TIN. 249 



stone, of which Cornwall, England, is the principal 

 locality. 



How is tin 615. PRODUCTION. Tin is produced, 



produced ? \fa e j ron an( j mos t other metals, by heating 

 its oxide with carbon. The materials are heated in a 

 small blast furnace. The carbonic oxide produced in 

 the fire, as before explained, is the reducing agent. It 

 takes the oxygen from the ore, and passes off with it 

 as carbonic acid, while the metal fuses, and runs to the 

 bottom of the furnace. By heating tin before the 

 blow-pipe, it is rapidly converted into white oxide. 

 How do adds 616. ACTION OF ACIDS. Tin resists 

 act on tin ? we ak acids remarkably. Dilute muria- 

 tic and sulphuric acids, which dissolve most of the 

 metals before described, act upon it but feebly. The 

 concentrated acids dissolve it with comparative ease. 

 Its solution, although less poisonous than those of 

 lead, are still injurious to health. Acid food should, 

 therefore, never be allowed to stand for a long time in 

 tin vessels. The solutions of tin are colorless. 



617. Nitric acid acts upon tin with en- 



Whatisthe 



action of ni- ergy ; but, like a ferocious animal that de- 

 tnc acid? stroys without devouring its prey, leaves 

 it undissolved. It converts it into a white 

 insoluble powder of oxide of tin, with the 

 evolution of the usual red fumes. This case 

 is an exception to the usual action of nitric 

 acid. One portion of the acid commonly 

 acts to produce oxide, while another portion dissolves 

 the oxide formed. The experiment for the solution 

 11* 



