ACCOUNT OF A NEW EUDIOMETER. 89 



$, which is well secured in the neck of it, by means of 

 waxed thread wound tight round it : and a "lass tube, T, 

 fig. 3, also graduated, but into tenths of the former divisions, 

 or into thousandth parts of the measure. 



The glass stopper, made fast in the neck of the gum elas- 

 tic bottle, as aboVe mentioned, has its exterior end ground 

 with emery, exactly to tit the mouth of the measure. To 

 the lower end of the graduated tube T is cemented a small 

 steel cock, which is secured into the neck of a very small 

 gum elastic bottle, fig. 2, by means of waxed thread. The 

 other end of the tube is conical, so as to present a very 

 small orifice. 



Beside this, the apparatus is furnished with a kind of 

 movable cistern C, in which the tube can be slid easily up 

 and clown, and yet in such a manner, that the water or other 

 liquid in the cistern may not pass. This is easily accom- 

 plished by means of a cork fitted into its mouth, with a 

 perforation through its axis to receive the tube. The cis- 

 tern, when in use, is to be filled with water, or mercury, as 

 the experiment may require, and becomes a secondary cis- 

 tern for the measure, as will be more clearly understood, by 

 the following description of the method of performing ex- 

 periments with this instrument. 



The measure is filled with the air, or gas, over mercury in Manner of 

 the usual manner; and the elastic bottle is charged with the usill S **• 

 solution, intended to be employed as the reagent : the orifice 

 of the stopper is then inserted into the mouth of the mea- 

 sure, in the mercury, and pressed home to its place. 



The bottle and measure, being thus united, are to be 

 firmly held at the joint. Upon pressing the former, a por- 

 tion of the fluid is injected into the latter, and the gas suf- 

 fers a degree of compression, by which the action of the af- 

 finitv, between it and the fluid, is accelerated. On taking 



o 



off the pressure, the bottle, by its elasticity, endeavours to 

 obtain its original form, and receives back the fluid. This 

 process should be continued as long as any absorption is ob- 

 served to take place. When absorption ceases, the bottle is 

 to be separated from the measure under mercury, and the 

 quicksilver which remains in the measure being brought to 



the 



