COMBUSTION OF CHARCOAL AND OF HIDROGEN. I69 



limewater I used was prepared by mixing two handfuls of tion of oxig*a 

 quick lime with six quarts of very pure rainwater, and fil- &* s > 

 tcring the solution at t-he end of eight and forty hours. The 

 oxigen gas was not mixed with the limewater, till it had 

 been in contact with liquid potash. After this operation, 

 hidrosulphuret of potash indicated in it one per cent of 

 nitrogen. 



Exp. 1. A hundred parts of this oxigen were shaken 80 by liiaetfater, 

 times, during one minute, with 400 parts of limewater by 

 measure, in Fontana's eudiometrical tube, and were thus 

 reduced to 96 parts. On repeating the operation, these 

 06 parts were reduced to 92. I made the same experiment 

 several time? with common air, but no perceptible change 

 in its purity or quantity took place. 



Exp, 2. A hundred parts of pure oxigen gas were mix- 

 ed with 900 of limewater in a bottle closed with a glass 

 stopple. After a minute's agitation the 100 parts were re- 

 duced to 92*5 ; and these 92*5 contained 8 parts of nitrogen 

 gas. Previous to their mixture with the limewater they 

 contained but one part, and they had been in contact with 

 a quantity of liquid potash sufficient to absorb more than 

 200 parts of carbonic acid gas. This experiment was re- 

 peated by mixing with limewater 100 parts of common air, 

 which wus not perceptibly altered either in quantity or qua- 

 lity. 



Exp. 3. A hundred parts of pure oxigen were intro- by potash in s 

 duced into a closed phial with 900 parts of rainwater hold- 5^ i J uantil7 

 ing in solution a fourth part of its weight of pure potash. 

 After shaking for a minute, these were reduced to 92*5 

 parts. I obtained a similar result with rainwater alone. 



Exp. 4. A hundred parts of pure oxigen gas were kept & hy concen- 

 for six hours in contact with four parts of concentrated so- ^ fiff *** 

 lution of potash. The gas was not perceptibly altered ei- 

 ther in quality or quantity, though the mixture was shaken 

 several times. 



When common charcoal, or wood, or an oil, or [any ve- Presenc* of 

 getable substance of which hidrogeu constitutes a part, is JJogen 'ja^hi- 

 burned in pure oxigen gas, hidrogen gas is at WaYs found therto conri- 

 mixed with the oxigen gas after the combustion," though defed * pur * % 

 the quantity of oxigen gas be much greater than is neces- 

 sary 



