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

88desired size. It is as well to have a couple of limes so drilled andcleaned always ready in the bottom of the lantern tray, in the case of morethan one lantern being used the heat from the jet below will keep thelime warm ; when putting limes on the jets for first time, a little hydrogenshould be allowed to play, and so gradually warm them, and to make thehealing equal, the lime turner should be gently turned once or twice.We can never see the object of putting limes up in boxes with thelime dust, such packing to the general idea is to keep them from bursting.Now we have very strong proof that it has a tendency to act just thereverse ; a box of limes filled up with powder will burst much soonerthan one packed without. Lime powder absorbs the moisture muchquicker than will a piece of solid lime, the lime powder is often very oldbefore it is put in with the limes and boxed up, saying nothing of themess of lime dust every time a lime has to be used from the box.The class of lime to give the best result is found by proof, to be of thenature known as soft lime, yet it is not soft, but brittle, like a biscuit, webelieve it to be very rare as it is the picked lime from a quantity, andcauses much waste in turning. The ordinary soft lime is suitably adaptedfor safety jets, and may even be used with chamber jets, only it is verynecessary to keep a constant watch by frequently turning, as holes aresoon bored by the gases which causes the flame to rebound at an equalangle and crack the condense*".A soft lime gives a light superior to the hard stone limes, known asNottingham, Excelsiors, etc., scfme of which are not pure limes, but acomposition ; another advantage of the soft lime is that it becomes incandescentas soon as the gases are turned on to it, and dies off as readilywhen turned down, which is not the case with hard limes, as they takesome time to become incandescent, which is very inconvenient when quickdissolving is required.Hard stone limes have their advantages over soft in certain circumstances,although there is a loss of light where a jet is required to beconstantly burning, or when it is not possible to give the necessaryattention to the jet, as in the case of light boxes for theatrical work.The form of lime which for want of a better title is known as " Incandescent"may be depended upon for uniform quality, it is made from alime obtained in France, and possesses the advantage of not being toohard or yet soft, when first acted upon by the gases the edges will turnslightly red, which goes ofif as soon as that part becomes heated ; afterhaving been used once, say fur two hours, it appears to lose some of its