Double overlays of this type appear to have become popular at the Court during the second half of the Qianlong period. For other examples, and a discussion on their provenance and dating, see Moss et. al., A Treasury of Chinese Snuff Bottles, vol. 5, Glass, nos. 1000-6. Apart from the style of overlay, the subject matter here is also typical of Courtly production from the mid-Qing period, with its archaistic subject and its chi and kui dragons, although the rather dull, dense nature of the snowstorm ground may indicate a date from the very early nineteenth century rather than the late Qianlong period. The bi-disc with its 'C' scrolls was also typical of Courtly design, derived from Qianlong Emperor's massive collection of ancient artifacts and his need to establish his foreign rule as rooted in an ancient Chinese past. For a Qianlong-marked glass bottle of similar design, still in the Imperial Collection, see Chang Lin-sheng, Snuff Bottles in the Collection of the National Palace Museum, no. 284.