Zou Zhengjun yishu 鄒徵君遺書

Zou Zhengjun yishu 鄒徵君遺書 is a collection of the literary remains of Zou Boqi 鄒伯奇 (1819–1869), courtesy name Yi'e 一鶚, Zhijun 徴君 or Tefu 特夫, from Nanhai 南海, Guangdong. He never obtained an office, but remained at his family's residence and studied various aspects of natural sciences. Zou declined Guo Songtao's 郭松濤 (181-1891) invitation to take over the post of director of the Astronomical College (tianwen suanxue guan 天文算學館) in the College of Languages (tongwenguan 同文館) in Beijing, and likewise did not accept Zeng Guofan's 曾國藩 (1811-1872) request to serve in the new Arsenal and Shipyards (jiqi zhizao ju 機器製造局) in Shanghai.

The Yishu was compiled on the basis of Zou's manuscripts and collections and was published posthumously in 1874 by his friends and disciples. It includes writings on astronomy, geography, physics, metrology and mathematics–mainly geometry. Zou approached his field of study not only by consulting books but also through observation, experimentation, drawing, and calculation to explore the principles. Zou Boqi manufactured instruments such as telescopes, microscopes, cameras, armillary spheres, and astrolabes. The Guangzhou Cultural Relics Management Office (Guangzhou Shi Wenwu Guanli Chu 廣州市文物管理處) still preserves some of the astrolabes, maps, telescopes, and manuscripts he created.

Figures 1-3. Illustrations from the Zou Zhengjun yishu 鄒徵君遺書

Calculation of the centre of gravity of a sound stone (qing 磬) from Xueji yide 學計一得.

Rulers with logarithmic scales.

Calculation of half-conic sections from Xia Luanxiang's 夏鸞翔 (d. 1864) Zhiqu tujie 致曲圖解.

The book Geshu bu 格術補 "Supplement to the study of optics" is Zou Boqi's representative work in the field of physics. It is one of modern China's earliest and relatively complete works on geometrical optics. Building upon the optical discussions in the ancient book Mojing 墨經 (see Mozi 墨子) and Shen Kua's Mengxi bitan 夢溪筆談, the Geshu bu further employs geometrical optics methods to thoroughly analyse concepts such as pinhole imaging, lens principles, lens imaging formulas, combined focal lengths of lens groups, the optical principles of the eye and vision, as well as the structure and principles of telescopes and microscopes. It also discusses telescopes, field lenses, exit pupils (chusheguang tong 出射光瞳), and vignetting phenomena (jianyun xianxiang 漸暈現象).

In addition, Zou Boqi made significant contributions to the art of photography. In 1844, he created a photographic device (sheying zhi qi 攝影之器), which was described as follows: "A box made of wood, lined with white paper or white glass, with an aperture at the front fitted with a tube and an adjustable lens, and a viewing hole at the back for observing by moving it as desired." This device is essentially a viewfinder (quyingqi 取景器). Later on, he added a "light gatherer" (shouguangy 收光; aperture) and a "spring mechanism" (tanhuang huodong 彈簧活動; shutter) along with self-made photosensitive plates, transforming these parts into a camera. Zou provided detailed descriptions on the production of photosensitive plates and the processes of taking, developing, and printing photographs. Zou Boqi's achievements in optics and photography were influenced by Western techniques.

The books Xueji yide 學計一得 (1844) and Cungao 存稿 deal with astronomical and calendric calculations. Chengfang jieshu 乘方捷術 and Duisuan chiji 對算尺記 are mathematical texts which explain, for instance, calculations of logarithm (duishu 對數). Yudi quanshu 輿地全圖 (1844) consists of 66 geographical maps.

Not included in the Zou Boqi yishu are Zou's Celiang beiyao 測量備要 on surveying and his phonological study Yupian leiyin 玉篇類音.