Abstract
An experiment on the growth of ice crystals in a super-cooled fog (-4.4°C) was conducted. The replicas of ice crystals which had fallen on glass slides were measured. The slides were held horizontally and exposed one minute at 50, 100, 200, 500 and 700 metres leewards of the seeding point. When the seeding was made with a lump of dry ice, ice crystals were produced and grew to columnar form. During about the first 2 minutes, the crystals grew in both directions, i.e., along their principal and lateral axes, but thereafter they grew only along their principal axes. The rate of increase of the length of columnar crystals was about 2μ/sec. The length attained to 550μ in about 5 minutes, which was observed at the position 700 metres leewards of the seeding point, while the width of the same crystals remained at about 50μ. The obtained growth rate is compared with that calculated by Houghton.
