Note 3 — BOOK III. OBSERVATION

See Dreyer’s article on these instruments in Copernicus, Vol. I. They were stolen by the Germans after the relief of the Embassies, in 1900. The best description of these instruments is probably that contained in an interesting volume, which may be seen in the library of the R. A. S., entitled Chinese Researches, by Alexander Wyllie (Shanghai, 1897).