After explaining the method by which sea-water is received into the first series of prepared trenches, in which the first stage of evaporation takes place and is thereafter carried into the second basins, where it is thickened by further evaporation to the constituency in which it is ready to be converted into salt, Agricola tells us that the liquor is then boiled in pans placed in sheds arranged for the purpose. Each shed is divided into three parts. In the first part is stored the firewood or straw, and in the second is the fireplace on which is placed the caldron. To the right of the caldron is a tub for the brine that is to be converted into salt, and on the left is a bench upon which the salt is placed before being removed to the third compartment, where it is moulded into cones or tablets and left to dry in the warm air. The fireplaces are made 8½ ft. long and 7¾ ft. wide; if wood is burned in them they are nearly 4 ft. high, but if straw fuel is used, they are 6 ft. in height. The caldrons are rectangular, 8 ft. long and 7 ft. wide, and 6 in. deep. They are made of sheets of iron or lead, “not very thick so that the water is heated more quickly by the fire and is boiled away rapidly.” To prevent the brine from leaking out at the points where the metal plates are fastened with rivets, the caldrons are smeared over with a cement of ox-liver, or ox-blood, mixed with ashes. As soon as the first dipperful of brine is poured from the brine tub into the caldron, the wood or straw is ignited in the fireplace. If the firewood consists of faggots or brushwood, the salt will be white, but if straw is burned the salt is not infrequently blackish from the sparks which rise with the smoke and settle upon the water.