points 275 (399) Analytical ..... (397) Geometrical Solution 275 | (400) Maritime Surveying PART VII. OBSTACLES IN ANGULAR SURVEYING. CHAPTER I. Perpendiculars and Parallels. (402) To erect a perpendicular to a line at a given point..... (403) To erect a perpendicular to an inaccessible line, at a given point of it 280 (404) To let fall a perpendicular to a line, from a given point..... (405) To let fall a perpendicular to a line, from an inaccessible point... (406) To let fall a perpendicular to an inaccessible line from a given point.. 281 (407) To trace a line through a given point parallel to a given line 279 280 280 281 (408) To trace a line through a given point parallel to an inaccessible line.. 281 AETIOLE CHAPTER II. Obstacles to Alinement. (409) General method (410) By perpendiculars A. To prolong a line 282 PAGE 282 (413) When the line to be prolonged is inaccessible... 283 (411) By an equilateral triangle. 282 (414) To prolong a line with only an angular instrument... 283 (412) By triangulation.. 283 (421) Previous means .......... ......... ... 287 . 287 287 | (423) A broken base B. When one end of the line is inaccessible C. When both ends of the line are inaccessible........ 290 (433) When no point can be found from which both ends can be seen 288 289 290 $92 £92 (434) To interpolate a base CHAPTER IV. To Supply Omissions. (439) General statement. 297 (440) CASE 1. When the length and bearing of any one side are wanting.... 298 CASE 2. When the length of one side and the bearing of another are wanting When the deficient sides are separated from each other. 299 299 (444) CASE 3. When the lengths of two sides are wanting. 800 300 (445) (4.16) When the deficient sides are separated from each other 301 301 447) CASE 4 When the bearings of two sides are wanting. 302 802 (448) When the deficient sides are separated from each other..... 802 (459) General principles..... (460) Distances by pacing 311. (463) Distances by sound.................... 318 311 (464) Angles...... (461) Distances by visual angles. 312 | (465) Methods of operation. (462) Distances by visibility.... 313 814 314 PART X. MAPPING. (466) Necessity (467) Stretching the paper. (468) Copying by tracing.. 316 (475) 317 469) 66 on tracing-paper.. 817 (476) (477) CHAPTER I. Copying Plats. 316 | (474) Reducing by squares...... 819 320 by proportional 318 (478) Enlarging plats by squares 319 ...... 330 331 332 PART XI. LAYING OUT, PARTING OFF, AND DIVIDING UP LAND. ARTICLE (491) Its object CHAPTER I. Laying out Land. (492) To lay out squares. (500) Its object.. ...... (501) To part off a rectangle.... 330 (496) To lay out circles 332 333 (498) Land sold for taxes.. 333 (499) New countries 334 CHAPTER II. Parting off Land. ... 331 A. By a line parallel to a side. 335 (502) (503) 66 a parallelogram 335 E. By a line passing through a given point within the field. (535) By lines passing through a point within the triangle (540) Do, 851 the point being to be found.... 353 Do. (541) 352 354 Division of Rectangles. (543) By lines parallel to a side.... 354 |