52 BULLETIN OF THE NEW YORK STATE MUSEUM 



and serve as storage rooms for the manufactured salt. 

 Their bottoms are made of 2 in. plank and are from 8 to 12 

 inches above the ground to permit the circulation of air 

 under them and in order to provide for a proper drainage of 

 the salt — the planks are not closely fitted. Since the heat 

 in the front portion of the arch is so intense that it not only 

 penetrates through the 18 inch brick wall and the five to 

 six feet of earth adjoining but would also pass through the 

 wooden lining of the bins, an air space of 8 to 12 inches is 

 left between them to prevent any discoloration by "baking'' 

 of the salt stored in these bins. When the salt has been 

 removed from these bins they are washed with fresh water 

 for the purpose of dissolving any salt that may remain in the 

 crevices of the bottom planks. The time during which 

 these blocks are in operation extends from the middle of 

 April to the first of December. Originally there were 316 

 salt blocks. Their number to-day is less than 100 and of 

 these about 20 are in active operation. 



The brine employed in the manufacture of boiled or com. 

 mon fine salt, as it is usually called, is the same as that used 

 in the solar fields. Since the object of the manufacturer is 

 to use the brine in the shortest possible time, and since 

 there is present in it, as previously explained, carbonic acid 

 gas, holding in solution some ferrous carbonate, it becomes 

 necessary on the part of the workman to use some means to 

 remove them both, since otherwise the salt would be discol- 

 ored by ferric oxide. For this purpose he takes a small 

 amount of quick lime, and slackens it with brine into a very 

 thin milk, which he distributes evenly over the entire sur- 

 face of the fresh brine. The lime unites with the carbonic 

 acid to form calcium carbonate and the ferrous oxide takes 

 up the necessary oxygen and water to form the hydrated 

 ferric oxide, which gradually sinks to the bottom of the cis- 

 tern. To assist this process as much as possible, the brine 

 is well stirred whereby the caustic lime is brought in better 

 contact with the brine and the removal of the carbonic acid 



