As early as 1829, George MacKenzie proposed that solar activity drove a 54 year cycle in the price of wheat. Then, in 1847, Dr. Hyde Clarke, published a paper, "Physical Economy" in the .British Railway Journal. that supported MacKenzie's "circle" of wheat prices. Clarke speculated that the "cyclar period of famine" was related to fluctuations in the earth's electromagnetic field (Klein 1997, p. 113; see also Mager 1987, p. 21). Ten years later, in 1857, William Langton, founder of the Manchester Statistical Society, reported that he found statistical evidence that cycles appear more or less regularly at ten-year intervals (Peart 1991, p. 246). Not long thereafter, William Stanley Jevons, who was teaching in Manchester, attempted to reduce economic fluctuations to cycles of solar activity (Jevons 1879). Jevons reasoned that solar conditions affected the weather, which in turn affected agricultural yields, which were then the decisive factor in determining the level of economic activity. Michael Perelman