While this diagram shows a typical model N setup it applies to all models having an ignitor with battery and coil ignition.  The number of dry cells could have varied but usually between 4 and 6 were used.  The same configuration would also have been present on large engines having both a geared magneto and starting batteries, only the connection to the insulated electrode would have been made using a 2 position switch.  A copy of this diagram would have been stapled inside the battery box lid for quick reference.