Dèng Yùhán 鄧玉函 / Johann Schreck (Terrentius), S.J.
German Jesuit. Born Bingen-on-the-Rhine (then Imperial city, Holy Roman Empire), 1576; died Beijing, 11 May 1630 — eight months after the official inauguration of the Chóngzhēn calendar-reform project, before the bulk of his contributions could be completed. The Chinese name Dèng Yùhán is conventional; in Latin scholarly writings he most commonly used the toponymic adoptive name Terrentius or the variant Joannes Terrentius Constantiensis (Constantia = Konstanz).
Trained as a physician and natural-philosopher at the universities of Freiburg, Padua, and elsewhere; admitted as the seventh full member of the Accademia dei Lincei (Lincean Academy of Rome) in 1611, alongside Galileo Galilei (the third member) — the only Jesuit ever admitted to that pre-eminent late-Renaissance scientific academy. Joined the Society of Jesus in 1611, after his Lincean election; sent to Asia 1618 with Nicolas Trigault 金尼閣’s recruiting mission, arriving Macao 1619 and Beijing 1623.
His contributions to the Chinese-language scientific corpus, all completed in his short Beijing period (1623–1630):
(1) Anatomy: the Tàixī rénshēn shuōgài 泰西人身說概 (manuscript completed 1623–1625, posthumously printed) — the first systematic exposition of European Vesalian anatomy in Chinese, derived primarily from Caspar Bauhin’s Theatrum anatomicum (Frankfurt 1605) which Schreck had brought from Europe.
(2) Mechanics: the Yuǎnxī qíqì túshuō lùzuì 遠西奇器圖說錄最 (1627, with Wáng Zhēng 王徵 as Chinese collaborator-and-translator) — the first systematic exposition of European Renaissance mechanical engineering in Chinese, based primarily on Vitruvius and on Agostino Ramelli’s Le diverse et artificiose machine (Paris 1588) and Jacques Besson’s Théâtre des instrumens (Lyon 1578).
(3) Calendar reform: when the Chóngzhēn project began in 1629, Schreck was named one of its four Western collaborators. He brought to the project the most up-to-date European astronomical materials in the China mission: Tycho Brahe’s Astronomiae instauratae progymnasmata (1602) and Astronomiae instauratae mechanica (1602), Kepler’s Tabulae Rudolphinae (1627) — works obtained in Europe during his 1611–1618 European period — and his own correspondence with Galileo Galilei and with Kepler himself. Galileo had declined to share his telescopic observations with the Jesuits (the Galileo trial would not begin for another four years), but Kepler had responded warmly to Schreck’s inquiries with detailed astronomical-mathematical advice. Schreck’s Beijing notes — the Dàcè 大測 (Great Measurement), the Cètiān yuēshuō 測天約說 (Brief Treatise on Measuring the Heavens), the Huángchì jùdù biǎo 黄赤距度表 (Tables of Ecliptic-Equatorial Latitudinal Distance) — were absorbed into the Chóngzhēn lìshū (KR3f0013 Xīnfǎ suànshū) by his successors after his death.
Schreck died of fever in 1630, only fourteen months into the calendar-reform project. His remaining Tycho-Kepler material was inherited and developed by Giacomo Rho 羅雅谷 (羅雅谷) and Adam Schall von Bell 湯若望 (湯若望), who completed the Lìshū in installments under Lǐ Tiānjīng’s 李天經 direction over the next five years. Through the Schreck inheritance, Tycho’s geo-heliocentric system and Kepler’s elliptical-orbit reform (the post-Copernican-but-pre-Newtonian European synthesis) became the foundation of the Chinese state calendar from 1645 onward.