A request was received in December, 1951, from the Director of Ordnance and Underwater Weapons of the Department of the Navy for assistance in selecting an area suitable for the electrical balance testing of the pistol-firing rod unit of the torpedo. It was desired that this site should be at the R.A.N. Torpedo Establishment at Neutral Bay, Sydney, New South Wales. The only condition laid down in the relevant specification is that "the rod may be supported in a suitable wooden structure or in such other manner provided that the complete rod unit is not less than ten feet from any ferro-magnetic materials". In order to arrive at a more specific definition of the requirements for the testing site, the problem was discussed with the Chief Superintendent and officers of the Torpedo Establishment. The appropriate test specifications were consulted and a series of measurements were carried out to determine the actual requirements. The magnetic investigations described in this report were carried out in August, 1952, and the overall results and conclusions were communicated verbally at that time to the officers concerned.