In most producing areas sun-drying is preferred, but in countries where much rain falls, artificial dryers are slowly but surely coming into vogue. These vary in pattern from simple heated rooms, with shelves, to vacuum stoves and revolving drums. The sellers of these machines will agree with me when I say that every progressive planter ought to have one of these artificial aids to use during those depressing periods when the rain continually streams from the sky. On fine days it is difficult to prevent mildew appearing on the cacao, but at such times it is impossible. However, whenever available, the sun's heat is preferable, for it encourages a slow and even drying, which lasts over a period of about three days. As Dr. Paul Preuss says: "II faut eviter une dessiccation trop rapide. Le cacao ne peut etre seche en moins de trois jours."[5] Further, most observers agree with Dr. Sack that the valuable changes, which occur during fermentation, continue during drying, especially those in which oxygen assists. The full advantage of these is lost if the temperature used is high enough to kill the enzymes, or if the drying is too rapid, both of which may occur with artificial drying. [5] Dr. Paul Preuss, _Le cacao. Culture et Preparation_. Sun-drying is done on cement or brick floors, on coir mats or trays, or on wooden platforms. In order to dry the cacao uniformly it is raked over and over in the sun. It must be tenderly treated, carefully "watched and caressed," until the interior becomes quite crisp and in colour a beautiful brown. Sometimes the platforms are built on the top of the fermentaries, the cacao being conveyed through a hole in the roof of the fermentary to the drying platform. [Illustration: "HAMEL-SMITH" ROTARY DRYER. (Made by Messrs. David Bridge and Co., Manchester). The receiving cylinders, six in number, are filled approximately three-quarters full with the cacao to be dried. These are then placed in position on the revolving framework, which is enclosed in the casing and slowly revolved. The cylinders are fitted with baffle plates, which gently turn over the cacao beans at each revolution so that even drying throughout is the result. The casing is heated to the requisite temperature by means of a special stove, the arrangement of which is such as to allow the air drawn from the outside to circulate around the stove and to pass into the interior of the casing containing the drying cylinders. The fumes from the fuel do not in any way come in contact with the material during drying.] [Illustration: DRYING PLATFORMS, TRINIDAD, WITH SLIDING ROOFS.] In Trinidad the platform always has a sliding roof, which can be pulled over the cacao in the blaze of noon or when a rainstorm comes on. In other places, sliding platforms are used which can be pushed under cover in wet weather. _The Washing of Cacao._