Sparklets were a custom made bottle that allowed for the carbonation of water. The bulbs (below) provided the carbon acid required to aerate the water. At the time of the author's use they were a relatively new invention having only been developed for the first time 1896. There is a great resource for learning more about Sparklets https://www.sparklets.net/sparklets-history/. Images are courtesy of that site.
Charles Orr's Memoirs Volume 5
