Essay Review: Astronomy in Japan: A History of Japanese Astronomy: Chinese Background and Western Impact

In the present review, in accordance with the English usage, given names precede surnames.

For a detailed analysis of the passage I refer to a paper under preparation.

See Beer A. Ping-Yü Ho Gwei-Djen Lu Needham J. Pulleyblank E. G. and Thompson G. I. , “An Eighth-Century Meridian Line: I-Hsing's Chain of Gnomons and the Pre-history of the Metric System”, Vistas in astronomy (ed. Beer A. ), iv (1961), 3–28, Table 2 (p. 15).

This linear interdependence does not of course hold true of the Winter solstice or equinox shadows. For the Winter solstice umbra at Yang-ch'eng we obtain the length 13·5 ft, exactly as indicated in the Chou-pi suan-ching; 7° North (ϕ = 42°20′) it measures 18·3 ft, 7° South (28°20′), it is 10·4 ft, the differences being 4·8 and 3·1 ft respectively. The corresponding values for the solstices are 5·67 (Yang-ch'eng), 7·30 (at 42°20′) and 4·32 (at 28°20′), with differences 1·63 and 1·35 ft. In the second part of the Chou-pi suan-ching the shadow lengths for each of the 24 solar terms (ch'i), which divide the solar year into 24 equal parts, are given with an accuracy of one-hundredth of an inch (hsiao-fen) or 0·3 mm. At closer inspection it is seen that only the solstitial shadows (1·6 and 13·5 ft) were observed and the rest obtained by linear interpolation. This meaningless procedure may have been due to the unjustified belief that an analogy must obtain between the linear progression of the Summer solstice shadows as demonstrated above and any other kind of shadow measurements. This demonstration may prove capable of shedding new light on I-Hsing's measurements as discussed in the paper cited above (ref. 3). In particular, the statement: “it is hard to see how he [I-Hsing] could have given a constant li per degree, if he had not had at least some arrière-pensée of a curved Earth's surface” (p. 25) will have to be reconsidered.

See Hartner W. , “Naṣīr al-Dīn al-Ṭūsī's Lunar Theory”, Physis, xi (1969), 287–304.

See Hartner W. , “Das Datum der Shih-ching-Finsternis”, T'oung Pao, xxxi (1934), 188–236, reprinted in Hartner W. , Oriens-Occidens (Hildesheim, 1968); and Hartner W. , “Eclipse Periods and Thales' Prediction of a Solar Eclipse: Historic Truth and Modern Myth”, in Centaurus, xiv (1969), 60–71.

See Hartner W. , Das Datum… (see ref. 6), pp. 199 ff.

“Honpō kodai no nisshoku ni tsuite”, in Nihon tenmongakkai yōhō, vi (4) (1941), 143–69.

See Maspero H. , “L'astronomie chinoise avant les Han”, T'oung Pao, xxvi (1929), 267–356, pp. 271 ff.

See Beer A. , “Astronomical Dating of Works of Art”, in Vistas in astronomy, ix (1967), 177–223, pp. 207 ff.

See Hartner W. , “Le problème de la planète Kaīd”, in Les Conférences du Palais de la Découverte, Série D, no. 36 (Université de Paris, 1955); reprinted in Oriens-Occidens.

“Shōchōhō no kenkyū (Variation of tropical-year length in Far Eastern astronomy and its observational basis)”, in Kagakushi kenkyū (Journal of History of Science, Japan), nos. 66 and 67 (1963).

There are no such early observations. Apart from this, by including them the whole procedure would of course become meaningless.

See the end of section.

See Nakayama's article cited above (ref. 12), no. 66, p. 70, formula (21).

To 0^d·0075 exactly there corresponds a difference in years of 3544, which brings us back to year 7 of the reign of Yao.