A.—Table to construct Maps on Mercator’s Projection.
| 0° | 1° | 2° | 3° | 4° | 5° | 6° | 7° | 8° | 9° | |
| ° ´ | ° ´ | ° ´ | ° ´ | ° ´ | ° ´ | ° ´ | ° ´ | ° ´ | ° ´ | |
| 0 | 1 00 | 1 00·1 | 1 00·1 | 1 00·1 | 1 00·2 | 1 00·3 | 1 00·4 | 1 00·5 | 1 00·6 | |
| 10 | 1 00·9 | 1 01 | 1 01·2 | 1 01·5 | 1 00·7 | 1 02 | 1 02·2 | 1 02·6 | 1 02·9 | 1 03·3 |
| 20 | 1 03·6 | 1 04·1 | 1 04·5 | 1 04·9 | 1 05·5 | 1 05·9 | 1 06·5 | 1 07 | 1 07·7 | 1 08·2 |
| 30 | 1 09 | 1 09·6 | 1 10·4 | 1 11·1 | 1 12 | 1 12·8 | 1 13·7 | 1 14·6 | 1 15·7 | 1 16·7 |
| 40 | 1 17·6 | 1 19 | 1 20·1 | 1 21·4 | 1 22·7 | 1 24·2 | 1 25·6 | 1 27·1 | 1 28·8 | 1 30·6 |
| 50 | 1 32·4 | 1 34·3 | 1 36·4 | 1 38·6 | 1 40·8 | 1 43·4 | 1 45·9 | 1 49 | 1 51·4 | 1 54·8 |
| 60 | 1 58·3 | 2 01·8 | 2 05·8 | 2 09·9 | 2 14·5 | 2 19·14 | 2 24·7 | 2 30·5 | 2 36·8 | 2 43·8 |
| 70 | 2 51·3 | 2 59·8 | 3 09·1 | 3 19·6 | 3 31·3 | 3 44·6 | 3 59·8 | 4 17·1 | 4 37·4 | 5 01·1 |
| 80 | 5 29·5 | 6 03 | 6 46·4 | 7 40·3 | 8 51·1 | 10 27·7 | 12 47·9 | 16 29·6 | 23 14·3 | 39 42·2 |
Use of the table.—Find the required parallel; the tens at the side, and the units at the top. At their intersection will be found in degrees and minutes the distance of the required parallel from the next less degree, to be measured from the scale of longitude on the map in progress.
Given the parallel of 30°, required that of 31°. 30 at the side and 1 at the top intersects at 1° 09·6´, the required distance of the two parallels.
Given the parallel of 31°, required that of 33°:
| ° | ° | ´ | |
| 32 = | 1 | 10·4 | |
| 33 = | 1 | 11·1 | |
| 2 | 21·5 | the distance between the 31° and 33° parallels. |
B.—Given the Departure to find Difference of Longitude.
| 0° | 1° | 2° | 3° | 4° | 5° | 6° | 7° | 8° | 9° | |
| 0 | 1·0001 | 1·0006 | 1·0013 | 1·0026 | 1·0038 | 1·0055 | 1·0075 | 1·0098 | 1·0125 | |
| 10 | 1·0154 | 1·0187 | 1·0224 | 1·0261 | 1·0306 | 1·0353 | 1·0403 | 1·0457 | 1·0514 | 1·0578 |
| 20 | 1·0642 | 1·0711 | 1·0785 | 1·0864 | 1·0946 | 1·1034 | 1·1126 | 1·1224 | 1·1326 | 1·1434 |
| 30 | 1·1547 | 1·1666 | 1·1792 | 1·1924 | 1·2062 | 1·2208 | 1·2361 | 1·2521 | 1·2690 | 1·2868 |
| 40 | 1·3054 | 1·3250 | 1·3456 | 1·3673 | 1·3902 | 1·4142 | 1·4395 | 1·4663 | 1·4945 | 1·5242 |
| 50 | 1·5557 | 1·5890 | 1·6242 | 1·6616 | 1·7013 | 1·7435 | 1·7883 | 1·8361 | 1·8871 | 1·9416 |
| 60 | 2·0000 | 2·0626 | 2·1301 | 2·2027 | 2·2812 | 2·3662 | 2·4586 | 2·5593 | 2·6695 | 2·7904 |
| 70 | 2·9238 | 3·0716 | 3·2361 | 3·4204 | 3·6280 | 3·8637 | 4·1337 | 4·4454 | 4·8097 | 5·2406 |
| 80 | 5·7587 | 6·3925 | 7·1856 | 8·2057 | 9·5664 | 11·475 | 14·334 | 19·108 | 28·653 | 57·307 |