conventional manner is contained in a beaker 19 the aspirating action of a venturi type restriction in the nebulizer draws solution out of the beaker through capillary like tubing 20 the aspiration of the sample is achieved by the rapidly moving gas which draws the solution in the nebulizer and atomizes it into a fine spray the rapidly moving gas enters the nebulizer via air line 17 the auxiliary inlet line 18 to the burner may be adapted not shown to enable fine tuning adjustment to the air flow to compensate for the last adjustment to the nebulizer via knob 21 this adjustment may be effected automatically via ports 22 and 22a being directed to a so called 34 computing relay 34 as more fully described in u s pat no 4 220 413 with reference now to fig2 there is shown in block diagram form the automatic gas flow safety system 11 in accordance with the invention the automatic gas flow safety system 11 comprises a miniature control valve 22 a valve actuator 23 and a solenoid valve 24 interconnected and coupled between the acetylene line 16 and the air line 17 to form an on off safety valve between the acetylene line 16 and the acetylene source 26 in a few situations the reference numerals in fig1 and 2 are identical to identify the same components or tubing lines even though in fig2 they are illustrated as a block diagram equivalent control valve 22 has an inlet and an outlet port not shown which are connected in line between acetylene line 16 and.