The raisins which are to be sweated are only the clusters or layers, and not the loose, which as we have seen should at once be taken from the field to the stemmer, while the stems are yet crisp and dry. It is therefore of importance that the bunches or layers should be separated from the loose already in the field, or, which is much preferable, before they are dried, at the time when they are picked from the vines. If the latter is done properly, there will be only a small quantity of loose which will go in the sweating-house with the layers. The layers should at any rate be placed at once in sweatboxes when taken from the trays, and between every two layers of bunches there should be a stout sheet of manilla paper, in order that the bunches may not become mixed. When taken to the sweathouse the boxes should be so placed that air can enter every one. It will not do to place one box on top of another so as to cover up the top entirely, as the raisins are then apt to ferment in a very short time, and, before the raisin-packer is aware, whole piles may be absolutely spoiled. It is not necessary to place the boxes crosswise, as it is enough to allow the short side of each box to overlap the underlying box a little; sufficient air will then enter. In very dry weather the floor of the sweathouse may be sprinkled with water, but this is generally not needed, as the underdried raisins will give out moisture enough to soften those that are too dry, as well as the stems. Every day the sweathouse should be aired, and it is a mistake to believe that all air should be excluded. If air is not daily admitted, the raisins will mold and spoil, and it is even advisable to keep a circulation of air constantly through the house during the daytime. The attentive packer will soon learn to regulate this, and nothing but actual experience with his particular sweathouse will enable him to decide how much air should be let in and to what extent the doors should be closed.