B£4 On the Nature of Muriatic Acid. [Oct". 



Article III. 



On the Nature of Muriatic Acid. By Jacob Berzelius, M.D. 

 F. R.S. Professor of Chemistry at Stockholm. 



(Letter from Dr. Berzelius to Dr. A. Marcet.*) 



DEAR SIR, 



You ask of me an explanation of my ideas respecting muriatic 

 acid, and the reasons that prevent me from adopting the new 

 theory of Sir Humphry Davy respecting this substance. I shall 

 in the first place state the difference between the old theory and 

 that of Sir H. Davy, and then give my reasons for considering 

 the old theory as the most accurate. 



According to the old hypothesis, muriatic acid is composed of 

 a combustible radicle still unknown, and of oxygen. Muriatic, 

 like several other acids, cannot be obtained in a separate state. 

 It does not seem capable of existing except in combination with 

 some oxide or other. When combined with water, it constitutes 

 common muriatic acid gas. In this compound the water consti- 

 tutes a base for the acid, just as I have proved it to do in concen- 

 trated sulphuric and nitric acids, in effloresced oxalic acid, &c. 

 The muriatic radicle is capable of combining with different doses 

 of oxygen. I have proved that muriatic acid neutralized by a 

 base contains exactly twice as much oxygen a* the base with which 

 it is saturated ; that is to say (to employ the expression of Dal- 

 ton), that the acid is composed of one atom of radicle and two 

 atoms of oxygen. The other compounds formed consist of one 

 atom of radicle combined with three, four, and six atoms of 

 oxygen, constituting oxymuriatic gas (superoxidum muri- 

 alosum), euchlorine gas of Davy (superoxidum muriaticum), 

 and hyperoxymuriatic acid (acidum oxy muriaticum). Muriatic 

 is one of the most powerful acids, and possesses in a high degree 

 the property of forming with salifiable oxides, both neutral salts 

 and salts with excess of base. 



According to the new hypothesis, oxymuriatic gas, in the 

 present state of our knowledge, must be considered as an 

 elementary body, though its great specific gravity, and the pro- 

 perty which it has of crystallizing with water at a low tempera- 

 ture, leads one to conjecture that it is a compound, and even 

 that it contains oxygen. The illustrious author of this hypothesis 

 has given it the name of chlorine. Chlorine has the property of 

 combining with an atom of oxygen ; and the oxide thus produced 



* Dr. Marcet, having been reque-ted by Dr. Berzeliuj to publish this letter, 

 in order to promote discussion, has complied with the tiSqoetA 



