Leg press, deadlifts, RDLs, lunges, leg extensions, leg curls, hack squats, split squats. All those will hit your legs, plus there variations. Do some sprints, run hills, stairs, those will hit your legs. Im sure there are more lifts I can't think of this second as well.
While natural gas occurs in nature as a mixture of methane and other gases, propane is actually a byproduct of both petroleum refining and natural gas processing.
There are also two main differences in the way that LPG (Propane) and natural gas (Methane) are burnt. The first difference is in the energy content. LPG has a higher energy content than natural gas, with 93.2MJ/m3 vs 38.7MJ/m3. With this higher calorific value, less LPG is required to produce the same amount of heat.