No. 27. [From Phil. Mag., January, 1874.] 



ON AN APPARATUS FOR GAS-ANALYSIS 



A VERY important subject of investigation in the chemistry 

 of the ocean is the nature and quantity of the atmospheric 

 gases dissolved in it. These are extracted by boiling in vac no 

 in an apparatus recently described by Jacobsen 1 , and at the 

 end of the operation are obtained hermetically sealed in a glass 

 tube, in which they are capable of indefinite preservation. 

 Although it would be absurd to waste time in making necessarily 

 imperfect analyses of valuable specimens at sea, which are 

 capable of being kept and analyzed with the greatest accuracy 

 on shore, still cases might occur during a three years' voyage 

 where it would be very desirable to make an approximate 

 analysis of a specimen of gas, not necessarily proceeding from 

 sea-water, but, for instance, from hot springs or volcanoes on 

 shore. 



The first desideratum for such an apparatus for use on 

 shipboard appeared to be freedom from a mercurial trough. 

 All existing apparatus, besides having this source of incon- 

 venience, were far too large and cumbrous to be at all suited 

 to the modest allowance of laboratory space available on board 

 ship. What seemed to give most promise of success was in 

 some way or other to adapt the original Ure's eudiometer to 

 the purpose. The form of apparatus finally adopted is that 

 represented in Fig. i. It was constructed, according to my 

 drawings and instructions, by Dr Geissler, of Bonn; and it 

 is needless to add that as a piece of glass workmanship it is a 

 chef-d'oeuvre. 



Before describing it, it may be as well to state the objects 

 sought to be attained, when the motives in the design of the 



1 Ann. der Chem. und Pharm., vol. CLXVII. p. i. 



