Tyndall Figures formed in Crystallographic Plane Perpendicular to Basal Plane of Ice Crystals

Abstract

SINCE the classical work by Tyndall¹, the liquid figures in ice crystals caused by internal melting have been well known as ‘Tyndall figures’. Recently, Nakaya² and Krüger³ examined in detail the Tyndall figures formed in the crystallographic basal plane of ice crystals, namely, dendritic figures with such hexagonal symmetry as a six-petalled flower or a plane dendritic snow crystal. However, no attention has been paid to the Tyndall figure with no hexagonal symmetry but rather tetragonal, in spite of the fact that such figures can be seen in the original sketch by Tyndall as shown by the arrows in Fig. 1. (Since the original book by Tyndall is not available, this figure is reproduced from Krüger's paper⁴.) I had a chance to observe such figures during experiments on internal melting of ice samples cut from the stratified ice of Fletcher';s Ice Island, T–3 (ref. 5). The production and observation of Tyndall figures were carried out by the same method as that of Nakaya². The temperature of the ice samples was considered, to be nearly equal to 0° C, since melting occurred on the surfaces of ice samples during the experiments carried out in a room warmer than 0° C.