An article by Mr. E. W. B. Gill in Nature (Vol. 162, No. 4119, 1948, p. 568–69) describes an experiment in which sand was allowed to fall about r m. on to the floor. An electrometer plate was placed about 3 m. away. While the sand was falling there was no effect on the electrometer, but soon afterwards it showed a deflexion which increased for three or four minutes, then decreased the needle coming to rest near its original zero position. The inference drawn by Mr. Gil] after describing the experiment in detail, is that “the sand rubbing on itself must produce positive charges on the smallest particles and negative charges on the larger.” He goes on to say, “When sand is blown about on a big scale, very large charges must be produced. …”
This raises the question as to what happens during the drifting of snow and whether any charge present on the flakes as they come to rest has an influence on wind-packing.Footnote *