The Kettle process, which is exclusively employed on the Onondaga Salt Reservation, consists of from 60 to 100 hemispherical cast-iron kettles suspended or hung on “lugs” or pins in two parallel flues, called arches, ending in one chimney, which has a height of 50 to 100 ft., according to the length of the flues. In front the arches are provided with cast-iron, flat-topped grates, 3 ft. in width and 5 ft. long, perforated with holes ⅜ in. in diameter and 1 in. apart. These are well adapted for the burning of anthracite dust, which is now exclusively used for the purpose. The necessary artificial draught is furnished by a pressure blower. The kettles are from 23 to 26 in. in depth, and from 3 ft. 10 in. to 4 ft. 2 in. in diameter, with a capacity of 100 to 150 gallons. The distance from the bottom of the kettle to the top of the grate is 3 ft. 6 in., with a solid fire-brick arch in each, extending somewhat beyond the length of the grate. The distance from the bottom of the kettle to the crown of this arch is 10 to 12 in. Beyond the grate the fire-brick arches are constructed in sections, the air spaces between the arches increasing in size with the advancing distance from the grates. This construction allows the heated gases to pass through these spaces without striking the kettle bottoms directly. While the distance between the bottom of the front kettle and the top of the grate is 3 ft. 6 in., these flues decrease in depth as they advance towards the chimney, so that under the last kettle the distance is but 6 or 8 in. The kettles are hung as close as possible with their rims against each other, and the space between the walls and kettles above the lugs is properly covered by masonry, etc., for the purpose of confining all the heat as much as possible within the two arches. The system of kettles is fed by means of a conduit connected with large wooden cisterns situated outside the building and sufficiently elevated to supply the brine contained therein by gravity to the kettles in the block. The manufacture proper of salt is commenced by lighting the fires under the kettles and filling them partly with brine as soon as they become warm, and from within 3 to 4 in. of the top when evaporation has well commenced. When salt commences to separate, the pan is withdrawn and the evaporation is allowed to go on undisturbed till a sufficient amount of salt has separated, when the contents of the kettle are well stirred with the ladle and dipped into the basket resting on the so-called basket-sticks laid across the rim of the kettle. While the process of taking the salt from the kettle is going on, the workman opens the faucet for a few minutes to add some fresh brine to the concentrated pickle of the kettle, and washes the salt, so to speak, with this mixture, thereby freeing it as much as possible from the adhering calcium sulphate and the calcium and magnesium chlorides.