SOUTHERN JOURNEY DISTANCES
BY THE COMMANDER OF THE EXPEDITION
The following Table gives detailed information regarding the distances travelled day by day on the Southern Journey.
The number of geographical miles given in the first column covers the period from November 15, 1908, to January 9, 1909. The distances have been taken from the chart after all corrections have been made, and represent a direct line from camp to camp.
In the second column will be found the noon latitudes, calculated from observations taken as opportunity offered.
The last column shows the distances travelled day by day according to sledge-meter, and these figures take into account all deviations and detours so often rendered necessary by the condition of the surface. The reliability of the sledge-meter is proved by the fact that on the homeward journey we were able to determine our positions without taking latitude observations. Only one observation was taken on the return journey (January 31, 1909), and on that occasion the theodolite confirmed the record of the sledge-meter.
The latitude observations noted in this Table were taken with a three-inch theodolite, which was carefully adjusted before the start for the southern journey. An observation taken on the return journey, in February, when the position was known from bearings, showed that the instrument was correct. The observations were only taken with the theodolite "face left," but as the instrument was in good adjustment this was sufficient.
On the outward journey the last latitude observation was taken in latitude 87° 22' South. The remainder of the distance marched towards the south was calculated by sledge-meter and dead reckoning. The accuracy of the sledge-meters used was proved by the fact that on the return journey we were able to pick up the depots without taking observations. The "slip" was ascertained by careful tests before the start of the journey.
The chronometer watches taken were rated before leaving and on the return, and the error was only eight seconds. All bearings, angles, and azimuths were taken with the theodolite. Variation was ascertained by means of a compass attached to the theodolite, and the steering compasses were checked accordingly. At noon each day the prismatic compasses were placed in the true meridian, and checked against the theodolite compass and the steering compasses.
The total distance marched, from October 29 to March 4, as recorded on the sledge-meters, was 1755 miles 209 yards statute, this including relay work and back marches.