaries of a claim are unacceptably located as pointed out by the claimant, the surveyor will proceed with a proper survey of the tract in accordance with rules already stated which will result in a suitable relation to the original survey, and the corners of the tract as thus located will be monumented. If the claimant protests against such location, the surveyor will request that the pro- test be made in writing (to be submitted with the returns of the re- survey), and will thereupon make an accurate connection with the corners of the claim as unacceptably located, to be made the subject of a complete report by the surveyor in his field notes, reviewing the facts with reference to the question of location. As a further protection to an entryman thus unacceptably located see sec. 455. 4th. Where, through a compliance by the surveyor with the general rules above laid down, the metes-and-bounds segregation of a claim (or the conformation thereof to the lines of the resurvey) within the field of an independent resurvey (or the related subdivisions within the field of a dependent resurvey) fails to cover any or all of the lands, occupied, improved or claimed by the entryman, patentee or present owner, and the latter indicates a desire to amend his entry, a full report will be made by the surveyor in his field notes, describing therein the subdivisions actually occupied and sought to be acquired under the amended entry, but which are not covered by the tract as surveyed, all looking to the protection of the title to the lands actually earned. 1 5th. Where it so happens that the regular quarter-quarter sections embraced within a claim fall in approximately the same position as the regular quarter-quarter sections of the resurvey, and the entry- man or patentee indicates a desire to conform his claim to the re- survey, and no apparent objection is found by the surveyor, the facts will be stated in the field notes, and the claim will be so indi- 1 See current circular relating to amendment of entries. RESURVEYS. 301 cated upon the resurvey plat. Under this circumstance the metes- and-bounds survey of the tract will be omitted. However, where any tract whose original description includes any fractional lot, or where any part of a tract falls upon any fractional lot of the resurvey, the tracts will be segregated as a whole by metes-and-bounds survey, even though some or all of the lines of the tract may coincide with certain subdivisional lines of the resurvey. 6th. Conflicting tracts, each acceptably located, will be surveyed and monumented, and conflict shown upon the resurvey plat. Each intersection of conflicting boundaries will be determined upon the ground and recorded in the field notes. 7th. The angle points of a tract will be designated by serial num- bers beginning with No. 1 at the northeast corner, and proceeding around the claim, running westerly from the initial corner. An angle point may be common to one, two, three or four tracts, and will be monumented and marked as provided in Chapter IV; as for example: r3 T26N R ' 7E T26NRI7E TR 37 S 14 - AP AP 4 TR 38 AP I TR 45 AP 2 AP I TR 46 TR 38 AP 2 TR 37 919 1919 8th. No accessories will be required with the monuments at the angle points of the metes-and-bounds survey. 446. The proper supervising officer will furnish the surveyor with an abstract of the valid entries, selections, reservations, patents, and grants, based upon the original plat of any township (or portion thereof) subject to resurvey, and the said resurvey can not be re- garded as complete until each and every claim described in said abstract of entries (and shown on the status diagram) as in the town- ship to be resurveyed has received full protection in the matter of location. Aside from those disposals described as in the township to be resurveyed, there will also be furnished to the surveyor, as a matter of information, the status of all claims in the adjacent sec- tions of all adjoining townships ungrouped for resurvey. The abstract will be included with the other data to accompany the writ- ten special instructions providing for a resurvey. 447. The field notes of the metes-and-bounds survey of each valid claim will be preceded by a copy of the abstract of entry thereof. A brief statement will then follow in each instance (or 302 MANUAL OF SURVEYING INSTRUCTIONS. with suitable reference), concerning the principal factors controlling the location of the particular tract, and whether or not the claimant was consulted, or communicated with, in the matter of the identifi- cation of the boundaries of his claim. The statement should be clear as to whether the location of a claim, shown either as a tract segregation or as conforming to the lines of the resurvey, was controlled by improvements alone, or by one or more identified corners of the original survey, nearby or remotely located, or by its relation to adjoining tracts. In case all of the tract segregations within a township can be covered by one general statement, the same should appear at the beginning of the field notes of the metes-and- bounds surveys. The field notes should be made to account for each and every tract shown upon the status diagram. 448. All claims should be accounted for on the resurvey plat, and all will be shown either as segregated tracts or as conforming to the lines of the resurvey, as the case may be, with outline indicated by heavy black lines. An exception to this rule will be made in those rare cases where all the claims within a township have been conformed to the lines of the resurvey under their original description, in which event a statement may be made on the margin of the plat that * ' All claims originally described as in this township are intended to conform to the lines of the resurvey under their original description." 449. As a further safeguard that the returns of independent resurveys may be conclusive in the matter of the significance of the tract segregations, the plats thereof will show a statement that 4 ' All tract segregations shown hereon represent the position and form of said tracts under the original description as referred to the original survey, located as such on the ground according to the best available evidence of their true position.'* 450. The above statement will be modified if one or more of all the claims shown on the status diagram are conformed to the lines of the resurvey, either under the original description or by different legal subdivisions, as follows: ' l All tract segregations shown hereon and all other claims shown to conform to the lines of the resurvey. whether by the original or new legal subdivisions, represent the position and form of said tracts un- der the original description as referred to the original survey, located as such on the ground according to the best available evidence of their true position . " RESURVEYS. 303 451. The projection and measurement of the lines of the metes- and-bounds survey and the technical record in respect to the same will conform to the usual practice in regular surveys. While the mapping of important items of topography and valuable permanent improvements will be given attention with regard to this feature of the resurvey plat, yet it will be apparent that the amount of data to be shown in connection with the metes-and-bounds surveys makes it impossible, at the usual scale, to show objects of little relative importance. This class of memoranda taken during the progress of the work will not be required in the field notes of metes-and-bounds surveys. 452. At least one angle point of each tract survey will be definitely connected with one of the regular corners of the resurvey, and where lines of claims are intersected by lines of the resurvey a connection will be made from the point of intersection to the nearest claim cor- ner and recorded in the field notes of the regular section line. The latter will be considered a satisfactory connection to all adjoining claims located within the interior of either section. Where an ex- tensive system of tract segregations has been surveyed, the interior tracts of the block will not require individual reference connections. The establishment of closing corners on the regular line when entering or leaving public land will conform to the general practice in this respect as provided in sec. 191, Chapter III. THE PROJECTION OP NEW LINES. 453. The peculiar conditions of the situation which necessitate an independent resurvey render it impossible to formulate general rules suited to all cases. Experience has demonstrated the neces- sity for giving deliberate attention to the unique problems of subdi- vision which are to be found in each definite example. The general practice is to secure a surveyor's report of the actual conditions involved in a particular independent resurvey, upon consideration of which there may be devised the best plan for a re-subdivision of the .vacant public lands, and the latter will be set forth in the special instructions. The possibility of placing the regular lines of the independent resurvey so as to obtain maximum agreement with the position of the boundaries of conformable claims will be fully con- sidered with a view to eliminating or reducing the necessity for tract Segregations, if possible, where this can be accomplished in harmony with the rules previously outlined. The examiner's 304 MANUAL OF SURVEYING INSTRUCTIONS. recommendations in these matters should be explicit and responsive to his special advantages in the opportunity of working out the tech- nical problem while on the ground. 454. A problem involving the re-subdivision of vacant public lands, as in an independent resurvey, should be approached in the same way as practically all problems in fragmentary subdivision, though the independent resurvey may at times involve the re-sub- division of a group of many townships wherein ail conditions, except perhaps with relation to the tract segregation surveys, may be comparatively regular. First attention will be given to completing the new township exteriors which are to be independently resur- veyed after having reestablished the outboundaries of the group on the dependent plan. The new exteriors will be carried forward and completed in harmony with the rules set forth in Chapter III for the establishment of original surveys. The new section lines will be run out and marked as in regular or fragmentary subdivision as the situation may be and new meander lines will be run as required. The new exterior and subdivisional lines will usually be extended across small blocks of tract segregation surveys, noting connections as previously stated, and in such cases the new lines and corners will be fully monumented regardless of the fact that some points will fall within the tract segregation surveys. The latter points are required in their usual function to determine the subdivision of the public lands affected. 455. A general exception to the rule of extending the lines of the independent resurvey across the tract segregations will be made in those townships or portions thereof so densely covered by private claims that the remaining parcels of public lands may be as well or better identified and described for expediency with reference to isolated tract numbers. In such cases closing corners will be re- quired on the regular lines when entering or leaving public land. The regular lines may or may not be extended as blank lines across the tract segregations, according to the plan of running the new section lines of the resurvey. Where this method is employed it will be necessary to assign tract numbers to the vacant parcels of public land and to mark the angle points thereof accordingly. Where a parcel of vacant public land is to be identified on this plan, such vacant tracts will be surveyed by metes and bounds in accordance with the usual rules. Rare cases may arise where it will be deemed expedient to segregate by metes-and-bounds survey certain quarter- RESURVEYS. 306 quarter sections of vacant lands in accordance with the system of the original survey as indicated by adjoining tract segregations for the purpose of affording a better basis of disposal or for amendment of entries. Such segregations will hot be made unless it is con- clusively shown by the surveyor that the fractional lots and regular quarter-quarter sections of the resurvey are inadequate as a basis of disposal under existing conditions of occupancy on the part of settlers or of entrymen who may propose to amend. The special instructions will be made as explicit as possible in these details, which will be determined upon when the plan of the resurvey is under consideration by the supervising officer. 456. Where a section of the resurvey is invaded by patented tract segregations, but not by unpatented entries or selections, the lotting of the public lands will be carried out in accordance with the usual plan of lotting within fractional sections as outlined in Chapter III. The numbering of the fractional lots will begin with the number next higher than the highest number employed in the section of the original survey which bears the same township, range and section number. This plan is intended to avoid any possible confusion which might arise from a duplication in the use of the same lot numbers. 457. A departure from the usual rule for lotting is necessary in order to provide suitable descriptions within unpatented entries and selections where such tract segregations may be subject to relin- quishment or cancellation, also in other cases, to facilitate a subdi- vision of isolated tracts of public lands surveyed by metes and bounds. Two methods have been found available, each one better suited to particular situations. Neither method involves any change in the instructions for the field procedure heretofore laid down. The discussion of the merits of the two methods and the examples of their use are better adapted to the text of Chapter IX, where the subject will be found in connection with other details to be shown upon the resurvey plats. 458. The general requirements of Chapters II, III and IV will be fully observed in every respect throughout the execution of the independent resurvey and in the technical record thereof. General titles (in addition to the regular page heading) will be inserted in the field notes to indicate clearly the character of the independent resurvey, the technical record of which follows; such titles will be 306 MANUAL OF SURVEYING INSTRUCTIONS. inserted in the body of the field notes, as appropriate, and will show the full significance of all lines; as for example: (a) " Metes-and-bounds survey of private claims as originally lo- cated in accordance with the 'survey executed by John B. Smith, U. S. Surveyor, in 1842;" and (b) " Independent resurvey, superseding the survey executed by John B. Smith, U. S. Surveyor, in 1842." 459. All monuments of the original survey, not otherwise re- ported upon, when traces thereof have been found, will be con- nected by course and distance with a corner of the resurvey, and such connection and a description of the traces of the original corner as identified will be recorded in the field notes of the resurvey. A useless monument will be destroyed after the point is found to be no longer needed for the survey of a claim of any kind whose loca- tion may in any way depend upon such monument. (See sec. 163, Chapter III.) 460. Further exemplification of the approved practices incident to the successive field steps and preparation of the field notes and resurvey plats will be found in the chapters that follow. o UNIVEESITY OF CALIFOENLA LIBEAEY BEEKELEY THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW Books not returned on time are subject to a fine of 50c per volume after the third day overdue, increasing to $1.00 per volume after the sixth day. Books not in demand .may be renewed if application is made before expiration of loan period. 1924 DEC 15 ; 50w-7,'16 UNIVERSITY OF CALIFORNIA LIBRARY