458 Proceedings of Philosophical Societies. [June, 



former, which ajipeared more analogous to what takes place in the 

 greater number of acidificktions. 



Sir H. Davy, who had been led to the same conclusions, made 

 his decision with greater boldness. He adopted the latter hypothesis, 

 and gave to oxymuriatic acid the new name chlorine, from which 

 he derived that of the other acids into which it enters. One of 

 these [muriatic), in which it is combined with hydrogen, has been 

 called hydro-chloric acid; the other, in which it is combined with 

 oxygen, chloric odd. 



The experiments on the acid, called finoric acid, led soon after 

 to the notion that it was likewise composed of hydrogen and of a 

 simple body of a peculiar nature, distinguished by the name of 

 fluorine. This opinion was first entertained by M. Am|)ere, lately 

 named a member of the section of geometry. '\ ' 



Thus the property of acidifying Itydrogen, or of becoming acid 

 by its means, was admitted in three substances ; namely, sulphur, 

 chlorine, and fluorine. Iodine has presented itself as a fourth body. 



In our analysis of the labours of last year, we stated that iodine 

 was discovered by M. Courtois. This skilful manufactui'er appears 

 to have discovered it about the end of 1811 ; but he mentioned it 

 only to his friend M. Clement, who did not make it known to the 

 public till towards the end of 1813. * But this delay was soon com- 

 pensated. In a few days M. Gay-Lussac and Sir H. Davy deter- 

 mined its principal properties, pointed out its analogy to chlorine, 

 and described the two acids which it i'orms, like chlorine, with 

 hydrogen and oxygen. Davy presented this analogy as a new argu- 

 ment in favour ot the theory which he had embraced. 



Since that period iodine has been examined with that interest to 

 which it is entitled. M. Colin has examined its combinations with 

 mercury and ammonia, and ascertained that it forms iodic acid (a 

 combination of iodine and oxygen) whenever it is treated with those 

 oxides in which the oxygen is feebly combined. He explained the 

 generation of the fulminating powder of iodine, first discovered by 

 Al. Courtois. Ammoniacal gas is absorbed by iodine, and forms 

 with it a viscid liquid, which changes its nature when put into 

 water. The hydrogen of a part of the ammonia forms with a part 

 of tiie iodine hydriodic acid, which combines with the rest of the 

 alkali, and the azote of that first portion of ammonia forms with 

 the other part of the iodine the fulminating powder. 



The same M. Colin has laboured with M. Gauthier Claubry to 

 determine the way in which iodine acts on organic bodies. These 

 two young chemists have ascertained that those substances in which 

 the oxygen and hydrogen are in the same proportions as in water 

 merely mix witli iodine : that those in which there is a greater pro- 

 portion of oxygen combine with it intimately; but that neither of 

 these bodies is altered, unless a heat be employed capable of de- 

 composing them. On the other' hand, those substances in which 

 hydrogen abounds convert iodine into hydriodic acid. The same 



