The Weather Experiment: The Pioneers Who Sought to See the Future is a somewhat tedious book that covers the infancy of weather forecasting. There is an interesting anecdote about a 19th century effort to determine whether or not prayer was effective:
Never one to quake in the shadows of old institutions, [Francis] Galton had turned his mind to the practice of prayer. The question was troubling him. Did prayers work? In his usual methodical way he began to tackle the issue statistically. He started his experiment with a hypothesis: ‘We are encouraged to ask special blessings, both spiritual and temporal, in hopes that thus, and thus only, we may obtain them,taken from Smith’s Dictionary of the Bible. He then devised a way of testing the claim. He found a copy of the Journal of the Statistical Society, which listed the mean life expectancy of kings and queens with those of other classes of people. Galton pointed out that at every church service, Protestant or Catholic, it was customary to pray for the sovereign: ‘Grant him/her in health long to live’. If prayer worked, Galton argued, specifically such targeted and constant prayer as this should result in longer lives for kings or queens. But according to the Journal of the Statistical Society, this was not the case. A member of the royal house lived an average of 64.04 years, while clergy, lawyers, medical doctors and the aristocracy lived much closer to 70 years. ‘The sovereigns are literally the shortest lived of all who have the advantage of affluence,’ Galton summed up. ‘The prayer has therefore no efficacy.’27 Galton’s paper would not see the light of day until it appeared with predictable controversy in the Fortnightly Review in 1872. But its very existence was significant. If he had written such a paper three hundred years before he would have been burnt; two hundred years before he would have been thrown into prison, or a hundred years before into a lunatic asylum. Yet by the 1860s such questions about the power and integrity of religion had found their place in contemporary debate. Galton was only writing what many were already thinking. [emphasis added]
Separately, how is it that medical doctors, constantly exposed to contagious diseases for which there were no effective vaccinations or cures, managed to live so long? Is it that germs were so prevalent that everyone else was equally exposed?