Apparatus for Rapid Gas- Analysis. 377 



heavy glass, graduated in tenths of cubic centimetres, and hold- 

 ing one hundred cubic centimetres to within about two inches 

 of the lateral tube, E, below ; the upjier end is closed by a 

 stop-cock, B, over which fits a funnel, A, in the same manner 

 as in the apparatus described above. The graduations on the 

 tube are made so that the stoj)-cock is the zero point, and the 

 100 mark is below, near the lateral tube, E. 



Into the U23i)er end of the burette, at C, are fused two plati- 

 num wires for an ignition-spark. At the lower end of the 

 burette, the glass is drawn out to receive, at F, a piece of soft 

 rubber tubing about three feet long, which in turn communi- 

 cates with the aspirator bottle, G. Care should be taken that 

 the opening of F and the tubulatnre of the bottle, G, are not 

 smaller than the bore of the rubber tubing used to connect 

 them, since any contraction would prevent the cushioning of 

 the explosion when th.e spark is passed.* The bent piece, H, is 

 ground to fit over the stop-cock, B, when the funnel. A, is re- 

 moved, and facilitates the transfer of the gases from the ab- 

 soi'ption-burette before described, as it is easier to sli]:» a piece of 

 rubber tubing over the smooth end of H than over the ground 

 end of the stop-cock, B. The stop-cock, and also the fitting, 

 H, have capillary tubing of about one millimetre bore. The 

 stop-cock at F, and its tube attaching it to th.e burette, are of 

 ordinary size, about one-eighth to three-sixteenths of an inch. 



The operation of the burette is as follows : — 



The funnel is removed from the absorption-burette of the 

 previously described apparatus, and a fitting exactly like H is 

 substituted for ir. 'J'he gas should be previously transferred to 

 the measuring-tube of the absorption-apparatus. The explosion- 

 burette is placed in a vertical position in a stand near the ab- 

 sorption-apparatus. The bent tube on the upper stop-cock of 



* It is also most important that tlie clamp holding the burette should not 

 hold too tightly, as pressure upon the glass will cause a fracture on explod- 

 ing the gases. It is better to use a spring clamp. 



