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
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
(422) By triangulation

..........

.........

... 287

. 287

287 | (423) A broken base
287 (424) By angles to known points. 288

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
(435) From angles to two points.. 293
(436) From angles to three points 293
(437) From angles to four points. 294
438) Problem of the eight points 296

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.
Otherwise by changing the meridian

299

299

(444)

CASE 3. When the lengths of two sides are wanting.
When the deficient sides adjoin each other.

800

300

(445)

(4.16)

When the deficient sides are separated from each other
Otherwise by changing the meridian.....

301

301

447)

CASE 4 When the bearings of two sides are wanting.
When the deficient sides adjoin each other

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)
by transfer-paper. 317
by punctures
by intersections.. 318

(477)

CHAPTER I. Copying Plats.

316 | (474) Reducing by squares...... 819

320

by proportional
scales....
by a pantagraph 321
by a camera luci-

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.
(493) To lay out rectangles
(494) To lay out triangles

(500) Its object..

......

(501) To part off a rectangle....

330 (496) To lay out circles
(497) Town lots.

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)
the point to be equidistant from the angles
(512) By the shortest possible line......

352

354

Division of Rectangles.

(543) By lines parallel to a side....

354