2. Subtract it from 24h 00m 00s, or vice versa, according as to whether L.A.T. is just before or just after local apparent noon. Call the result "Time Interval from Meridian Passage."
3. With your D.R. latitude, declination and Time Interval from Meridian Passage, enter Table 26 to get the proper amount of Variation of Altitude in one minute from meridian passage.
4. With the Time Interval from Meridian Passage and the Variation, enter Table 27 to get the total amount of Variation of Altitude.
5. Add this total amount of Variation to the true observed altitude taken before or after noon, and the result is the corrected altitude.
6. Then proceed to get your latitude according to the rules already given you for latitude by meridian altitude.
Example: At sea, Jan. 23rd, 1919. CT 4h 22m 14s. CC 1m 10s fast. Longitude 66° 04' W. Latitude by D.R. 19° 16' 00" N.
50° 51' 00" S. HE 49 ft. IE - 1' 30". Required latitude in.
| CT | 4h - 22m - 14s |
| CC | - 1 - 10 |
| —————————— | |
| G.M.T. | 4h - 21m - 04s |
| Eq. T. | - 11 - 50 |
| —————————— | |
| G.A.T. | 4h - 09m - 14s |
| Lo. in T | 4 - 24 - 16 (W-) |
| —————————— | |
| L.A.T. | 22d - 23h - 44m - 58s |
24h - 00m - 00s
- 23 - 44 - 58
——————————
15m - 02s = Time Interval from Meridian Passage.