320 Of the Progress of the spontaneous Mixture 



what proportions the saturated solution should be mixed 

 with distilled water, that the mixture might have the 

 same specific gravity as the oil of cloves, I found that 

 a mixture composed of i measure of the solution and 

 9 measures of distilled water had a slightly higher spe- 

 cific gravity than the oil ; but with 10 measures of dis- 

 tilled water the oil sank in the mixture. 



As the little ball of oil, designed to serve me as an 

 index, was suspended a very little above the upper sur- 

 face of the layer of the saturated solution, this showed 

 me that the precautions which I had taken were suffi- 

 cient to prevent the mixing of the distilled water and 

 the saline solution when I put one upon the other, and 

 I knew that this mixture could not take place subse- 

 quently without causing at the same time my little 

 sentinel^ which was there to warn me of this event, to 

 ascend. 



There was, however, a single source of error which 

 I was obliged to guard against. I had observed, in 

 other experiments of this kind, that the air which was 

 disseminated through or dissolved in water containing 

 in solution a small quantity of muriate of soda left 

 the liquid, and attached itself to the little ball of oil of 

 cloves which I had introduced into it, and, having 

 formed on top of it a little bubble scarcely visible, 

 caused it to ascend 'in the liquid, even when the density 

 of the liquid had not changed at all. 



To prevent this accident, I boiled for some time 

 both the saturated solution and the distilled water em- 

 ployed in the experiment, in order to free them from 

 air, and, for the same reason, I subsequently covered 

 the water with a layer of olive oil to prevent the contact 

 of this water with the atmospheric air. 



