A new method of cinematography was devised by the authors, for taking pictures of the. formation of ice crystals in water. By this, the successive stages were observed in the develop-ment of ice crystals. The conditions for giving a circular ice-disc, stellar crystal and needle-like crystal were studied. In every case, ice-discs were the slowest to be produced, stellar and especially needle-like crystal requiring less time as seen in Fig. 3-7. Some tiny particles as silver. iodide, kaolin, carbon or clay were not directly active as nuclei of ice crystals in this experiment.