j<)8 On an Apparatus for Gas-analysis 



running out itself at the delivery-tubes. The stopcock G is 

 now shut and the battery connected, as circumstances may 

 require, either with the two electrodes in A, or with one in A 

 and one in B. Gas is allowed to escape freely until all dissolved 

 air is eliminated. The stopcocks F, F are then closed, G opened, 

 and the liquid in A and B allowed to sink until it just co\vi> 

 the electrodes. G is then closed, and F, F opened, when the 

 gases may be introduced into the eudiometer in the ordinary 

 way, or into the above-described apparatus in the way there 

 indicated. Connection between the gas-generator, the tubes A 

 and B, and the reservoir E being shut off by the stopcock G, 

 there is never any difficulty in forcing the gas through the 

 mercury into the eudiometer. 



The whole apparatus is attached to a mahogany board, H, 

 which fits into the box K, shown cut through the middle in the 

 drawing, either as represented, when in use, or, when not in 

 use, as a lid, with the apparatus attached to its inner side. 

 The box thus fulfils the double purpose of a convenient stand 

 and a safe packing-case. The only alteration which I should 

 be inclined to make, would be to have the lid to which the 

 apparatus is attached made of vulcanite, to avoid the risk of 

 the wood's warping in damp weather. 



