Abstract
Measurements have been made of the time lag which silver iodide particles exhibit in the nucleation of ice crystals at temperatures between −8C and −16C. The time tag is approximately exponential, the decay constants being 3.6 minutes and 1.4 minutes at −8.5C and −15.5C, respectively. The decay constant at −15.5C is less by a factor of 4.5 than that for natural ice nuclei. The observed time lag is in qualitative agreement with Fletcher's theory.