48 MURIATIC AND OXYMURIATIC ACIDS. 



ther over" mercury, a gradual diminution ensues in their bulk,* 



and the mercury becomes tarnished, precisely as by the contact 



of oxymuriatic acid. I have lately examined the agency of 



Muriatic acid tn j s p rocess on a considerable quantity of the two gases 



gases, electrifi- confined in a vessel, into which they were admitted after ex- 



«d alone, hausting it by the air-pump. The phenomena, which in this 



afford water Jr ,. , ■ . .... . 



and oxymuri- wa y of making the experiment are extremely decisive and 



*tic acid gas. interesting, are the production of water and of oxymuriatic 

 acid. The former, combining with a portion of the uudecom* 

 posed muriatic acid, is deposited in drops upon the inner sur- 

 face of the vessel, in the state of liquid muriatic acid. When 

 the stop-cock, which confines the gases, is opened under mer- 

 cury, a quantity of that metal rushes in, and has its surface 

 instantly tarnished. Besides this test of the production of oxy- 

 muriatic acid, its presence is rendered unequivocal (after ab- 

 sorbing the undecomposed muriatic acid by a few drops of 

 water), both by its smell, and by its effect in discharging the 

 colour of litmus paperf. 



These result* These results, it will be found, may be reconciled with 



agree with J 



either theory, either theory. According to the one which has been com- 



The exigen monly received, the oxygen unites with the real acid of mu- 



■nay unite . . J , . ;e . • , , 



with the muri- r| atic gas, which becoming oxymuriatic acid, deposits water. 



atic acid and On Sir H. Davy's view, the oxygen unites with the hydrogen 

 Water be dnw- r . .... , ,., . . . 



rited — or the °* tne muriatic acid, and composes water, while the oxymuriatic 



oxigen may acid is merely aneduct. I am not aware of any refinement of 

 hydrogen as me P r °cess, by which the value of these two explanations can 

 one of the be compared. Something, however, would be gained by a pie- 

 mur" add and cise determination °f tne proportions, in which the two gases 

 form water, saturate each other. For since, on Sir H. Davy's theory, mu- 



™" ih( .\ . oxy " riatic acid contains half its volume of hydrogen gas, two mea- 

 mur. acid is / s & ' 



disengaged as sures of which are known to be saturated by one of oxygen, 

 the other prin- 

 ciple. 

 v * Phil. Trans. 1800, p. 193. 



f Those who wish to repeat this experiment need not be deterred by 

 the apprehension of the labour attending it ; for 3 or 400 discharges! 

 from a Leyden jar of moderate size, are sufficient to occasion a distinct 

 precipitation of moisture. When a mixture of oxygen and muriatic 

 acid gases is even suffered to stand over mercury, a gradual contraction 

 of volume takes place; the muriatic acid, if in proper proportion, 

 entirely disappears ; and calomel is deposited upon the surface of the 

 glass vessel ; but, in this case, there is no visible production of moisture. 



