improved St iding-Rod Eudiometer and of the Volumescope. 179 



tuated, which is to cause ignition. Tliis tube would be the 

 only part of the apparatus which it would be desirable to have 

 transparent. Indeed transparency may be dispensed with al- 

 too-ether, the explosion being i)erceptible from the noise, and 

 the effect upon the gauge, 



Anahjsis of a Gaseous Mixture in which Bihjjdrogurct of Car- 

 bon, Carbonic Oxide, and cither Hydrogen or Azote, or both 

 the latter, are intermingled. 



When, as in the case under consideration in the preceding 

 article, there is no azote present, the gas which remains after 

 the action of the lime-water may be considered as oxygen ; 

 but if azote be present, the res'idual gas must be analysed 

 in order to ascertain the quantity of oxygen which remains 

 unconsumed. 



This is easily accomplished by propelling the residual gas 

 into the receptacle for carbonic acid R, fig. 1, and substitu- 

 ting a self-regiilating reservoir of hydrogen for the bell-glass. 

 Then having filled the gauge and pipes with the pure hydro- 

 gen, by the manipulation already described in the case of oxy- 

 gen, the residual gas may be drawn into the receiver, exploded, 

 and the resulting deficit ascertained ; to one-third of which 

 the oxygen is equivalent. 



Instead of resorting to tlie method just mentioned, the re- 

 sidual gas, after being included in the receptacle, may be trans- 

 ferred to the i^neumatic cistern, and analysed by the aqueous 

 sliding-rod eudiometer. 



If we subtract from the weight of the " residual gas," the 

 weight of the oxygen found in it, the remainder being both in- 

 conTbustible and insusceptible of absorption by lime-water, 

 should be considered as the weight of the azote. This would 

 have to be deducted from that' of the gaseous mixture, the 

 calculation being otherwise unaltered. 



If after having analysed a gaseous mixture, agreeably to 

 the directions given in the last article, it be found that the 

 (juantity of hydrogen indicated exceed in weight, one-third ot 

 the carbon allotted to it, the excess must be considered as 

 pure hydrogen ; since, agreeably to ihe table of e(]iiivalents, 

 the weight of the carbon in the biiiydroguret is to the hydro- 

 gen as 3 to 1 *. 



'I'luil is, putting 11 for the pure hydrogen, we should Inivc 

 ~ T V 1 1 4 / 



M+ O-C 1 /3c; 3 X 



2 A 2 Method 



