10: 



riF.XSTTTKS OK OXVCKN ANH llVDltOdKN 



The stopcock m is u[iL-ueii so as lo adiail say liall' an aliii<>si)liere of u.\ \ • 

 geii to the aj)[taratus, after which it is closed. Sparks aie passed between the 

 points /■/■ uud stopcock n is cautiously opened. Hydrogen enters and mixes with 

 the oxygen which already fills the ai)paratus, and the mixture soon comes to the 

 jets; it takes fire, and for a moment burns within the asbestos at G. Soon the gas 

 burns ijuietly at one of the jets; beat is a[)[)lied to the palladium, and the pressure 

 of tlie gas from the palladium is watched by means of the gauge. Tiie stopcocks 

 /// and n are legulated by the indications of the other gauges and the ajjpearauce of 

 the flame. The combustion chamber is kept cool by renewing the water sur- 

 r<)undin<; it. 



Fit;. 38. — Manipulator, rear view, willi globes and palladium tube connected. 



The coiiiliustiou of [)ure hydrogen in pure oxygen is a very interesting [>he- 

 homenon. Since it was convenient to liave a visiljle indication by whidi to 

 regulate the admission of gas, I conunoiily atljusted so as to produce vivid 

 incandescence tif one or the otlier of tlie platinum jets. In this case, nothing else 

 couhl be seen unless for a niument thi> heat was sufficient to volatilize something 

 from one of the wires used to ignite the ga.ses. But often, when the current was 

 made nioiv rapid, tlie incandescence of the jet ceased, and then there was a small 

 pointed flame, invisible except on careful cxcliisioii of other light. l')iil ilie risk 

 and consequent anxiety attending the a])pcaiance of this flame prevented minute 

 and tnistworthv observation. The risk was due to the fact that if tlie flame were 



