124 ANSWERS TO PRACTICAL QUESTIONS 



8. Is it well to scald pickles , make sweetmeats, or fry cakes 

 in a brass kettle ? 



(See Chemistry, page 159.) 



9. What danger is there in the use of lead pipes ? Is a 

 lining of Zn or Sn a protection ? 



(See Chemistry, pages 156 and 160, and Fireside Science, page 149.) 



Zinc and tin are corroded by oxygen, though less read- 

 ily than Pb, and, while their salts are poisonous, the lead 

 is soon laid bare, and this also oxidizes. 



10. Is water which has stood in a metal-lined ice-pitcher 

 healthful? 



(See Chemistry, page 157.) 



The dissimilar metals fastened with solder which cor- 

 rodes in the presence of water, develop a galvanic current 

 which hastens the oxidation. The salts thus formed are 

 very dangerous. 



11. If you ask for " cobalt" at a drug-store, what will 

 you get ? If for " arsenic ? ' ' 



Impure metallic arsenic is sold as "cobalt," while 

 arsenious anhydride is called "arsenic." 



12. What two elements are fluid at ordinary tempera- 

 tures ? 



Bromine and mercury. 



13. Should we touch a gold ring to mercury ? 



The mercury will form with the gold an amalgam. 



