What is "salt cake"

Salt \Salt\, a. [Compar. Salter; superl. Saltest.] [AS. sealt, salt. See Salt, n.]

1. Of or relating to salt; abounding in, or containing, salt; prepared or preserved with, or tasting of, salt; salted; as, salt beef; salt water. ``Salt tears.''
   --Chaucer.

2. Overflowed with, or growing in, salt water; as, a salt marsh; salt grass.

3. Fig.: Bitter; sharp; pungent.

   I have a salt and sorry rheum offends me.
   --Shak.

4. Fig.: Salacious; lecherous; lustful. --Shak. Salt acid (Chem.), hydrochloric acid. Salt block, an apparatus for evaporating brine; a salt factory. --Knight. Salt bottom, a flat piece of ground covered with saline efflorescences. [Western U.S.] --Bartlett. Salt cake (Chem.), the white caked mass, consisting of sodium sulphate, which is obtained as the product of the first stage in the manufacture of soda, according to Leblanc's process. Salt fish.

   1. Salted fish, especially cod, haddock, and similar fishes that have been salted and dried for food.

   2. A marine fish. Salt garden, an arrangement for the natural evaporation of sea water for the production of salt, employing large shallow basins excavated near the seashore. Salt gauge, an instrument used to test the strength of brine; a salimeter. Salt horse, salted beef. [Slang] Salt junk, hard salt beef for use at sea. [Slang] Salt lick. See Lick, n. Salt marsh, grass land subject to the overflow of salt water. Salt-marsh caterpillar (Zo["o]l.), an American bombycid moth ( Spilosoma acr[ae]a which is very destructive to the salt-marsh grasses and to other crops. Called also woolly bear. See Illust. under Moth, Pupa, and Woolly bear, under Woolly. Salt-marsh fleabane (Bot.), a strong-scented composite herb ( Pluchea camphorata) with rayless purplish heads, growing in salt marshes. Salt-marsh hen (Zo["o]l.), the clapper rail. See under Rail. Salt-marsh terrapin (Zo["o]l.), the diamond-back. Salt mine, a mine where rock salt is obtained. Salt pan.

      1. A large pan used for making salt by evaporation; also, a shallow basin in the ground where salt water is evaporated by the heat of the sun.

      2. pl. Salt works.

         Salt pit, a pit where salt is obtained or made.

         Salt rising, a kind of yeast in which common salt is a principal ingredient. [U.S.]

         Salt raker, one who collects salt in natural salt ponds, or inclosures from the sea.

         Salt sedative (Chem.), boracic acid. [Obs.]

         Salt spring, a spring of salt water.

         Salt tree (Bot.), a small leguminous tree ( Halimodendron argenteum) growing in the salt plains of the Caspian region and in Siberia.

         Salt water, water impregnated with salt, as that of the ocean and of certain seas and lakes; sometimes, also, tears.

         Mine eyes are full of tears, I can not see; And yet salt water blinds them not so much But they can see a sort of traitors here.
         --Shak.

         Salt-water sailor, an ocean mariner.

         Salt-water tailor. (Zo["o]l.) See Bluefish.

n. Solid sodium sulfate, a product of various industrial chemical processes.