210 



SCIENTIFIC APPARATUS. 



water, so that the temperature remains constant, and the absorp- 

 tions are effected by means of liquid re-agents, in a laboratory 

 tube which communicates with the top of the measuring tube by a 

 capillary tube provided with stopcocks. In this way the absorp- 

 tions are complete in about five minutes, and the measurements 



may be made as soon as 

 the gas has been brought 

 to the proper volume in 

 the measuring tube. The 

 latter is provided with 

 wires, so that the explo- 

 sions are made in a eudio- 

 meter surrounded by water, 

 and no time is lost be- 

 tween the explosion and 

 the measurement. Since, 

 in Frankland and Ward's 

 apparatus, a barometer is 

 in connection with the 

 eudiometer, the measure- 

 ments are independent of 

 variations of atmospheric 

 pressure, which enormously 

 simplifies the calculation 

 of results. A modification 

 of the apparatus of Frank- 

 land and Ward has been 



Apparatus of Frankland-and Ward.* described by Me Leod. 



More recently, Russell has described an apparatus in which 

 ordinary eudiometers are employed surrounded by a cylinder of 

 water. The corrections for changes of temperature and pressure 

 are entirely obviated by the employment of a tube of about the 



* This and the two following Figures are taken from " Sutton's Volumetric 

 Analysis." 



