Appendix_3: Duan Cheng Shi & Shen Kuo

Youyang Zazu by Duan Cheng Shi

As described in the main text, Arabian and Chinese records of the middle ages concerning the pinhole phenomenon have been passed down to the present.  Among them we would like to describe several points on the Chinese documents, Youyang Zazu (酉陽雑爼: Miscellaneous Morsels from Youyang, 863) and Meng Xi Bi Tan (夢渓筆談: Dream Pool Essays, 1088).  Youyang Zazu was written by Duan Cheng Shi(段成式: 803? – 806), a government official of Tang Dynasty, and is composed of 20 main volumes and 10 supplemental volumes.  ”Youyang Zazu” is a miscellany of Chinese and foreign legends and other various topics, which were described on the basis of fabulous “1000 volumes of books” pretended to be stored in a cave at the south slope of Mt. You.  Though a large part of Youyang Zazu consists of teratology, for the extreme extensiveness which it covers Youyang Zazu receives recognition as such from a naturalistic viewpoint.  One of the famous stories in Youyang Zazu is, though it has no relation with the pinhole phenomenon, the story of Ye Xian, which is written in the supplemental volume 1.  This story is considered as the oldest version of the well-known Cinderella story, different versions of which are found all over the world.  The pinhole phenomenon of a tower located near a sea is described in the volume 4 of the main part of Youyang Zazu.  In this part it is described that a resupinate image of a tower was observed because of vicinity of a sea.

Meng Xi Bi Tan by Shen Kuo

On the other hand, in Meng Xi Bi Tan (Dream Pool Essays), Shen Kuo (沈括: 1031 – 1095) described  that image of direction of flight of a bird was inverse from the reality and image of a tower was changed upside down by the pinhole projection.  And, moreover, he pointed out that the description in Youyang Zazu, i.e., “the inverted image of a tower is caused by the fact that the tower is located near a sea”, was erroneous and described that the inversion of the image is due to the light passing through a small hole.  He was understanding the principle of the pinhole phenomenon correctly.  As a matter of fact, Shen Kuo was a super-polymath of Song Dynasty (960 – 1270) and played active parts in various fields as government, military affair, scholarship, art, and so on.  In the following his career and accomplishments are summarized.  He was born in a family of a somewhat lower-class provincial level official.  When he was 32 Shen Kuo successfully passed the Imperial Examination and became Jinshi (presented scholar).  In addition to a scholar-official for the central government, Shen Kuo was also an ambassador to the Western Xia Dynasty and Liao Dynasty, a military commander, a director of hydraulic works, and the leading chancellor of the Hanlin Academy. Shen was appointed as the head official of the Bureau of Astronomy, and he was responsible for projects in improving calendrical science. Moreover,he was appointed as the Finance Commissioner. He took an active role not only as a competent bureaucrat in this way but also as a scientist he produced  excellent results in the fields of pharmacology, engineering , anatomy, mathematics, optics,geology, archeology, meteorology, philosophy, and so on.   Especially he is famous of observing refraction of the sunlight by the atmosphere, explaining formation of a rainbow, discovering the difference between the magnetic poles and the geographic poles of the Earth, inventing a magnetic needle compass usable for navigation on the sea and determination of the position of the polaris.  After retirement, Shen had purchased a lavish garden estate which he named “Dream Brook” (“Mengxi”) and moved there, where he completed his written work of Meng Xi Bi Tan.