During the period October-November 1914, field-based measurements of the earth's total magnetic field strength were carried out by the South Australian Government Astronomer as part of the scientific activities performed for the second part of the Department of Mines' Musgrave Ranges Expedition. This work was commissioned by the Commonwealth of Australia as a geophysical data contribution, also being provided by each of the other States and Territories of Australia, towards the compilation of world charts of terrestrial magnetism being prepared by the Carnegie Institution of Washington, D.C. That institution had lent the Musgrave expedition the use of a magnetometer, and a Barrow Dip Circle instrument was also lent by the Sydney Observatory. Seven survey trig stations were occupied to take the magnetic observations, which included dip and variation of a compass needle, plus the horizontal force component of the earth's magnetic field. In addition, measurements of magnetic variation were obtained at the daily camps pitched each evening en route to the Ranges, and when possible, at midday also, the object being to take readings at places approximately 10 miles apart. Half-hourly barometric pressure readings were also taken for determination of height, and latitude and longitude observations were made at the main camps. One innovation employed in the field work was the use of radio-telegraphic time signals for determining longitude, received with the aid of a portable outfit (wireless tuner, masts, aerial, etc.). A detailed qualitative analysis of the measurement procedure is provided in this report. Provide that good atmospheric electrical conditions prevailed, rhythmically timed (every 0.1 seconds) radio clock signals emanating from the Port Adelaide Wireless Station could routinely be heard at all places, whilst at Moorilyanna, the furthest west camp occupied, roughly 700 miles directly distant from Adelaide, other wireless transmitter stations at Townsville, Sydney and Melbourne could likewise be heard.