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. 13 . After the crystal grew for 30 to 180 seconds, a slide coated with silicon oil captured and preserved the crystal that was to be examined under a microscope and then melted to determine its mass and dimension by methods employed by Fukuta (1969). For thin plates, two experimental runs were necessary to determine both the a. and c.axial lengths. Ice crystals reportedly aggregated on the slide or just prior to collection at -15 and -17"<:. Thus, either the aggregate was ignored or the mean mass of all crystals forming the aggregate was determined. The data consisted of the mass and dimensions of the ice crystal after 30 to 180 seconds of growth, at temperatures between -3 to -2IOC. The fall velocity was not taken during the entire experimental investigation. The data were then plotted on a log-log graph as a function of time at constant temperature. Equations describing the data were fitted between the points. and the mass and the dimensions were calculated from these empirical expressions at 50, 100 and 150 seconds. The calculated values were then plotted as a function of temperature and extrapolated from the graph in order to make a data set suitable for use in this thesis. Despite some improvements in the methods such as the popping bubble technique, some serious problems existed in this experimental study. Perhaps the biggest drawback was the absence of fall velocity data. This data void hindered any study of the aerodynamic behavior of the crystal, a major topic to be discussed later in this thesis. Another problem was the presence of a heated vapor source at the base of the chamber, which could have caused significant thermal gradients in the the vertical direction despite recording only a O.soC change between the two thermocouples. Thus the assumption of homogeneous temperature implicit in each log.log plot as a function of time . . . . . . . . .