i^ 



Subjoined are the results of a few of the experiments on 

 iron wire. 



IV. — Effect of Pyroligneous Acid. 



The effect of pyroligneous acid on iron and steel appears 

 to be exactly similar to that of hydrochloric and sulphuric 

 acids, causing it to become more brittle, &c., though the 

 effects are perhaps somewhat less intense. As in their case^ 

 heat restores the iron to its original toughness. 



V. — Eff^ects of Acids on Copper and Brass. 



Sulphuric acid appears to have no effect whatever on 

 copper. After 18 hours' or longer immersion in sulphuric 

 acid copper is as tough as ever, the action being confined to 

 the surface only. 



Brass becomes rotten after long immersion in vitriol, 

 doubtless, because the zinc of which it is partly composed is 

 attacked by the acid, and, as might be expected, heat does 

 not restore it to its original condition. Prolonged exposure 

 to a moist damp atmosphere appears to make brass brittle 

 just as acid does. 



