One manifestation of the belief in question is found in the common assertion that rain is the usual sequel of battles. This idea originated, however, long before the invention of gunpowder. It is mentioned by Plutarch and other writers of antiquity. Whatever superstition or crude process of reasoning may have first given support to this notion in the popular mind, the explanation now commonly advanced is that the condensation of moisture is promoted by the concussion due to cannonading, or that the drops already condensed and constituting the clouds are jostled together by the same disturbance, with the result that they coalesce and fall as rain. There is no ground for such assumptions. As was once pointed out by the late Professor Simon Newcomb, the effect of a violent explosion upon a body of moist air a quarter of a mile distant is about the same as that which the clapping of one’s hands would produce upon the moist air of the room in which the experiment is performed. Again, if we stand in the steam escaping from a teakettle and clap our hands we shall not produce a shower, though we jostle the water drops much more than the explosion does at a distance of a quarter of a mile. In recent years another explanation has been offered for the alleged production of rain by explosions; viz., that the smoke and gases arising from an explosion increase condensation by increasing the number of “nuclei” in the atmosphere. As we have seen, however, in considering the natural formation of rain, the number of condensation nuclei normally present in the atmosphere is so great that it must be diminished, rather than increased, before drops as large as raindrops can be formed. Moreover, the nuclei required for the condensation of water vapor, including molecules of highly hygroscopic gases, are given forth in abundance by great manufacturing centers, yet these places do not have a heavier rainfall than the surrounding country. Pittsburgh, for example, is actually one of the driest places in Pennsylvania. One obvious reason why rain often follows a battle is that battles are frequently fought in regions where rain normally occurs every two or three days, on an average, whether in peace or war. In northern France, for example, where the battles of the World War were plenteously interspersed with showers, meteorological records show that the average number of rainy days per annum is upward of 150. The drenching rains that made “Virginia mud” a byword during the American Civil War gave great currency to the belief in “rain after battles,” Here, again, we have accurate weather records to help us dispel a fallacy. Thus at Richmond rain falls on 122 days in an average year, at Lynchburg on 124 days, and at Petersburg on 105 days.