The present lot is unique in its form and decoration among the very few enamelled glass wares produced in the Beijing workshops of the Qianlong period. Compare a related example of the same size with a lipped mouth rim, decorated with plum blossom branches and bears a Guyuexuan mark, believed to be produced by a Beijing private workshop dating to the 1750s-1850s, illustrated by Huge Moss, By Imperial Command, Introduction to Ch'ing Imperial Painted Enamels (Plates), Hong Kong, 1976, pl. 42.
In an essay by Zhang Rong, 'Qing in the Imperial Workshops of the Qing Court', the author mentions that single-coloured and overlay glass wares were the most prevalent types produced in the Imperial workshops during the Qianlong period. It appears that very few enamelled examples were commissioned and of these only 20 pieces remain in the Beijing Palace Museum Collection. See Luster of Autumn Water Glass of Qing Imperial Workshop, Beijing, 2005, pp. 19-20.
The portrayal of the Chi dragons is closely related in design to imperial carved glass water pots, such as the Qianlong-marked example with a green overlay on blue ground in the Qing Court Collection, illustrated by Zhang Rong, op. cit., p. 244, pl. 79. A related Qianlong period example of this type of small water pot, produced of carved crystal, was included in the Oriental Ceramic Society of Hong Kong exhibition, Arts from the Scholar's Studio, Fung Ping Shan Museum, University of Hong Kong, 1986, and illustrated in the Catalogue, no. 93.