276 M. V. Regnault on the Elastic Forces of Vapours 



The inspection of these tables shows that the thermonuiter 

 immersed in the vapour constantly indicates a temperature a little 

 higher than that of the vapour of pure water under the same 

 pressure ; but the difference is small, and may perhaps be attri- 

 buted to the radiation of the hot liquid and the drops of fluid 

 which are thrown up in abundance by saline solutions during 

 ebullition. As to the thermometers which descend into the 

 boiling liquid, their course is extremely irregular, presenting 

 rapid variations which often rise to several degrees. It is im- 

 possible to deduce anything certain from the indications which 

 they furnish. 



It may consequently be admitted that the phaenomenon ob- 

 served by Rudberg with regard to saline solutions in ebullition 

 under the ordinary pressure of the atmosphere, is also presented 

 when they are boiled under pressures greater or less than this. 



To observe more readily the circumstances under which the 

 phenomenon occurs, I made some experiments in a glass balloon 

 with a wide mouth, upon mixtures of water and sulphuric acid in 



