10 PHOTO-MICROGRAPHY 



Mr. Beard now makes right and left-handed regulators and gauges so that they fit 

 the right and left-handed nozzles of the oxygen and coal-gas cylinders ; hence there 

 is no danger of an interchange being made in a moment of forgetfulness. For a full 

 and detailed description of gas bottles, regulators and gauges, the reader is referred 

 to an excellent brochure on the subject by Mr. K. S. Murray, M.I.M.E., engineer of 

 the Messrs. Brin's works, Horseferry Road, Westminster. 



To use the mixed jet is somewhat of an art, but one that may quickly be learnt. 

 On the brass tube of each " regulator," where the india-rubber tube is attached (P jn 

 Fig 5), it is a great convenience to have fixed, in addition, a common tap, for there 

 are times when one may want to shut off the gas temporarily, or even suddenly as 

 in the case of an emergency, and this can be done with far greater speed and ease by 

 these common gas taps than by shutting off the cylinders themselves. A common 

 tap suffices, as there is no pressure worth noting in this situation. 



To start the light, having placed the lime upon the pin made for its support, the 

 screws which regulate the amount of gas passing into each pipe of the jet are screwed 

 completely down, both gases being gently turned on at the cylinder, and if gauges 

 are used as shown in the diagram, they can be watched to see when the valves are 

 sufficiently opened. The "cut off" handle is then placed horizontal, which means 

 both gases, if not controlled by the screw-down valves in the tube of the jet to which 

 reference has been made, would rush on towards the lime. We undo first the red 

 one, which permits the hydrogen or coal gas to pass to the jet and thus impinge on 

 the lime. 



It is then lighted. Still leaving the "cut off" untouched, slowly turn on the 

 oxygen screw-down-tap on the jet until the light is quite bright. These two screws 

 must now be slowly opened one against the other till the best light is obtained, 

 always remembering that it is better to turn the hydrogen on first, as suggested ni 

 the Gwyer pamphlet. If too much oxygen be put on, the light will fade and requn-e 

 more hydrogen, but we recommend any one using the mixed light having a few 

 lessons before attempting it. With Beard's jet very little " snapping " occurs, but in 

 some forms made by other makers the slightest misproportion of oxygen will produce 

 it. There is no danger in this snap in a well-appointed jet, but we venture to 

 suggest to any reader who is contemplating buying this form of illumination 

 only to go to best makers. Cheap jets are always to be avoided for they are often 

 dangerous. 



Before quitting the subject it should be again noted that the gases should always 

 be turned on gently, especially when using a gauge, as accidents have been known to 



