Page images
PDF
EPUB

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.

[blocks in formation]

141234

100-00024 00004 00020 1.0 00010 00001 00009 150-00054 00008 00046 1.5 00024 0000300021 200-00096 00013 00083 2.0 00042 00006 00036 250-00149 00021 00128 2.5 00065-00009000561 300-00215-00031 00184 3.0 00094 00013 00081 1 350-00293 00042 00251 3.5 00128 00018 00110 2 400-00383 00055 00328 4.0 00167 00024 00143 20 450 00484 00069 00415 4.5 00211 00030 00181 3

[blocks in formation]

7.0035

9-1474

500-00598-00085 00513 5.0 -00261 00037 00224 3 8-1708 1-1673 550-0072400103 00621 5-5 00315 00045 002704 10-6720 1-5246 600-0086100123 00738 6.0 00375 00054 00321 44 13-5468 1-9295 11-5773 6500101000144 00866 6.5 00440 00063 00377 5 16-6750 2-3821 14-2929 700-01172-00167 01005 7.0-00511 00073-00438 54 20-1769 2.8824 17-2945 75001345-00192 01153 7.5 00586 00084 00502 6 24-0120 3-4303 20-5817 800-0153100219 01312 8.0 00667-00095 00572 64 28-1809 4.0258 24-1551 850-0172800247 01481 8.5 00753-0010800645 7 32-6830 4.6690 28-0143 90001938 00277 01661 9.0 00844 0012100723 7 37-5190 5-3599 32-1591 95002159 00308 01851 9.5 00940 00134 00806 8 42-6880 6-0997 36-5883 100002392-00333 02059 10-0 01042 00149 00893 84 48-1910 6-8844 41-3066 1050-02638-00377 02261 10-5 01149 00164 00985 954-0270 7-7181 46-3089

1100-02895-00414 02481 11.0 01261 00180 01081 9

115003164-00452 02712 11-5 01378-00197 -01181 10

120003445 00492 02953 12.0 01501 00214 01287 11 1250-0373800534 03204 12-5 01628 -00233 01395 12 130004043-00578 03465 13.0 01761 -00252 01509 13 135004361 00623 03738 13-5 01899 -00271 01628 14 1400 04689 00670 04019 14.0 02043 00292 01751 15 1450 05030-00719 04311 14.5 02191 00313 01878 16 1500-05383 00769 04614 15.0 02345 00335-02010 17 155005748 -00821 04927 15.5 02504 00358 02146 18 1600-06125-00875 05250 16.0 02668 00381 02287 19 165006514 00931 05583 16-5 02837 -00405 02432 20 170006914 -00988 05926 170 03012 00430 02582 175007327 01047 06280 17.5 03192 00456 02736 1800-07752 01107 06645 18-0 03377 00482 02895 1850-08188 01170 07018 18-5 03567 00509 03058 1900 08637 01234 07403 19-003762 00537-03225 1950-0909801300 07798 19-5 03963 00566 03397 2000-09570 01367 08203 20.0 04169 00596 03573

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

[merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small]

TABLE ΧΙΧ.

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

CENTESIMAL THERMOMETERS.

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

[blocks in formation]

Cent. +

[ocr errors][ocr errors][ocr errors][ocr errors][merged small][ocr errors][merged small][merged small][ocr errors][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small]

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

[blocks in formation]

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."

[blocks in formation]

30.6

28 8-55

777-3

30.7

28 9.67

779-8

30-8.

28 10.80

782-3

30.9

28 11.93

784-8

31.0

29 1.05

787.4

[blocks in formation]
[graphic]

These tabular forms can of course be varied to suit different localities, where different instruments are used, or where other periods of observation may be preferred. Those given above are recommended by Sir J. Herschel where only three daily readings are recorded.

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.

« PreviousContinue »