Saliferous Rock Formation in the Valley of the Ohio. 55 



fourteen inches in length, and from three to four inches wide, as the 

 operator may think best, it being very useful to have the well of a 

 greater diameter at the top, as it necessarily and unavoidably grows 

 narrower as it descends, and would not afford sufficient water, unless 

 an allowance of this kind were made. The operation gradually cuts 

 away the sides of the auger, and as it is repaired or a new one ap- 

 plied, unless this adaptation is carefully attended to, it becomes fast 

 in the bottom of the well, and is with great difficulty removed. The 

 progress made, each day, varies, with the density of the rock, from 

 one inch to five or six feet, but is necessarily slower as the well deep- 

 ens ; for much time is necessarily consumed in taking up and letting 

 down the poles, for the purpose of pumping or clearing out the detri- 

 tus, which is composed of sand or mud, according to the nature of the 

 rock. It is often necessary to line the upper portion of the well, for 

 one hundred and fifty or two hundred feet, with a copper tube, to 

 prevent the process of caving, occasioned by the disintegration of the 

 soapstone or argillite, which principally composes the upper strata 

 to this depth. It is also sometimes needed to keep out the springs 

 of fresh water, which, mingling with the salt, would occasion addi- 

 tional labor in the evaporation. 



Process of making the salt. 



When a sufficient supply of water is obtained, the next operation is 

 the erection of the furnace, with the cisterns, salt house, shed over 

 the furnace, &c. The evaporation of the water is conducted in 

 large cast iron kettles, of the capacity of sixty or ninety gallons, set 

 over a flue made of stone, sunk so much in the earth as to bring-the 

 tops of the kettles nearly on a level with the surface of the soil. 

 The bottom of the flue gradually rises, as it goes forward under the 

 kettles, and ends in a chimney. 



The wood required is from five to six cords per day, for a furnace 

 of thirty or forty kettles. One half the kettles are used for boilers, 

 and the other half for graining the salt. This, however, varies ac- 



■ • 



more 



grainers than boilers. In some furnaces, the boilers, or evaporators, 

 are made of large sheets of cast iron, with their sides turned up an 

 inch or two, and connected to each other with rivets in their bottoms. 

 As the water flows or is pumped from the well, it falls into a large 



kettles 



cistern, made of planks. 



furnace, the water is conducted by means of a bored log, or logs, as 



