SOS Proceedings of Philosophical Societies, [Oct. 



chlorine of a quantity of oxygen. Davy applies a similar theory, 

 founded on the same analogies, to the fluoric comhinations. 



This celebrated chemist, recently named a corresponding membeF 

 of the Institute, has presented a paper upon this new substance, in 

 which he insists upon its analogy to chlorine, and upon the mo- 

 tives and reasons which induce him, to consider hoth of them as 

 simple substances, capable, like oxygen, of burning and acidifying 

 combustible substances. Thus when the new substance (which has 

 been called iode, from the colour of its gas,) combines with potas- 

 sium, it exhibits a fine blue flame, but no gas is disengaged ; but 

 if potassium be dissolved in iodic acid, hydrogen gas is disengaged. 

 The same thing holds with the other metals. Davy ascribes the 

 formation of this acid by phosphorus to the humidity which always 

 adheres to the iode, and which it decomposes. He was not able to 

 procure oxygen from iode nor its acid, nor to make oxygen act upon 

 the one or the other ; nor had they any action on carbon; nor was 

 iode decomposed by the galvanic battery. But iode, like chlorine, 

 forms triple compounds with the alkaline metals and oxygen, which 

 detonate with charcoal, and may be employed instead of nitre. 



The detonating powder obtained from iode by MM. Clement and 

 Desormes by means of ammonia is, according to Davy, a compound 

 of iode and azote ; so that it is analogous to the dreadful substance 

 discovered by M. Dulong, which is a compound of azote and 

 chlorine. 



Another manufacturer, enlightened by chemical science, M. 

 Tassaert, has made a remark which may be of consequence in the 

 arts. The floors of his soda furnaces are composed of sandstone. 

 On pulling them clown he observed a blue matter, which never 

 made its appearance when the furnaces were built of brick, and in 

 which Vauquelin found nearly the same constituents as in ultrama- 

 rine ; so that our learned associate does not despair that, by follow- 

 ing out this process, we shall be able one day to imitate nature in 

 the production of this very precious article. M. Pelletan, jun. has 

 remarked that there appears in many cases during the manufacture 

 of soda, a blue colour more or less intense, which is not destroyed 

 by calcination, and that this colour appears principally when iron 

 comes in contact with soda not yet entirely deprived of its sulphuric 

 acid. 



Crude platinum as it comes from Peru is a very compound sub- 

 stance. Besides pure platinum, a noble metal, heavier, and equally 

 unalterable with gold, it contains iron, copper, mercury ; and the 

 successive researches of Wollaston, Tennant, Descotils, Fourcroy, 

 and Vauquelin, have shown ten" years ago the presence of four 

 metals, distinct from all others previously known, and called 

 palladium, rhodium, osmium, and iridium. 



M. Vauquelin has this year resumed the study of these substances, 

 and has read a memoir on the most convenient methods of obtain- 

 ing palladhon and rhodium in a state of purity. 



