When the mercury falls to one end, it allows an electric current to flow between two wires and the furnace turns on.
(the mercury; falls; to one end) (the furnace; turns on; ) (it; allows; an electric current to flow between two wires and the furnace turns on; T:When the mercury falls to one end) Context(it allows,List([35, 44))):(an electric current; to flow; between two wires and the furnace turns on)
it allows,List([35, 44))
the mercury the furnace it an electric current
falls turns on allows to flow
to one end
an electric current to flow between two wires and the furnace turns on T:When the mercury falls to one end
between two wires and the furnace turns on