THE work of the American writer Charles Dudley Warner, who died in 1900 has largely failed the test of time. And his only memorable aphorism, which is still occasionally quoted, is not strictly true: "Everybody talks about the weather," he once remarked, "but nobody does anything about it."
"Doing something about the weather, however, is a daunting task. The amounts of energy involved even in very small scale atmospheric processes, are so vast that any human input can only act as a catalyst to trigger something which was perhaps just about to happen anyway. Witness producing rain by "cloud seeding".
The technique originated in 1946 when a US chemist called Vincent Schaefer found that if powdered carbon dioxide, or "dry ice", were dropped into a bank of cloud from an aeroplane, it sometimes acilitated rain. The reason is that the particles of dry ice, or the silver iodide that is sometimes used nowadays, act as a catalyst encouraging the water droplets of the cloud to change into natural ice crystals, which in turn enhance the cloud's ability to produce rain. In the years that followed, the "crop dusters" - those adventurous aviators who earned their living by spraying crops from the air on the vast plains of the United, States - found a new outlet for their skills: they were asked to spray the clouds!
In practice, however, it turned out to be very difficult to assess the efficacy of such a process rain may well occur after the operation - but who is to say that it might not have rained in any case, even without this human intervention?
During the early 1980s, detailed studies were carried out in Australia, Israel and the US, to test the effectiveness of cloud seeding, and the results were analysed by the British cloud physicist Sir John Mason. He concluded: "In the case of the Tasmania and Florida experiments the evidence does not provide strong support for a positive seeding effect.
"Statistical evaluation of the Israeli experiment, however, provides much more convincing evidence, and suggests an average increase in rainfall due to seeding of about 15 per cent. But why the clouds in Israel should be more responsive to seeding than rather similar clouds in other parts of the world is not immediately clear."
How Irish clouds might react to such an onslaught, no one knows. Luckily it is only rarely, as at present, that such an experiment might seem in any way attractive.