In Table XVI. of Mr. Baily, the Equation of equal Altitudes is given for the entire interval of 24 hours, but it is seldom required beyond the above limits.

R

TABLE XV.

LENGTH OF A SECOND OF LATITUDE AND LONGITUDE IN

FEET

ON THE SURFACE OF THE EARTH, THE COMPRESSION BEING
TAKEN AS 3 ਹੈ ਹ·

102-02

1 2

50 51 52

26 27 28 29

3

53

101.42 101:40 101:36 101.28 101.17 101.03 100-87 100.67 100.44

54
55

101.67

102:11

31

4 5 6 7 8 9

56

100:18

34

35

101.75

102.19

65.32 63.95 62.57 61.17 59.75 58:30 56.84 55.37 53.87 52:36 50.84 49:30 47.74 46.17 44:58 42.98 41:37 39.74 38.10 36:45 34.80

11

36

61

12

37 38

91.21 90.43 89.62 88.77 87.90 87.01 86.09 85.14 84.17 83.17 82.15 81.10 80.02 78.92 77.80 76.65 75.48 74.29 73.07 71.83 70:57 69.29 67.99 66-66

62 63

13

99.89 99.57 99.22 98.84 98.43 97.99 97.52 97.02 96.49 95.44

64

14 15

16

17 18 19 20 21 22

69

101.54

101.93

70

102:40

95.36 94.74 94.09 93.41 92.70

71 72 73 74

47 48 49

31:43
29.74

23

24

28.04

One second of time, at the Equator

1521:3 feet, or 507 yards.

Puissant, calculating the compression from the measurement of the great arc in France, obtains different results on different sides of the Meridian of Paris, making it as low as zšo on the side of the Atlantic, and 3óg to the Eastward; which latter quantity is generally assumed on the Continent.

TABLE XVI.

CORRECTIONS FOR CURVATURE AND REFRACTION.

Showing the difference of the Apparent and True Level in Feet, and Decimal parts of

Feet, for Distances in Feet, Chains, and Miles.

-4 ore

100.00024 .00004 .00020 1.0 .00010.00001 -00009

0417 0060 •0357 150.00054 .00008 /.00046 15.00024 .00003 ·00021

•1668 0238 •1430 200.00096 .00013:00083 2:0 1.00042 .00006 :00036

•3752 •0536

•3216 250.00149 .00021 .00128 2:5.00065 .00009 :00056

-6670 ·0953 •5717 300·00215 .00031 :00184 3.0 .00094 |.00013-00081 11 1:5008 .2144 1.2864 350.00293 .00042 .00251 3.5 .00128 .00018 .00110 | 2 2-6680 -3811 2.2869 400.00383 .00055 .00328 | 4:0 .00167 .00024 .00143 24 4:1688 •5955 3.5733 450.00484 00069 .00415 4:5.00211.00030 |·00181 6.0030 .8561 5.1469 5001:00598 00085 .00513 500 .00261 :00037 -00224 34 8.1708 1.1673 7.0035 550.00724 00103.00621 5.5 .00315 :0004500270410.6720 1.5246 9.1474 600.00861 .00123 .00738 6:0.00375.00054 |·00321 44 13.5468 | 1.9295 11.5773 650 .01010 .00144 |:00866 6:5 .00440 :00063 .00377 5 16.6750 2.3821 / 14.2929 70001172 .00167 01005 7:0:00511 :00073-00438 51 20:1769 2.8824 17.2945 750.01345 .00192 •01153 7.5 .00586 |.00084 .00502 6°240120 3.4303 20:5817 800|•01531 00219 01312 8:0 00667 00095 .00572 64 28:1809 4:0258 24:1551 850.01728 .00247 -01481 8.5 .00753 .00108 -00645 7 32.6830 4.6690 28.0143 9001:01938 .00277 01661 9.0 .00844.00121 -00723 7 37.5190 5.3599 32.1591

950.02159 .00308 01851 9.5 .00940 .00134 |·00806 8 42.6880 6.0997 36.5883 1000·02392 00333 02059 10.0 .01042:00149 00893 8448.1910 6.8844 41.3066 1050.02638 00377 02261 10.5 .01149 .00164 .00985 9 54:02701 7.7181 46•3089 1100·02895-00414 02481 11:001261 .00180 .01081 | 92 60.1971 8.5996 51.5975 11501•03164 00452 .02712 11.5 .01378 .00197 .01181 10 66•7000 9.5286) 57.1714 1200 .03445 .0049202953 12.0 1.01501 |·00214 .01287 11 80•7070 11:5296 69.1774 1250.03738 .00534 .03204 12.5 .01628 .00233 .01395 12 96.0480 13.7211 82:3269 1300 .04043 .00578 03465 13.0 .01761 .00252 01509 (13 (112:7230 16.1033 96.6197 1350 .04361 -00623.03738 13.5 .01899 .00271 .01628 14 130•7320 18·6760 112:0560 1400 .04689 .00670.04019 14:0 .02043 .00292-01751 15 150.0750 21.4393 128·6357 1450 .05030 .00719 .04311 14.5 .02191 |·00313 01878 16 170-7520 24.3931 (146.3589 1500 .05383 .00769 04614 15.0 .02345 :00335.02010 17 192.7630 27.5376 165.2254 1550 .05748 .00821 04927 (15.5.02504 .00358 :02146 18 216.1086 30.8727 (185•2359 1600•06125 .00875 1.05250 16.0 1.02668 -00381 .02287 19 240•7870 34•3981 206.3889 1650 .06514 .00931 |·05583 16.5 .02837 .00405 .02432 20 266.8000 38.1143 228.6857 1700 .06914 .00988 -05926 17.0·03012 -00430 \.02582 1750 .07327 .01047 1.06280 17.5 .03192.00456 02736 1800 .07752 -01107 \.06645 18.01.03377 1.00482.02895 1850 .08188 .01170 .07018 18.5 1.03567 -00509 .03058 1900.08637 -01234 •07403 19.0 1.03762.00537 .03225

1950 .09098 .01300.07798 19.5 -03963-00566 -03397 2000/:09570 .01367 08203 20.0 1.04169 .00596 .03573

TABLE XVII.

REDUCTION IN LINKS AND DECIMALS UPON EACH CHAIN'S LENGTH

FOR THE FOLLOWING VERTICAL ANGLES.

TABLE XIX.

COMPARATIVE SCALE OF FAHRENHEIT'S, REAUMUR'S, AND THE

CENTESIMAL THERMOMETERS.

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

F C + 32 = 4 R + 32
C

32)= R
R

32) = jc

Freezing point Boiling point.
Fahrenheit

32°

2120 Reaumur

0

80 Centigrade

.