BAIRD &TATLOCK (LONDON) LTD. 



4711 



4711 s Macfarlane and Caldwell's Gas Analysis Apparatus, complete on mahogany stand, 

 with four mounted absorption pipettes and sloping stand for holding same 



A modified form of apparatus for the analysis of gases. By Messrs. Walter Macfarlane, F.I.C., 

 and Peter Caldwell. 



INSTRUCTIONS FOR USE. 



See Journal of the West of Scotland Iron and Steel Institute, No. 2, Vol. i., 1892. 



After introducing and measuring the sample of gas, the stopcock is closed and the absorbing bulb E is attached. 

 By gently blowing at F, the capillary G is filled with absorbing liquid. The stopcock is then half turned. We thus 

 have the gas and the liquid all but meeting, as the gas was measured to the end of the stopcock bore, i.e. to the 

 point marked H. The apparatus is then tilted, the stopcock is turned so that the measuring tube (M) and the 

 absorbing bulb (E) are placed in communication, and the gas is, by regulated pressure, forced to bubble through 

 the absorbent. After closing the stopcocks and rocking (if necessary), the stopcock is opened, and the apparatus 

 is so tilted as to facilitate the transfer of the gas back to the measuring tube. When the liquid from E has followed 

 to the point H, the stopcock is closed, the pressure adjusted, and the volume of the remaining gas is read off and 

 noted. The bulb containing the absorbing liquid next in order is then substituted for the first one. Turning the 

 stopcock back to the position shown at B, we blow into the bulb from F, until the liquid in the capillary o is 

 replaced by the new absorbent. Again we have the gas and the absorbent all but meeting. In this manner it is 

 possible to go on through a complex gas analysis without losing even a small bubble of the gas, and yet keep the 

 measuring tube absolutely free from absorbing liquids, a happy state of matters unknown in any other form of 

 works apparatus that we are acquainted with. Another advantage of our arrangement is that there is no danger 

 of an enclosed bubble of air at j (which might be entrapped when the junctions are brought together) being allowed 

 to mix with gases under analysis. The absorbing bulbs are kept charged, and are thus ready for immediate use ; 

 the absorbing liquids are kept free from other liquids, and waste is reduced to a minimum. Some forms of 

 apparatus are very wasteful of chemical absorbents. 



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CHEMICAL AND SCIENTIFIC APPARATUS AND PURE CHEMICALS. 



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