Cycles longs des prix des produits de base : cycles Kondratiev ou cycles Kuznets?

The recent empirical researches that have been carried out about the super cycles of commodity prices have led us, in this article, to return to the works that N.D. Kondratiev and S. Kuznets devoted to the issue of prices between the two World Wars. On the one hand, the long-term price cycles which had been highlighted by these two authors and which presented a periodicity of about fifty (Kondratiev) and twenty (Kuznets) years, were outlined from an analysis of the dynamics of the prices of raw materials. On the other hand, the average durations of the super cycles of the staple goods prices, that have been identified over these last years, enfold over a particularly large sequence of time (22 to 54.5 years) that includes, amongst others, the two periodicities of Kuznets and Kondratiev. This result is worth noting as, since the 1980s, most empirical contributions that have corroborated the existence of long cycles, have mostly insisted not on the presence of these two types of recurrences among the studied series, but on the presence of one and the absence of the other one. In contrast to these studies, the latest ones that have been recently carried out about the super cycles of commodity prices, invite us not to oppose Kuznets and Kondratiev but, on the contrary, to reconcile these authors regarding the issue of prices as they are both pioneers in the study of long cycles of staple goods prices.