OCR Text |
Show This report discusses a continuation of experiments first described earlier in this series ( Project C, Progress Report No. 3, published in February 1962)• Laboratory Tests Another test of artificial depth hoar formation in the presence of organic vapors was run over a 19- day period from late February to mid- March, 1962, Experimental conditions were the same as those described in the previous report, 630- cc samples of fresh snow being subjected to a strong temperature gradient in a deep- freeze unit. In this case the number of specimens tested was doubled to twelve. Snow used in the experiment was partly metamorphosed new snow consisting largely of stellar crystals. Initial density ( collected in sample containers) was 0.12 at beginning of experiment on 20 February. Two of the 12 samples, one in each plastic block, were reserved as control, and various chemicals were added to the other samples in the quantity of 2- 3 drops per sample. N- heptaldehyde, which proved to be a strong depth hoar inhibiting agent in the first experiment, was tested again in two different concentrations. Hie samples settled to 2/ 3 their original volume by the time the experiment was terminated on 13 March, resulting in an average terminal density of 0. l8 g/ cm • The following results were noted from this second test of chemical effects on artificially- generated depth hoar: Sample with General Electric Dri- Film ( methyldichlorosilane); About 75# of the snow was converted to typically fragile depth hoar, crystal size 2- 3 mm. This sample was very similar to the control samples, indicating little noticeable effect from the Dri- Film. |