Adeney — An Apparatus for Gas Analysis, 8fc. 547 



kathetometer. A similar arrangement may be made for each 

 division line on the burette, but, generally speaking, it will only be 

 found necessary for the 10, 15, 50, and 100 c.c. lines. "With this 

 arrangement the mercury may be adjusted to the level of a 

 division line by the operator, with the naked eye, even more 

 accurately than with the kathetometer, the operator being very 

 much aided by the magnifying effect that the water in the 

 cylinder has upon the burette, and upon the line gummed to the 

 back of the stand. 



The method of working the apparatus will be understood from 

 the following description of the analysis of a water residue : — 

 The residue is mixed with copper oxide, and packed in a combustion 

 tube with oxide of copper and metallic copper ; and the open end 

 of the combustion tube is drawn out and shaped according to the 

 directions given by Frankland and Armstrong in their method for 

 the determination of the organic carbon and nitrogen in waters. 

 The combustion tube may be directly attached to the tube h of 

 the apparatus, but it is more convenient to interpose between them 

 a U shaped connecting tube, in the bend of which a bulb is blown 

 for collecting the water formed during the combustion of a 

 residue. The connections are made with pieces of indiarubber 

 tubing protected with water jackets in the ordinary way, to 

 prevent diffusion of air through them. 



The burette and pressure tube, let it be supposed, are full of 

 mercury, the stopcock of the latter closed, and the laboratory vessel 

 detached from the apparatus. If now the cock of the burette be 

 opened to the combustion tube, and the reservoir lowered, air will pass 

 from the combustion tube into the burette as the mercury flows out 

 of the latter ; when the mercury has reached the lowest level prac- 

 ticable in the burette, the stopcock is turned to close connection with 

 the combustion tube, and to open to the tube g, and the reservoir is 

 raised to refill the burette with mercury and expel the air that has 

 been drawn into it, into the atmosphere. If, when the burette is 

 again full of mercury, connection with the combustion tube be for 

 a second time opened, and the cycle of operations described be 

 repeated, a further quantity of air will be drawn from the 

 combustion tube, and will be expelled from the apparatus. After 

 several such repetitions the quantity of air remaining in the 

 combustion tube will be inappreciable. 



