Perhaps the most important portion of work connected with the preservative treatment of Southern Pine wood is the proper preparation of it for the reception of the preservative. The so-called empty cell processes of treatment with creosote oil are based on the fact that the material is thoroughly seasoned. Although a great quantity of unseasoned wood is prepared for treatment by a period of heating with live steam most of the authorities connected with the wood preserving industry are agreed that seasoned wood will receive a better and more uniform treatment than wood prepared by the steaming process. Most of the drying, curing, or seasoning is the result of slacking the material in the weather and giving what is commonly called air seasoning. Such being the case, the chief concern of the wood preserver is to secure the proper seasoning in the open, of the wood before it is sent to the wood preserving plant for the treatment with the designated preservative.