IV. On the determination of the scale value of a Thomson’s quadrant electrometer used for registering the variations in atmospheric electricity at the Kew Observatory

Abstract

The Meteorological Council, being desirous of discussing the photographic traces produced by their electrograph at the Kew Observatory some time since, requested the Kew Committee to institute a series of experiments, with the view of determining the scale value of the instrument, in order to prepare a suitable scale for measuring the curves. The Kew Committee, at their meeting in November, entrusted the matter to me, and accordingly, having obtained the loan of a battery of 300 Bunsen cells, some preliminary experiments were made, which showed that the greatest potential which could be obtained with them was very inadequate for the purpose.