NEW PROPERTIES OF THE ALKALINE METALS. 43 



wished to find in the substance, which was to be employed 

 in my experiment. 



In fact, having heated silex in a glass tube with a little of dscompos?t 

 the alkaline metal, it combined with the alkali, and set free Ji'Swif 

 the carbon. tree. 



The carbon thus separated no longer took fire in the air; 

 it required the assistance of heat. 



Exp. 2. This experiment is that to which I alluded in Sodium end*- 



the note I had the honour to address to the Class. It con- f ed in Xef fl fe 



immersed in 



gists in enclosing in a thin bit of lead a ball of the metal of iimewater, is 



soda, and then immersing it in a vessel filled with lime-wa- ^composed,* 

 ... iorms carbonic 



ter. The metal thus confined is obliged to oxigenize itself acid. 



at the expense of the oxigen of the water. Two affinities 

 concur, to effect this decomposition: the first is that of the 

 alkali for water, the second that of carbon for oxigen ; an 

 affiuity so much the more energetic, as in this state the car- 

 bon exhibits to us a very remarkable instance of its great 

 propensity to become oxided ; a propensity, which I shall 

 refrain from explaining at present, for the consequences I 

 should deduce from it would no doubt appear premature, 

 considering the present state of our chemical knowledge. I 

 therefore defer till another opportunity the communication 

 of my ideas on this great and important question. 



If in this second experiment I recommend taking the me- Sodium pre- 

 tal of soda, it is on account of its solidity, which allows it ferable to P°/ 

 to be handled ; and because its destruction is more slow, an experiment. 

 advantage, that allows us to observe the phenomenon of 

 the decomposition of water for some time. If, on the con- 

 trary, the experiment were made with the metal of potash, 

 the decomposition of the water would be instantaneous; 

 which, on the one hand, would oppose the combination of 

 carbonic acid with lime-water, and on the other would force 

 the gasses resulting from the decomposition of the metal to 

 break the obstacles opposed to it by the lead, in which they 

 would be included. 



We see then, that the metal of potash is eminently com- Cause of the?r 



bustible, and that of soda is less so; a property explicable (iiiFerem P r °- 



by the difference of affinity of these alkalis for water. 



One remark that I have made, and that will form the sub- Detonation of 



ject of a very curious experiment, is, that, in collecting the P olassl «m in 



, -water, 

 metal 



