40 BULLETIN OF THE NEW YORK STATE MUSEUM 



There are three sets of these vats, or as they are more 

 familiarly called, rooms. The first are called " deep 

 rooms," and serve for the reception of the brine as it 

 comes from the wells or pumphouse. The brine when 

 received in these rooms is usually perfectly clear, but soon 

 it becomes turbid and of a yellowish red color. This 

 change is due to the escape of carbonic acid gas with which 

 the brine is highly charged when it comes from the wells 

 and by which the trace of ferrous carbonate present is held 

 in solution. The solvent escaping, the ferrous oxide takes 

 up oxygen and separates from the brine as a hydrated 

 ferric oxide in a very finely divided state, causing a yellow- 

 ish turbity, which disappears gradually as the ferric oxide 

 settles to the bottom of the vat, and leaves the brine clear 

 again. The deep rooms are constructed higher above the 

 ground than the following set, which are called " Lime rooms," 

 — (this is a misnomer, since in the manufacture of solar 

 salt lime is never used) — in order to enable the workmen 

 to draw from them into the lime rooms as occasion re- 

 quires. The evaporation of water from the brine which 

 commences in the deep rooms, continues in the lime rooms 

 till the brine reaches its point of saturation which is recog- 

 nized by the workman, when small cubic salt crystals make 

 their appearance. While the brine is evaporating and be- 

 coming saturated a second change takes place in it, namely, 

 a certain amount of sulphate of lime or gypsum separates 

 from it in beautiful crystals on the sides and bottom of the 

 room. This separation is especially marked when the 

 brine is near its point of saturation. The now fully satu- 

 rated brine is called pickle and is drawn into the third 

 or lowest set of rooms, called the salt rooms. Here an- 

 other change takes place. Salt and a portion of the 

 remaining sulphate of lime crystallize out, the former in 

 more or less perfectly developed cubic crystals, the latter in 

 fine slender crystals often twinned. As the evaporation of 

 the water from the pickle progresses, the salt crystals first 



