“Sources, Cultural Value and Knowledge Transfer in the Biligui jie 比例規解 (An Explanation of the Proportional Compass)”

One of the main problems in studying missionary texts in Chinese language concerns their sources. Since composing such texts implied a complex process that involved several individuals - the missionaries who dictated the texts, the Chinese assistants who wrote them, the revisers, the editors, the censors, among others - very seldom Chinese missionary texts can be traced back to a single known source. Besides, even if a source is clearly identified, a thorough analysis of the Chinese text may reveal major divergences from the alleged original.  Identifying sources is far from being an easy task — a task that seems to be even more challenging in the case of writings that describe the use of technical instruments. An analysis of the Biligui jie (An Explanation of the Proportional Compass, 1631) by Giacomo Rho and other collaborators in the Chongzheng lishu corpus (Calendrical Compendium of the Chongzhen Reign, 1635) will offer the opportunity to formulate new hypotheses regarding its sources and, at the same time, allow for a new appreciation of the cultural value of that great mathematical and astronomical collection.