This bottle exhibits a standard overlay design of nine chilong or chi dragons that was used on glass snuff bottles at the height of the Qing dynasty. The imagery of nine dragons would have been considered auspicious.
For a related glass snuff bottle with six colors of overlay, and a discussion of this group, see Moss, Graham, Tsang, A Treasury of Chinese Snuff Bottles, the Mary and George Bloch Collection, Volume 5, Part 3, Hong Kong, 2002, pp. 631-632, no. 980.