We put the world before you by means of the Bioscope and Urban films (Nov 1903)

190 All parts of the flame are not equally hot; you must therefore adjust your lime to bring it into the hottest part of the flame. Attend carefully to the distance of the lime from the nipple of the jet. and do not forget thas the more gas you turn on the greater the distance must be between the lime and the nipple, or you will get a black spot on centre of lime instead of a bright one. This is done after you have adjusted your taps by working lime backwards and forwards until you have the light at its best. Roughly speaking, for a low pressure about £ inch will not be far off, gradually increasing the distance to § or \ inch, as you open jet taps more and more to increase the light. For the most powerful light, rack lime up until jet plays almost upon the bottom of the lime cylinder, which should be rendered incandescent right up to the top ; and where it is imperative to maintain light for a long time at the utmost power, it will be preferable to move the lime witli the tongs and invert it, rather than lower the level very much, so that no portion of its incandescent spot may be sacrificed. For the greatest light use large limes of medium hardness, but when only a moderate light with extreme economy of gas is required, it will be far better to use a medium size lime : very large hard limes do not yield such a rich light with a very low pressure of gas as a moderately hard medium size lime. The limes must be turned frequently when used with full pressure of gas, and when working the jet at its utmost power. The smaller the hore of the nipple, the quicker the pitting of the lime. Do not forget to rime out the hole in the lime until it will drop easily upon the pin; if the limes are forced down slightly upon the jet pin the expansion of the pin when heated must crack or burst the lime. If the jet becomes unduly hot, combustion is probably taking place inside the mixing chamber or the tubes of the jet. This is generally caused through a leak in the jet, or the tubes leading to the jet. Keep the nipple of the jet clean. If you find the flame roars when only a little gas is being used, it is probably due to some foreign substance getting into the bore of the nipple. There is danger of melting the end of the nipple if it is allowed to touch the lime. Platinum tips are sometimes inserted in the end of the nipples, but this arrangement reduces the efficiency. Unless the nipple is allowed to get too near the lime, it may be used any length of time without deterioration. As oxygen has no smell, it may be easily wasted. Great care, therefore, must be taken in attaching the regulator and tubes. Test after attaching by means of a piece of brown paper made red hot, but not in flame. The incandescent portion will glow brightly if it comes in contact with escaping oxygen. If after turning on more gas the light is unsatisfactory or even diminishes, the compressed coal gas is at fault and is coating the lime. If you have a Pendant Saturator, it may be charged and the coal gas passed through it. This will enable you to get the full amount of light. If you have not a saturator handy you can only reduce the pressure of gas and put on a new lime. An excess of hydrogen is indicated by flame round the lime, fnich a flame means excessive heating of the lantern, and should be avoided.