1 22 Account of a new Kudiometer. 



For ascertaining the purity of nitrous gas, the bottle may 

 be charged with the solution of green sulphate or muriate of 

 iron. 



For carbonic acid gas, with lime or barytic water. 



For oxysren gas, with the solution of green sulphate of 

 iron impregnated with nitrous gas. 



For sulphurated hydrogen gas, a solution of nitrate of 

 silver was put in the elastic bottle, and sulphurated hydro- 

 rcn eras t into the srraduated measure. Upon the first in- 

 jection, the solution took a black flocculent appearance, 

 and a consiilerablc portion of the gas was absorbed. After 

 repeating the process as before mentioned, the residuum was 



TolTo"* 



Tlie instrument may be likewise geuirally applied to the 

 analysis of mixed gases. 



I have been able completely to separate the carbonic acid 

 gas from the sulphurated hydrogen bv a solution of the ni- 

 trate of silver or of mercury, employed hot. The carbonic 

 acid gas is expanded in this process, but on standing over 

 mercury it returns to its original volume. The sulphurated 

 hvdrogen, in this instance, is taken up by the metallic ni- 

 trate. It shonld be here observed that the acetite of lead 

 must not be used, as the carbonic acid gas, even at a high 

 temperature, decomposes it, forming carbonate of lead. 



The propriety of using the solutions hot, will be seen, 

 when we recollect that the carbonic acid gas is soluble in 

 the water of solution at the common temperature of all these 

 compounds. 



Nitrous gas and carbonic acid gas may h& separated by 

 means of the hot solution of the green sulphate of iron. Ta 

 effect this, heal a solution on a glass capsule, over a spirit 

 lamp, until ebullition. Having filled the measure with the 

 compound gas, charge the elastic bottle with the hot solu- 

 tion, and unite them. The nitrons gas, in two or three in- 

 jections, will be absorbed, changing the colour of the solu- 



* obtained from oxymuriate of pctaOa bj' heat. 



f Obtained fri m sulphuret of potash by diluted munatic acid, and collected 

 and preserved wi'.h the greatest care. 



tion^ 



