'I'.^.V: ^ [ 193 1 • *-^— »ir,0 ^« t 



,. .J\tr . -<n ; 'i^kt 



^Ll, Experiments on the Influence of Time, as a Chemical, 



* jge?ii, in depriving an Elastic Fluid of its Elasiicitj/* 



In a Letter fiom M. BioT to M, Berthollet *. , . 



1. i!«'i-b 'Iff' ff'l' -t ::,rriO0 

 HAD lately occasion to converse with that excellent ob- 

 server M. de Marty, upon the sulycct of several experiments, 

 with which he has been a long time occupied, and I havQ^ 

 received his permission to make iheni public. 



The experiments which I shall first mention, have for 

 their object the influence of time upon the exercise of che- 

 mical actions, when they tend to deprive an elastic fluid o(^ 

 its elasticity : 



1. Into a glass flask, closed with a ground stopper,. 

 M. dc Marty introduced a certain quantity of oxygen gas , 

 and a certain quantity of rain water boiled or not boiled. J ' 

 There may be any proportions of water and gas. Supposing^ 

 that tiitre is but a small quantity of water; by shaking this 

 mixture for some minutes the water will absorb a certain 

 quantity of gas, as may be ascertained upon opening the 

 flask into a tub full of water. But after having shaked it 

 arid opened it several times, the water contained in the flask 

 will soon finish by being saturated, and will absorb no 

 more. 



Things being thus disposed, close up the flask and place 

 it out of the reach of the sun ; observe at the same time the 

 barometer and thermometer: then after two or three days 

 of rest, shake the flask again and open it under the water, 

 and you will see the latter ascend a little : close the flask, 

 return it to its place and renew the shaking from time to 

 'time ; you will find that it has every time absorbed a new 

 quar.i'ty of gas. This eflect will appear so much the more 

 striking, the longer time it has been since you last opened 

 the fl<isk. and in this case the water of the tub will rise 

 much more than if you had opened it within a few days. 



I have witnessed these eff'ects at M. Marty's house. He 

 uncorked under water, in my presence, a flask which had 

 been closed upwards of a year and a half, and which coa- 



• From /4nn. de Chimie, torn. Ixi. p. 271. 



Vol. 30. No. 119. v^j&^iV 1608. N taincd 



