The Art of projection and complete magic lantern ... - Yesterday Image

6sNO DANGER WITH GAS CYLINDERS,OR BAGS.The few accidents that we hear of are very far between, when it isconsidered fairly,with the thousands of lanterns in use at all times, in allplaces, and under various conditions.When practically considered, an accident has never yet occurred inwhich gross carelessness could not be traced. Many simple things indaily use are dangerous, when perverted from their intended use, andthe same applies to lantern apparatus. As all students of chemistry areaware, when oxygen and hydrogen gases are mixed, in the proportionof three parts to one, and a light applied, an explosion results.Supposing the gases were so mixed together in a single cylinder, noexplosion would take place unless a light was applied, and even thenunder certain conditions, the gases will burn without an explosion, theignition inside only takes place when the cylinder is nearly empty or thepressure reduced, then the light passes back.Example.— If a bladder filled with a mixture of these two gases intheir most explosive form, has a small hole pricked in it and a lightapplied from the end of a stick, the result is the gases burn steadilywith a bright flame, until the bladder is all but empty, and at thatpoint when there is no pressure to force the remaining gas out, the lightappears to be drawn back, then the report.Now, supposing by misadventure (which we do not admit possible), thetwo gasses have been mixed in one cylinder. What happens ? Theoperator lights up his jets, if mixed in the hydrogen cylinder, a brightlight appears at once, as though the oxygen tap was also on, and if theoperator is wise, he shuts off the jet at once, and tests the hydrogen,not by applying a light— that would be worse than the evil,—allowa little of the gas to escape into a tin can (the lime tin is the handiest),allowing sufficient to force the air out, cover the top, apply a light ifyou like, at a distance from you, if the gases are mixed a slight reportwill take place, if pure hydrogen, or coal gas, it will burn with a smallflame around the top of the tin.Now, presuming the hydrogen this time has become mixed withoxygen. What happens ? The gas from the hydrogen cylinder or bagis alight in the lantern, the oxygen tap is turned on, and if mixed,the usual brilliancy of light is not obtained, as is usual when the oxygenis turned into the hydrogen, in that case the oxygen tap should beturned off at once, do not wait or continue to try again, but test theoxygen in a tin in the same manner, filling the tin by allowing the gasto run in, and oxygen being considerably heavier than the atmosphere,Ethe