Lot Essay
Wright visited the observatory in Potsdam, near Berlin, to become familiar with the use of the pendulum apparatus that the expedition was taking to measure the value of gravity at their southern hemisphere and in the Antarctic. While in Germany, 'Wright also collected the equipment that he would need to continue the measurements of penetrating radiation in which he had been engaged since 1906. The apparatus included a new Wulf Electrometer, which he found to be relatively immune to modest rolling of the ship.' (C. Bull and P.F. Wright (eds.), Silas, p.xxviii). The [Wolff string] electrometer measures doses of electrical charges and x-rays by the amount of movement in a conducting fibre or 'string' viewed through a quadrant scale on the eyepiece.