251 
Mr. Pep ys’ Account of a new Eudiometer. 
which is secured into the neck of a very small gum elastic 
bottle, by means of waxed thread : S B. fig. 4 ; the other end 
of the tube is conical, so as to present a very small orifice. 
Besides this, the apparatus is furnished with a kind of 
moveable cistern C, in which the tube can be slid easily up 
and down, and yet in such a manner that the water or other 
liquid in the cistern may not pass. This is easily accomplished 
by means of a cork fitted into its mouth, with a perforation 
through its axis to receive the tube. The cistern, when in 
use, is to be filled with water, or mercury, as the experiment 
may require, and becomes a secondary cistern for the mea- 
sure, as will be more clearly understood, by the following 
description of the method of performing experiments with this 
instrument. 
The measure is filled with the air, or gas, over mercury 
in the usual manner ; and the elastic bottle is charged with the 
solution, intended to be employed as the reagent : the orifice 
of the stopper is then inserted into the mouth of the measure, 
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 portion of the 
fluid is injected into the latter, and the gas suffers a degree of 
compression, by which the action of the affinity, between it 
and the fluid, is accelerated. On taking 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 observed to take place. When 
absorption ceases, the bottle is to be separated from the mea- 
sure under mercury, and the quicksilver which remains in the 
