The Durability and Preservation of Woods 255 



five inches in diameter and about ten feet long. Insert 

 one end between the posts and under the cross piece, let- 

 ting the other end protrude across the tank. Under the 

 loose end of the pole anchor a pulley. By means of this 

 pulley and a rope attached to the end of the pole, the pole 

 may be drawn down and tied. Then cut a two-inch plank 

 of a length that will fit loosely in the tank crosswise. Lay 

 this flat. Cut another piece about two feet long. Nail 

 one end of this to the center of the first piece so that it 

 stands at right angles to it. Brace it securely. When the 

 posts are placed in the tank lay this long piece on them. 

 Then place the pole across the upright piece. Draw down 

 the end of the pole with the rope and the posts will be 

 submerged. This apparatus has worked very successfully. 



The penetration secured by this method varies from 

 an eighth of an inch to two inches according to the species, 

 the degree of seasoning and the thickness of the sap wood. 

 It usually is possible to get complete penetration of the 

 sap wood ; the heart wood is little affected. This penetra- 

 tion is sufficient to prevent small checks and cracks from 

 exposing the untreated interior of the post. The life of a 

 post is increased under normal conditions of use and 

 atmosphere to about twenty years. 



Experience in Minnesota has shown the following 

 equipment to be best suited for use on the farm on which 

 steam is not always available. It is inexpensive, can be 

 transported easily from one farm to another in any wagon 

 and is more easily heated than the ordinary tank. It 

 consists of a single cylindrical tank, built of twenty gauge 

 galvanized iron, three feet in diameter and three and one- 

 half or four feet deep. The iron may be plain or corru- 



