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

20back of lantern, in that case the operator is very Uable to knock his handagainst the jet, and move it out of the central focus, especially as he islikely to do it hurriedly.JETS.Of jets there are three kinds, and unfortunately their names are notvery distinctive : for brevity we will call them the Spirit or Oxy-calciumjet; the Safety or Blow-through jet; the Chamber or mixed gas jet.We will use the above-named titles in future.OXY-CALCIUM SPIRIT JETS.Fig. 13-SpiritJet.—With this a fine jet of oxygen is blown through a volatilespirit, usually methylated spirit or alcohol, the former being the cheapestis generally employed, and is mostly used in villages and places abroadwhere gas is not procurable. The jet is clamped to the rod of the limetrayin the usual manner, the cistern being outside where it cannot bedangerously heated, lamp-wick of a soft and fluffy nature is introducedinto the wick holder in front of the oxygen nipple and should not protrudetoo far above the top : experience will give the correct height, usuallyabout a quarter of an inch, and is fed with spirit from the cistern ; takeout the inner cistern and when inverted, fill with methylated spirit, pullthe pin attached to the check-valve up, now invert the cistern to itsproper position, and gently lower into the outer holder or cistern, it willthus automatically feed the wick, taking care to tilt the jet sufficientlyso that the spirit will flow to the wick. If the lantern is tilted there is aswing attachment fitted to the jet, so that the jet always keeps at the onelevel,— this is a very important addition, which no spirit jet should bewithout ; a soft or incandescent lime is fixed on the lime-pin, the flamefrom the spirit is almost non-luminous ; the oxygen is now turned onfrom jet tap, and the lime is watched until the highest state of incandescenceis obtained.