Outline of the Method of Conducting a Trigonometrical Survey, for the Formation of Geographical and Topographical Maps and Plans

Distances in Feet.

Showing the difference of the Apparent and True Level in Feet, and Decimal parts of Feet, for Distances in Feet, Chains, and Miles.

Correction in Feet.

CORRECTIONS FOR CURVATURE AND REFRACTION.

TABLE XVI.

8.000667 0009500572 6
8.50075300108 00645 7

100 00024 00004 00020 1.00001000001 00009
150 00054 0000800046 1.500024 00003 00021
20000096 00013 00083 2.000042 00006 00036
25000149 00021 00128 2.500065 0000900056 1
300 00215 00031 00184 30 00094 00013 00081 14
35000293 00042 00251 3.5 00128 00018 00110 2
40000383 0005500328 40 00167 00024 00143 24
450 00484 00069 00415 4.50021100030 00181 3
500 00598 00085 00513 50 00261 00037 00224 31
55000724 0010300621 5.5 00315 00045 00270
60000861 00123 00738 6.000375 00054 00321 4
65001010 00144 00866 6.50044000063 00377 5
700 01172 00167 01005 70 0051100073 00438 5
750 01345 00192 01153 7.5005860008400502 6
800 01531 00219 01312
85001728 00247 01481
900 01938 00277 01661 90 00844 00121 00723 7
950021590030801851 9.50094000134 00806 8
100002392 00333 02059 10-0 01042 00149 00893 8
105002638 00377 02261 10.50114900164 00985 9
1100 0289500414 02481 11-001261 00180 01081 9
115003164 00452 02712 11.5 01378 00197 01181 10
1200 03445 00492 02953 12.00150100214 01287 11
1250 037380053403204 12.5 0162800233 01395 12
130004043 00578 03465 13.00176100252 01509 13
1350043610062303738 13.5 01899-00271 01628 14
140004689 00670 04019 14-0 02043 00292
1450050300071904311 14.5 0219100313 01878 16
150005383 00769 04614 15.002345 00335 02010 17
1550 05748 00821 04927 15.5 02504 00358 02146 18
1600 0612500875 05250 16.002668 00381 02287 19
1650 065140093105583 16.5 02837-00405 02432 20
1700069140098805926 17.00301200430 02582
175007327 0104706280 17.5 03192 00456 02736
1800 077520110706645 18.00337700482 02895
185008188 01170 07018 18-5035670050903058
190008637 01234 07403 19 003762 0053703225
195009098 01300 07798 19-5039630056603397
2000 09570 0136708203 20-0 04169 00596 03573

01751 15

⚫0417

⚫0357

•0060 •1668 ⚫0238

•1430

•3752 •0536

⚫3216

•6670

⚫0953

⚫5717

1.5008

•2144

1.2864

•3811 2.2869

2.6680
4.1688
6.0030

.5955

3.5733

•8561

5.1469

1.1673

7.0035

1.5246

9.1474

8.1708
10.6720
13.5468 1.9295
16.6750 2.3821
20-1769 2-8824

11.5773

14.2929 17.2945 24.0120 3.4303 20.5817 28.1809 4.0258 24.1551 32.6830 4.6690 28.0143 37-5190 5-3599 32-1591 42.6880 6·0997 36.5883 48-1910 6.8844 41.3066 54.0270 7.7181 46-3089 60-1971 8.5996 51.5975 66-7000 9.5286 57-1714 80-7070 11-5296 69-1774 96.0480 13.7211 82.3269 112-7230 16-1033 96.6197 130-7320 18.6760 112.0560 150-0750 21-4393 128.6357 170-7520 24-3931 146-3589 192-7630 27.5376 165.2254 216-1086 30.8727 185.2359 240-7870 34-3981 206-3889 266-8000 38.1143 228-6857

Angle.

REDUCTION IN LINKS AND DECIMALS UPON EACH CHAIN'S LENGTH FOR THE FOLLOWING VERTICAL ANGLES.

O

30

3 15

3 30

3 45

4 0

4 15

4 30

4 45

5 0

5 15

5 30

5 45

6 0

6 15

6 30

645

7 0

Angle.

O /

0 15

0 30

0 45

1 0

1 15

1 30

1 45

2 0

2 15 230

245

Reduc-
tion.

3 0

3 15

3 28

Angle.

19

18

17

O 1

7 15

730

745

8 0

8 15

8 30

8 45

0

9 15

9 30

9 45

10 0

10 15

10 30

10 45

11 0

11 15

11 30

Angle.

O

3 35

3 49

4 6

4 24

4 45

5 0

5 12

5 27

542

TABLE XVII.

6 0

6 21

6 43

7 7
7 36

Reduc

tion.

•800

•856

913

•973

1.035

1.098

1.164

1.231

1.300

1.371

1.444

1.519

1.596

1.675

1.755

1.837

1.921
2.008

RATIO OF SLOPES FOR THE FOLLOWING VERTICAL ANGLES.

To one perpendicular.

16

15

14

13

12

111

11

TABLE XVIII.

Angle.

8

O

"

11 45

12 0

12 15

12 30

12 45

13 0

13 15

13 30

13 45

14 0

14 15

14 30

14 45

15 0

15 15

15 30

15 45

Angle.

O

/

8 8

8 45

Reduc-
tion.

9 27

9 52 10 18

10 47

11 19

11 53

12 32

13 15

14 2

14 55

15 56
17 6

2.095

2.185

2.277

2.370

2.466

2.553

2.662

2.763

2.866

2.970

3.077

3.185

3.295

3.407

3.521

3.637

3.754

Angle.

O

/

16 0

16 15

16 30

16 45

17

17 15

17 30

17 45

18 0

18 15

18 30

18 45

19 0

19 15

19 30

19 45

20 0

Angle.

Reduction.

O

/

18 26
19 59

21 48

23 58

26 34

29 44
33 42

38 40

45 0

53 8

63 28

75 58

78 41

COMPARATIVE SCALE OF FAHRENHEIT'S, REAUMUR'S, AND THE CENTESIMAL THERMOMETERS.

Fah. Reau. Cent. Fah. Reau. Cent. Fah. Reau. Cent. Fah. Reau.

+

1

2

3

4

"1

14.2 17.8 25

13.8

17.2

26

13.3

16.7

27

12.9

16.1

28

1.8

12.5 15.6

29 1.3

22222

13.3

23

24

12.8

15

7.6

9.4 40

16 7.1 8.9 41

//

3.1

2.7

2.2

17 6.7 8.3 42

18

6.2 7.8

43 19 5.8 7.2 44

0.9

0.4

10 9.8 12.2

35

1.3

11 9.3 11.7 36 1.8 12 8.9 11.1 37 2.2 13 8.4 10.6

38

2.7

14 8.0 10.0

39

3.1

0.0

34 0.9

+

Fahrenheit
Reaumur

Centigrade

33 0.4 0.6

3.6

4.0

4.4

4.9

5.3

FOR

TABLE XIX.

5.8

6.2

6.7

7.1

"1

3.9

3.3

2.8

2.2

1.7

1.1

955949

0.6

0.0

1.1

O

"/

50 8.0 10.0

75 19.1

51

8.4

10.6

76

19.6

52

8.9

11.1 77

20.0

53

9.3

11.7 78

20.4

54 9.8

12.2 79

20.9

55

60 12.4

61

2.8 62

12.9
13.3
13.8

3.3

63

3.9 64

14.2

+ 32

༄ཆ། ཐ ཁྱ་

4.4

65

5.0 66

5.6

67

6.1

68

6.7

69

10.2

56 10.7

11.1

57

=

58 11.6

12.0

20 5.3

6.7

45

7.2

70

16.9

21.1

95 28.0 35.0

21

4.9

6.1 46

7.8

71

17.3

4.4 5.6 47

8.3

72 17.8

21.7 96 28.4 35.6 22.2 97 28.9 36.1 98 29.3 36.7

8.9

73 18.2

22.8

4.0 5.0 48
3.6 4.4 49 7.6 9.4 74 18.7 23.3

99 29.8

37.2

The following formula will serve for the comparison of these Thermometers.

=

14.7

15.1

15.6

16.0

16.4

=

12.8

13.3

13.9

R+ 32

R

32) 32)

C

Freezing point.
32°

80 21.3

81 21.8

82 22.2

14.4 83 22.7
15.0 84 23.1

15.6 85

16.1 86
16.7 87
17.2 88
17.8 89

Cent.

+

"1

23.9

24.4

25.0

25.6

26.1

26.7

27.2

27.8

23.6

29.4

30.0

24.0
24.4 30.6
24.9 31.1
25.3 31.7

28.3

28.9

0

The Logarithms answering to every degree of the graduations of the above Thermometers will be found at page 296, vol. i., of Dr. Pearson's "Practical Astronomy."

English.

COMPARATIVE SCALE OF BAROMETERS.

Inches.

29.0

29.1

29.2

29.3

29.4

29.5

29.6

29.7

29.8

29.9

30.0

30.1

30.2

30.3

30.4

30.5

30.6

30.7

30.8

30.9

31.0

TABLE XX.

28

0.66

1.79

2.91

4.04

5.16

6.29

7.42

8.55

28

9.67

28 10.80

28 11.93

1.05

28

8.16

29

11.53

French.

Millimetres.

736.6

739.1

741-7

744-2

746.8

749.3

751.8

754.4

756.9

759.5

762.0

764.5

767.1

769.6

772.2

774.7

777-3

779.8

782.3

784-8

787.4

The barometer should be fixed in a good light, but one not exposed to the rays of the sun, drafts of wind, or very sudden changes of temperature. Its actual reading should always be recorded, leaving all corrections, for index errors, temperature of the mercury (for which a column is provided), capacity, &c., to be subsequently applied. The thermometer should be hung for observation out of doors, in a perfectly-shaded situation, but otherwise fully exposed, care being taken that it is not so placed as to be affected by reflected rays from water, buildings, or light-coloured hard soil, or by radiated heat from its proximity to the ground. The self-registering thermometer should be fastened so as to admit of one end being detached and lifted up, to allow the indexes to slide down to the extremities of the fluid columns, which is better than using a magnet for the purpose. These instruments are unfortunately very liable to get out of order.

TABLE XXI.

Books

Outline of the Method of Conducting a Trigonometrical Survey, for the ...