Checks on absolute level were frequently obtained by observing depression angles to the sea horizon, using the formula θ = 107·8 √{_h_}, where θ is in seconds of arc and _h_ is the altitude in metres. But for high stations the horizon is so distant that very small variations in refraction cause rather large errors in the result, so that this method only furnished a rough check. =Summary of Triangulated Positions.= The following tables give the geographical positions and altitudes above sea-level of all points triangulated, arranged in order of diminishing latitude, _i.e._, from north to south. The list includes the points fixed within the Sudan for connexion with the Sudan Surveys. Stations occupied are indicated by an asterisk against the number of the point. It will be noticed that in some cases several different mountains bear the same name though widely distant from each other; also that where a single mountain mass possesses several peaks or summits, each of these has been fixed separately. SUMMARY OF TRIANGULATED POSITIONS. --------+--------------------+-----------+--------+---------+--------- Field | | | | | Number| Name. | Mark. |Latitude|Longitude|Altitude of | | | N. | E. | Metres. Point.| | | | | --------+--------------------+-----------+--------+---------+--------- | | | ° ′ ″| ° ′ ″ | | | | | | 21 |G. Hamrat Wogud | cairn. |25 9 34|34 20 0 | 1,103 | | | | | 29 |G. Iteima | „ |25 8 1|34 11 13 | 849 | | | | | * 204 |G. Igli | „ |25 4 6|34 36 16 | 975 | | | | | * 26a|G. Atut | „ |25 0 56|34 23 49 | 908 | | | | | * 203 |Erf el Fahid | „ |25 0 5|34 11 52 | 579 | | | | | 14 |G. Hagar Dungash | „ |24 59 12|34 2 33 | 815 | | | | | * 218 |G. Sukari | „ |24 56 50|34 42 50 | 476 | | | | | 216 |G. Um Tundeba | summit. |24 55 48|34 47 29 | 550 | | | | | * 202 |Muelih base | E. peg. |24 54 44|34 5 7 | 406 | | | | | 219 |Isolated hill near | summit. |24 54 23|34 54 21 | 190 |sea | | | |