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

82Wlicn two of these automatic arrangements are in use for a chamberjet, it will be necessary to put about 5lbs. extra on the hydrogen, to preventa fiickering of light. In adjusting these in position, press all air out ofthe bag, and place between the boards, connect with flexible tubing theregulator on cylinder to the inlet pipe of gas bag (at back of bag), thenattach the long lever rod to side of pressure boards, place the hole in therod over the pin, fixing the nut in position to prevent rod falling off, not tootight or it will prevent the lever moving easily. The top end of the leverrod has a series of holes, to which the lever on regulator tap is attachedin a similar manner, but not until the gas has been turned on at regulatortap, filling the bag just over three parts ; this done, shut the gas off at theregulator lever, when in that position connect to the nearest hole in thelong rod.Fig. 40.PRESSUREGAUGE.The occurence in the past of some more or less violent explosions inpressure gauges have given rise to no little uneasiness to those who haveno particular desire to attempt anything that has the appearance of risk,and before urging the discontinuance of their use, careful enquiries havebeen made to ascertain the precise cause of their bursting, so far this hasbeen successful, and the means found for preventing their re-currence inthe future, and we wish to place, so far as our experience goes, the causeof these failures on the part of the pressure gauge. The explanation issimple enough ; they are, in fact, the result of gross carelessness orignorance on the part of the maker and possibly of the operator.Beforegoing further in the matter, a cursory description and mode of manufacturewould be the most practical.—A Bourdon's gauge, the essential part ofwhich is a steel tube of elliptical section, bent to form a semi-circle, oneend of which is screwed to a boss, through which the gas is admitted to