132 Dr Davy's Miscellaneous Cliemkal Observations. 



Glauber salts are a more tonic aperient than Epsom salts. The 

 presence of a little iron in the one (and I have never been 

 able to detect it in the other) aids in accounting for this difference 

 in effect. No doubt, Epsom salts may be made tonic by the 

 addition of a very minute portion of iron ; and particularly of 

 the sulphat. 



10. Oxygen disengaged during solution of pure Potash in 



Water. 

 The pure potash of the shops (hydrate of potash), which I 

 have made trial of, and the pota«sa fusa, during solution in 

 water, give off gas, which I have found to be oxygen. The 

 former, in the act of dissolving, effervesced strongly, and af- 

 forded a considerable quantity of oxygen : the latter a much 

 smaller quantity. Of course, it must be inferred, that this dis- 

 engagement of oxygen is owing to the presence of some peroxide 

 of potash, gradually formed by the absorption of oxygen from 

 the atmosphere. I have not found any oxygen gas disengaged 

 by hydrate of soda, when dissolving in water. 



11. A new compound of Muriatic Gas and Muriatic Ether. 



When alcohol is agitated with chlorine gas, I have found that 

 the temperature is suddenly very much raised ; that the chlorine 

 disappears ; and that a fuming, pungent, etherial vapour is form- 

 ed, which, from the few experiments I have made on it, appears to 

 consist of muriatic acid gas and muriatic ether, as it is common- 

 ly called 



12. There are more than two distinct combinations^ of Ammonia 

 and Carbonic Acid. 

 Subcarbonate of ammonia, when exposed to the atmosphere, 

 it is well known, emits a pungent ammoniacal odour. After a 

 time, this odour ceases, and the residual salt is inodorous and 

 neutral; but it is still volatile, and gradually disappears. I 

 have confined a portion of subcarbonate of ammonia in a tali 

 bottle, with a glass stopper. After several weeks, it had not 

 apparently diminished in bulk. Crystals of two different kinds 

 had formed on that side the bottle which was nearest the wall of 

 the room, — needle crystals and octohedrons, with truncated sum- 



