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

78which is of metal, D^ to which is attached inside a lazy tongs arrangement,Z, which lays comparatively flat when the rubber bag is empty,when this is inflated, the lazy tongs arrangement is drawn up, this in turnclosing the pinhole orifice by means of a small plunger, /, which admitsthe gas from the cylinder. To control the supply of gas to the jet andto keep it at an even pressure, a spring or weight 6", forces the rubber bagdownwards, thereby preventing the supply being completely shut off.After a time the dust and particles of grit blown out of the cylinder,congregate at the bottom of the plunger, /, causing a leak, and wearing itout of the round. When this takes place, the gas escapes into the rubberbag, and when sufficiently full, forces it away from its fastening. Whenthis happens, it should be sent back to the optician, to have the plungerre-ground.Considering the immense number made, and the great pressure that isbrought to bear on such a delicate piece of mechanism, it is surprisingthat so few are put out of gear in this manner. We have had some dozensthrough our hands, and have only had this happen once, still it is wellto mention these points, to put the users on their guard. A mostnecessary adjunct to all regulators is a small tap, fitted to tlic outlet, P,by this means the full pressure may be turned on at the cylinder, and thesupply regulated from the tap at the regulator, preventing any tendencyof roaring at the jets, this may be done to a great nicety, whereas if notap is fitted to the regulator, the adjusting has to be done at each jet itself,aud when sufficient gas is adjusted for one lantern, there is not sufficientfor two or more and vice versa ;to the nicety of gas bags.although no single regulator will regulateIt is well not to turn on the gas too suddenly at the cylinder, the gasrushes into the regulator, filling the small bag to excess,which forces thespring up close against the top, where it will stick, not having sufficientroom to regain its elastic power, this spring works exactly in the samemanner on the bellows, as the weights do on gas bags. Should the bagbecome too full, thus closing the inlet, give the regulator a knock withthe hand to shake it down, taking care that the outlet tap is openwhen so doing. As a preventive of this, when turning on the gasfrom the cylinder valve, allow a little of the gas to escape from theregulator tap or at the jet. When turning off the oxygen for any lengthof time, (if not leaving a leakj, take c^ire to turn the oxygen tap off atthe jet,or the hydrogen will creep down the tube mixing with the oxygen,and when the jet is turned up, will cause a report, possibly blowing offthe tubing.