OF ARTS AND SCIENCES. 



71 



" Table VII. — Experiments with Lead and Iron. — Iron upper- 

 most. Lead solder. Volume of water as in previous experiments. 



" The discoloration of the bars of lead was least in this order : — Al- 

 bany, Cambridge, Croton, Fairmount, Distilled Water, Jamaica, Co- 

 chit uate. That is, Cochituate, apparently, most promptly and com- 

 pletely coats the lead. 



" Table VIII. — Experiments with Lead and Iron. — Lead up- 

 permost. Lead solder. Volume of water same as in previous exper- 

 iments. 



" Sections of each bar at first less coated near the iron. Larger 

 measure of protoxide of iron in Cochituate and Croton waters than in 

 the others, as indicated by ferrocyanide of potassium. Discoloration 

 of the bars least in this order : — Fairmount, Distilled Water, Alljany, 

 Troy, Croton, Jamaica, Cochituate. 



Table IX. — Experiments with Lead and Iron. — Soft solder. 

 Volume and other conditions as in previous experiments. 



"As the stopcocks will, many of tliem, be of brass, it was impor- 

 tant to ascertain the influence of this connection. 



