| Show no man made device stops or starts rain many suggestions for stopping the severe douth of 1934 have come in to the united states weather bureau the last few weeks just as many are received for stopping floods in times of excessive rainfall in fact a single cause for example the wide use of radio is often advanced for both drouth and flood no device yet developed by man is of any practical value in starting or stopping rain according to dr W J humphreys of the weather bureau natures method of making rain dr humphreys explains is first to get an abundance of water into the atmosphere by evaporation from water surfaces ice surfaces growing vegetation and damp soil and then to squeeze it out by lowering the temperature ordinarily there is enough moisture in the air to provide at least a moderate rainfall whenever the machinery mr chinery for its condensation densa tion into rain drops is working right this machinery calls for the proper distribution and movement of air masses differing in temperature and density in other words when a normal movement of atmospheric highs and lows is interrupted and a relatively stagnant atmospheric condition is 13 established and persists for a long time drouth develops notwithstanding the fact that there may be enough moisture in the air to prodie cram crain obviously dr humphreys points out radio which neither hastens nor retards regards evaporation and does not cool the air or in any way promote condensation of the moisture in the air cannot be a factor in promoting or hindering rainfall electrical devices sprinkling the clouds with dry ice starting large fires and setting off loud explosions among other rain making schemes suggested either do not work or cost too much for practical use all of the electrical schemes in vesti gated by the weather bureau dr humphreys says ar utterly useless sending cooling substance up into the clouds to cause rain he be adds is about a century old even liquid air has been tried this plan however is wrong in principle and no rain has ever cvar result cd from such auch practices I 1 the use of fire to produce rain was strongly advocated 80 or 90 years ago and this suggestion continues to bob up from time to time |
