The Hodgkinson furnace is not placed under the pan, as in the old system, but in front of the plant, and the heated gases pass under the primary pan, where the temperature ranges between 1,800 and 2,000°F. In this primary pan is made a finer and better salt than can be manufactured by any other system in the world. Moreover, by means of the mechanically-stoked furnace, and the consequent uniform high temperature, it is possible, for the first time, to control the character of the salt produced. Where the temperature varies, as in the open-pan system, crystals of varying shapes and sizes are produced, and this mixed salt must be ground to make it suitable for table purposes. Where steam heat is employed, as in the vacuum process, the temperature is not high enough to make crystals of the smallest size. By the Hodgkinson system the primary pan produces a precipitation which requires no grinding, which flows in a cascade of salt from the pan, and can be delivered to the consumer without having come into contact with the hand of man in the whole course of the operation. The heated gases, having passed under the primary pan, are then divided and sent under the two secondary pans, and from thence they pass under the open rectangular pans, the gases being distributed by the broken columns of brickwork on which the pans stand. The temperature of the gases passing under the open pans commences at about 600° F., and gradually decreases to about 200° F. under the farthest pans. By the automatic regulation of the temperature, the waste gases are utilized to produce salts of the various degrees of coarseness required for the dairy, the stock-yard, and fishery purposes. In the two secondary closed pans, finely divided table salt is also produced, but it is possible, by opening the manhole traps in the covers, to increase the size of the crystal and make dairy salt in these pans. The coarser crystals and flake salts are made in the open pans in which the crystallization is at the lowest rate. The grain of the salt can be altered at will. In order to meet any change in the market requirements, coarser salt can be produced at a moment’s notice in the secondary pans. One very marked superiority of the whole system over all other processes is seen in the fact that a change in the type of salt produced can be immediately effected, and a constant and uniform output of any combination of products can be absolutely guaranteed.