No, John Francis, it is not a reference to the Maine Farmer's Almanac of 1937. It is to J. Hugh Pruett, writing in Sky and Telescope in 1946 (57 years ago). It appears that your search did not reveal this reference. This information is from Scientific American response to an "Ask the Experts" Query posed by B. Purvis of Carlisle, Pa. George Spagna, chair of the physics department at Randolph-Macon College, provided the explanation. I provided the link earlier, but you didn't read it.
http://www.sciam.com/askexpert_question.cfm?articleID=0009335C-8A1B-1CD1-B4A8809EC588EEDF I will now do the work for you and quote the article: "A "blue moon" once meant something impossible or at least highly unlikely, much like the expression "when donkeys fly!" This was apparently the usage as early as the 16th century." "Then in 1883, the explosion of Krakatau in Indonesia threw enough dust into the atmosphere to turn worldwide sunsets green and the moon blue. Forest fires, prolonged drought and volcanic eruptions can still do this. So a blue moon became synonymous with something rare-hence the phrase "once in a blue moon." "The connection of a blue moon with the calendar apparently comes from the Maine Farmers' Almanac published in 1937. The almanac relies on the tropical year, which runs from winter solstice to winter solstice. In it, the seasons are not identical in length because the earth's orbit is elliptical rather than circular. Further, the synodic month is approximately 29.5 days, which doesn't fit evenly into a 365.24-day tropical year, nor into seasons only approximately three months in length." "Most tropical years have 12 full moons, but occasionally there will be 13, so one of the seasons will get four. They called the occasional third full moon in that season in which there happened to be four a blue moon. (The full moons closest to the equinoxes and solstices already have traditional names.) J. Hugh Pruett, writing in Sky and Telescope in 1946, misinterpreted their version to mean the second full moon in a given month. That version was repeated in a broadcast on National Public Radio's Star Date in 1980, and the definition has stuck!" "Although it is true that the phrase comes from a folk tale, the current folk tale isn't very old. So when someone talks about a blue moon today, they are referring to the second full moon in a month." The answer was posted on December 31, 2001 You may now be happy! Regards, Bob... -------------------------------------------- "Do not suppose that abuses are eliminated by destroying the object which is abused. Men can go wrong with wine and women. Shall we then prohibit and abolish women?" -Martin Luther From: "John Francis" <[EMAIL PROTECTED]> > The belief that the second full moon in a calendar month is a "blue moon" > has *not* been around for six decades, assuming that to be a reference > to the Maine Farmer's Almanac of 1937. That stated (with no references, > and no easily discovered antecedents) that the fourth full moon in a > season was a "blue moon". (That wouldn't be all that rare, of course, > but neither is a month containing two full moons). > > This article was mis-interpreted (in a 1999 article in Sky & Telescope) > to support the popular belief of the second new moon in a calendar month. > A retraction was published a little later, but by then the damage was done. > > AFAIK no reference to the "two moons in a calendar month" meaning has been > found in any source prior to 1985 - slightly less than two decades ago. > > I'd be happy to be proved wrong, but I'd want to see some evidence.
