Gas chamber carbon monoxide as the lethal agent. Sometimes a box filled with anesthetic gas is used to anesthetize small animals for surgery or euthanasia. Gas chamber A gas chamber is an apparatus for killing humans or other animals with gas, consisting of a sealed chamber into which a poisonous or asphyxiant gas is introduced. The most commonly used poisonous agent is hydrogen cyanide; carbon dioxide and carbon monoxide have also been used. Gas chambers were used as a method of execution for condemned prisoners in the United States beginning in the 1920s and continue to be a legal execution method in
Lawn mower are still available. The reel is attached to the mower's wheels by gears, so that when the mower is pushed forward, the reel spins several times faster than the plastic or rubber-tired wheels turn. These types of reel mowers offer the benefit of zero pollution being produced. Since all of the energy necessary comes from the user, however, this method of mowing is the most strenuous and is not recommended for large lawns. Depending on the placement of the reel, these mowers often cannot cut grass very close to lawn obstacles, like trees, driveways, edging, etc., and also require a