Since ancient times man has dreamed of manipulating the weather to his advantage. His efforts to this end have ranged from drawing pictographs, lighting ceremonial fires, participating in rain dances and then during the past twenty-one years in directing his attention toward utilizing certain scientific relationships to initiate physical and chemical reactions in the atmosphere.
There are certain of these reactions which can be demonstrated in both the laboratory and the field. They are spectacular to see, are fairly well understood from the scientific viewpoint and can be used to produce definite and predictable reactions.
There no longer is any question that it is quite feasible to modify supercooled clouds wherever they occur. There is still much uncertainty as to subsequent developments which may occur due to such actions especially in unstable cloud systems. Unlike supercooled fogs and stratus clouds where the seeding results may be photographed and quantitatively measured, these less stable systems involving convection, convergence and divergence of moist and dry air are difficult systems to evaluate.
This paper reviews briefly certain aspects of weather control prior to 1946 and then attempts to provide an accurate historical chronology of the significant advances which occurred during the early period of this new phase of atmospheric science.
The control of the weather within our global atmosphere has been a dream of man for many centuries. In its earliest phases this ambition was limited to the rain needed for a tiny patch of corn or some similar local and immediate need. As man's knowledge of the atmosphere increased and his needs became more urgent and widespread, his approach to such problems were increasingly directed toward a scientific consideration of the possibilities as well as limitations of changing atmospheric processes.
Prior to 1946, all of the proposals advanced toward doing something about modifying atmospheric processes failed to consider the massive nature of the atmosphere and the need to depend on triggering mechanisms to utilize the latent energy which develops from some of the physical reactions and interactions which occur in clear and cloudy skies.