Gravity cells were used to provide local circuit power at telegraph offices. Jesus! I despised them. In my first years as a telegrapher I invariably was stationed at a one man office or was low man on the totem pole at two or three man offices and had maintain the jars and rebuild them as the reacting metals and chemicals were consumed by electrolysis.
Gravity cells were a pain in the butt; dry cells at each telegraphone were more so - and expensive. Sub-zero temperature lowered their voltage; snow that filled booths or filtered into battery containers; rainstorms that saturated batteries; grounds not being moistened occasionally in hot, arid locations; birds and rodents nesting atop battery terminals and farmers or hikers taking batteries for their own use - you name it, I could tell you a dozen stories of ordinary occurrences that escalated into crisis for lack of the 9 volts needed at each telegraphone installation.