French Nalionallnstilufe. 90^ 



only, it may decompose water like the phosphures; but 

 when it is combined with potash and silex, it does not de- 

 compose it : doubtless, because this triple combination ia 

 insoluble." 



Mr. Davy has also made attempts to obtain in a free 

 state the fluoric radical, and has obtained results analogous 

 to those above referred to : he ascribes the hydrogen pro- 

 duced in the combination of the potassium with the gas, to 

 the water which he thought was contained in this acid, 

 and which the metal had decomposed. 



The muriatic acid has also been the subject of numerous 

 and interesting experiments by Mr. Davy and Messrs. Gay 

 Lussac and Thenard. • All three have made some fruitless 

 attempts to dect)mpose this acid, and to insulate the radical 

 which has been considered as forming one of its elements. 

 But Messrs. Gay Lussac and Thenard have ascertained 

 that the nuiriatic acid could not exist without water in the 

 state of gas ; that it then contains one fourth oF its weight; 

 and that water alone possessed the property of taking it up 

 from its dry combinations. Jt nmst be remarked, that in 

 all the experiments made with the metals, the water, on 

 being decomposed, has always produced a quantity of oxide 

 equal to what was required by the acid in order to neu- 

 tralize it ; so that, for every result, hydrogen and a neutral 

 salt were obtained. The limits of this report do tiot admit 

 of our detailing all the experiments made bv Messrs. Gay 

 Lussac and Thenard ; but we ought not to pass over the 

 happy application which these chemists have made, in the 

 decompositions of the nuiriate of soda, ot" the affinity which 

 the muriatic acid has for water. We know that soda enters 

 as a primary matter into several branches ot" manufacture, 

 and it is very important to possess a simple and direct me- 

 thod of extracting this alkali from common salt. 



As to the oxygenized muriatic acid, Messrs. Gay Lussac 

 and Thenard subjected it to numerous experiments: — 

 " These,'* they inform us, *' ought to give an idea of the 

 constitution of this acid totally diflerent from that which 

 has been formed. It has been regarded as the most easily 

 decomposed body, and on the contrary it resists the action 

 of the most energetic agents. We cannot extract the 

 niuriatic acid from it in the state ot gas, except by means 

 of water or hydrogen." This acid weighs 2*47 more than 

 air. It contains the half of its volume of oxygen gas, and 

 all the water which it can form with the hydrogen is re- 

 tained by the muriatic acid which it contains. This water 

 .makes one fourth qf the weiciht of this last acid. 



U 3 The 



