gO ACCOUNT OF A NEW EUDIOMETER. 



the level of that in the cistern, the quantity of absorption is 



then to be determined, which is done as follows : 



Method of as- Suppose atmospheric air has been the subject of the expe- 

 certaining the j ,, , • «»«.',» 



absorption. nment, and consequently a large residuum hit: rirst note 



the hundredth parts: and then, to obtain a knowledge of 

 the fractional parts, remove the measure into the small cis- 

 tern, in which the graduated tube tilled with mercury is 

 placed; slide the tube above the surface of the fluid in the 

 measure, and, opening the stop-cock, sutler the mercury to 

 descend, till it has drawn the fluid in the measure to a regu- 

 lar division ; then stop the rock, and register the hundredth 

 parts on the measure, and the thousandth parts on the gradua- 

 ted tube; the united quantities give the sum of the residual 

 gas. Observe well in registering the thousandth parts, that the 

 fluids are exactly on a level, on the outside and the inside of 

 the measure; this may be easily effected, by pouring out a 

 portion of the liquid o*' the small cistern, or adding thereto. 

 When the re If instead of atmospheric air, a gfts is tried, which so far as 

 small™ 1S ^ '* * s "^contaminated can be nearly wholly absorbed by the 

 reagents employed, the process becomes exceedingly simple; 

 for if the residuum is under a hundredth part of the measure, 

 it may be transferred completely into the graduated tube, 

 and its quantity at once ascertained. 



The stopper S would have injected the fluid with greater 

 velocity had it been straight ; but it would not then have been 

 so convenient in the analysis of compound gasses, where both 

 mercury and hot solutions are occasionally employed; as the 

 mercury would have so compressed the fluid in the bottle, in 

 introducing it under that metal, as to have thrown out a por- 

 tion of its contents, and also have robbed the hot solutions of 

 the temperature, which was necessary to their perfect action. 

 Mode of re- As to the size of the measure M, 1 have generally preferred 



ducing the ^ cu |^ c ^^ divided into hundredth parts. This is easily 

 measure to a i . ; 



proper size, effected by taking a stout glass tube about half an inch cali- 

 bre, sealing one end, then weighing 3422 grains of mercury, 

 equal to 252 grains of distilled water at temperature 50° 

 Fahrenheit. This is introduced into the tube; the extra 

 length is cut off with a sharp-edged file, care being taken to 

 leave a sufficient portion to grind the perforated stopper S 



into its mouth. 



The 



Advantage of 

 the bent tube 



