in Metallurgy, a round pit of stone, lined with clay within, for receiving the metal on its first fusion from the ore.

in the British salt-works, where sea-water is boiled into salt, is the name of a sort of pond, which is made at some distance from the faltern on the sea-shore, between full sea and low-water mark. From this pond a pipe is laid, through which, when it is full sea, the water runs into a well adjoining to the faltern; and from this well it is pumped into troughs, through which it is carried to the cisterns, in order to be ready to supply the pans. See SALT.

in Mining, denotes a pit sunk down in the bottom of the mine, to cut or prove the lode still deeper than before; and in order to slope and dig it away if necessary, and also to drive on the lode in depth. The sump principally serves as a bason or reservoir, to collect the water of a mine together, that it may be cleaned out by an engine or machine.