# Variation of the Compass, as Observed on Board the Endeavour Bark, in a Voyage Round the World. Communicated by Lieut. James Cook, Commander of the Said Bark

**Author(s):** James Cook  
**Year:** 1771  
**Journal:** Philosophical Transactions (1683-1775)  
**Volume:** 61  
**Pages:** 12 pages  
**Identifier:** jstor-106114  
**JSTOR URL:** <https://www.jstor.org/stable/106114>  

---

XLIV Variation of the Compass, as observed on board the Endeavour Bark, in a Voyage round the World. Communicated by Lieut. James Cook, Commander of the said Bark.

N. B. THE day of the month is noted according to the nautical account, which therefore in all the observations noted P. M. is one day forwarder than the civil account. The latitude in is deduced from the last preceding meridian altitude of the sun; and the longitude in is corrected by the last observations of the distances of the moon from the sun and stars.

| Time       | Lat. in | Long. in | Variation | Remarks |
|------------|---------|----------|-----------|---------|
|            | North   | West     | How found | Means   |
| 1768       |         |          |           |         |
| August 8   | English Channel | C. Finestre S. by ½ | pr. Azimuths | 23° 6' W. |
| September 5 | W. 6 leagues |          | pr. Azimuths | 18° 42' |
| 6          | 42° 9' 50" W. |          | pr. Azimuths | 21° 40' |
| 7          | 40° 29' 10" 11' |          | pr. Azimuths | 21° 4' |
| 9          | 37° 4' 11" 34' |          | pr. Azimuths | 19° 50' |
| P. M. }    | 36° 46' 11" 58' |          | pr. Azimuths | 21° 19' |
| A. M. }    | 35° 40' 13" 4' |          | pr. Amplitudes | 20° 39' |
| P. M. }    | 34° 58' 13" 50' |          | pr. Azimuths & Amplitudes | 18° 32' |
| A. M. }    | 34° 20' 14" 20' |          | pr. Azimuths & Amplitudes | 17° 27' |
|            | Funchal island of Madeira |          |           |         |
| 32° 33' 33" 16' 49" |          | pr. Azimuths | 15° 30' |
| 20°        | Funchal island of Madeira | N. 76° E. dist. 19 leag. | pr. Azimuths | 16° 30' |
| 22°        | Salvages S. dist. 9 or 10 leag. | pr. Azimuths | 17° 50' |

These are taken from Dr. Heberden, F. R. S., who resided upon the island.
| Time       | Lat. in | Lon. in | Variation | How found | Means | Remarks |
|------------|---------|---------|-----------|-----------|-------|---------|
|            | North   | West    |           |           |       |         |
| 1768       |         |         |           |           |       |         |
| September  |         |         |           |           |       |         |
| 23         | 29 40   | 15 30   |           |           |       |         |
| P. M. D.   |         |         |           |           |       |         |
| A. M.      | 29 7    | 15 50   |           | pr. Amplitudes | 18 30 |         |
|            |         |         |           | pr. Azimuths | 16 30 |         |
| 24 P. M.   |         |         |           | pr. Azimuths | 16 43 |         |
|            |         |         |           | pr. Amplitudes | 15 46 |         |
|            |         |         |           | Ditto     | 14 58 | Passage to Rio de Janeiro. |
| 24 A. M.   | 26 50   | 17 12   |           |           |       |         |
| 25 P. M.   | 25 20   | 18 50   |           | pr. Amplitudes | 15 1  |         |
|            |         |         |           | pr. Sev. Azim. | 12 46 |         |
|            |         |         |           | Ditto     | 12 43 |         |
|            |         |         |           | pr. Azimuths | 12 33 |         |
| 28 P. M.   | 19 33   | 20 50   |           |           |       |         |
| 29 P. M.   | 18 38   | 21 0    |           |           |       |         |
| October    |         |         |           |           |       |         |
| 1 P. M.    | 15 40   | 22 0    |           | Ditto     | 10 37 |         |
| A.M.       | 14 35   | 22 8    |           | Ditto     | 10 0  |         |
|            |         |         |           | Ditto     | 11 40 |         |
|            |         |         |           | Amplitudes | 8 49  |         |
| 3          |         |         |           |           |       |         |
| 5 P. M.    | 11 53   | 22 0    |           | pr. Azimuths | 6 10  |         |
|            |         |         |           | pr. Amp. 5 59 | 6 10  |         |
| 6 A. M.    | 9 45    | 22 20   |           | pr. S. Az. 6 21 | 8 52  | Towards Rio Janeiro. |
| 8 P. M.    | 9 42    | 22 19   |           | Ditto     | 9 0   |         |
| A.M.       | 8 46    | 22 4    |           | Ditto     | 8 0   |         |
|            |         |         |           | 7 47      | 8 0   |         |
|            |         |         |           | Ditto     | 8 23  |         |
|            |         |         |           | 8 20      | 8 21\(\frac{1}{2}\) |         |
| 9 P. M.    | 8 12    | 22 4    |           | pr. Amplitudes | 7 48  |         |
| A.M.       | 8 6     | 22 13   |           |           |       |         |
|            |         |         |           | 7 48      | 8 39  |         |
| 10 P. M.   | 7 48    | 22 13   |           | pr. Sev. Azim. | 8 39  |         |
| 13 P. M.   | 7 13    | 22 33   |           | Ditto     | 8 54  |         |
| 16 P. M.   | 6 50    | 23 46   |           | Ditto     | 8 40  |         |
|            |         |         |           | Ditto     | 4 2   |         |
|            |         |         |           | Amplitudes | 3 13  |         |
|            |         |         |           | pr. Azimuths | 3 17  |         |
|            |         |         |           | pr. Am. 2 16 | 2 24\(\frac{1}{2}\) |         |
| 22 A. M.   | 2 0     | 27 55   |           |           |       |         |
| 25 P. M.   | 0 55    | 28 55   |           |           |       |         |
| Time   | Lat. in | Lon. in | Variation | Remarks |
|--------|---------|---------|-----------|---------|
|        |         |         | How found | Means   |
|        |         |         |           |         |
| 1768 October |         |         |           |         |
| South West |         |         |           |         |
| 27 A.M. | 2 3     | 31 0    | Ditto     | 2 48 W. |
| 29 P.M. | 3 59    | 32 30   | Ditto     | 2 25    |
| 30 P.M. | 5 46    | 32 48   | pr. Sev. Azim. | 1 31 |
| 31 P.M. | 7 30    | 33 4    | Ditto     | 0 15    |
| November |         |         |           |         |
| [P.M.] | 9 22    | 33 16   | Ditto     | 0 58    |
| [A.M.] |         |         | Ditto     | 0 18    |
| 2 P.M.  | 10 3    | 33 0    | Ditto     | 0 34 E. |
| 3 P.M.  | 12 27   | 33 0    | Ditto     | 0 47    |
| 4 P.M.  | 15 25   | 33 40   | Ditto     | 1 23    |
| 7 P.M.  | 18 30   | 36 10   | Ditto     | 4 41    |
| 8 P.M.  | 20 4    | 37 18   | Ditto     | 5 26    |
| [A.M.] | 21 16   | 37 50   | Ditto     | 7 52    |
| 12 P.M. | Cape Forio W.N.W. dist. 12 leagues |         | Ditto     | 6 40    |
|         | Entrance Rio de Janeiro |         |           |         |
|         | W.N.W. dist. 5 leagues |         |           |         |
| 13 P.M. |         |         |           | 7 34    |
| December |         |         |           |         |
| [P.M.] | 25 44   | +1 4    | pr. Amplitudes | 8 40    |
| [A.M.] | 26 0    | 41 20   | pr. Sev. Azim. | 8 23    |
| 13 P.M. | 26 34   | 41 33   | Ditto     | 8 23    |
| 16 P.M. | 30 20   | 41 49   | Ditto     | 9 36    |
| 18 P.M. | 32 30   | 42 48   | Ditto     | 11 3    |
| 19 P.M. | 32 54   | 43 38   | Amplitudes | 11 3    |
| 20 P.M. | 34 34   | +5 38   | pr. Sev. Azim. | 13 44    |
|         |         |         |           |         |
| [P.M.] | 36 50   | 48 32   | Azim. 15 1 | 15 1    |
| [A.M.] | 37 8    | 49 1    | Amp. 15 1 | 16 1    |
|         |         |         | pr. Amplitude |       |
| [P.M.] | 37 8    | 49 0    | pr.Az.15 24 | 15 45   |
| [A.M.] | 36 46   | 49 2    | Amp. 16 5 | 15 30   |
|         |         |         | pr. Amplitude |       |
|         |         |         | pr. D°. 16 12 |       |
| 29 P.M. | 41 40   | 56 25   | pr. Azimuth | 16 22   |
|         |         |         | pr. D°. 18 44 |       |
|         |         |         | pr. Amplitude | 18 36   |
|         |         |         |             |         |

Time
| Time     | Lat. in | Lon. in | Variation | Remarks |
|----------|---------|---------|-----------|---------|
|          |         |         | How found | Mean    |
| 1769     |         |         |           |         |
| January  |         |         |           |         |
| 5 P.M.   | 48° 42' | 60° 51' | pr. Am. 20° 0' | 20° 4½ E. |
| 9 P.M.   | 51° 30' | 63° 30' | pr. Several Az. | 22° 24' |
| 10 P.M.  | 52° 40' | 65° 20' | Ditto     | 21° 57' |
| 11 A.M.  | 54° 00' | 67° 30' | Ditto     | 23° 30' |
|          | 10 leag. from Terra del Feugo |         |           |         |
| 21 A.M.  | Strait le Mare | Ditto | 24° 9'    |         |
| 22 A.M.  | 56° 7'  | 65° 45' | pr. Several Az. | 25° 4' |
|          | Near some isle on the coast of Terra del Feugo | ditto | 21° 0' |
|          | E. of C. Horne. |         |           |         |
| 24       | 55° 40' |         | C. Horne S.W. | pr. Amp. 21° 16' |
|          | 3 W. 8 leag. |         |           |         |
| 25 A.M.  | 55° 40' |         | pr. Amp. 21° 16' |         |
| 28 P.M.  | 57° 0'  | 69° 0'  | pr. Several Az. | 22° 0' |
| 30 P.M.  | 60° 10' | 74° 26' | Ditto     | 27° 9'  |
| February |         |         |           |         |
| 1 P.M.   | 59° 23' | 76° 45' | Ditto     | 24° 53' |
| 3 P.M.   | 58° 30' | 80° 58' | Ditto     | 24° 4'  |
| 13 P.M.  | 49° 13' | 89° 36' | Ditto     | 17° 0'  |
| 15 P.M.  | 48° 56' | 91° 27' | Ditto     | 12° 0'  |
| 15 A.M.  | 48° 10' | 92° 0'  | Ditto     | 11° 0'  |
| 21 A.M.  | 44° 39' | 103° 0' | Ditto     | 6° 30'  |
| 23 P.M.  | 39° 43' | 105° 52' | Ditto | 5° 34' |
| 27 A.M.  | 39° 43' | 110° 26' | pr. Amp. 2° 17' | 2° 20½ |
|          |         |         | pr. Azim. 2° 24' |         |
| March    |         |         | Ditto 2° 6' |         |
| 4 P.M.   | 36° 49' | 111° 54' | Amp. 2° 46' | 2° 26' |
| 8 P.M.   | 37° 8'  | 116° 8' | pr. Several Az. | 3° 13' |
| 9 P.M.   | 37° 24' | 117° 41' | Ditto     | 4° 41' |
| 10 P.M.  | 35° 30' | 119° 30' | Ditto     | 1° 42' |
| 11 Ditto | 34° 0'  | 121° 0' | Ditto     | 4° 12' |
| 12 Ditto | 32° 40' | 123° 0' | Ditto     | 4° 23' |
|          | P.M.    |         | Amplitudes | 3° 20' |
| 13 A.M.  | 30° 56' | 125° 20' | pr. Azimuths | 3° 0' |

Passage from Cape Horne to Ota-hitee.

Mean result of many azim. the sea calm and smooth.

Passage from Cape Horne to Ota-hitee.
| Time   | Lat. in | Lon. in | Variation | Remarks |
|--------|---------|---------|-----------|---------|
|        |         |         | How found | Means   |
| 1769 March |         |         |           |         |
| South  |         |         |           |         |
| 15 P. M. | 30 30 | 126 0 | pr. Azimuths | 3 45 E. |
| A. M.  | 29 36 | 126 50 | Ditto     | 3 22    |
| 16 P. M. | 29 32 | 126 48 | pr. 21 Azimuths | 1 30 |
| A. M.  | 29 28 | 127 4  | Ditto     | 2 18    |
| 17 P. M. | 29 10 | 127 16 | Ditto     | 3 27    |
| A. M.  | 27 40 | 129 20 | Ditto     | 3 14    |
| 21 A. M. | 25 21 | 129 28 | Amplit. 3 o | 3 21 1/2 |
|         |       |         | pr. Azim. 3 43 |         |
| 22 Ditto | 25 21 | 129 32 | Azimuth   | 3 10    |
| 28 P. M. | 21 14 | 127 38 | Amplitudes | 3 56    |
| 29 P. M. | 20 29 | 127 44 | pr. Several Az. | 2 27 |
| 31 P. M. | 19 30 | 129 10 | Ditto     | 2 25    |
| April  |         |         |           |         |
| 1 P. M. | 19 7  | 131 40 | Ditto     | 2 32    |
| P. M.  | 18 46 | 138 0  | Ditto     | 2 54    |
| A. M.  | 18 36 | 139 10 | Ditto     | 2 54    |
| 5 P. M. | 18 36 | 139 40 | Amplitude | 3 30    |
| 8 P. M. | 17 48 | 143 50 | Several Azim. | 6 32 |
| 9 P. M. | 17 36 | 145 30 | Ditto     | 4 54    |
| 10 P. M.| 17 42 | 146 16 | Ditto     | 5 41    |
| 11 P. M.| 18 0  | 147 59 | Ditto     | 6 30    |
| August |         |         |           |         |
| 17 29 | 149 30 | Meridian line | 4 45 1/2 |
| 18 A. M.| 17 15 | 151 41 | pr. Several Az. | 5 50 |
| Ditto | 21 20 | 151 15 | Ditto     | 5 40    |
| 15 P. M.| 22 8  | 150 55 | Amplitude | 5 37    |
| A. M.  | 23 37 | 150 37 | Ditto     | 6 7     |
| 18 P. M.| 26 10 | 149 46 | Ditto     | 8 8     |
| A. M.  | 26 30 | Ditto   | Ditto     | 7 58    |
| 23 P. M.| 30 43 | 148 0  | Azimuths  | 7 30    |
| 24 A. M.| 32 40 | 147 14 | Ditto     | 7 18    |
| Ditto | 33 8  | 147 25 | Ditto     | 6 40    |
| Ditto | 38 3  | 147 6  | Ditto     | 7 9     |
| September |         |         |           |         |
| 5 P. M.| 38 29 | 145 32 | Ditto     | 7 0     |
| Ditto | 33 0  | 153 0  | Ditto     | 8 8     |

On shore at Fort Venus by four of Dr. Knight's compasses, which appeared to be all good.

From the Society Isles to New Zealand.
| Time       | Lat. in | Lon. in | Variation | How found | Means | Remarks                                      |
|------------|---------|---------|-----------|-----------|-------|---------------------------------------------|
|            |         |         |           |           |       |                                             |
| 1769       |         |         |           |           |       |                                             |
| September  |         |         |           |           |       |                                             |
| South      |         |         |           |           |       |                                             |
| 19 P.M.    | 29°     | 159°    | 42'       | pr. Amplitudes | 8° 36' E. |
| 19 A.M.    | 29°     | 159°    | 25'       | pr. Sev. Azim. | 8° 29' |
| 25 P.M.    | 33° 30' | 163°    | 40'       | Ditto     | 10° 48' |
| October    |         |         |           |           |       |                                             |
| 3 P.M.     | 36° 50' | 173°    | 46'       | Ditto     | 13° 22' |
| 4 P.M.     | 37° 6'  | 174°    | 46'       | Ditto     | 12° 48' |
| 6 P.M.     | 38° 33' | 179°    | 0'        | Ditto     | 12° 59' |
| 6 A.M.     | 39°     | 180°    | 0'        | Ditto     | 14° 2' |
| 7 P.M.     | 39° 11' | 180°    | 30'       | Azim. 15° 4' | 15° 4½' |
| 15 P.M.    | 39° 37' | 182°    | 30'       | Ampl. 15° 5' | 14° 10' |
| 17 A.M.    | 40°     | 182°    | 0'        | Ditto     | 10° 22' |
| November   |         |         |           |           |       |                                             |
| 9          | 36° 48' | 184°    | 12'       | Several Azim. | 11° 9' |
| 25         | 35° 50' | 185°    | 15'       | Ditto     | 12° 40' |
| 26         | 35° 15' | Ditto   | Amplitudes | 13° 10' |
| 28         | 35°     | 185°    | 30'       | pr. Azimuths | 11° 45' |
| December   |         |         |           |           |       |                                             |
| 8          | 34° 42' | 185°    | 30'       | pr. Amplitude | 12° 51' |
| 10 P.M.    | 34° 40' | 186°    | 15'       | Azim. 12° 40' | 12° 40' |
| 11 P.M.    | 34° 40' | 186°    | 45'       | Ampl. 12° 40' | 12° 20' |
| 25 A.M.    | 34°     | 188°    | 0'        | Several Azim. | 11° 25' |
| 1770       |         |         |           |           |       |                                             |
| January    |         |         |           |           |       |                                             |
| 6 A.M.     | 35°     | 188°    | 0'        | Ditto     | 12° 26' |
| 12 P.M.    | 38° 12' | 185°    | 3'        | Ditto     | 15° 0' |
| 12 A.M.    | 39°     | Ditto   | Ditto     | 14° 15' |
| 14 P.M.    | 39° 40' | Ditto   | pr. Amplitudes | 13° 0' |
| 15 A.M.    | 40° 30' | 186°    | 0'        | Azimuths  | 13° 5' |
| February   |         |         |           |           |       |                                             |
| 11 A.M.    | 41°     | 183°    | 0'        | pr. Amplitudes | 14° 0' |
| 12 P.M.    | 41° 26' | 184°    | 0'        | Ditto     | 14° 0' |
| 14 Ditto   | 42° 8'  | 184°    | 15'       | Azim. 15° 8' | 15° 4' |

In sight of the East coast of New Zealand.

Off the Northern parts of New Zealand.

West coast.
| Time   | Lat. in | Lon. in | Variation | How found | Means | Remarks |
|--------|---------|---------|-----------|-----------|-------|---------|
|        |         |         |           |           |       |         |
| **1770** |         |         |           |           |       |         |
| February |         |         |           |           |       |         |
| South   |         |         |           |           |       |         |
| 17 A.M. | 44° 0'  | 186° 30' | Ditto     | 14° 32'   | 14° 24' E. |         |
| Ditto   | 45° 0'  | 186° 15' | Ditto     | 14° 16'   | 15° 36' |         |
| March   |         |         | pr. Amplitudes |       |       |         |
| 1 P.M.  | 47° 34' | 187° 30' | pr. Azimuths | 16° 34' |       | East coast. |
| 4 A.M.  | 46° 30' | 189° 0'  | Ditto     | 16° 16' |       |         |
| 7 P.M.  | 46° 54' | 191° 0'  | Amplitude | 15° 10' |       |         |
| 7 A.M.  | 47° 0'  | Ditto    | pr. Azimuths | 15° 56' |       |         |
| 9 P.M.  | 47° 12' | 191° 30' | pr. Amplitudes | 16° 29' |       |         |
| 15 P.M. | 45° 0'  | 192° 30' | Ditto     | 15° 2    |       |         |
| Ditto   | 44° 27' | 191° 15' | pr. Azimuths | 13° 48' |       | West coast. |
| 25 A.M. | 40° 30' | 186° 0'  | pr. Amplitudes | 12° 20' |       |         |
| April   |         |         |           |           |       |         |
| 7 P.M.  | 37° 15' | 196° 40' | Several Azim. | 13° 50' |       |         |
| 8 P.M.  | 37° 40' | 197° 40' | Ditto     | 13° 56' |       |         |
| 10 A.M. | 38° 45' | 202° 23' | Ampl. 11° 25' | 11° 22½' |       | Between New Zeland and New Holland. |
|         |         |         | Azim. 11° 20' |       |       |         |
|         |         |         | Amplitude |       |       |         |
|         |         |         | Azimuth   |       |       |         |
| 13 P.M. | 39° 15' | 203° 40' | Ditto     | 12° 25' |       |         |
| 13 A.M. | 39° 23' | 204° 0'  | Ditto     | 12° 29' |       |         |
| 14 P.M. | 39° 24' | 204° 4'  | Amplitude | 11° 28' |       |         |
| 14 A.M. | 39° 23' | 204° 15' | Azimuth   | 11° 30' |       |         |
| 20 A.M. | 37° 0'  | 210° 0'  | Ditto     | 10° 40' |       |         |
| 21 P.M. | 36° 35' | 210° 0'  | Ditto     | 10° 42' |       |         |
| 22 A.M. | 35° 35' | 209° 23' | Ditto     | 9° 50'  |       |         |
| Ditto   | 35° 35' | 209° 0'  | Ditto     | 7° 41'  |       |         |
| 25 P.M. | 35° 18' | 209° 11' | Ditto     | 9° 15'  |       |         |
| 25 A.M. | 34° 0'  | 208° 50' | Ampl. 9° 36' | 9° 21½' |       |         |
|         |         |         | Azim. 9° 7' |       |       |         |
| 26 P.M. | 34° 18' | 208° 49' | Several Azim. | 8° 48' |       |         |
| May     |         |         |           |           |       |         |
| 7 P.M.  | 33° 50' | 208° 37' | Ditto     | 8° 0    |       |         |
| 7 A.M.  | 33° 22' | 208° 20' | D° with needles | 7° 56' |       |         |
| 8 P.M.  | Ditto   |         | Azimuths  | 8° 25'  |       |         |
| 10      | 33° 13' | 207° 20' | Ditto     | 8° 0    |       |         |
| 11 A.M. | 32° 40' | 206° 36' | pr. d° and Amp. | 9° 10' |       |         |
| 18      | 26° 20' | 206° 46' | pr. Azimuths | 8° 40' |       |         |
| 19 P.M. | 25° 34' | 206° 45' | Ditto     | 8° 36'  |       |         |
|         | 25° 24' | 206° 38' | pr. Amplitudes |       |       |         |
|         |         |         | pr. Azimuths | 8° 21½' |       |         |

*Time*
| Time   | Lat. in | Lon. in | Variation | Remarks |
|--------|---------|---------|-----------|---------|
|        |         |         | How found | Means   |
| 1770 May | South |         |           |         |
| 20 P. M. | 25 12 | pr. Azimuth | 8 45 E. |
| {P. M.} | 24 34 | pr. Amplitude | 8 3 |
| {A. M.} | 24 25 | Azimuths | 7 50 |
| 26 P. M. | 23 24 | Ditto | 7 28 |
| June   |         |         |           |         |
| 3 A. M. | 20 20 | Ditto | 6 57 |
| 5 A. M. | 19 18 | Amplitude | 5 35 |
| 6 A. M. | 19 4  | Ditto | 5 31 |
| {P. M.} | 19 0  | Amplitude | 5 25 |
| {A. M.} | 18 52 | Ditto | 5 0 |
| 9 A. M. | 16 59 | Ditto | 4 53 |
| August |         |         |           |         |
| 23 P. M. | 10 36 | Amplitude | 2 54 |
| 27 A. M. | 10 3 | Ditto | 2 30 |
| 28 P. M. | 9 51 | Ditto | 2 51 |
| September |       |         |           |         |
| 2 P. M. | 7 39 | Ditto | 2 34 |
| 3 Ditto | 7 2  | Ditto | 2 4 |
| 4 P. M. | 6 18 | Ditto | 2 30 |
| 9 P. M. | 9 36 | Azim. o 12 | o 8 3 W. |
| Amp. o 5 |         |         |           |         |
| 10 A. M. | 9 50 | Ditto | o 2 |
| 13 Ditto | 9 40 | Amp. i 10 | i 18 1/2 |
| Azim. i 27 |         |         |           |         |
| 14 Ditto | 9 50 | Amp. and Azim. | 2 4 |
| 17 P. M. | 10 8  | Amplitude | 1 49 |
| 24 Ditto | 11 10 | pr. Several Azim. | 2 44 |
| 27 Ditto | 11 10 | Ditto | 3 10 |
| 1771 January |     |         |           |         |
| 27 P. M. | 10  | Ditto | 2 51 |
| February |         |         |           |         |
| 3 P. M. | 15 52 | Ditto | 2 56 |
| 7 P. M. | 18 34 | Ditto | 3 24 |
| 14 P. M. | 21 56 | Ditto | 4 10 |

Time
| Time   | Lat. in | Lon. in | Variation | How found | Means | Remarks |
|--------|---------|---------|-----------|-----------|-------|---------|
|        |         |         |           |           |       |         |
| **1771** |         |         |           |           |       |         |
| February |         |         |           |           |       |         |
| 17 P. M. | South   | West    | pr. Several Azim. | 23° 20' | 20° W |         |
| 20 P. M. |         |         | Ditto     | 24° 57' | 12° 15' | Java head to the Cape of Good Hope. |
| 23 P. M. |         |         | pr. Amplitude | 26° 59' | 17° 30' |         |
| 25 P. M. |         |         | pr. Azimuth | 27° 55' | 24° 20' |         |
| 26 P. M. |         |         | pr. Amplitude | 28° 40' | 24° 0' |         |
| March   |         |         | Azimuths   | 28° 54' | 26° 10' |         |
| 4 P. M. |         |         | Ditto     | 31° 8'   | 25° 35' |         |
| 8 A. M. |         |         | Amp. 28° 30' | 34° 20' | 28° 19' |         |
| 10 P. M.|         |         | Azim. 28° 8' | 35° 40' | 24° 0' |         |
| 12 P. M.|         |         | pr. Amplitude | 34° 54' | 22° 30' |         |
| April   |         |         | Ditto     | Table Bay, Cape of Good Hope. | 20° 30' |         |
| 23 P. M.|         |         | Amplitude | 27° 12' | 17° 40' | By several observations. From the Cape of Good Hope to England. |
| 24 A. M.|         |         | Azimuth   | 26° 34' | 18° 37' |         |
| 24 P. M.|         |         | Amplitude | 26° 12' | 17° — |         |
| 28 P. M.|         |         | Amp. and Azim. | 25° 26' | 17° 30' |         |
| 29 Ditto|         |         | Azimuth   | 19° 50' | 14° 0' |         |
| May     |         |         | Ditto     | 18° 30' | 13° 53' |         |
| 5 A. M. |         |         | Ditto     | 15° 25' | 13° 10' |         |
| 7 Ditto |         |         | Ditto     | 12° 30' | 12° 50' |         |
| 9 P. M. |         |         | Ditto and Amp. | 10° 24' | 11° 00' |         |
| 13 A. M.|         |         | Azimuth   | 3° 18'   | 10° 00' |         |
| North   |         |         | Ditto     |          |       |         |
| 19 Ditto|         |         | Amplitude | 4° 20'   | 7° 40' |         |
| 23 Ditto|         |         | Azimuth   | 7° 40'   | 9° 40' |         |
| 26 Ditto|         |         | Ditto     | 10° 38'  | 6° 30' |         |
| 31 Ditto|         |         | Ditto     | 18° 25'  | 5° 9'  |         |
| June    |         |         | Ditto     |          |       |         |
| 1 A. M. |         |         | Ditto     | 20° 0'   | 6° 40' |         |
| 2 Ditto |         |         | Ditto     | 21° 4'   | 5° 4'  |         |
| 4 Ditto |         |         | Ditto     | 23° 30'  | 4° 30' |         |
| 6 Ditto |         |         | Ampl. 5° 5' | 25° 40'  | 5° 34½' |         |
|         |         |         | Azim. 6° 4' |          |       |         |
| Time   | Lat. in | Lon. in | Variation | How found | Means |
|--------|---------|---------|-----------|-----------|-------|
|        |         |         |           |           |       |
| 1771 June | North West |         |           |           |       |
| 7 A. M. | 27 22   | 43 43   | 20 Azimuths | Ditto     | 5 20 W. |
| 8 Ditto | 28 30   | 43 42   | Amp. 7 3  | Azim. 7 30 | 5 24 |
| 9 Ditto | 29 51   | 44 9    | Ampl. 9 18 | Azim. 9 — | 7 17 |
| 10 P. M.| 30 26   | 44 15   | Amplitude | Azimuths  | 9 9 |
| 12 P. M.| 32 16   | 45 14   | Amplitude | Azimuths  | 7 0 |
| A. M.   | 32 40   | 45 0    | Azimuths  | Azimuths  | 6 55 |
| P. M.   | 33 16   | 44 53   | Azim. and Amp. | Ampl. 8 15 | 8 23 |
| A. M.   | 33 53   | 44 25   | Azim. 8 14 | Azimuths  | 8 14½ |
| 14 P. M.| 34 36   | Ditto   | Amplitude | Azimuth   | 8 14 |
| 17 Ditto| 38 26   | 40 20   | Azimuth   | Azimuth   | 9 1 |
| P. M.   | 39 12   | 39 0    | Azim. 14 13 | Ampl. 14 18 | 14 15½ |
| A. M.   | 39 22   | 38 0    | Amplitude | Azimuth   | 14 24 |
| P. M.   | 43 55   | 17 16   | Azimuth   | Ditto     | 18 30 |
| A. M.   | 44 30   | 16 18   | Ditto     | Azimuths  | 19 30 |
| July    |         |         |           |           |       |
| 1 P. M. | 44 40   | 15 44   | Azimuths  | Ditto     | 23 0 |
| A. M.   | 44 50   | 16 10   | Ditto     | Ditto     | 22 50 |
| 3 P. M. | 45 —    | 13 0    | Azimuths  | Azimuths  | 20 36 |
| 4 P. M. | 45 30   | 10 45   | Azimuths  | Azimuths  | 21 25½ |
| A. M.   | 45 20   | 9 37    | Amplitudes| Amplitudes| 21 10 |
| 7 P. M. | 45 45   | 8 38    | Amplitude | Azimuths  | 22 30 |

Extract
Extract from Capt. Cook's Journal.

Nov. 9 At 8 A. M. Mr. Green and I went on shore, to observe the Transit of Mercury, which came on at $7^h\ 20'\ 58''$ apparent time, and was observed by Mr. Green alone; I at this time was taking the Sun's altitude in order to ascertain the time.

Mr. Green \begin{align*}
\text{Internal contact} & \quad h\ v\ '' \\
12 & \quad 8\ 58 \\
\text{External contact} & \quad 9\ 55
\end{align*}

C. Cook \begin{align*}
\text{Internal contact} & \quad P. M. \\
— & \quad 8\ 45 \\
\text{External contact} & \quad 9\ 48
\end{align*}

Lat. observed at noon $36^\circ\ 48'\ 28''$, the mean of this and yesterday observations gives $36^\circ\ 48'\ 5\frac{1}{2}''$ South, the latitude of the place of observation. The variation of the compass was found to be $11^\circ\ 9'$ East.

** These observations were made by the help of a Graham's watch with a second hand; corrected by observed altitudes of the Sun.

XLV. Transitus