20 



and oxygen, he now gives the name of oxyiodine ; and to its com- 

 pounds with water, oxyiodic acid. To this same compound M. Gay- 

 Lussac has given the name of iodic acid, and for the salts he uses the 

 generic term iodates ; but to this the author objects, that hydriodic 

 and chloriodic acids may each be as well entitled to the appellation 

 of iodic acids as a generic name, and that the termination in at places 

 those bodies, which he calls oxyiodes, in the common class of neutral 

 salts, from which they differ in many respects ; while the term oxy- 

 iodes expresses more definitely the nature of a combination, which 

 has the closest analogy with the bodies termed hyperoxymuriates. 



On the Action of Acids on the Salts usually called Hyperoxymuriates, 

 and on the Gases produced from them. By Sir Humphry Davy, 

 LL.D. F.R.S. Read May 4, 1815. [Phil. Trans. 1815,;?. 214.] 



M. Gay-Lussac having obtained, by the action of sulphuric acid 

 on hyperoxymuriate of barytes, a peculiar compound, to which he 

 gave the name of chloric acid, the author was induced to examine the 

 action of this and other acids on the hyperoxymuriate of potash, and 

 after various attempts, found the following process with sulphuric 

 acid to be the best. A small quantity, not exceeding fifty or sixty 

 grains, of the hyperoxymuriate are to be mixed with a small quantity 

 of the acid in its concentrated state, and to be rubbed together by 

 means of a spatula of platina till incorporated into a solid mass of a 

 bright orange colour. This mass having been introduced into a small 

 retort, is to be then warmed by immersion in water gradually heated, 

 but kept below the boiling point. As the heat rises, an elastic fluid 

 is emitted of a bright yellowish green colour. This gas may be re- 

 ceived over mercury, on which it has no action ; but it is rapidly ab- 

 sorbed by water. Its smell is aromatic, without any smell of chlo- 

 rine. It destroys vegetable blues, without previously reddening them. 

 By a temperature of 212 it explodes with more violence than euchlo- 

 rine, expanding more, and producing more light. After the explosion 

 the volume is found increased in the proportion of 2 to 3 ; two parts 

 of the product being oxygen, and the remainder chlorine. 



Phosphorus introduced into this gas occasions an explosion, and 

 burns in the liberated gases with its usual brilliancy ; but other com- 

 bustible bodies have no action on the gas. 



Water saturated with the gas is of a deep yellow colour ; it does 

 not taste sour, but astringent and corrosive, leaving a lasting and dis- 

 agreeable impression on the tongue. 



It appears to the author not impossible, that the gas to which he 

 formerly gave the name of euchlorine, may be a mixture of the new 

 gas with chlorine ; and indeed the action of water upon euchlorine 

 favours this idea, since it acquires the same colour from it, and leaves 

 a residuum of chlorine ; but, on the contrary, the circumstance that 

 Dutch foil has no action upon euchlorine, seems to show that it con- 

 tains no free chlorine merely intermixed, but that the whole is che- 

 mically combined. 



