Gas lighting explains why a large number of older gas lamps have been converted to electricity. Solar-rechargeable battery-powered gas light controllers can be easily retrofitted into existing gas lamps to keep the lights off during daylight hours and cut energy consumption and green-house gas carbon emissions by 50%. The use of natural gas (methane) for "indoor" lighting is nearly extinct. Besides producing a lot of heat, the combustion of methane tends to release significant amounts of carbon monoxide, a colorless and odorless gas which is more readily absorbed by the blood than oxygen, and can be deadly. Historically, the use of lamps
Lawn mower lifting air-cushion is destroyed by wide gaps between the chassis and the ground. Hover mowers are built to operate on steep slopes, waterfronts, and high-weeded areas, so they are often used by golf course greenskeepers and commercial landscapers. Grass collection is often available, but can be poor in some models. The quality of cut can be inferior if the grass is pushed away from the blade by the cushion of air. A robotic mower is contained by a border wire around the lawn that defines the area to be mowed. The robot uses this wire to locate the boundary of