176 



METALLOIDS. 



429. COMBUSTION BY NITRIC ACID. As 



How may com- 

 bustion be nitric acid contains much oxygen, combus- 

 effectedby ni- j. j on ^y fa means would seem to be a 



probable result. To 

 prove that it has this effect, boil 

 strong nitric acid in a test-tube, 

 the mouth of which is filled with 

 hair. As the vapors pass through 

 they will cause it to smoke, and, 

 if the acid is sufficiently strong, 

 produce ignition. 



430. COMBUSTION OF 



Describe the . 



experiment Phosphorus is readily 

 withphospho- ignited by throwing it 

 upon nitric acid. If 

 the acid is not very strong, it must be previously 

 heated. Particles of phosphorus, scarcely larger than 

 mustard seed, should be used in this experiment. 



PHOSPHORUS.- 



Whatisphos 

 phorus ? 



Where does i 

 occur? 



phosphate 

 portion. 



flow is it pre- 

 pared ? 



PHOSPHORUS. 



431. DESCRIPTION. Phosphorus is a 

 wax-like, and nearly colorless, solid, read- 

 t ily ignited by heat or friction.* 1 It forms 

 part of the mineral apatite, which is a 

 of lime. Bones also contain it in large pro- 

 It is never found umcombined. 



432. PREPARATION. Phosphorus is 

 made from bones. These are composed, 



* When phosphorus is cut, it should always be under water, and 

 every particle not used should be immediately returned to a bottle 

 containing water. 



