38 NITROGEN. 



out numerous sparks, exhibiting a very beautiful 

 appearance. Here the combustion pi'oduces a 

 combination of" the oxygen with the carbon of the 

 charcoal, and the result is carbonic acid. 



A small bit of phosphorus, put into a copper 

 spoon, burns in this gas with a light intensely 

 bright. It is necessary to inform the young prac- 

 titioner, that this experiment must be made with 

 great caution. The phosphorus must be cut under 

 water, and the piece employed must not exceed 

 half the size of a small pea. The glass jar, in 

 which the combustion is made, is not unfrequently 

 broken by the heat. The result of this combustion 

 is the phosphoric acid, from the combination of the 

 phosphorus with the oxygen. 



In all these cases, if the products of the com- 

 bustions be carefully weighed, it will be found to ex- 

 ceed that of the substances burned, and the oxygen 

 will be diminished, which shows they have ab- 

 sorbed a quantity of the oxygen employed. But 

 this is still further proved, because the oxygen 

 may be extracted from these newly-formed com- 

 pounds, and the original bodies will be thus made 

 to re-appear. 



If the metal potassium, or sodium, be burned in 

 oxygen, they form, by their union with it, the alka- 

 lis, potass and soda ; so that oxygen is not only an 

 acidifying^ but an alkalising principle. 



Oxygen appears to be connected with the cause 

 of the red colour in blood, for if dark coloured 

 blood be put into a phial of oxygen gas and shaken, 

 the blood will assume a bright red colour. 



