C)4 ACCOUNT OF A NEW EUDIOMETER. 



mercury; press the quicksilver out of the small bottle by 

 the fingers and thumb, and let the tube rise a sufficient 

 height within th<- measure, that the bottle extending itself 

 shall withdraw ihe whole of the gas from the measure, tak- 

 ing care that the cock be stopped as soon as '.t has completed 

 it, and also to prevent the solution from entering the tube. 



If the i f the tube is small, it may then be drawn 



down into the mercury, without the possibility of any portion 



of the g. 'bile the measure is dried or cleaned, 



or a fresh one tilled with mercury supplied to receive k. 



Convenience ^is WH * °* transferring will be found very advantageous* 



of this mode of particularly in the separation of gasses liable to be absorbed 



transferring un der certain temperatures ; and also where a new series of 



gasses. r 



reagents is to be employed, as from the depositions of for- 

 mer solutions on the glass measure a source of .considerable 

 -errour would arise. 



Farther in- ^ ne residual oxigen gas being thus transferred into a clean 



structions for <] r y measure, the processes before described for examining 

 using the ap- . , , , , , „ , 



paratus. oxigen gas may be then used ; or the quantity ot carbonic 



acid gas (for examination) being found by lime water, another 

 measure of the gas may be tried, iirst with the green sul- 

 phate of iron impregnated with nitrous gas, and then with 

 the green sulphate in solution only : these will take up both 

 the carbonic acid gas, and the oxigen gas, leaving only such 

 residual gas as the oxigen might have originally contained. 



Transferring is not here necessary, as the two solutions 

 may be used one after the other, taking care to use the so- 

 lution of green sulphate last. 



Where it is not requisite to transfer the gas into a dried or 

 clean measure, previous to the use of another solution, as in 

 the instance I have just mentioned, a quantity of the first 

 solution may be withdrawn, by simply filling the elastic bot- 

 tle with mercury, then joining it to the measure, and by in- 

 clining the measure, the mercury by its gravity will displace 

 the former solution. 



If at any time the gas should get drawn into the elastic 

 bottle, it may be very easily returned into the measure, by 

 inclining sometimes the bottle, and sometimes the measure. 

 The only errour that could arise from this is, an increase of 

 temperature in the gas, which may be rectified, by plunging 



the 



